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NASkeet Wed Nov 11, 2015 9:34 am

When I was researching performance & reliability enhancing modifications for the 1911 cm³, VW Type 4 style air-cooled engine, which I was developing for my family’s 1973 VW “1600” Type 2 Westfalia Continental campervan, I came across various coatings and treatments, referred to in the VW books and magazines. However, I have so far yet to find any information about the durability, reliability or effectiveness of any of these treatments:

• Crown Manufacturing in the USA, recommend aluminising the fins on the cast-iron cylinder barrels (by applying molten aluminium, using a high-pressure aluminising gun), to improve cylinder cooling.

The only benefit I can visualise, is that a reasonably thick coating of high-thermal conductivity aluminium (10x the k-value of mild steel), would inhibit the formation of a thick rust coating (iron oxide is a poor conductor of heat, relative to either iron or aluminium), which would otherwise form quite quickly, in a cold, damp climate such as Great Britain. I suspect that an aluminium coating would be preferable to using paint, which might tend to act like an external thermal insulator.

• It is suggested that one should black-anodise the cast aluminium parts, such as the crankcase (only applicable to the VW Type 4 style engine) and cylinder heads, to increase emissivity and hence heat loss by thermal radiation. Whether this could also be implemented with aluminium-coated, cast-iron cylinder-barrel fins, is open to question.

I suspect that the cylinder-head & cylinder-barrel cooling fins, predominantly loose heat by forced convection, but there will also be some heat loss by radiation, so any reasonable means to enhance this, which is not too costly, should be considered, especially for an engine whose maximum power output has been increased.

• Use of ceramic thermal-barrier coating for the valve heads, piston crowns and combustion-chamber surfaces (i.e. internal surfaces of cylinder heads), is suggested as a means of retaining heat within the combustion chamber & cylinder, whilst simultaneously reducing the running temperatures of the cylinder heads, pistons and engine as a whole.

If the combustion gas are hotter as a consequence of insulating ceramic coating the valve heads and aluminium surfaces in contact with the combustion gases, then either the cylinder barrel cooling needs to be effective to compensate or the internal surfaces of the cylinder barrels need to be insulated with a hard-wearing, abrasion-resistant ceramic coating such as Nicasil (aka Nikasil), which is commonly used to line aluminium cylinder barrels (e.g. Porsche 911) or cylinder blocks. However, it is vital that low-sulphur fuels are used otherwise nicasil coatings can rapidly be damaged acid erosion.

• Use of molybdenum, graphite & Teflon based, wettable dry-film lubricant, is said to hold oil in place, on bearings (main, connecting-rod & camshaft), piston skirts, valve stems, valve springs, valve rockers and valve-rocker shafts; hence reducing overall friction and associated power wastage.

I know little if anything about dry-film lubricant, so would be wary of employing it at the moment.

As a general rule, the hotter an engine runs, the greater the thermodynamic efficiency and hence the result is improved power and/or fuel economy. However, in practice, the maximum reliable working temperature, is dictated by the limitations imposed by the material properties of the engine. If the cylinder heads, valves and pistons can be insulated (i.e. ceramic coating) from the hot combustion gases (i.e. burning petrol & air mixture) and the external surfaces of the cylinder heads & barrels, more effectively cooled by radiation and/or convection, then the combustion gases may be permitted to operate at a higher temperature and pressure (aided and abetted by increased compression ratio); consistent with the available petrol octane rating (95 RON unleaded in Europe, for all practical purposes). Engine components that run at less extreme temperatures, are less prone to uneven temperature distributions, warping or cracking, plus limiting the risk of detonation.

At the moment, I am unclear about the use, interdependence and means of applying these coatings, which may be summarised as follows:

1) If the cylinder head, valve heads & piston crowns (i.e. combustion chamber surfaces) are insulated using a ceramic coating, must the heat transfer from the cylinder barrel fins be enhanced, to compensate for the higher combustion-gas temperatures?

2) If the cylinder heads & crankcase are black anodised, is there a build-up in material thicknesses and what effect will this have on internal bores for bearings, oil pump and cam followers, etc?

3) How much benefit (in terms of temperature reduction, reduced risk of pre-ignition and/or detonation, etc) is gained by ceramic coating, black anodising and aluminising?

4) If the cylinder barrels are aluminised, can the aluminium coating be black anodised and to what extent would this increase the cooling effect?

5) If dry-film lubricant is applied to the valve stems, rocker shafts, piston skirts and bearings, what precautions must be taken regarding clearance dimensions between the rubbing surfaces?

6) How are these coatings applied & cured and can it be done on a DIY basis? If DIY is not possible or practical, where in the United Kingdom are such coating services available?

7) How durable are these coatings, in terms of years, mileage and/or operational hours? What procedures would be necessary, to remove and/or replace ‘worn out’ or deteriorating coatings?

Alstrup Wed Nov 11, 2015 10:29 am

Contact Camcoat:
http://www.camcoat.com/main/contact.html
they´ll help you through the selections and keep you from wasting money on unnessessary options.
T

raygreenwood Wed Nov 11, 2015 12:08 pm

NASkeet wrote: When I was researching performance & reliability enhancing modifications for the 1911 cm³, VW Type 4 style air-cooled engine, which I was developing for my family’s 1973 VW “1600” Type 2 Westfalia Continental campervan, I came across various coatings and treatments, referred to in the VW books and magazines. However, I have so far yet to find any information about the durability, reliability or effectiveness of any of these treatments:

• Crown Manufacturing in the USA, recommend aluminising the fins on the cast-iron cylinder barrels (by applying molten aluminium, using a high-pressure aluminising gun), to improve cylinder cooling.

The only benefit I can visualise, is that a reasonably thick coating of high-thermal conductivity aluminium (10x the k-value of mild steel), would inhibit the formation of a thick rust coating (iron oxide is a poor conductor of heat, relative to either iron or aluminium), which would otherwise form quite quickly, in a cold, damp climate such as Great Britain. I suspect that an aluminium coating would be preferable to using paint, which might tend to act like an external thermal insulator.

I have done in the past...some relatively extensive research on the stock type 4 cylinders. I wrote about it on the STF. This was a controlled test start with one cylinder...used...with normal rust, then cleaned with acid to be bare and neutralized, then with a flat black paint with some metals in it, then stripped and a gloss black paint then stripped and white painted....then stripped with a black iron phosphate coating that was oil pickled for preservation. I used a standardized heat source, control RH in the room and well controlled and measured airflow. I worked in a shop with quite a good lab and had time on my hands. Had it been a little later in the digital era I would have had video. I was doing it for my own build knowledge and learning.
Yes...the normal rust is a heat flow detriment. Not huge...but not insignificant. Manageable on a stock-ish engine. Its why most dont bother worrying about the rust and do fine.
However if you live in a very hot area like Texas as I did at the time...and/or do high speed sustained driving...especially in hot weather....like 70 mph for 4-6 hours at a time....controlling the heat flow out oof ALL engine surfaces is significant.

In order of best heat draw from 450F down starting to about 350F with a sustained uniform heat source.....it was: 1. flat black pickled oxide 2. flat black low metals paint, 3. gloss black low metals paint, 4. normal rust, 5. flat white...very poor.

I will have to dig for the actual results somewhere in large boxes of notes....but the flat black oxide was about 25F better than flat black paint...mostly because its very, very thin and has no insulating properties. The flat black paint was about 40F better than rust. White paint was terrible.

The gloss paints while reflecting infrared from outside sources ...will bounce the radiant energy back and forth between the fins absorbing some of the heat before it can be insulated. We have found this issue in many industrial cooling situations as well....remembering that you have radiant heat, convected heat and conducted heat.

The other problem that others in long past conversations on STF have found is that adding anything that is a thick build up to the fins is a problem. There is already an issue with turbulence and the aim of the airflow through the fins that can reduce cooling efficiency. Any narrowing of the passages will likely cause less heat draw simply because of airflow restriction.

• It is suggested that one should black-anodise the cast aluminium parts, such as the crankcase (only applicable to the VW Type 4 style engine) and cylinder heads, to increase emissivity and hence heat loss by thermal radiation. Whether this could also be implemented with aluminium-coated, cast-iron cylinder-barrel fins, is open to question.

I was working toward this a decade ago.....a conversation or a snippet thereof with Jake Raby on the STF and he noted that they have done this....and it is indeed effective....but must be selectively done....only in certain areas.

This is because just like flat black coating on cylinders which will draw more heat to the black surface and hold it there where the airflow is.....the black surfaces on a head draw heat to those areas. Having black anodized coating in certain areas of the head...can actually cause those areas to run hotter. Jack did not elaborate which areas were critical...and I did not want to pry. I would speculate that rocker box andodizing may not be what you want. Fins only I would suspect. How effective it may be on a street engine...no idea. Masking will be critical

I suspect that the cylinder-head & cylinder-barrel cooling fins, predominantly loose heat by forced convection, but there will also be some heat loss by radiation, so any reasonable means to enhance this, which is not too costly, should be considered, especially for an engine whose maximum power output has been increased.

The radiant heat is what we were talking about with cylinder coatings above. Black...and especially flat black are efficient at collecting heat because they have very little ability in the spectrum to reflect it away. No gloss...and no reflected color.
So really what is happening....is that the flat black of one adjacent fin to another....draws more radiant heat to the black surface because it cannot reflect it away. Radiant heat is transmitted in the infrared spectrum. Though its not visible...it is in effect a light wavelength. This outer black surface is presented to the airflow to draw heat away.
So as one fin surface gets cooler it can draw more heat energy from inside the casting from the relatively constant heat source of the combustion. It works because at any given second or millisecond...just like in a combustion chamber.....every section of metal is different in coolness or hotness. Yes they saturate to a general temp level...but due to size, thickness, mass and surface treatment levels.....they radiate at different rates. We saw this during testing by looking at the different rates of cooling of the various fins with a constant heat source while trying to decide where to place the thermocouples.

Many dont understand the "black" and heat thing...or think its all BS...simply because they lack the instruments to test and measure for their own knowledge. In the industrial world, heat absorption, reflection and conduction...and teh part gloss and colors play in materials is well known and heavily tested for.....especially in industrial ovens or in heat critical processes.

• Use of ceramic thermal-barrier coating for the valve heads, piston crowns and combustion-chamber surfaces (i.e. internal surfaces of cylinder heads), is suggested as a means of retaining heat within the combustion chamber & cylinder, whilst simultaneously reducing the running temperatures of the cylinder heads, pistons and engine as a whole.

I dont know enough about these coatings to say anything. People that do that I know.....who test a lot...swear by some of them....but will tell you that like anodizing the heads....the location and thickness are critical....and sometimes the cost is higher than the benefit which can range from small to very significant. None of these people are in the VW engine building industry.

If the combustion gas are hotter as a consequence of insulating ceramic coating the valve heads and aluminium surfaces in contact with the combustion gases, then either the cylinder barrel cooling needs to be effective to compensate or the internal surfaces of the cylinder barrels need to be insulated with a hard-wearing, abrasion-resistant ceramic coating such as Nicasil (aka Nikasil), which is commonly used to line aluminium cylinder barrels (e.g. Porsche 911) or cylinder blocks. However, it is vital that low-sulphur fuels are used otherwise nicasil coatings can rapidly be damaged acid erosion.

• Use of molybdenum, graphite & Teflon based, wettable dry-film lubricant, is said to hold oil in place, on bearings (main, connecting-rod & camshaft), piston skirts, valve stems, valve springs, valve rockers and valve-rocker shafts; hence reducing overall friction and associated power wastage.

I would be careful with Molybdenum. I have just recently read some articles with some lubricating products that contain moly. You have to be careful because the moly can actually bind itself to certain chemicals in some oil products....actually reducing the extreme pressure load capabilities of the oil. This was in reference to gear oils.....specifically synthetic gear oils. But the chemistry suggested makes me wary.

The anti-scuff properties of a graphite moly lube on pistons for initial start up and break in is well known. In the past....virtually all KS pistons came with this. Compared to pistons that did not....over the years...I found less scuffing on the KS pistons. Definitive?....hardly....but all of my pistons will have it applied if they do not come with it.
I would also say its a good item to have on cam bearings and main bearings. But I would be careful about oil additives and also about moly dry film on cam lobes and lifter faces. I have read a few snippets here and there that suggest that its slick enough that it may prevent proper rotation for break in. A moly assembly lube...not as big of a problem because its readily washed off by the oil.


I know little if anything about dry-film lubricant, so would be wary of employing it at the moment.

As a general rule, the hotter an engine runs, the greater the thermodynamic efficiency and hence the result is improved power and/or fuel economy. However, in practice, the maximum reliable working temperature, is dictated by the limitations imposed by the material properties of the engine. If the cylinder heads, valves and pistons can be insulated (i.e. ceramic coating) from the hot combustion gases (i.e. burning petrol & air mixture) and the external surfaces of the cylinder heads & barrels, more effectively cooled by radiation and/or convection, then the combustion gases may be permitted to operate at a higher temperature and pressure (aided and abetted by increased compression ratio); consistent with the available petrol octane rating (95 RON unleaded in Europe, for all practical purposes). Engine components that run at less extreme temperatures, are less prone to uneven temperature distributions, warping or cracking, plus limiting the risk of detonation.

At the moment, I am unclear about the use, interdependence and means of applying these coatings, which may be summarised as follows:

1) If the cylinder head, valve heads & piston crowns (i.e. combustion chamber surfaces) are insulated using a ceramic coating, must the heat transfer from the cylinder barrel fins be enhanced, to compensate for the higher combustion-gas temperatures?

2) If the cylinder heads & crankcase are black anodised, is there a build-up in material thicknesses and what effect will this have on internal bores for bearings, oil pump and cam followers, etc?

3) How much benefit (in terms of temperature reduction, reduced risk of pre-ignition and/or detonation, etc) is gained by ceramic coating, black anodising and aluminising?

4) If the cylinder barrels are aluminised, can the aluminium coating be black anodised and to what extent would this increase the cooling effect?

5) If dry-film lubricant is applied to the valve stems, rocker shafts, piston skirts and bearings, what precautions must be taken regarding clearance dimensions between the rubbing surfaces?

6) How are these coatings applied & cured and can it be done on a DIY basis? If DIY is not possible or practical, where in the United Kingdom are such coating services available?

7) How durable are these coatings, in terms of years, mileage and/or operational hours? What procedures would be necessary, to remove and/or replace ‘worn out’ or deteriorating coatings?

My replies are in the quote box in RED. A lot of this has been explored here...and for sure on the STF in the type 4rum and Jakes archived forum.

Also....running synthetic oil is HUGE. The anti-friction properties are well documented and are a major reason why new cars with their precision cylinder coatings run so efficiently and for such high mileage.

By the way....and I dont know how many know this.....but virtually all new cars by any manufacturer...and by new I mean virtually all cars built since 2000 and some before....all have sophisticated cylinder coatings. GM has their own and so does Ford and VW/AUDI....BMW...the Japanese cars...all of them. These are very similar to Nikisil...some even more advanced. Many of them are either oxides and some are even sputter plated. The honing processes are computer controlled and very detailed. There are lots of article out there about these coatings. Minor changes in application process and honing at the microscopic levels can cause extreme longevity and mileage...or unexplained issues.
The current class action against the VW audi group with regard to oil usage on the 2.0L turbo engines....maybe a handful or less in 1000 engines or less...but still significant when you have millions of cars out there...is an example of this. The cars run perfectly. No visible oil smoke...but are consuming oil at a rate higher than 1 quart per 1000 miles. It eventually kills the catalyst....but the owners say the cars run perfect. Its a coating anomaly. Ray

nextgen Wed Nov 11, 2015 12:18 pm

Nigle and Alstrup.

I have been involved in T-4's since the late 90's and a mechanical design engineer for the elevator / Lift companies World Wide for the last 50 years.
We used synthetic oil in motors before anyone hear of it in the buildings like the Late WTC Twin Tower , Empire and Chrysler Bldg. and your Canary Waif using all cutting edge chemicals.

The money and time involved is massive. Which brings me to the percentage of results, which will be small. The best bet is Synthetic Oil. Covers all the bases for each of the other products and you just pour it out of a bottle, no spraying molten aluminum etc. Ha. A T-4 is a very forgiving engine. In light cars like bugs our problem is get the T-4 to running temp.
You are talking Bus, Two ton not very aerodynamic vehicle. More HP, Better Cooling like a DTM fanhousing. Also Sandwich oil cooler adapters for an extra oil cooler, should be the direction you should be following. We are not talking aircraft, you can always pull over if you have a problem, ha. Serious all that is overkill vs the results.

vwracerdave Wed Nov 11, 2015 12:23 pm

On a top end race car all the coatings can be beneficial in winning a world championship.

For a Street driven VW Bus driving the family across the country they are pretty much a waste of money.

nextgen Wed Nov 11, 2015 2:53 pm

vwracerdave, totally agree! Kind of like waxing your jet plane for better aerodynamics. But if you are only going to Taxi on the runway you don't need it.

modok Wed Nov 11, 2015 5:36 pm

Coating engine parts does not make anything more "reliable".
It may have some benefit, it will improve SOMETHING, but advanced technology is barely a factor in making a machine "reliable".

Unreliable means there are factors "unknown" or unpredictable. The way to avoid the unknown is to know it. So, get learning!!

The good news is the type-4 engine is OLD, so we know more about it than when it was made, so there are many improvements you can do that will make it longer lived and more predictable, with less to go wrong.
You can use SS valves and better valve seats and stronger springs and throw out the headgaskets and set it up tight deck and use a better cam and solid lifters and a better exhaust system. IMO DFL coated main bearings might be good idea too. Only the aluminum ones.
Mark will say do them all.... but that's three different bearing materials, that assumes you can find somebody to DO the job right.........anything can be FK'd up, trust me!!

Fixing problems that you don't have on the other hand can potentially create more problems. The cylinders overheating is not generally a problem, so, don't fix it. Sputtering aluminum on iron is a cool idea but..... I'm afraid I don't really get excited about it because I know it will make very little difference, and it is far more likely as a novice builder.....that you will have more fundamental problems. Master the basics first!

raygreenwood Wed Nov 11, 2015 5:54 pm

With regard to actual "mechanical reliability"....I concur with the others. I was simply responding to what I knew of the items you asked about. The cylinder oxide coating on the outside is the only item that actually may help longevity in that list. You are driving a type 4 bus probably with a hideous deck compared to what I run in my high compression 1.7. You will run higher cylinder temps. The coating can help a noticable amount.

But other items type 4 specific....and mechanical. ...that factually will promote higher longevity than stock:

1. Stay with a stock type 4 oil pump. Go through the steps to blueprint it. Check on STF. Its more than you will need.

2. Best...get brand new AMC head castings with the hardware updates. Next best....complete rebuild of yours...seats, guides and re-annealing of the heads. Do not skimp on valves. Manley, certain specs of SI valves and Intervalve brand in that order there are others....but do not use generic stainless. Make sure you have stellited tips and stems.

Along with that....genuine lorsche 911 adjusters along with the stellited valve tips also alleviate the need for lash caps.

3. Personally.....go with solid lifters and a BETTER CAM than stock. One of the very best bang for the buck.....is a Raby cam kit from the type 4 store. New split pattern cam, gear, bolt kit, new rocker studs, new rocker shafts, a set of single hd springs matched to the cam ,chromoly push rod set, new keepers, and a full set of 911 adjusters. The price for all of that in one box.....is very good.

4. Buy double thrust cam bearings. Type 4 store or aircooled.net....do this. Its cheap and necessary.

5. Delete the bead gasket and lap the jugs to the heads....always. factory bulletin on it as well.

6. Install either 914 style pistons squirters...best.....or do the rod notch as per the VW bulletin.....decent. Contact me for alternate piston underside oilers and I will show you a method or two that works well on the type 4.

7. Get a better than stock ignition....even if you stay with factory EFI

There are other items that are more tunability based that can actually improve longevity simply because they allow it to run cooler with less oil contamination. ...but are not mechanical mods so I will leave them out for now. Ray

NASkeet Thu Nov 12, 2015 7:22 am

It seems that there is much more to read and even more to think about! :shock:

I certainly won't be racing my VW Type 4 style engine, but getting onto motorways, autoroutes & autobahns, via an uphill slip road ("on-ramp" in USA parlance!?!), can at time seem to be an exercise in drag racing.

When the campervan still had its factory-stock 50 DIN hp, VW 1600 Type 1 style engine, the above exercise typically involved revving the engine to 4500 rpm (at which the rotor-arm centrifugal governor shorted the HT to Earth, causing the whole vehicle to judder violently!) in 3rd gear before changing up to 4th.

I later substituted a non-cut-out type rotor arm and retro-fitted a Microdynamics Formula 1 FCD electronic ignition with integral smooth-cut rev-limiter, set to 5000 rpm, but even this made joining traffic at 70~80 mph rather challenging.

http://forums.kombiclub.com/threads/fitting-electronic-ignition.8135/

http://www.vwkd.co.uk/bb/viewtopic.php?t=229

http://www.justkampers.com/forum/viewtopic.php?f=15&t=155577

http://www.larkspeed.com/index.pl?c=MICROIGNI&s=category

http://www.demon-tweeks.co.uk/micro-dynamics-ignition-system

nextgen Thu Nov 12, 2015 9:55 am

NA Skeet, as for getting to 70 mph, with the T-4 you will have twice the HP and much better torque, so you should be happy. But let's look at the fact you are driving a large heavy box, pushing a lot of air.

Things like the Bed, I an understand, but think of things you don't need. Every pound adds up.

I am not trying to be funny.

I have a 1700 lb bug with 2.0 T-4 when my 225 lb son in law rides with me I intermediately feel the difference, especially on hills.

It is all relative, I know how my bug feels with just me and I am sure you know what your bus feels with just you. See if you can put the bus on a diet.

NASkeet Fri Nov 13, 2015 7:58 am

nextgen wrote: NA Skeet, as for getting to 70 mph, with the T-4 you will have twice the HP and much better torque, so you should be happy. But let's look at the fact you are driving a large heavy box, pushing a lot of air.

Things like the Bed, I an understand, but think of things you don't need. Every pound adds up.

I am not trying to be funny.

I have a 1700 lb bug with 2.0 T-4 when my 225 lb son in law rides with me I intermediately feel the difference, especially on hills.

It is all relative, I know how my bug feels with just me and I am sure you know what your bus feels with just you. See if you can put the bus on a diet.

225 lb (16 stone 3 pounds) is a LOT of weight for an adult male. If you have four of those in a VW Beetle, it would probably exceed its maximum payload! :shock:

My 1973 VW Type 2 campervan, has spent most of its 64,000 miles being used as a campervan since November 1972 and I am unlikely to use it as a daily driver, so routinely removing the campervan furniture & equipment (which would have to be safely stored somewhere) isn't really an option.

I generally try to avoid motorways if I can (too boring driving on them, and little if any scenery to see along the way).

The comfortable (influenced by cross-wind stability) maximum cruising speed for this vehicle on motorways or dual-carriageways, is about 55~60 mph, but on single-carriageway roads (especially twisty, windy rural roads), driving speeds are typically 20~45 mph, so maximum speed in 4th gear is somewhat irrelevant most of the time, but acceleration and hill-climbing ability is rather more important, especially on those 1-in-20 motorway hills or 1-in-2½ hill & mountain roads.

nextgen Fri Nov 13, 2015 9:36 am

Sounds like with a T-4 and it's torque you have found the the perfect recipe, for the driving band in which you love to live in.

I had my original T-4 test running out of the car in my driveway for days, tuned it as best I could before putting it in my bug. I was expecting a much faster car on my first test drive and that expectation was fulfilled, but what I didn't expect was the Torque and holding power of the massive bus clutch.
I drove it slow till I reached the bottom of several mile long steep mountain road. Never did my T-1's have this torque, the engine just keep pulling till I reached the top. At the top I was behind several cars waiting for a Traffic light which on a steep angle. That is when I felt the power of the 210 mm clutch, with the stopping and going it had an instant powerful grip. Instantly felt the difference.

Got to drive it .

NASkeet Mon Nov 16, 2015 9:18 am

1973 VW “1600” Type 2 Engine Compartment, for VW 1900 Type 4 style engine, with Bosch D-Jetronic fuel injection




VW Type 4 (i.e. 1971 VW 411 LE) camshaft & windage tray




VW 1800 Type 4 cylinder heads, with reworked combustion chambers and reprofiled 41 mm inlet valves & 34 mm exhaust valves




Magnom Magnetic Oil Filtration





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http://www.bing.com/images/search?q=Magnom+magneti...;FORM=IGRE

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NASkeet Fri Dec 11, 2015 9:25 am

nextgen wrote: I have been involved in T-4's since the late 90's and a mechanical design engineer for the elevator / Lift companies World Wide for the last 50 years.

We used synthetic oil in motors before anyone hear of it in the buildings like the Late WTC Twin Tower , Empire and Chrysler Bldg. and your Canary Waif using all cutting edge chemicals.

The money and time involved is massive. Which brings me to the percentage of results, which will be small. The best bet is Synthetic Oil. Covers all the bases for each of the other products and you just pour it out of a bottle, no spraying molten aluminum etc. Ha. A T-4 is a very forgiving engine. In light cars like bugs our problem is get the T-4 to running temp.

You are talking Bus, Two ton not very aerodynamic vehicle. More HP, Better Cooling like a DTM fanhousing. Also Sandwich oil cooler adapters for an extra oil cooler, should be the direction you should be following. We are not talking aircraft, you can always pull over if you have a problem, ha. Serious all that is overkill vs the results.

Despite living less than 30 miles from London, I have never visited Canary Wharf, which used to be an important part of the Port of London, at which goods to and from the British Empire, were loaded or unloaded.

I first started using fully-synthetic oil in the mid-1980s, when I bought up a 40 litre stockpile of SAE 5W/50, API SF, Mobil 1 “Rally Formula” oil at £4•50 (normally about £12) per 4 litre can, which was virtually the same price as ordinary premium-brand, multi-grade oil. At that time, Mobil 1 had a specified oil-drain interval of 1 year or 25,000 miles, whichever came first!

When I used the Mobil 1 oil in the VW 1600 Type 2 engine, oil consumption was reduced from circa 1 litre per 1 thousand miles to circa 1 litre per 3~4 thousand miles, the oil barely changed colour between oil changes, produced no sludge and one no longer observed the acrid smell of burnt, oxidised oil after a long, fast run on the dual-carriageways and motorways, during hot, summer weather. If I can still obtain fully-synthetic oil, with an appropriate “old-school” additive formulation, for push-rod type engines having no catalytic converter, this would be my first choice.

However, fully-synthetic engine oils are extremely expensive these days, so I ideally need to investigate the possibility of extending the oil-drain interval, without compromising the lubrication and corrosion-protection; possibly by using positive crankcase ventilation and improving filtration efficiency, using a combination of magnetic filtration, plus full-flow & bypass-flow media filters (e.g. Evergreen combination spin-on filter), or even the automotive equivalent of dialysis, whereby the oil is periodically circulated through an external filtration system, as used in some industrial applications.

One of my particularly important reasons, for choosing to substitute into my 1973 VW 1600 Type 2, a VW Type 4 style air-cooled engine, in place of the original AD-Series, VW Type 1 Beetle style air-cooled engine, was the Type 4’s engine-cooling fan being driven directly by the crankshaft, rather than via a pulley system, textile-reinforced rubber V-belt and dynamo or alternator shaft.

During Easter 1991, whilst travelling on the M25 London orbital motorway, at about 60 mph, the VW Type 1 style engine’s alternator shaft seized-solid in its bearings, instantly disabling the engine-cooling system, as well as the electrical generating system. Had I NOT immediately coasted to a halt on the motorway’s hard shoulder, after observing the illumination of the ignition-warning light and checked the rapidly rising temperature reading, on the cylinder-head temperature gauge, the engine would probably have been destroyed in minutes, if not seconds!

Replacing an alternator or dynamo on a VW Type 1 style air-cooled engine, installed a VW Type 2, is not a simple road-side procedure; even assuming that a spare is readily available at short notice! After contacting the police control room, via the nearest roadside emergency telephone (spaced at 1 km intervals) I spent 3 hours beside the M25 London orbital motorway, waiting for an RAC (i.e. Royal Automobile Club) recovery vehicle to take me home.

The DTM (i.e. Down The Middle) and similar after-market engine-cooling systems (including , Porsche 911 or Chevrolet Corvair style), feature this same fundamental design flaw as that of VW Type 1 style engine, so I would NOT consider substituting any of these on a VW Type 4 style engine, in a VW Type 2.

For those who wish to retain a VW Type 1 Beetle style air-cooled engine in their VW Type 2, there is the option of substituting the cooling system from a 1980~83 VW 1600 Vanagon’s air-cooled engine, whose cooling-fan was also driven directly by the crankshaft. This engine (not normally found in North America!) was a further development of the VW Type 1 style engine, with cast-in oil-filter mount, like that of the 1983~92 VW 19/2100 Vanagons’ water-cooled flat-four engines.

1974 VW "1800" Type 2, with a substituted 1980~83 VW 1600 Vanagon (i.e. Type 25 or Transporter T3) CT/CZ-Series, air-cooled engine, associated cover-plates, cooling system and ancillaries.

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Retro-fitting a supplementary oil cooler would be an option, but increased oil cooling might be regarded as simply treating the symptoms of engine overheating rather than the cause. I would expect the majority of waste heat transferred to the cylinder heads & barrels, to be dissipated by the air-cooling system and external radiation. The pistons, and to some extent the cylinder heads, will certainly be cooled by the oil.

NASkeet Fri Dec 11, 2015 9:27 am

raygreenwood wrote: I have done in the past...some relatively extensive research on the stock type 4 cylinders. I wrote about it on the STF. This was a controlled test start with one cylinder...used...with normal rust, then cleaned with acid to be bare and neutralized, then with a flat black paint with some metals in it, then stripped and a gloss black paint then stripped and white painted....then stripped with a black iron phosphate coating that was oil pickled for preservation. I used a standardized heat source, control RH in the room and well controlled and measured airflow. I worked in a shop with quite a good lab and had time on my hands. Had it been a little later in the digital era I would have had video. I was doing it for my own build knowledge and learning.

Yes...the normal rust is a heat flow detriment. Not huge...but not insignificant. Manageable on a stock-ish engine. Its why most don’t bother worrying about the rust and do fine.

However if you live in a very hot area like Texas as I did at the time...and/or do high speed sustained driving...especially in hot weather....like 70 mph for 4-6 hours at a time....controlling the heat flow out of ALL engine surfaces is significant.

In order of best heat draw from 450F down starting to about 350F with a sustained uniform heat source.....it was: 1. flat black pickled oxide 2. flat black low metals paint, 3. gloss black low metals paint, 4. normal rust, 5. flat white...very poor.

I will have to dig for the actual results somewhere in large boxes of notes....but the flat black oxide was about 25F better than flat black paint...mostly because its very, very thin and has no insulating properties. The flat black paint was about 40F better than rust. White paint was terrible.

The gloss paints while reflecting infrared from outside sources ...will bounce the radiant energy back and forth between the fins absorbing some of the heat before it can be insulated. We have found this issue in many industrial cooling situations as well....remembering that you have radiant heat, convected heat and conducted heat.

The other problem that others in long past conversations on STF have found is that adding anything that is a thick build up to the fins is a problem. There is already an issue with turbulence and the aim of the airflow through the fins that can reduce cooling efficiency. Any narrowing of the passages will likely cause less heat draw simply because of airflow restriction.

Would I be correct in interpreting the reference to STF as being the Shop Talk Forums, or more specifically, the Type 4rum!?! I have been a registered subscriber for several years, but I have mislaid details of my “user-name” and pass word.

During the early-1980s, I studied fluid flow, engineering thermodynamics & heat transfer (forced & buoyancy-driven convection, conduction and radiation – including heat-exchanger theory, shape-factor algebra, spectral emissivity of “grey” surfaces and extended heat-transfer surfaces or fins, plus mass transfer with latent heat of vapourisation), as part of my M.Sc. in Applied Energy Engineering, so I’m still reasonably familiar with the fundamental principles.

For my dissertation, I mainly specialised in heat transfer within and through porous thermal insulants, as used in the building industry. I subsequently worked in R & D, testing and consultancy, mainly specialising in thermal insulation, heat transfer and general building physics, pertaining to the building & building services industries, until the start of the LONG 1990s-period economic recession, which obliged me to re-establish myself as a self-employed tutor of mathematics, physics, technology and engineering, having previously qualified as a high school teacher in 1979.

However, without reliable data values re temperature distributions, thermal conductivity, spectral emissivity, air density & flow velocity and convective heat-transfer coefficients, it’s difficult, if not impossible, to accurately predict the relative importance of the various heat-flow paths, under different conditions; especially if one lacks the necessary computational facilities and computer software.

As a predominantly experimental scientist by nature (I also hold a B.Sc. in Applied Physics, a B.A. in Applied Mathematics & Statistics, and a Pg.Dip. in Scientific Computing), I much prefer a practical, experimental approach to determining system behaviour, although I appreciate computer simulation, as an extremely valuable aid during the initial design phase. Hence, I would be interested to learn more of your experiments and experimental results, pertaining to the finned cylinder barrel under controlled conditions.

I can appreciate that cooling-fin thermal conductivity, fin-dimensions (depth & variable thickness – ideally thicker at the fin-root), number of fins and spacing would need to be optimised as part of the original design process; requiring one to strike a balance between the conflicting requirements of maximising air-flow velocity & turbulent heat exchange in the boundary layers at the fin-air interface, whilst minimising air-flow pressure loss, associated with turbulence and general air-flow resistance of the cooling-system’s physical configuration.

With paint pigments and other coatings, one has to bear in mind that what appears white, grey or black to the visible portion (i.e. approximately 400~700 nm or 4000~7000 Å) of the electromagnetic radiation spectrum, might not appear “white”, “grey” or “black” to the near, median & far infra-red portions. In general, surfaces which are good emitters are usually good absorbers (i.e. poor reflectors) and poor emitters are usually poor absorbers (i.e. good reflectors); but these properties are temperature dependent, at least to some extent.

Great Britain has a damp “temperate” climate, with frequent rain, drizzle, mist and overnight dew formation, plus hot, humid summer weather, so over relatively short periods of time, unprotected steel or iron (including finned cylinder barrels, shrouded by cover plates), can form quite thick layers of rust, which is crusty and pitted.

Apart from one occasion in France, when I was obliged to drive continuously for several hours (mid-afternoon until late-evening), on the “wrong side of the road”, at 15~30 mph in varying-density fog (there was nowhere safe to pull off the road!), I cannot otherwise envisage wishing to drive any vehicle for more than circa 2 hours, without taking a break.

However, driving our VW 1600 Type 2 at speeds of 50~60 mph on motorways, for less than 1 hour, during summer conditions, with air temperatures of circa 25 ºC (i.e. 77 ºF), typically resulted in the VW Type 1 style engine’s oil temperatures, being 110~120 ºC (i.e. 230~248 ºF). When previously touring parts of Europe, prior to retro-fitting the supplementary gauges, air temperatures had sometimes exceeded 35 ºC (i.e. 95 ºF) in summer, so I suspect the oil temperature was also higher.

raygreenwood Fri Dec 11, 2015 6:22 pm

Nigel....i concur with and understand your two paragraphs about fin colorant and wavelengtb absorption. I deal with it all the time as well. Its also most probably the real reason why a simple black oxide (sacrifical surface oxide)....not an applied pigment...worked noticably better than any of the usable paints I could find.

With black paints....you have to find new with a resin base whose film strength is high enough to be thinned up fo about 40%.....and still have the ability to evenly suspend its pigments.....and the pigments themselves if they were heavily metallic.....caused even worse problems. This rules out most super high temp anti-rust style paints (that high of a temp rating is unnessesary anyway on cylinders).

Typically nothing but carbon as a pigment. Too much of a pain to get a paint like that. In fact I made the best one I used. The black oxide was excellent....probably sub-micron in actual thickness.....and can be applied with a large pot, a gas burner and a thermocuple.

Of course its not long term rust proofing when heated over 300F.....so after the black oxide is done. Submerge the cylinders in a pot with a 10 weight machine oil or similar (with a clash point of around 450F) and heat to about 400 and oil "pickle". The cylinders. Cools slowly....solvent rinse in normal mineral spirits.....not,MEK or somethkng of that high of a,degreasing level.

This is nice for very hot climates in high speed driving. Simple....cheap.....anti-rust at the very least. Ray

modok Sat Dec 12, 2015 3:25 pm

I have wondered about copper plating.

nextgen Sat Dec 12, 2015 4:28 pm

I'll Pass on this one, these guys are talking serious S***. Ha.

Boolean Sat Dec 12, 2015 4:39 pm

Me too. I imagine a slowly rotating cylinder with the fins submerged in the appropriate medium deposited with copper from coppersulphate or whatever is best at it.
Electroplating that is.

nextgen Mon Dec 14, 2015 12:14 pm

Bath one, Bath two, Rinse, done!!



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