Wind direction affect oil temperature?

[LouisB]

Not related to your question but you might try to put a heat shield around your headers where they pass under the heads/push rod tubes. This might help keep the oil temps down. Hot VWs did an article on this a while back.

--louis
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Louis Brooks
'67 Manx II

Old people at weddings always poke me and say "Your next." So, I started doing the same to them at funerals.

[madmike]

I would try a true merged header!!! I have seen issues with the type you have ,like baffles coming loose and partial blocking the exit
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'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[Skulptorchaz]

Readin and learnin.
Great thread. Thanks Vincent and contributors.

[oprn]

Interesting read! How did it turn out in the end?

[Luftwagen 2180]

I'm not sure if it's legal to revive an ancient post, but here goes. I'm with OPRN as to wondering how it all turned out. I've got a Manx clone and am trying to understand oil temp issues too. I'm running an oil temp gauge but not a cylinder head temp gauge. Apparently oil temp naturally climbs as RPM's increase, makes sense. The OP was concerned about side wind affecting oil temp, very interesting. The great part was the temps he took at various points at various speeds. What struck me was the relation between fan inlet and ambient temp. At 3700 RPM and 70 MPH the inlet was about 25 degrees above ambient. Where is the heat coming from?
A beetle has an enclosed engine compartment that gets all it's cooling and combustion air through the deck lid and louvers. Any missing tin around the engine seems to suck in exhaust heat and has cooling issues. So I wondered if a Buggy could be sucking in exhaust heat, probably #1 J tube? Since a Buggy has a low pressure area right behind it, it would make sense that the air under the buggy would be blowing over the J tubes and up towards the engine tin work.
So with this in mind I figured that I would run a test. I got a indoor/outdoor thermometer from Wal Mart and mounted it more or less between the fan inlet and #1 J tube, just off the flywheel housing. I made up a tin heat shield around #1 J tube and went for a 30 min highway drive at 65MPH at 3000 RPM. Ambient was about 85 degrees. The fan inlet was about 10 degrees above ambient with the heat shield and 18 degrees above ambient without. A short run to 75 MPH made the fan inlet temp start to climb almost immediately. My oil temp was about 5 degrees warmer without the shield to, 205" to 210". If I run for any length of time above 75 MPH my temp will climb to 240" on a warm day.
Since the OP is running at a higher RPM, I would think that the exhaust would be running hotter and the fan would be pulling more air too. So perhaps a side wind (passenger side) would be blowing more exhaust heat into the fan inlet?
I was thinking about exhaust wrap, but the consensus is that it rusts out the exhaust. The other thing that made me want to try redirecting the exhaust heat was my valve cover gaskets. The gaskets started to leak just below #1 and #3 on the bottom front. When I changed them the gaskets were soft and pliable except at those two spots where they were hard and brittle. The power coating on the covers aren't discolored though.

[oprn]

Thanks for bringing this thread back up. I have forgotten most of it and need to go over it again.
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[Skulptorchaz]

I too am happy to see this reposted and more research done. THANKS!
I still have my overheat problem and just stay off the freeways, except for short trips. (I still need to get a head temp gauge at some point, as well.)
I too have a Manx clone and was always wondering if a "scoop", of sorts, possibly one on either side in front of rear tires, that would help directly feed the fan, would help?
I don't think it has to be a sealed system, or even close to it, just more air being "pushed" (hard) to the open area between the body and the fan/shroud. I would assume more pressure/air in that area "might" help cool the engine better.
My buggy does what I need it to just fine but, I have a goal of traveling East Coast to West Coast on Hwy 50.......if I don't get too old first.
Thanks again for bringing this back up!

[oprn]

Here is what I will ad for now to the discussion. Originally my Manx copy had a 1600 DP without flaps and thermostat. Did it run too hot? Not around town it didn't, in fact it ran too cold. Ran like crap and would not hold a tune. The addition of flaps and thermostat made the world of difference on that front!

Did it run too hot on the highway? Not that I am aware of because there was no temperature gauges of any kind. We did several long distance runs with it including a 10 hour trip through the mountains. Could have run a bit too warm at times but just like in the stock car there was nothing to indicate that it did.

No information = no worry. But... that does not mean there isn't a problem.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[oprn]

I just finished re-reading this thread and yes it is disappointing that the OP stopped his testing or whatever it was that happened.

I have done a bit of experimenting myself, again not done to any scientific standards but conclusive enough in my mind to be of value. I could share it if anyone is interested. I don't by any means claim to be any kind of an expert at all nor will I say that what I did is the only way or that it can't be improved on. It's just that we have a huge hole in our collective knowledge on this subject and there is a need to start somewhere...

This thread was that start but the subject was left at the question with only a little follow up. A bit of a teaser if you will!
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[Luftwagen 2180]

I agree that the thread didn't end with an answer. Feels like not seeing the end of a movie! It seems that a light Buggy with all the air in the world would never run hot. However running an engine way faster at times than it was engineered for and drastically different air intake and body shape seems to come with it's own issues. I love a challenge and trying to figure things out, probably why I have a Buggy. My wife and I are planning a road trip to do route 66 Friday, and I'm not planning that oil temp will be a problem at lower speeds.
In the old days (when I had hair) I wasn't running a temp gauge, sometimes I would overheat the oil. Turned black and started using oil for a little while. Now I've switched to synthetic and that hasn't happened since.
Seems to me that higher than ambient fan intake just has less cooling on the cylinders and the oil cooler. I will be running on the interstate and 401 for awhile at first so I will see what the oil temp is with my heat shield. Dino oil would cook at 240-250 degrees. Seems like it's going to be well into the 80's for awhile yet.

[oprn]

True they are lighter but that is only part of the story. The aerodynamics are completely different and as is talked about in this thread, the hot and cold air (don't forget the exhaust too) is mixing.

I learned a lot with the Missus driving and me facing backwards on the rear seat hanging out over the rear of the car. I used both a temperature gauge and my hands to get a mental picture of what is going on back there. Some things really surprised me and some did not.

It would not surprise me at all if the OP'er of this thread were correct in his observation that side winds effect the temperature.
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[oprn]

The first thing I learned about the airflow behind our Manx copy (bare in mind this is an open car, no roof) is that all the air in the passenger area is moving forward from the backside of the windshield right back to 6 or 8 feet behind the car. Have you ever "felt" the shape of the wind around the mirrors of a car while driving on the highway? Same thing. You can feel the high pressure wall of air with your hands. It starts at the top of the windshield, goes up to about 2 feet high over the front seats and about 2.5 feet high over the rear seat. The air below that is moving forward.

This means that there is a low pressure area in the cabin region. The air directly behind the engine is moving upward to fill that void.

Confirmation of this air movement came in two ways. First thing I noticed was on a cool evening sitting in the rear seat was noticeably warmer than sitting in the front seats. The second was when I accidently left the oil filler cap off after topping the engine oil up. In a few short miles the backside of the windshield and the backside of my eye glasses were covered in a fine oil mist! We also have found that when driving in the rain, no rain drops ever reach us from above or from the sides but there is a fine mist coming from behind us and we have to squeegee off the backside of the windshield to see.

About this time Clonebug added an intercooler to his Buggy. He put it on the horizontal with a slight forward tilt above the engine and slightly higher than the top of the rear seat back area. His thinking was that the air would blow down through the intercooler but I already knew that was not so and suggested it wouldn't. Sure enough! He found that there was little to no air movement so had to add a fan. I don't know which way his fan is blowing, down counter to the natural air flow or up assisting it...

Further investigation with my hands and with a bobber on a fishing rod revealed that the air that is moving in to fill the void in the cabin area is coming from underneath the car, through the wheel wells and from the sides. This air is a mixture of fresh air, spent air from the cooling system and exhaust gasses. And yes it is warm. I found that the hottest spot was directly behind the crankshaft pulley and was on average 30 to 40*F above ambient. I could feel the temperature difference with my hands and a Fluke test meter confirmed it. The warm air bubble rose up to about 3 feet or more above and forward of the rear of the car and tapered off to the sides both ways. So yes there is definitely a big bubble of warmed air following our Buggies!

My conclusion was that there is a high pressure air mass under the car trying to get over the transaxle and out through the wheel wells. Although I did not test it further I think that removing the vertical stock engine tin that seals the engine compartment to the firewall in the Beetle would allow more air from under the car to come over the transaxle and reach the fan inlet on the type 1 upright engine. The fan shroud itself helps to block the hot air directly behind the car. Perhaps a couple of deflectors could be made to extend that further out into the wheel well area directing even more cooler air toward the fan. A certain amount would of course still spill forward over the top of the fan shroud.
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[Skulptorchaz]

OPRN.
I had the same thought above. Some sort of scoop or deflectors to bring air in from the sides of the buggy, in front of the tires, to help feed the fan.
My pods could be the culprit in robbing ambient air from the sides.

I would have tried to make a set of the testarossa side pod "functional", in that regards but, my pods are glassed on.
Just a thought.
Thanks for the info.
Chaz

[oprn]

I think some gains and losses on the hot air recirculation front are also related to the exhaust systems we run. Again this is speculation as I have not tested and documented different systems. Any system that exits directly behind the car and have most of the pipes and collector right at the pulley like the Bob tail systems will increase the temperature in that hot air zone. Mufflers that exit out to the side past the wheels, stingers out to the rear and headers that are down low should be much better.
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[Luftwagen 2180]

Hmmm... sounds interesting! In the Off Road forum someone was having heating problems in a Baja. After a number of tries the solution was to duct the fan intake above the roof for constant ambient air.
Orpn, it's good that you seem to live off the beaten path. Your info is good and informative, however you would have been quite the site doing those tests! Owning an air cooled VW probably just confirms to the neighbours that you're "special". I was watching your posts on the type 4 engine you were working on for fresh air intake, and was wondering how you made out with that. Seems fresh air into the fan would be tough to get to ambient.
So getting ambient air to the fan intake seems to be the key. EVERY other VW seems to have a dedicated path for fresh air and exhaust somehow segregated from the intake air. I'm wondering if a rectangular pipe running from just inside the back wheel to the fan intake would supply enough air to work?
I'm off for about a month tomorrow driving the Buggy so I'll have lots of time to think about it, or a way to test it.

[oprn]

Ah yes, Luftwagen 2180, I have been special all my life! Curiosity over conformity I say!

You are correct that I put a type 4 engine in the Buggy. All this testing was with the type 1 engine, not because I had an overheating problem really, I attribute that mostly to the fact that I did not have a bobtail exhaust and the vertical firewall tin was missing. It was to confirm in my mind where the hottest area behind the car was. No surprise that it is exactly where the cooling air intake is on the stock type 4 (and type 3 by the way) cooling system. I was hoping to use the stock system as found to save time and expense.

In spite of those findings I went ahead anyway (the Lord hates a coward) and put the engine in with the crank mounted cooling fan but with some small changes.

First off was that with the high pressure area under the rear of the car I left the vertical firewall tin off. With no fan shroud in the way the hope was that lots of air would come up over the transaxle and through the wheel wells to fill the void behind the car.

The second change was to keep ALL of the exhaust system out to the sides as much as possible and away from the fan hence the home made Dune Buggy dual system. The idea here was that by the time the air that followed the tires and picked up the exhaust heat got around to the rear of the car it would be "mixed down" enough to not be as big of a problem.

The third consideration was to not build "industrial tins" to replace the heater boxes. The thinking here was to allow some of the spent engine cooling air to exit sideways past the tappet covers instead of all of it going straight back. Again an attempt to disperse the heat quickly over a larger area.

So this is how it turned out. Initial testing of the air temperature at the fan inlet shows only a 3 to 4*F increase over ambient! Yup that surprised me too! There is indeed a warmer air zone both sides of center and they merge further back so I think my efforts and theories were not totally in vain. Not all is rosy though, I was hoping for oil temperatures in the 180 to 200*F range but on a moderate day (up to 75*F) it runs 190 to 210*F and on a hotter day (80 t0 90*F) and after 3 hours or so at 65 to 70 mph it will climb to 225 to 230*F. Not alarming but getting into the "keep an eye on it" range.

As Jake Raby pointed out in this thread, CHT is very important to track. My attempts at a CHT system failed so I do not have that info unfortunately. I have used a heat gun (crude and not very accurate, I know!) and shooting past the tinwork the highest I have gotten is 275*F. The heads under the valve covers look bright and new, not burnt brown like when the engine came out of the Bus. I have not had any percolating sounds from the carbs or any hard starting issues hot so I think the head temps are ok.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[clonebug]

This past winter I spent a considerable amount of money on my winter upgrade.

This included a new MS3PRO-EVO ecu, an EcuMaster PMU16 power management system and finally an EcuMaster ADU5 digital dash.
What that gave me was a ton of info right in front of my eyes every time I drove my buggy.

It was enlightening on my Cali trip this year because I could watch my engine info in real time.
Intake air temps, Head temps(not from the plug), vacuum/boost(Map), Oil temp, TPS, EGT, AFR, battery voltage, rpm, Speed and even gear if I wanted.
What ever the ECU will log I could display on my dash if I want and can figure out the logic to get it on there.
I've since added blinker indicator lights and high beam indicator.

I have even added a Baro gauge so I can watch that if and when I go up in the mountains again.

What this allowed me to see was a actual running temps of all the above.

What was interesting was my oil temps and head temps along with my cruising Map especially in high elevations. Resting kpa....engine off with key on at over 8000 ft ASL was 73 kpa.

Some of the passes we climbed are nothing but brutal. South of Reno in the Sierra Nevada's aren't too bad due to 70-80 degree temps but there is one pass heading to Barstow that is 6% grade for 20 miles plus. It is never ending. Ambient temps were 95* F plus. The first year we went it was 106* F.
My highest head temp was 249.6* F. This is reading off the #2 cylinder tin bolt and is really only a warm up reference but driving all these years logging and now watching gives me a good idea of the temps. Average cruise temp locally is 218* F. and might very 10 degrees either way.
Oil temp max was 214* F. at the end of that climb. Average Oil temp usually is 176-190* F. locally.....most of the time it never gets much over 180*.
In order to maintain 60 mph and have the turbo help on the 6% grades I need to pull 1-3 lbs boost but in high elevations it shows boost but the kpa is usually barely 100 kpa.
Needless to say it was quite interesting to have that info in front of me since asking the Wife to hold a 15 inch computer on her lap at 65 mph is probably not a good idea for marital longevity.

I have a FI bug shroud, all the tins, a higher opening temp thermostat, (installed trying to get higher oil temps due to Vaseline gunk in the crankcase), homemade sled tins and a sedan header with a turbo up-pipe.
My intake temps will range about 15-30 degrees above ambient...some due to the turbo heating the air and in the summer I think the heat off the header will contribute some to the inlet temps.
Max intake temp at cruise was 135*F on the above pass climbing at 62-65 mph.

So in closing the long winded ramble.......I never saw any of the issues that Vincent was seeing and my engine is only slightly larger than his at 1679 cc's instead of 1600 cc's.

I have never had hot issues.....it's usually the opposite. I can't get my oil temps warm enough...especially when I only drive to work and back at 10 miles each way.
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[oprn]

Good info Clonebug! Do you have the vertical firewall tin on your engine?

Maybe you could watch wind directions for us and report back to help answer the question the OP posed?

I certainly will be watching wind direction and oil temperatures on mine now to see if there is any noticeable effect.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[clonebug]

[oprn]

Ok, thanks. You must have more clearance than I do at the firewall. There would not have been room on mine for lines between the body and that firewall tin.

I see you have an extra oil cooler too. Many of us are just running the stock one. That changes the picture too.

On gearing, was told this Buggy was built on a '73 chassis, the pan # and the engine # confirmed that so I assumed that I also had the 3.88 final drive but... it is a swing axle (from Mexico?) so... who knows? Any hoo, I'm at 2900 rpm at 60 mph with 26" rear rubber. If the tach can be trusted...

Also, I am running 41* BTDC at that speed and 15.5 to 16 AFR for just a hair under 30 mpg. (Imperial gallons)

I like 60 mph too. As you say much faster and these short wheel based rear heavy cars become much more of a handful. All good at higher speeds on a new road but older rougher ones really bring out the bump steer and tendency to ride the ruts. On a good road 70 mph is just fine. As for going nowhere fast - I'm retired now...

With your set up then you are cruising right at crossover. That's awkward! No rolling on the throttle for a quick pass, you need to drop a gear.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)