Flaps & Thermostat…

[garym999]

So I have not been on the scene for that long (4 years now) so every day is a school day. When we first got the bus it ran rough and to cut a long story short I ended up buying a long block from a well known uk builder.

I soon realised I was missing loads of tinware, flaps, thermostat etc. and set about collecting the pieces. These got installed with the new engine. Which as been running great but I have noticed runs hot on long runs at 60MPH ~3600RPM. Oil gets up to 100-110C.

Although we use the bus all year I now have a little downtime between events so have pulled the engine to give it a once over and check a few things regarding engine temps. The operation of the flaps is one thing another is checking the castings for flashings between fins etc.

I think the thermostat and bracket are correct, 65-75c and operates fine one the bus and with a heat gun.

I brought the flaps and the link as a set at a swap meet but now suspect the link is not correct as it’s fouling and causing ware on the oil cooler bracket. Despite the ware it does not seem to impede operation

The parts did not come with any fixings and I just used washers and circlips but looking through the gallery I now realise that’s not original.

The 13mm of bellows travel relates directly to 13mm of bar/flaps travel although with the links disconnected there is a much greater range of travel available.

Where the link rod connects to the bellows and hooks on to the first flap there is a curved arm on the flap which was slightly bent.

Depending on how it is bent will affect the amount of travel does anyone know how much travel there should be at the flaps and what link arm I should have.

While the engine is out I am considering modifying the doghouse for a type 4 cooler so I will have to mod the link anyway. I also have an APC Venturi ring to fit
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1975 South African Fleetline

[mikedjames]

What is hot for a bug is not hot for a bus.

Running at 100-110C(212-230F) is quite normal.

I used to run a VeGe 1641 at 122C / 252F, with the bus doing 57-62 mph. With smaller than stock tyres , it gets to 4200 rpm at times.

I bought it a full flow oil filter and additional external cooler - that dropped the temperatures maybe 10 degrees C . With working flaps and all tinware.

Then I damaged that engine and built another for about £600 and some of the old engine, and including an AS21 case I got for £51, which ran the same sort of temperatures until it dropped a valve and bent a rod and put bits of piston everywhere and that was the end of that. Each of the first two engines lasted around 30000 -40000 miles.

Now I have a new-parts engine based on an Autolinea aluminum case, with EMPI rather than stock VW heads and this runs about 10 degrees C cooler with the old engine's tinware and other ancilliaries. The latest engine has taken me another 40000 miles.

After it was run in, I refitted the full flow filtration and cooler, so when the air is about 0 degrees C, you have to drive hard for many miles to see the oil temperature reach 95C. Like this weekend.


Maybe you can bend the rod for the flaps a little more to clear the cooler.

My original thermostat did not fully contract, I found another one mis-described on eBay for £30.
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[garym999]

Cheers Mike. In an ideal world I think I would like the norm to be more like 80-90 for a bit more headroom. This time of year like last weekend hovering around 2C I can get 100-110. In the height of summer in Europe at 35C getting close to 115-120C and need to manage engine.

I think the engine has always been like this but has only come to light since fitting the worry gauges a year ago. Glad I have though cos it gives me a much better understanding of the engine.

As soon as the oil temps start to pass 85C you can visibly start to see it thin as the oil pressure starts to drop. Below this it’s the recommend 10PSI per 1000RPM. And that’s with a CB Maxi 2 spin on filter and 26mm pump

The stat is fine, fully closes and expands as designed. Since my last post I have pulled the fan shroud. And taken a look at the flaps using the pushrod, 14mm seems to be full travel from the bump stop to vertical. So things seem to be about right.

As per the thread about electronically controlling flaps I’m planning on using a 20mm travel slider pot to monitor the position so moving forward I’ll have some definitive data. Looking simple enough to 3D print a couple of brackets to pick up the motion
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1975 South African Fleetline

[mikedjames]

The oil temperature needs to reach around 100C fairly regularly to clear out condensationb and the emulsion that forms.

Yes the oil does thin and pressure drops, its expected to, to help control the engine temperature by flowing more through the stock cooler, by bypassing it less at lower pressure.
Provided you are still running around 2-3 bar at speed that should be OK.

What makes me back off is cylinder head temperatures- oil temperature is a slowly changing proxy for the heads. I have CHT sensors in a strange place , normally it reads maybe 10C more than the oil, but on a long hill on a hot summers day, it goes about 30-40C hotter.
_________________
Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[dunk]

[74 Thing]

I had the same problem with where the thermostat rod connects to the flaps that round spring metal was pulled and it would not go back to the original position so I had to purchase a good used flap.

FYI you can use a heat gun or hair dryer to make sure everything moves and fully opens and closes properly before installing the engine into your car.

[nogoodwithusernames]

I think I would personally be more concerned with CHT in a bus than oil temp. Oil temps aren't going to drop a seat if they get too hot. Does OP have a thermocouple under the spark plug?
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71 Squareback, 1.7l T4 w/ crank trigger fuel and spark
(Conversion thread https://www.thesamba.com/vw/forum/viewtopic.php?t=732508&highlight= or https://shoptalkforums.com/viewtopic.php?f=1&t=151375&sid=f0542d44a322d290c29d6609fac7f215 )
74 914, 2.0L w/ D-Jet

-Derek

[runamoc]

[oprn]

[garym999]

I do regularly drive several hours and have been doing just that,.. backing off until things drop a bit. Would still like to loose 10c if possible.

Flaps look to be in good order but will alter the link bar a bit to stop fouling.

Looked at the heads and they seem to have had a bit of cleaning up from the builder so not much in the way of obstructing casting flashings. Still room for a little more clean up though.

The barrels on the other hand, don't look like they have been touched and there is a vertical rib directly at the point where the air blows down. Effectively the air is directed to between the barrels and not around, so will clean that up. I have been searching pics but don’t see much reference to barrel flashings.

The other option I have with the engine out is to modify the doghouse for a 8 fin cooler instead of the 6 it has now. I have read mixed opinions on this
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1975 South African Fleetline

[Murt]

Not for everyone @garym999
But I am pretty sold on my Andrig set up on my split Bus
Evolution 1 Fan, Velocity Ring, and Fixed Flaps, all OE tins. Admittedly, I do not run the Bus in Winter, and always let it warm up before a drive. I have a remote filter and cooler with a fan, all thermostatically controlled
I have Oil Temp and Pressure gauge, and a Tacho, but not CHT or AFR. It ran cool this summer, not cold
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1966 VW Beetle ‘Jules’
1967 Kombi Splitscreen ‘Barney’
2018 VW Caddy Maxi R Line
2017 Golf GTD saloon
2008 VW EOS 2.0 TFSi

[garym999]

I do have a APC velocity ring to fit.

Adding an external thermostatically oil cooler would give me the headroom but I don’t really want the added plumbing that goes with it. After all it is a pretty near stock 1600 so shouldn’t need much of an assist
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1975 South African Fleetline

[dunk]

Ok. The condensation on the oil cap imo is irrelevant...

Can anyone find a car manufacturer that tells you "if seen, increase oil temp to at least 100 degrees c to remove condensation from the oil filler cap"?

It doesn't matter how fast it's removed from the crankcase...

Again, is their any official documentation that says it must be removed in a certain time?!

Nobody has ever broken their AIRCOOLED engine, because they saw, or had what they thought was excessive mayo on the filler cap... all engines do it. Its part of the combustion process.. It won't destroy them.
The filler cap is one of the highest points in the breather system.. youre going to see some residue there..
On most aircooled vws, it's on its way through the breather, to the air filter at that point so I'd rather see it there than inside the case!

Anyway..

Gary..

What engine do you have?! What modifications?

You have many options available to try and bring the temp down.. some bolt on, some not..

Thermostat and flaps which you're doing.
Having ALL stock tinware.
Making sure engine bay is sealed as best as possible
Velocity ring.
Industrial tins, if you're not using heat exchangers.
Changing your oil viscosity/type
Changing oil pump if pressure too high, pressure relief springs also can help here...
Deep sump.
External cooler.
Fan belt length.
Pulley size.
Extra cooling ducting/holes in the tinware.
Alternative fanshroud.
Gearbox ratio.
Rear tyres.

Are just a few...

Im sure others may suggest other alternatives also..

And of course checking the engine over for unforseen problems/interesting fixes... as you've been doing!

I'm personally not a fan of the type4 oil cooler mod. Not worth the hassle with so many other better options available. Imo.

Many will recommend that higher overall temps are fine. Thats theyre personal experience.. I'm cool with that.
I'm only recommending whats worked for me. I can't control what engines other people have, what mods they've done, what oil they use, how accurate their temp gauge is!, etc...
Because of this, recommending staying on the safe side of the "range" in which these cool little engines can operate, seems sensible to me.

Again, trying to be specific.. imo 90-95 degrees c... at cruising speed.. which I'm going to say is 3400 to 3900rpm and approx 60-65mph.. should be possible for hours on end without problem. I know this works. Irrespective of engine size, and vehicle.

Other speeds and temps may work! Each to their own:)

Again good luck with it!

[dunk]

Also... add...

Full flow oil filter
New oil cooler

To the above list of possible mods.

[garym999]

1600 DP

- All stock tinware with attention to fit. Removing to give a good clean and paint
- Standard heater boxes
- VS SS143 exhaust
- Solex 34 PICT 4 centre mount carb on stock manifold. Heat riser pipe cleaned
- Flaps and stat (which was working until I dropped it yesterday, )
- New 6 fin cooler supplied with engine
- CB 26mm Maxi2 26mm pump with spin on filter
- Both relief valves checked together with spring tension
- 10W30 oil
- Stock alternator pulley

- APC velocity ring to be fitted
- Plans to fit 4 cyl CHT and flaps position sensor
- Plan to fit small APC under head centre tins that kept falling out
- Option to fit 8 fin oil cooler but would need to modify doghouse
- Deflash heads and barrels

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1975 South African Fleetline

[dunk]

[garym999]

Thanks for the pointers Dunk, yes the engine is out.

Stock(ish) oil bath filter. I say “ish” as being a South African bus it came with a high capacity filter but without the preheat and in the UK climate pre heat is definitely needed. It now has a “thing” filter which is the same but with thermostatically controlled preheat.

Since I got the engine (as a long block) I have always used 30W. When I added the spin on filter I switched to 10W30. It’s my understanding that synthetic oils keep the dirt in suspension so the filter can catch it.

I have been thinking of making some sort of heat shield to go over the filter

I don’t think I’m going to change the oil cooler. Whilst I can weld it’s not that neat and I can see that I’d muck up the tinware while trying to extend it.

I do like the idea of the extra hole in the bulkhead tin though and that’s within my capability. It’s easy to play with and block of it’s not needed.

The heads are very clean from flashings which is surprising. The barrels though were not so I have done the tops.

As to the hoover bit, I purchased one a while back but think it’s not needed with my tinware (Mexican I think). But now is the time to check and the new sealing foam has turned up along with a new thermostat after dropping mine during the strip down and bursting it

All the tinware including the fan is dirty with a rough surface mixed in with rust so I plan to clean it all up and paint. I think the fan could do with shimming forwards towards the opening as there as about a 5mm gap
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1975 South African Fleetline