How to keep your VW engine cool

[roland]

The 356 pulley thing is a great idea, I must do that on my bus..

Not too sure about the holes in the decklid though.. Doesn't that allow the air coming from the "scoops" on the side of the bus to get right out when driving at speed?

This might also be a good idea to get fresh air while driving:



It seems that, sitting still, it does not affect the temperature of the engine.. so not so much hot air being sucked by those holes.. Still the holes right under the outlet of hot hair from the doghouse are pretty stupid...

A lot more info on this thread on thesamba: http://www.thesamba.com/vw/forum/viewtopic.php?t=270720

[bilboa2]

here is an idea from doug berg. He cut up a berg sumo. used traction bar matereial as venting tubes through sump, then wellded back up. Volume was increased as well. bill

[Torben Alstrup]

Definitely a different aproach

Those holes drilled in the front plate in Rolands picture is doubtfull to do much good, especially those along side of the oil cooler air outlet. I have copyed an idea tha Ralf Bernaur gave me many years back. - In the starter side of the front plate we drill a 2½" hole and attach a flex hose to it. Then route it down so that the end of the hose sits about height with the frame horns. Then make a reverse "hat for the flex hose out of fine mesh chicken fence, and at the same time make a brace to secure the hose. This prevents leaves and other light debris to be sucked into the engine compartement. On convertibles, pre 66 beetles and split busses this mod makes good for a 10 degree temperature drop at the cylinderheads.
T

[pughdog]

Definitely a different aproach

Those holes drilled in the front plate in Rolands picture is doubtfull to much good, especially those along side of the oil cooler air outlet. I have copyed an idea tha Ralf Bernaur gave me many years back. - In the starter side of the front plate we drill a 2½" hole and attach a flex hose to it. Then route it down so that the end of the hose sits about height with the frame horns. Then make a reverse "hat for the flex hose out of fine mesh chicken fence, and at the same time make a brace to secure the hose. This prevents leaves and other light debris to be sucked into the engine compartement. On convertibles, pre 66 beetles and split busses this mod makes good for a 10 degree temperature drop at the cylinderheads.
T

Any chance of some pictures of this modification?

[Phil West]

Next trip out I will note head temps then pull over and tape up all the holes and get another reading.

Inccidentally my head temp sensor is drilled into the head above spark plug #3 so I'd say that's about the hottest reading I could take (have dogouse cooler).

With stock top pulley towing in 70F air on flat road reading was 340F.  Going down a hill 300F.
With 356 pulley readings were 300F and 260F.

Towing at 2,700 revs 57mph.

Oil system is sorted and can maintain 180F nearly all the time with the fan on - a long upward hill towing and it climbs to 195F then drops down to 180 again.

[AntLockyer]

This may be way off but can you try something? Tape the holes in the decklid back up and do a hill run (without towing) before and after to see what the temp does.

I've got a feeling the holes aren't helping. I'm going to be facing all the same issues as you with my split when it comes to towing.

On another note my old 1914 ran very very cool, it was in my bug but running at 85 all the way to the pod the case was cool to the touch after. What I think was different about that engine I think was small ports and thus higher port velocity. Might have made a difference with efficiency/heat. Just throwing ideas out there as I have been giving this some though over the years.

[Neil Davies]

Definitely a different aproach

Those holes drilled in the front plate in Rolands picture is doubtfull to do much good, especially those along side of the oil cooler air outlet. I have copyed an idea tha Ralf Bernaur gave me many years back. - In the starter side of the front plate we drill a 2½" hole and attach a flex hose to it. Then route it down so that the end of the hose sits about height with the frame horns. Then make a reverse "hat for the flex hose out of fine mesh chicken fence, and at the same time make a brace to secure the hose. This prevents leaves and other light debris to be sucked into the engine compartement. On convertibles, pre 66 beetles and split busses this mod makes good for a 10 degree temperature drop at the cylinderheads.
T

Interesting. On our late 'vert I want to use my Empi eyebrow lid, but I was a little worried about cooling so I thought about cutting out behind the numberplate to allow air to be drawn in, but I also thought about adding a scoop below the car. Think I'll work out the area of all the vents in a 2 vent and 4 vent lid and cut out the same area hole in the lid!

[Neil Davies]

Ok, worked out the area of a 4 vent lids vents - just over 32,000mm². I reckon that a 230x140mm hole behind the number plate will be enough (32,200mm²) if I have the plate spaced off by an inch or so. Do you think that it'll be enough on a stock 1500 single port?

[m.m.p]

just put a stock 2.1 wbx in there and keep it floored

[Neil Davies]

just put a stock 2.1 wbx in there and keep it floored

I might have known you'd go for a "wet" engine! How you doing mate? Coming back over for a visit soon?

[Phil West]

So I taped up the holes in the decklid and the oil and head temps went up 10F.  When I removed the tape and they went back down 10F.

So looks like for my setup the motor benefits from having the holes.

Cheers
Phil

[roland]

Interesting info..

I finally wired my oil temp gauge and i'm most of the time around 110°C... a bit hotter than expected...

So I guess I have some work to do: smaller fan pulley, external radiator, etc...

[Phil West]

reckon so I am at 82C towing so you should be able to get that down a fair bit!

[Fasterbrit]

reckon so I am at 82C towing so you should be able to get that down a fair bit!

An oil thermostat is designed to open around 88c to bypass oil to a cooler, so you are not even coming close to running hot Phil . Tepid, more like

[AntLockyer]

So I taped up the holes in the decklid and the oil and head temps went up 10F.  When I removed the tape and they went back down 10F.

So looks like for my setup the motor benefits from having the holes.

Cheers
Phil

Thanks Phil, that's another one of my theories that turned out to be rubbish

[kuleinc]

Interesting thread. I think having a properly sized header does wonder for keeping the heads cool as well. We're just getting into building a stockish motor for our bus, after building two motors for our beetles, I still need to put my oil cooler on with electric fan and get a head temp gauge. I like the idea of the smaller alt pulley, do they make one with fins? My alt pulley is a mexico one and pulls loads of air out of the alternator keeping it nice and cool...

[Phil West]

I've not seen any finned smaller top pulley.

When I was struggling with oil temps I ditched the heater boxes which brought the oil temp down.  However I didn't have a head temp gauge then.  My header is only 1.5" for a 1915cc however I have a custom towbar which makes replacing the header tricky but if I can find one to fit/borrow one in say a 1 5/8" it would be v. interesting to see the effect on head temps.

[kingsburgphil]

Another great thread. We tackled these problems decades ago, its good to see good ideas still in use. The 36 hp crank/912 gen pulley combo works well with a type 4 oil cooler in a slightly modified doghouse. A fan cooled stackplate cooler w/thermostat is a must. I prefer large idle jets, large
enough that the motor stumbles @ 1/8 turn (r or l) of the mix screw, like a 60 idle. Also, I like big cams (more overlap) with ported heads as VW
engines are cooled with fuel as well as oil/air. We used Corvair plug wire seals, they snap into place and last for years. After all that work we
eventually switched to V8 trucks for towing here in Calif. where today its a pleasant 98 f deg.   

[Jim Ratto]

Another great thread. We tackled these problems decades ago, its good to see good ideas still in use. The 36 hp crank/912 gen pulley combo works well with a type 4 oil cooler in a slightly modified doghouse. A fan cooled stackplate cooler w/thermostat is a must. I prefer large idle jets, large
enough that the motor stumbles @ 1/8 turn (r or l) of the mix screw, like a 60 idle. Also, I like big cams (more overlap) with ported heads as VW
engines are cooled with fuel as well as oil/air. We used Corvair plug wire seals, they snap into place and last for years. After all that work we
eventually switched to V8 trucks for towing here in Calif. where today its a pleasant 98 f deg.   

good to hear somebody agrees with me that idle jetting has a huge influence on cooling on street rides. You can see a big difference in temp by setting idles up a little fat. My car will miss, ping, hunt, and run hot if it isn't nice and fat @ idle. And I completely agree with you that big cams, when setup in the right combo, assist in keeping a motor cool. The engine is often referred to as an air pump. Pumping losses cause heat. If you ask these big 520cc+ lungs (cylinders) to pull in, comepress and expel air/mixture, and you do not give them enough (valve) timing to do that, you're going to increase losses and increase heat. I don't think some guys have caught on that higher CR and larger displacement REQUIRE more cam timing. You can't build a 9:1 2276 and expect 250' @ .050 duration is going to make for an efficient combo, even for street.

[Airspeed]

I don't think some guys have caught on that higher CR and larger displacement REQUIRE more cam timing. You can't build a 9:1 2276 and expect 250' @ .050 duration is going to make for an efficient combo, even for street.

Amen!

[kingsburgphil]

Seems I've found some kindred spirits here. For the benefit of the young'ins, I'll embellish my previous post. In 1974 I ran a typical DRF/DKP style weber motor, 82x88, 48's, 130 cam w/11.25 comp. 1 1/2 exhaust, 170 hp on FAT's dyno. No big deal. Stock fan housing & oil cooler, small santana pulley, berg sump and a 1.14 4th. gear 4.37 r&p. Nothing special for the time, ran consistant 12.60's.....average times for the times.

Never overheated on the street, averaged 12 mpg during the gas crisis (fun). Cruised at 3,500 rpm on freeways.....maybe 60 mph? who cared!



 

[Phil West]

Finally got round to fitting some test scoops - these are the EMPI plastic ones - I presume they based the design on the standard toilet cistern.  Tilt your head left then go look in your bathroom.  Same thing right?  Particularly if you have an avocado suite.  Which we don't.

On here purely for R&D.  I attached them with tape so can remove in future.

So head temps reduced from 280 to 260F.  I can confirm a 20F drop by using these scoops.

Now I just need to get some good looking ones made......

[Russell]

Phil great thread.
The best engine I've had for towing with my old bay cost a mere £250, 1700 FI from a type 4 !! Never had any cooling problems, sat at 80mph whilst towing at took most hills at 60, maybe too simple but it worked well and we went to france, belgium, etc no problem, ps it was a standard type 2 1600  gearbox

[roland]

I tried to driver while towing my bug with the decklid of the bus opened at the bottom (with a good old juice can "fixed" on the latch mechanism) and I lost 10 degrees.. So I guess I'll have to make some holes behing my number plate & see how that goes..

Btw phil your garage appears to be pretty cool! & seems you like white