ShopTalk Forums | Aircooled VW Tech & Restoration Help

How hard is it to set up an engine for the flexibility of air cooled cylinders/pistons, while sticking with the water cooled heads? I'm thinking this would be an ideal solution for the karmann ghia we are building, with eventual plans to turbo charge it - we could then use a 2.1L water pump, using both an oil cooler and a water cooled turbo...

What are the snags with this setup? The radiator could be quite a bit smaller, but would there be a significant problem with all the cooling tin?

Thanks,
-Damon

I have had the Evil Plan of stuffing a small MC radiator in a 911 setup, and ducting the exhaust.

I think I'll just keep it water cooled..
Other than having more flexilbility on the deck, the air/water combo has few advantages.

(Still have the Itty-bitty chambers, thus wierd pistons)

You mention having the itty bitty chambers - very true, but is that something simply increasing the volume above the piston (ie. higher than normal pin height) take care of?

Also, it would seem to be a lot easier to machine - not having to worry about relocating head studs, etc. I think i remember hearing something about how this was bad, but i can't recall what that was (shrouding of the flame front, or something?).

I guess you can also get by with a much smaller radiator because you are typically not running the engine *nearly* as hard because it is pushing something light and relatively aerodynamic, as opposed to a heavy (5,000lb ) brick

What i like about the air-cooled P&C is that you get a lot more options in combos (rather than being stuck with ranges from 94-97 or so...)

-damon

The Wasser can apparently take up to 103 with machining, and even with iron jugs, should not have the sealing issues of the T4 due to a) water cooled and b) symetrical head stud spacing.

Reboring the stockq wasser jugs allows 94-97MM bores...

The jugs for the wasser SHOULD be very easy to make, the hard part is getting quality materials in the right sizes.

It's just a flanged tube with 2 o-rings... No hard-to-get-right fins, etc.

As to the funky pistons, just leaving a big gap at the top is a no-no, as without any squish, all you make is heat... Just ask anybody who ever added an exra head gasket to lower compression and found the ping far worse afterwards... Current wisdom is 1mm or slightly less piston/head clearance, allowing steel rods. Motors actually built for Nawwwwws will have aluminum rods (act as a cushion) that grow a bit, and need twice that IIRC.

Someone here (been awhile) had some beautiful heads done by Oliver Knuf (sp?) and had the chambers made bigger, looked to me like he moved the valve seats up a hair to have SOME room to work with, managed like 35CC chambers with massive work.

Many modern cars probably have chamber-in-piston high swirl configurations... I just have no idea which ones. Those would be ideal candidates for a supply of pistons, otherwise custom (John???) or stock are your options.

I sort of have this hope/suspicion that "someone" will develop a drop in 96x80 wasser kit with squishies... Let the CR be 14:1... water cooled and with squishies and EFI+chip, that would make a KILLER rebuild kit for vanagon owners, especially with good quality CrMo rods/3/8" ARP bolts... Likely have both killer torque and great gas mileage in a Vanagon.

I hereby volunteer to beta-test this in my 914;-)

I personally think something like that would sell very, very well, especially in Europe.

A 103x80 kit would shut down the Subaru swap guys permanantly, save for the few who do
the 6 cylinder swaps.

Of course it would also probably make 200+HP easily with a different cam combo/porting etc.

With the right cam and a chip, you would never be passed by a Caravan again.

There is a drop in 80mm stoke motor being evaluated right now. Still using stock pistons and has 44idfs. In a camper vanagon........

Tom, Any more publicly available details?
(Commercial devel or roll your own?)

Rods?

With the stock pistons, a mild turbo setup is still possible..

http://www.shoptalkforums.com/viewtopic.php?t=52097

'tis now fitted with two rads/elec pumps, 2" stainless header/stinger, T1 55amp alternator, dog-house cooler, oxy on the fins, water through the heads and oil through a T1 5 row cooler

Each head is cooled by its own rad, each water system is independant but they share a common expansion tank and pressure relief cap.

We hope to be 1/4 mile testing in September, if we can get the flip front in time. the plan is to hike the CR and fit large valves. We don't expect to boil the coolant

1914cc
Scat C55
hydro's
48drla's

Anyone have examples of how the head mods are done?

kunf did my WBX heads, he got 28cc in them, he moved the vavles into the head 3mm and fitted 45mm/40mm nimonic valves for the extra heat the turbo makes, im shooting for 350/400bhp, 18/20psi

John is working on Squishy pistons for the T5. I'm all for it, my T1 squishies allow 12.8:1 on pump gas every day (108 degrees two days ago!!). I can't overheat it.

Steve

Those are still beautiful, but I was wondering aloud about the mods to the heads/plumbing so they stay water cooled, and having aircooled jugs.

It has been done: No need to reinvent the wheel... Someone has already done the R&D cycle... Just have to find the info.