2.2S top end on a 2.4T bottom?

[KevinG]

Is it possible, or even desirable to put 2.2S pistons, cylinders, heads, cams and MFI on a 2.4T short block with the stock 2.4 T internals?

[davidppp]

In a word, Yes.

This is a nice motor..






I

[Henry Schmidt]

A very nice upgrade.
Be careful of high compression and low octane.

[Cupcar]

I surveyed doing this many years ago with an early 2.0 aluminum case and figured I would have issues with the longer 2.2 S piston skirt hitting the main bearing webs at the cylinder base. You may want to check this and provide clearance.

Also the theoretical compression you will have will be 10.4:1, great for race gas but may not work in areas with lower octane like California's 91 octane.

Twin plug anyone?

[KevinG]

Thanks for the info guys.

If there is a piston skirt clearance issue, I assume you machine the webs?

[Cupcar]

That would be my solution, particularly on an aluminum case.

[davidppp]

Hello, Kevin.

There is no such issue with this conversion..always good to check of course..

The actual measured CR is likely to end up round 9.8:1 IIRC.

That said, provision in the heads for twin plugs are a sensible thing to put into any new build as future-proofing IMHO.

Kind regards
David

[Cupcar]

That there is no clearance issue is what I have been told by others as well. Maybe the very early aluminum case I used had the problem and this is not seen on later cases better to check than be sorry. I would presume one would want a minimum of .035" clearance.

Interesting that your experience is same as mine ie that mesured compression is actually lower than the "nominal" provided by Porsche or Mahle for the piston. The 2.2 S has a 9.8:1 nominal ratio and this should theroetically go to 10.4:1 with the increased 2.4 L displacement and same combusiton chamber volume as 2.2 S.

The times I have used Mahle pistons at a nominal 10.4:1 the CR has come out at around 9.8:1. A lot of this has to do with how the valves are recessed in the heads, spark plug pocket volume etc., but it always has been low.

I wonder what a 2.2 S would really measure at and wonder if Porsche allows for some carbon build up before the actual nominal CR is achieved.

[Johan123m]

I don't want to hijack this tread, but I'm following with special interest, because I intend to do +- the same thing...

I have a 2.4T engine with MFI

I can get the following:
2.2S cylinders&pistons
2.4S injection pump
2.2 or 2.4s cylinderheads (is there a difference?)
E-cams (I'm still searching for s-cams)
Can this puzzle be put together????

What's the best way to go: use the 2.2 pistons and the 2.4 cylinders or the 2.2 pistons and 2.2 cylinders? I'm looking for high compression.

Thanks

[Cupcar]

The 2.2 S and 2.4 S heads are basically the same with 46 mm intake and 40 mm exhaust valves 36 mm intake and 35 mm exhaust ports.

The 2.2 and 2.4 both have the same 84 mm bore and their pistons and cylinders can be interchanged and as pointed out the 2.2 pistons on the 70.4 mm crank will give higher compression than when used with a 66 mm crank- and much more compression than the 8.5:1 2.4 S pistons.

The question here is the availability of high octane gas if you run the car on the street.

Personally, I would continue to search for S cams and use the 2.4 S injection pump. You will also have to use the S injection stacks and throttle bodies or port the one's you have if you use S heads.

I have not personally done this exact combination so can't speak from direct experience.

[trekkor]

I also am pursuing a small SIX build this winter.

I have an early 914-6 two liter core.
Thinking about 2.2 p's and c's with a 2.7 crank and rods.

Bigger valves and some port work. "S" cams.

Is this a motor that will make power?

I'll run it on triple 40 Webers.

KT