2.4t with 2.2s pistons

[rsrguy]

So, I'm looking around for some 2.2s P&C's to put into my 2.4t with my top end rebuild. I was hoping you guys out there could help on a couple a questions.
1. Since I'm doing this over the web, what denotes a 2.2s? What markings should I look for?
2. Are all the 2.2s cylinders nikisil?
3. Are there now alternate new forged pistons that would work as well or better?
4. I'll be using my MFI rebuilt to match, what cams will work best ?
5. What other options should I considder?

Any help will be appreciated-Guy

[YTNUKLR]

1. See the pictures at this link - this is what to look for: 2.2S piston mahle

2. None of the 2.2S cylinders was originally Nikasil. They could possibly be Nikasil if recent production (year ~2000 or newer) sets

3. Yes ; ... there are several companies that can do this, JE being most familiar to most. Can tailor compression to your needs. Probably less good for wear than Mahles, but if you don't plan to put 100,000 miles on the car (or if you are OK with engine work in 100,000 miles) ....

4. Cams for what? How do you plan to drive the car? Track? Sport Street? Cruise?

5. If going with 2.2S pistons, recommended you use a fairly aggressive cam, like S, or similar ; on a 2.4 Crank 2.2S pistons yield some pretty serious compression (10:1+) and you need a cam suited to this . The "Mod-S cam" is a good one , better objectively than an S cam IMHO (more torque, for longer) ...but if you are looking for the pure vintage feel just like it was in 1973, which is really cool in its own right , then a real 911S cam is what I'd get.

A 2.4S / 2.2S piston motor is an exciting combination.

[plumber]

I have just picked up a car with a similar motor but with e spec cams what is the difference in the motor,
911/91 2.4 ltr case
2.2 S pistons
2.2 S heads
e cams
carbs 40IDT redone by Harry Beiker
what would the estimate on hp and will the engine run ok?

[YTNUKLR]

sure it will run ok, but I would be careful about timing and premium octane only. An S cam would really make the use of the compression & ports you have there...

Better to have more timing than more compression... here you may be limited on timing sometimes and having an S cam will reduce your dynamic compression somewhat, helping the issue.

[plumber]

I have been informed by PO
MOTOR BUILD
2.4 cis case
2.2E pistons & cylinders
2.2s heads
2.2E cams
WHAT DO YOU THINK NOW

[BK911]

Originally Posted by YTNUKLR

...on a 2.4 Crank 2.2S pistons yield some pretty serious compression (10:1+) ...

You never stated your intended use. Unless you are looking to squeeze out every bit of HP from the engine, personally I would be looking for 2.2T pistons to use on a 2.4 crank. That will yield around 8.5:1 (2.4S) compression.

Why spend the $s for 2.2S pistons when 2.2T pistons can be had MUCH cheaper? Less stress on the engine and less chance for detonation.

You will end up with a VERY nice street engine. Nice throttle response from idle to redline. Easy around town and fun in the twisties.

Or get your existing jugs bored out to 85mm and get JEs around 9:1.

[rsrguy]

While that is a fantastic suggestion, and good for most apps, it's not what I was looking to do. I'm going to have the top end re-done in conjunction with, re-installing my re-built MFI..... some tool in the 80's took it off to put on webbers. It hasn't really run right since I got it. I'll be doing the twin mod to the heads, so detonation on pump gas won't be an issue. I've been looking around for the pistons and cams to do the 2.2/2.4 build. I like the mod s cam idea and I don't think I would be able to tell the difference between the two from a sound perspective. I figure I'm a big boy 265 @6'2" , so I can use a bit more than the 2.2t piston bump will give, plus It's the whole idea that It'll be as close to an rs as I the wallet can handle!

[rsrguy]

I like the idea of the 2.2t pistons though I think I'll start looking for a 2.4 crank to put in this little bundle of joy! What's the hottest drivable cam for a 2.2 w/ 2.4 crank and 2.2t pistons. It'll be a semi daily and autoXer. the five lugs are properly done and its got all the right 6 bits except the engine tin, I'll go to GT for that.









Here are some pics during paint.

[rsrguy]

Shot it in the garage, turned out to be a solid 4k job.

[Flieger]

Wow, a Saab Sonnet!

[YTNUKLR]

Originally Posted by plumber

I have been informed by PO
MOTOR BUILD
2.4 cis case
2.2E pistons & cylinders
2.2s heads
2.2E cams
WHAT DO YOU THINK NOW

Sounds like a high compression E motor, pretty much! It should run pretty well! but E heads would probably be better with the rest of the parts there. I dunno, maybe 180hp?

Originally Posted by BK911

You never stated your intended use. Unless you are looking to squeeze out every bit of HP from the engine, personally I would be looking for 2.2T pistons to use on a 2.4 crank. That will yield around 8.5:1 (2.4S) compression.

Why spend the $s for 2.2S pistons when 2.2T pistons can be had MUCH cheaper? Less stress on the engine and less chance for detonation.

You will end up with a VERY nice street engine. Nice throttle response from idle to redline. Easy around town and fun in the twisties.

Or get your existing jugs bored out to 85mm and get JEs around 9:1.

I wouldn't want to be running T or E (or any cast ) pistons to an S redline - they used forged pistons..I would go no more than 6800 (E) redline with those pistons. S is 7300, and forces grow as a square factor w.r.t. rpm....so 7300 is a lot more stress than 6800.

[rsrguy]

Scott, so what would a least painfull ($$$) build be for the 914-6 with recycled P&C's? 2.4 crank, and your experience w/output.

[rsrguy]

Yep that is a Sonnett my sons first car, he bought it for $800 bucks. Its a fun car and cheap for a kid too. He's an ARMY medic now, but he'll be out in late 2014 we get to finish it up then.

[arrivederci]

Originally Posted by YTNUKLR

Sounds like a high compression E motor, pretty much! It should run pretty well! but E heads would probably be better with the rest of the parts there. I dunno, maybe 180hp?

Probably in the ballpark. I've never torn down my 2.4L motor, but the previous owner said it has
2.2S P's and C's
2.4T MFI
2.4T heads
2.4T cams

I put it on a dyno and it pulled 145hp at the wheels. That's with T redline and power falling off on the top end. I have never physically verified the pistons.

[YTNUKLR]

I would probably recommend a 2.4 E motor with more compression.. 2.2E P/C or get some 84mm birals and bore to 84.5mm with new pistons from JE or someone. Target 9.3:1 or so...but you say you have twin plugs? Maybe 2.2S in that case, targeting ~10:1

[rsrguy]

To clarify. The 911 has a 2.4 t motor. It will be twin plugged with the modified s cams and s P&C's , the motor has MFI this will be rebuilt and modded as well.

The 914-6 has a 2.2 motor with carbs. It will be single plug. I'm thinking about a 2.4 crank for it and 2.2 pistons on my 2.4t C's. You mentioned boring these jugs out to 84.5. Will this make the JE pistons a good viable option on the biral cyls. Since they are forged will I be able to run with 2.2s cams? I think 9.3:1- would be a good target to shoot for, as this will be a semi daily driver. Both cars will see DE at the track, I like the idea of the S cams higher top end, but I'm guessing I'll need to account for this with heavier springs and new rotor? This brings me to my last question. Do JE's ride well in the biral cyl's? How does this setup compare to the issues I've read about in the past when you stick them into nikasil or alusil cyls? My guess is that it would be a perfect combo, as that's what I'm use to seeing in my muscle cars..... forged pistons in a cast iron block. -Guy

[YTNUKLR]

OK,
Your 2.4t w/ mod-S cams and 2.2S(?) p/c sounds good...

yes you could use 2.2 pistons in your 2.4 cyls, if they are to spec, otherwise yes you can bore those cylinders to 84.5 and use new forged pistons. of course you can run a non-forged piston with S cams but kind of missing the point if not using the last 500 rpm in the band up to 7300 . On S cams and single plug a 9.8:1 is a good target, mod-S cams a hair less, ~9.5:1, E cams, ~9.2...heavier springs? you mean the valve springs? or the distributor? valve springs, no, check your spring height settings; distributor, have it checked for S advance curve, and yes to the 7300 rotor.

JEs work well in Biral cylinders..not a match made in heaven but a perfectly good solution in my eyes, for a car that will see ~50k miles / 10 years+ given the relatively low annual mileage most 911s see...

[rsrguy]

I just got my email back with pricing from Henry. The pricing seems like it's about what I expected. He mentioned that I could bore my original plastic throttle-bodies to meet the new motor's needs. Who does this? What should I expect to pay? I know I don't have the injectors, or the fuel pump I need to feed the MFI pump. Where should I be shopping for these? Used that is.-Guy

[bavaria911]

Guy,
I had an old leaking MFI fuel pump rebuilt by a guy in Southern Cal for less that $300 - a great deal. New is $550+
Do you have an old core to ship him? Let me know and I can call the guy to help you out.
Let me know.

Scott

[bavaria911]

here is the donor I gave him, it came back paint and perfectly running w/ warranty of one year.