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Question 2.2 to 2.4 or 2.5, Way to go discussion.

I have a good 2.2 case, crank, heads, cams etc from a 2.2 T. P's and C's are shot. Here's my dilemma. For the want of a set of 90mm 2.7 P's and C's I could build a 2.5 as per Bruce Anderson's suggestion on what to do with a 2.2. The compression would be really low in the 7.5:1 range with the recommended machining of heads and case. On the other hand I could look for a 2.4 Crank and rods, E cams and 84 mm E P's and C's.
The 2.4 L route would disgard some perfectly good parts such as crank and rods, cams, heads. The 2.5 route would make use of everything I have and would need new P's and C's which I am going to need anyway.
The 2.4 configuration would be a 70.4 mm stroke with 84mm bore. The 2.5 would be a 66mm stroke with 90mm bore.
Any thoughts on whether I should trade off compression for a few extra CC's. I'm assuming cost might be a wash with the extra machining required of the 2.5 L conversion. I'd need less parts for the 2.5 as I'm going to have to get new P's and C's either way.
My current configuration in my 69 is a 2.0L E block with Webers. It's running fine so I'm not without motive power. Since I got Wayne's new book (the black and white version) I'm ready to go. Just don't know what with yet.

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Old 01-02-2003, 05:36 AM
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Hi Steve, i am in the exact same situation. here is what i have gathered so far form this board’s users. Please email me privatly. I am in Montreal. farleydw@videotron.ca

Please also see a topic i started yesterday.

http://forums.pelicanparts.com/showthread.php?postid=643103



- - -

Thought on 2.2 vs 2.4

2.4E hp, 165 DIN or 185 SAE there are threads on the differences between the two ratings. When comparing different engines hp ratings, make sure your talking apples vs apples....

You shouldn't have any clearence problems when using 2.2 E or S pistons with a 2.4 stroke. The heads are exactly the same in all respects. T's and E's have 32mm ports and both S's have 36mm ports. However, As any good engine builder will tell you, ALWAYS check piston to valve clearence when building an engine!

We argue all day long about wether carbs are better or MFI, If you've got Zeiniths and are happy with them, Great, use em.

My two cents from your pile of parts..

Id use athe 2.4 crank with 2.2E pistons. Stock 2.4 E CR was 8.0:1 and2.4S CR wa 8.5:1. 2.2E CR was 9.1 and put those with a 2.4 crank and you raise the effective CR by roughly half a point. So you then have say 9.5:1 CR. Use your S cams and port the heads to S spec (36mm) ports and you will effeectively have a 2.4 S engine which was rated at 190hp DIN and 210 SAE. You should even have a few more than that since you have a better CR. Now before you listen to the "drivability" issues with that, ask any 2.4S owner if he/she would rather have a 2.4E..... We all know the answer. From your pile, this will give you the most HP, If it were my pile, thats what I would do!

- - -

Farleyd, use the 2.4 crank and rods, I think in the past on here everybody agrees on 180+, maybe 190 at the crank, stock 2.4 E is 185 SAE and 165 DIN. If I had that stuff and was on a budget I'd say go for It will be a nice engine when your done. The important thing is to NOT skimp on the details, check the case, add case savers, oil bypass mod etc. OH yea....MFI nuff said..


- - -

you won't have a clearance problem if you use e pistons with e cams or t cams. e pistons may hit the valves with s cams because the s cams push the valves pretty far into the cylender. 2.4L pistons are shorter than 2.2 because porsche wanted the engines to run on a lower octane fuel. have you already bought the p/c's? if not get T p/c's and use E cams. you'll get 9.5:1 compression so it will run on pump gas and with e cams you'll have a nice power curve thoughout the rpm range. S cams arn't great for the street you can't get the engine to idle right and T cams are just not as hot as e's. 2.4 crank 2.2 t pistons and e cams are the way to go if you don't wanna spend a rediculous amount of money and want a quick engine. you'll have about 160 to 170 hp if you stay with zeniths and use k and n airfilters maybe more. i'm doing the same thing to my engine and its gunna be done in about a week. its going to end up costing me about $3000 to do it. thats not bad. and i'm sticking with the zeniths. if you have any questions please email me justincoolguy@hotmail.com

- - -

Warren Early S Man

Sabin,

I don't think there is much money to be saved, there!

Actually, the JE pistons cost essentially the same, regardless of the diameter ... so there isn't any money to be saved by going smaller!

If it turns out that the 2.7 cylinders are out of spec, they can always be bored and sleeved to 92 mm and 9.5:1 JE pistons can be purchased for them ... for a net gain to 2,808 cc, and no machine work needed on stock 2.7 crankcase. Even with carbs, still good for 220 hp using 'S' cams! Good luck!

- - -

The 32mm ports on a T/E head are going to choke off the motor just as the S cams start to make their peak HP. But at the lower end of the rev range when the engine is "off cam" your motor has less compression then an S would have. In essence you'll have less then an S at the top and the bottom of the rev range, without the broad torque range of a T or E. From what you describe, your engine sound similar to my E engine in that it comes alive at 4000 RPM. I suspect that if you had S ports on your head, that you'd find another step up above 4500-5000 RPM.
No matter what you do with the engine (cams, capacity, etc.) doubt that it is not going to make more then about 160 HP. If you use 2.4 liters and an E cam you can get the 160 HP at about 6200 RPM. If you use 2.7 liters, you'll get the 160 HP at about 5800 RPM assuming that your cam peaks at the same point. S heads had 36mm ports which can draw enough air to generate at least 210-210 HP. You can get there by spinning a 2.4 up above 7500 RPM (with a cam to match) or by using an S cam and 2.7 liters and 6800 RPM.
On the other hand I've often seen people use S pistons in T's or E's (in fact my E has S pistons) and this will not change the HP much if at all, but it does increase the torque somewhat.
Given the somewhat unique set-up that you have, you might need to set-up the engine on a dyno. Alternatively putting a couple of O2 sensors in the exhaust would at least tell you if you were running rich or lean at around 5000 RPM. If the mixture is OK, then I'd go after the timing. Recurving a distributor from scratch requires cutting/welding parts inside of it as well as a bag of different springs. You might find it easier to just go with a mapped ignition instead. The big problem is that if you are doing this on the road, you may not be able to hear the engine detonating until it holes a piston. When a car is set up on a dyno, a good shop should have the equipment to spot issues like this and propose some solutions. A side benefit is that you'll also find out how much HP you really have.

Please let me know how it all works out. If you do dyno the car, I'd be interested in adding the results to my database.

Thanks and I wish I could be more help.

- - - -

I think the 2.2E pistons wold be fine as they would give you a higher comp ratio than a stock 2.4 S. You could use 2.2S pistons, if you already had them go for it, but they would give you comp over 10:1 I would suspect. This isn't a great big problem really, but the early cars are notorious for fouling plugs and the high comp makes this worse, also you might have gas octane requirements tht are higher. If you don't care about the gas, the fouling can probably be taken car of by using a modern electronic ignition such as MSD.

I think with the 2.2 E pistons you wouldn't have either problem.

Sounds like if your parts are in good shape, you might have a cheap nice engine

- - -
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Old 01-02-2003, 07:26 AM
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Hi Steve, Mahle has created a new set of Sport 2.7 P/C that have a compression of 9:3.1 on the 2.7 crank, on the 2.2 that would give you about 8:0.1, a little better than the BA scenario. Better yet, and what I have planned is to get a set of reconditioned 2.7 Cylinders from EBS, and a set of JE Pistons designed for the 2.5 setup. I think that the cost is around $900 for the cylinders + $995.00 for the pistons. You can get a nice 9:5.1 compression with this. You may want to get a set of E or S cams depending on how you like your power, but even with the T's you should get a nice boost for a minimal (in Porsche terms) investment. The only concern is that unless you have a 7R case, the milling required from the larger bore cylinders may weaken the spigot area too much and cause leaks.

This is the route I am going with my 2.2T motor.
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Old 01-02-2003, 08:26 AM
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I've got the 2.5 described in BA's book, except for Solex cams. It's a fun motor. I've driven it back to back with a stock 2.2T and they are worlds apart in performance - you will be pleased. The higher compression 90mm pistons would be better yet. Or, why not go to 92mm RSR pistons which would result in (I think) about a 9.5 ratio and 2.6L?? -- Curt
Old 01-02-2003, 08:36 AM
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I have a 69 E Targa with MFI and I'm starting to think about more power as well. Why not go with a 3.0 and sell off your other parts? If the budget is around $3000, it seems like it would balance out but I don't claim to have a clear idea of what you would need for a good 3.0 conversion (hopefully others will clarify that area). I'm thinking that I could drop in a larger engine and then I would have to find a use for that lovely 2.0 E MFI in my 914.
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Though I'm doing the 3.2 thing in my '73, I like the idea of a 2.5 because since the actual size is a couple of cc's short, the car could compete in the under 2.5 classes.
Old 01-02-2003, 01:04 PM
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I don't really have a budget at this time, I'm looking at using as much of what I have as possible. There is always the law of returns, for a little bit more you can get a little more. I have the 3R case and not the 7R. I don't know what the differences are. My local P wrench had mentioned the possibility of leaks around the spigots on 2.7 engines but I don't think he would endorse the 2.5 configuration to the 2.2 case. He suggested the 2.4 route. I like the idea of putting some money into the EBS cylinders and JE Pistons.
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Old 01-02-2003, 02:10 PM
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The 2.5 would be a dog with that low compression - don't even think about it. As I told Farley, the 2.2T motor is not a good platform to start with:

- Weak early case
- non-counter weighted crank
- Zenith carbs
- Biral cylinders
- T pistons
- T cams

Basically, to get performance, you'd have to scrap all of the above. For that matter, it's best to buy a core 2.7L and rebuild it - you'll get a lot more HP. The 2.7S motor was rated at 175HP - the 3.0SC at 180.

This info is also documented in the new book...

-Wayne
Old 01-02-2003, 03:14 PM
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Basically, to get performance, you'd have to scrap all of the above.

Not true.

Next time I fire up my 2.2T ill have to remember I only have 158 RWHP. This was before the twin plug exercise. Granted I did put alot of money in to the engine inre machine work etc. Im confident after the latest round of mods Ill be near 200 flywheel HP. This is in a #1800 car.

The 2.2T crank is actually quite strong. Racers have been using it because it has a very low MOI, coupled with a lightweight flywheel/PP you have an incredibly easy revving engine..

Since your p/c's are trash that is what will drive the rebuild. I have sourced my p/c's from ebs. Take the compression over the CC's its not a huge dif in displacement anyway..

Id say have you crank gone over, your rods reconditioned ( the chevy boys can balance and stress relieve the rods with the best of them) get some 2.2 "S" P&C (mahle and JE) and have some fun

You will need to give the heads some attention..... have the ports opened, and do the handwork yourself..
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Old 01-02-2003, 04:44 PM
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I have a 2.5 built with a 66mm T crank, 90mm 2.7 pistons, "Solex" cam grind, 32mm Webers with the heads intake and exhaust ports opened to "S" specs, case main bearing area "boattailed, etc, etc. This engine is wonderfull to drive, good low end torque, rev's nicely to well over 6K, very smooth (very little noticable vibration) on the street and runs on pump gas 92 octane. Our local Porshce shop has built many of these engines and every owner always has a smile on their face after going out for a "horse power fix". I would recommend this engine to any one with a early 2.0 or 2.2 engine that they want to get a liitle more out of it.

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Old 01-02-2003, 04:49 PM
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I just diggeg under my engine only to notice that i have the 3R case. Does that make a difference? I mean if i decide to go with the 90mm pistons/cylinders and that i have to bore the case? Over the long-stroke 2.4 option?

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