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Stroking a 2.2 questions

Getting things organized for another 2.2-2.4 build. A few years ago I stroked a 2.2 T engine to a 2.4 taking advantage of the higher compression of the 2.2 T pistons and cylinders and ended up being quite pleased with the result. I had wanted to use E cams but never got the clearance I wanted so ended up re-using the T cams. The heads were not ported and I ran the rebuilt Zeniths such that the engine looked correct.
This current engine is a stock 2.2 T with no modifications. This will run in my 914-6 which will not see the track. I have had the heads ported to S specs and sourced a nice 70.4 crank. I will inspect, weigh and balance the rods. Getting the case align-bored currently. I have some 2.2 S pistons and cylinders on the shelf, S cams and a Carerra oil pump. And I am rebuilding a pair of Weber IDAs.
Given the 2.2 S cr was already at 9.8:1, and the fact that I will pick up a little more cr with the 70.4 crank, I imagine I will need to de-tune the engine with base gaskets to keep the cr under 10:1. Can someone who has done this weigh in on what I can expect to use for base gaskets to keep the cr from bumping up over 10? Any other suggestions as I get organized from someone familiar with this build?

Thanks in advance...
Speedo

Old 12-28-2019, 01:14 PM
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It all goes together. S pistons, you wind up at 10.3 cr.
With S, solex, or E cams everything ran and well
One dino placed horses at 220 on S cams and carbs
You do need to trim the piston corners to clear the crank counterbalances
Bruce
Old 12-29-2019, 10:44 AM
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The 2.2 in my old 914-6 was rebuilt to 2.4 (2.4 crank) ... ended up with ~~ 210hp w S pistons and a custom cam grind. It was a nice little motor.
Old 12-30-2019, 07:21 AM
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2.2-2.4

Quote:
Originally Posted by Flat6pac View Post
You do need to trim the piston corners to clear the crank counterbalances
Bruce
At Bruce's suggestion I was able (fortunately) to determine that my 2.2 S piston skirts were already trimmed.

Quote:
Originally Posted by Carbster09 View Post
The 2.2 in my old 914-6 was rebuilt to 2.4 (2.4 crank) ... ended up with ~~ 210hp w S pistons and a custom cam grind. It was a nice little motor.
Were you running a cooler of sorts? I posted this question on 914World and got a variety of responses. I am not planning initially to run a cooler (at least up front as I don't want to "cut" my 6) till I determine what kind of temps I am going to see. I will be doing most of my driving at 5,000 ft. If necessary, there are some alternative cooler applications/locations I can consider. Without question I will build the engine utilizing the smallest fan pulley and largest crank pulley to force more air over the cylinders than the factory configuration. This helped lower the temps on my 2.7 911 by 20 degrees F. Additionally the PO was running a 2.7 RS spec carbed-engine in this car when I purchased it...with no cooler and he was an avid auto-crosser.
Old 12-30-2019, 08:09 AM
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CRatio

The trick is to shave the top of the piston crown flatter to reduce CR.You also gain mid range torque because the air works less to pass over the crown and increases flow.Ciao Fred
Old 12-30-2019, 02:57 PM
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My 6 was not running a cooler. In the summer and in traffic temps would creep up. Once on a series of long uphill runs in the summer I ended up pulling off and getting a coffee to let her cool a little. However I rarely had an issue. The last long run from from my home at the time in Maryland to Tangerine Racing to see Chris Foley in Conn. Non-stop in August (?) without any cooling issues. Chris finally got the car to shift "right"! Hands down the best 914 guy I have run across. I nice guy that knows his stuff!

BTW that motor had been built by DeMan Motorsport. It was fun in the 914
Old 12-31-2019, 01:26 AM
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Need a cooler at anything over 9.5 CR. Detonation is not your friend.

Chris

Old 01-03-2020, 11:00 AM
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