911T 2.2 Displacement Increase Question

[OCG911T]

Gentlemen,

I’m writing this thread to solicit advice on upgrading my 911T 2.2 engine.

I am starting to purchase the parts and materials for my engine rebuild and need advice on what route to take regarding my displacement increase method.

My goal is more power and a reliability/longetivity. I’m not looking to build a monster, but would like something that performs like an “E” or better and am willing to perform modifications that will result in a bulletproof engine (or as close as you can with a 50 year old magnesium case!!!)

I would like to either increase my displacement to 2.5 liters by performing the modification recommended in the BA book, by installing 90mm RS P&C’s and performing the necessary case modifications, or to 2.4 liters via a set of 87.5mm Nickies with 9.5:1 JE pistons.

I want to keep my “T” crankshaft and 66mm stroke.

Will the 87.5mm Nickies fit in the small spigots without machining? If so, would this be my best course of action as far as keeping stresses down on a 50 year old case? Or is it ok to do the 2.5 upgrade with the case modifications and expect longetivity after machining the spigots to 97mm?

If I go the 2.5 route, would you choose to stick with the “T” Camshafts or regrind to “E” or Solex? I am planning to send the Camshafts and Rockers to Webcam for grinding/polishing/rehardening/rebushing if I upgrade the cam profiles, and WILL upgrade to “E” or Solex if I go with the 2.4 build as well as purchase a set of Pauter rods for the extra insurance with the higher rev limit (keeping the “T” crankshaft because I cannot find a reasonably priced counter weighted crankshaft.)

Any thoughts are greatly appreciated. I have spent months reading and keeping notes on the various options and realize there is a lot of information on these upgrades, but am hoping for some good recent advice, as many threads are 10+ years old and there appear to be more options available and I have not found anything on the 87.5mm option with an “E” or Solex grind...

Thanks and Happy Thanksgiving!

Oliver Garthwaite
Portland, Maine

[71gold]

Oliver
Engine rebuilds are great fun, mine is in process.
Not an expert al all but reliance on several good engine builders as resource .
Just some additional reading for you would be to visit Pelican Parts site,
There is an Engine Building section in their technical subjects.
Many posts re the questions your asking and the variations of engine builds.
Henry with Supertech is well respected for his knowledge and posts there.
He is also typically agreeable for a call to discuss .
Keep us updated
Frank

I ended up trading my 66mm for a 70.4mm crank going the 2.5 route .
Kept my mag case and significant machining.
Finalized on DC 40 cams and Italian Weber’s as I always love the look and simplicity of carbs.
Just my opinion.
My goal was S performance 190hp but low end torque not what the S is known for.

[OCG911T]

Frank,

Thank you for the advice. I just signed up for the Pelican Parts Forum and there seems to be endless threads on the 2.5 upgrades!

I have not heard of the DC40 cams, did you have to open up the ports on your heads to get the most from those cams? Are they like a Solex or S cam or more aggressive?

Thanks again,
Oliver

[71gold]

The DC 40 cams are similar profile to Modified S
Will get more specifics For you
Frank

[tfiv]

It's great fun keeping 2.0/2.2 S engines in their zone. I'd build a 2.2 S motor and put in earlier 901 gear ratios. But that's me!

[OCG911T]

Thanks, Tom.

I was hesitant to go with an S setup without a counterweighted crank and looking for something with a little more low end performance... do you have any experience with this type of build? I suppose the extra layout to increase displacement could also be spent on a counter weighted crank and then stick to the smaller displacement with a higher rev limit. I have always read the S is a great car but not unless it’s wound up in the 5k+ range. I’m shooting for something with a broad torque range that makes all it’s power by 6800, as I don’t want to stress my T crankshaft too often and will only be using the car for spirited driving and DE use, with an expectation the engine will last. Eventually I want to build a hot rod from a 2.7 or 3.0 engine and put it in an old SWB 912 or 911, like a poor man’s 911R inspired car.

Happy Thanksgiving,
Oliver

[daniel911T]

Interesting discussion on Pelican about the 2.0/2.2T crank in racing applications:
http://forums.pelicanparts.com/porsc...ted-crank.html

Bottom line: your 2.2T crank is probably fine for anything you want to build with a short stroke.

-Dan

[OCG911T]

Thanks for the link, Dan.

It sounds like for my application it would be fine to go up to a 6800 redline with an E or Solex setup according to those folks. Now my question is do I shuffle pin the case? I’m wondering if that would eliminate any potential problems from a crank that may have more of a tendency to work in the case/bearing surfaces?

Regards,
Oliver

[sebastianroher]

Oliver,

I had Ollies shuffle-pin my case I thought it was a good mod to have. They have a price sheet on their website you can see if it would be something you'd be interested in.

-Sebastian

[OCG911T]

Thanks, Sebastian.

Was it difficult to get the case together and did you experience any oil leaks with that modification? I am familiar with the process of shuffle pinning pump case halves on the ship I work on and could see how that would be a great modification for a 911 engine..

I see you also have a 71’ T, did you do any other mods to your engine? I’m excited about the rebuild and feel that it’s kind of difficult to just pick and move ahead with so many contradictory threads out there.... by and large it appears if you are willing to spend the extra money on the case work for the old magnesium cases the possibilities for an engine in the 125-220hp are endless.... looking to pick the best reasonable option to end up with a fun but reliable engine.

Regards,
Oliver