Pelican Parts Forums - 911T rebuild ideas

Quote:

Originally Posted by rads (Post 5315308)

Hello! I am more of a lurker than a poster.
I have a 72 911T with MFI and over the next couple of years I plan to gather the parts to rebuild my engine. Before I start buying stuff needed I plan to get the spec right and work from there.
I have never built an engine before but do most of the mechanical stuff myself on my car at the moment. I have done a lot of reading but sometimes too much info can be dangerous!

My car is street only, with the occasional track day, I want something drivable through the rev range.

I am thinking of 86mm P&C's, 9.5 compression, with a DC 30 (mod-solex) cam. Does this sound ok?
My questions are:

1. what would you recommend for the ports?
2. Would I need to get my MFI pump recalibrate? If so to what e or s spec?
3. Money is an object so should I take my existing Cylinders to 85mm and get a set of pistons to match?

As I say I just learning!!!

First, WELCOME to the forum. You will find the answers here. Many, many Pelicans have asked the same questions, so if you find you are not getting the answers quickly enough, try the search feature and you will find that there are a lot of other people who have been in the same situation.

You're right, it's best to have a detailed plan, down to the specific part number, before you buy anything. This will save a lot of money and ensure you have everything when the time comes to assemble.

So let's start with pistons and cylinders-- your 911T has cast iron cylinders that aren't that thermally efficient- the aluminum fin "Biral" cylinders are better, and the Nikasil are better still. The less expensive route is to find a set of 84mm Birals and have them bored to 85mm, and have custom JE pistons made in 9,5 compression. That will run you around $1600 at today's prices. The better, and more expensive route, is to go with a set of Mahle or LN Engineering all-aluminium Nikasil cylinders, and either Mahle or JE pistons. There's a lot in the archives about this. My own experience with overbored Birals is here: http://forums.pelicanparts.com/911-engine-rebuilding-forum/368320-jugs-slugs-confessions-je-piston-owner.html

Next: having your MFI pump recalibrated is an operation that can be performed by about five people in the world. For an appreciation of the complexity of the process, look at this thread: http://forums.pelicanparts.com/porsche-911-technical-forum/460169-mfi-pump-dyno-build-my-newest-project.html If you send your pump to Gus Pfister at Pacific Fuel Injection, when it comes back, this is what it looks like:

http://forums.pelicanparts.com/911-engine-rebuilding-forum/351025-mfi-fuel-pump-rebuilt-photos.html

The space cam in the pump matches the cam profile of the engine-- you should theoretically be able to tune the fuel curve of the 911T pump to match the Mod-solex grind, but this requires a lot of specialized knowledge. See here: http://forums.pelicanparts.com/porsche-911-technical-forum/386414-mfi-pump-open-heart-surgery.html

Heads? Can be rebuilt by a number of sources. For street driving, you're probably OK with the existing ports, although you may want to consider taking them out to "E" spec. It's easy to overkill the ports and kill the gas speed-- and CNC porting can easily consume your entire budget. Extreme hardcore head porn!!! - Early 911S Registry Bulletin Board

Well that should get you started and give you a sense of the information available here. How about some photos of the car and the engine? Good luck!