1975 2.7 Main Bore.
 

Hello everybody. I am rebuilding a 1975 2.7 motor that Motor Meister did not do such a good job on. My machine shop called me today because they do not have the main bore specs and have had no luck finding them. If somebody could give me the main bore stock size or point me in the direction to find it, I would greatly appreciate it. Thanks in advance.

You R using the wrong machine shop!

I was tempted to say the same thing.

Truly, i do not mean to bad mouth who ever it is...But with Porsche there is a LOT of little **** to do on a 2.7 case
about 5 updates that i can rememebr
You NEED to be in a place VERSED in the P.deal..not a once in a life time
ON top of that I herd O.S> bearingins are hard to get now...AND you should have them in hand b4 doing the bore ! just common sense
you need new cyl studs
case savoors
oil mod
and some other options

Before proceeding any further, I highly recommend you locate a shop that actively works on Porsche engines. First step should be basic cleaning, inspection, and evaluation of the case BEFORE any machine work is done. You may be better off locating another case rather than proceed with the case you have, especially if you have significant trouble. I would be very hesitant to use a shop that doesn't have basic measurement info for a Porsche engine.

I also recommend you buy Wayne's engine rebuild book and read through that before getting any work done.

I had some 2.7 case machining done last year and had to source oversized bore / standard journal bearings. The shop I used politely and correctly asked to halt all work after initial inspection until those bearings could be located - and it took me 2 months to find them.

Hi guys, thanks for the advice. I've got the problem resolved and am able to proceed. I live in central Michigan so there are not that many Porches in my area (let alone machine shops that can service them). The motor I'm repairing has less than a mile or two on it after being rebuild and modified by Motor Meister. When MM rebuilt it, they cut the relief pockets too deep on the pistons to clear the oversize valves so when the owner put a load on it the first time, 5 of the 6 pistons blew holes through the reliefs. Since MM took 2 1/2 years and $18k to build the engine, the owner did not want to ship it back to them for warranty. MM did send him the proper 10:1 JE pistons the second time around and the owner installed them himself......incorrectly. The car would not start after the pistons installed so he ended up bringing the car to me. The no start problem was due to excessive internal drag on the engine. Long story short, teardown revield a multitude of problems from both MM and the owners "repair". I sent the the block to the machine shop to check everthing over and clean the block of metal chips and old piston pieces. I am very confident with the machine shop I use so I am not worried about their work. I will be going over everything they did when the block comes back to my shop and make sure everything is perfect during the reassembly.

I'm sure everyone is going to question my skills next. Don't worry about that, I read a book on auto repair once and I've even changed the oil on my Yugo. Just kidding. I am a Master Mechanic with many years of experience with cars from around the world, I even do diesels! I have my own very well equiped shop and I do all the work myself.

Thanks again for your input. I know these cars are special to you guys and I will reassemble this motor with love and passion and a degree of anal retentiveness that few shops in my area are willing to do. I take great pride in my work and I feel I sign my name on every job.

For any future Porsche machine shop work in Michigan you might want to talk with:

Craig [garrett@iserv.net]

Craig Garrett
5424 Greenboro Dr
Grand Rapids MI 49508

He has done work for many Porsche owners.
I am not affiliated with his business - just a satisfied customer.

Regards,

I will keep them in mind for the future. Thanks.

Has Craig Garrett changed his website, or business name? The website I knew about, namely, "www.G2Performanceshop dot com" doesn't work any more. Does he have a business phone number?

Thanks guys,

Yes...last year he was working from home...
616-532-74 two 4 ( I think this is it...)

Regards