Rebuilding Instructions....

[DMX]

What is the best way too add horspower when rebuilding a

2.7............ That's what a friend of mine wants to know.......

[MBAtarga]

This HAS to be a joke, right? A book on rebuilding a Porsche 911 engine? I don't think it exists

[RoninLB]

Originally posted by DMX

What is the best way too add horspower ......

your friend wouldn't be asking if he has plenty of bucks, IMO.. anyway, 2.7CIS pistons are beat after 100k miles, IMO.. so if he's going new pistons in a proper rebuild he could install RS pistons for a couple hundred extra and worry about the bucks HP later.. the RS pistons will be OK w/CIS.........Ron

[Wayne 962]

http://www.101projects.com/rebuild.htm

-Wayne

[IROC]

From a philosophical standpoint, the best way to add power when rebuilding a 2.7 is to swap in a newer motor. I'm doing this right now. From an economics standpoint, you'd have to throw alot of money at a 2.7 to even approach what a stock 3.2 does every day.

If there is an emotional attachment to the 2.7, I understand, but after thinking about this *alot*, I ended up going with a nice 3.2...

My two pfennig...

Mike

[Wayne 962]

Yes, but there are very few low-mileage, good 3.2s out there without any problems. Keep in mind that the 3.2s have the rod bolt problem, head stud problems, and the valve guide problems. So swapping in a tired 3.2 may cost you $7000 or more, and then you may find that you will have to rebuild it for another $8K or so in the very near future (total cost $15K). It is not black and white...

-Wayne

[IROC]

Actually, Wayne, I purchased the preview version of your book and was going to rebuild my 2.7 myself and then two things happened:

1. I saw the *realities* of what it was going to cost...and

2. I found a great 3.2 with 22k miles since full rebuild for less than what I could have built my beloved 2.7 for.....

From an "adding horsepower" standpoint, I found it prohibitively expensive to get alot out of my 2.7. Now I have a 3.2 with approximately 245hp for less than rebuilding my 2.7 to "stock" specs would have cost...

Point well taken, though.

Mike

[APKhaos]

What 3.2 rod bolt problem??

OK, granted there was a 1mm reduction in rod bolt dia between the 3.0 and the 3.2. Porsche engineering made that decision. For armchair engineers to call that a 'problem' is easy......but unfounded unless there is evidence of a good sample of failures. Watching this board, and Rennlist, I'm struggling to recall a reported case of 3.2 rod bolt failure in real life. There probably have been some, but nothing like the number or frequency that would justify the urban myth that this has become.

There are some things that ARE problems with various engine configurations, and plently of failure cases to support these as fact.
Not sure that there is much [any?] significant evidence of 3.2 rod bolt failure.

Caveat: I replaced my 3.2 rod bolts with Racewear [the myth lives!]

[ChrisBennet]

Tony,
Like a lot of Porsche problems, the 3.2 rod bolts probably get more attention than they deserve. As a "victim" of this problem myself I've looked into it a little. The problem might alsor be called the "spun bearing problem". The factory 3.2 rod bolts stretch and let the rod bearings get pounded out. When you try to find a good used STD/STD 3.2 crank you will get a better idea. IMO, the track guys are the ones who need to worry about this problem.
-Chris

[RickM]

I heard about the Valve guides and rod bolts but was unaware of a headstud problem on the 3.2. Can anyone shed light on this?

[speeder]

Rick, That would be the same headstud problem that SCs have, ie., they break. Same studs and case=same problem.

[Wayne 962]

Ha, obviously you haven't purchased my book yet, with the BIG UGLY picture of the 3.6 engine that self-destructed as a result of the rod bolt problem. $8000 down the tubes on that one. The rod bolts are a big problem, and you will weaken them if you over-rev the engine. The mere fact that you replaced your rod bolts with RaceWare bolts counters the fact that you say there is no problem?

IROC, as you may have read in my book, each and every rebuild is only as good as the person rebuilding it. Did the previous rebuilder:

- Use RaceWare rod bolts?
- Replace the Dilavar head studs?
- Have the valve guides replace (most likely)?

-Wayne