need help in buying 2.7S longblock 6340303

[bob tilton]

hey guys - i need some help in buying this engine. i have asked all the questions i could think of and the seller has provided even more answers to questions that i didn't think to ask. he has been very stand up guy and i have appreciated his patience and honesty with me in moving forward with this deal.

the longblock that i am going to buy is "somebody's finished project". it is a recently rebuilt 74 2.7S ,175 HP, longblock with approx 5K miles. the engine was rebuilt to CIS specs. it had all the appropriate updates as a complete engine except for the turbo valve covers (which i have) and the price is right. i will be using my 40 IDA webers.

my questions:

1 can anyone please confirm the serial number 6340303 (901.101.101.7R)?
2 leakdown test on cold engine less than 15% on all cylinders, acceptable?
3 one of the heads has a chipped off guide tube from when the new guides were pressed in(common occurance), problem?

4 magnet test done to confirm steel studs, what brand would these be?

again - i feel good about the transaction, i am just seeking a few answers from folks that are much more knowledgeable than myself, which isn't saying much .

thanks for your help in advance.

[Jeff Alton]

The serial number is from a 74 USA/CDN market carrera. I would be worried about that head though.

Jeff

[Wayne 962]

Yes, that head looks bad to me. If I were rebuilding the engine, I wouldn't have used it at all. This means:

1- the head was cracked post-install (BAD)
2- the head was cracked and the rebuilder decided to use it anyways (VERY BAD).

Who knows what other shortcuts the rebuilder took on this engine, if they thought that this guide boss was okay?

Get the Engine Book - there are lots of questions to ask in there - it will help you make an informed decision, instead of just guessing...

-Wayne

[andyjboy]

Bob - that's a type 911/93 engine - probably one of the least desirable starting points for a performance 911 engine.

What are your plans for it ?

If you're contemplating a 2.7RS spec or 2.5 L short-stroke engine then (unless it's very cheap) there are better starting points...

[Scott Clarke]

Bob-
I noticed in the ad that the case did not have case savers installed. I'd be nervous about this. You can get away without them with biral or iron cylinders, but there is a much higher risk of pulled studs with alusil/nikasil cylinders.
-Scott

[Wayne 962]

Originally posted by andyjboy
Bob - that's a type 911/93 engine - probably one of the least desirable starting points for a performance 911 engine.

I disagree completely. The 1974 2.7S engine is indeed what I recommend as the best engine to start with for making an RS-spec engine. It's what I rebuilt for the book. You can also use an early aluminum case (up to 1968 1/2), but there's a large cost in upgrading the rest of the parts and machining the case.

My guess is that your statement's scope is including the later displacement engines (3.0 and larger) - an unfair comparison, since you can't easily build a displacement less than 3.0.

Why do I recommend this? First of all, the 1974 2.7 case is a 7R case. It has the 11-blade flat fan. It didn't run with those nasty thermal reactors that caused the engine to be thermally stressed.

You can't make a lower displacement engine (2.9 or less) with a 3.0 case easily (the exception being the Euro Carrera case or by using a 962 crank). If you're looking to build an engine with displacement less than 3.0, I suggest that you indeed start with one of these 1974 blocks. In addition, the heads have larger ports as well. If you use an early case (1973 and earlier), then you have to machine the spigots, and the cases themselves are not as strong as the 7R cases.

-Wayne

[911SCfanatic]

Wayne, I was thinking that the 2.7 76/77 Euro cases are even a better starting point. First, they have the spigots you want and the oil bypass mod. Second, they didn't use thermal reactors. What do you think?

[andyjboy]

I meant that the barrels/pistons, cams, crank (if building a 2.5 L), induction system, etc will all be discarded...

[bob tilton]

thanks for the input guys. i will provide the seller with the new info.

[James Renfroe]

Concerning the valve guide boss, is this the intake side of the exhaust? I personally would use this head if all else looked good and this was the intake side. If it was the exhaust side, I still consider using it but I would probably dissassemble the head remove the guide (By someone who really knows how to do it right) and have damaged area ground smooth and stress relieved. ld sure have it inspected for residual cracks after the stress work. Looking at this head makes me wonder if the builder used the appropriate heating technique on the ports before installing the guides. I've read some where that you shouldn't just press in porsche valve guides, don't know if this was the case.

[Jim Richards]

Originally posted by Wayne at Pelican Parts
If you use an early case (1973 and earlier), then you have to machine the spigots, and the cases themselves are not as strong as the 7R cases.

-Wayne

FYI Bob, 7R cases were available starting in 1973, but Wayne's correct on the part about machining the spigots for a 73 and earlier case.

[Wayne 962]

Originally posted by 911SCfanatic
Wayne, I was thinking that the 2.7 76/77 Euro cases are even a better starting point. First, they have the spigots you want and the oil bypass mod. Second, they didn't use thermal reactors. What do you think?

Hmm, that is correct, but those motors don't show up in the states often, and an oil by-pass mod attached to a 1974 case would be functionally equivalent.

Good thinking though...

-Wayne