911 SC 3.0 upgrade to short stroke 3.2 Questions

[jons911]

Hey all. First, a little background on the car.
- '79 911 SC
-chain tensioner upgrade
-stock head studs
-stock CIS
-80k miles
-daily driver

I'm coming up on what looks to be a significant portion of down time (most of the day free for a few months) and I'm thinking it would be a prime opportunity to do an engine rebuild. I have sourced a set of bored out and replated carrera 3.2 cylinders for the upgrade and would complement that with a new set of J&E pistons (98mm 9.5:1 CR).

My questions are:
-Is it possible to only replace the p/c's or do I need to open the case all the way
-If I don't have to open the case, should I anyway and just do a full rebuild
-As a diy job, what kind of price difference am I looking at between the two (I ran through the rebuild wizard on here and it came out to 4k on the nose for a full rebuild including the head stud upgrade and the full turbo valve cover upgrade)

My main concerns:
-I'm kind of on a budget, and as this is my first major work, I have to buy quite a bit of equipment and tools
-The car only has 80k miles, so would a full rebuild be an expensive gesture so to speak when it's not really necessary

While I don't really want to spend about $9k on a full rebuild (all in), I can and will if it is only a slight price increase over the p/c's install and if it's a terrible idea to not do the full thing when I'm already there.

Sorry for the long post, but I've done a lot of reading on this forum and other sites and I can't quite seem to find the answer I'm looking for. Any help is appreciated. Please feel free to ask any questions that might help clarify things for you.

[LakeCleElum]

Thoughts:
1) I have a 3.0 that has a high compression 3.2 kit in my 73.5 and LUV it....209 RWHP.
2) At 80K miles, no need to go into the bottom end, but
3) why even to a top end unless: A) Broken studs B) low compression C) Using oil at the rate of more than 1 Liter per/600 miles......
4) you should not have oil pressure issues since you don't have a Mag case engine.
5) I Luv my CIS......If working OK, keep it for best driveability and fuel mileage.....

Just cuz you have free time, doesn't mean you have to tear into it.......Cheers

[jons911]

That was a thought. I'm pretty confident that my head studs are fine. It's more that the one major upgrade I wanted to do on the car is move to a short stroke 3.2. I'm in the military, so I'm not exactly sure about when I will get the opportunity to do a rebuild in the next several years and I don't want to come up on needing to replace the head studs and not be able to afford the time. But if easy driving will take me to more like 120k miles before the studs become a problem, then I think you might be right and I'll just hold on to the parts and wait.

[LakeCleElum]

Jonathan - Understood.......For reference: I know my 2.4 had issues with oil pressure for several years.......I shopped hard and hoarded parts for several years to do a rebuild like you are talking......In the end; I found a great hot rod 3.2 for a good price and did a swap instead of a rebuild.

I've stored my 2.4 for the next owner and since sold all those parts at double for what I had paid....

Your engine is known to go for 300-400K w/o coming apart........Good luck sir.

[Trackrash]

The pistons and cylinders will fit. Make sure you get the pistons designed for the SC motor with the 22mm wrist pins.

With that few miles, and with good oil pressure, most would say no need to split the case. I would pull the rods out. You can that way evaluate the condition of the bearings and crank.

Definitely replace the head studs with steel.

Do a valve job.

You should go to the 911 Engine Rebuilding Forum there is a lot of good info there.

Do you have Wayne's book? It has most of the answers.

[jons911]

Gordon,
J&E has pistons specifically for the 3.0 in both 95 and 98mm with the 22mm wrist pins, so the pistons should fit without a problem. You would think after all the hours I've spent reading through threads I would remember that there was a dedicated forum for engine rebuilding. I found a thread on here talking about diagnosing broken studs and it seems that there should be at least one sign to tell when one has gone (the sound, visually checking each stud when the valve covers come off, or black buildup on the cylinder near the stud). I'll take this over to the engine rebuilding forum to see what they say, but I think you guys may be right and I should just wait for now.