rebuild 2.7 or buy used 3.0 -3.2

[Crashly]

It seems as if it is time to rebuild. My 77 2.7 has 125K and it still runs good but The exhaust valves have around 1/8" of play. I have found a local rebuilder that is highly recomended here on the board and he wants 4k for the complete rebuild of my 2.7 (does not include new P&C), which seems really fair considering he has over 50 years into rebuilding these motors. But here are the downsides to the 2.7. It has alusils & Magnesium case. Without buying new P&c's and doing a lot of maching of the block it will never have the longetivity of the 3.0. My real goal in this rebuild is to have a long lasting motor (200K miles). I do not know if my 2.7 after rebuild is capable of that type of mileage. From what I can gather what allows the 3.0 to go so long is the stifness of the alumnium case. It does not allow the case to flex and wear the center bores etc. So what do you guys think? Rebuild or replace

[Bobboloo]

Tough call. Depends on the condition of the used motor. You could buy the used 3.0/3.2 and then still be facing a rebuild down the road. All it takes is for one of those Dilivar head studs to break and then your back in the same boat.

All things being equal it usually costs an additional $1000 in machine work to rebuild the 2.7 over the costs of rebuilding a 3.0/3.2 due to the case. Now if you need to buy P+C's in your rebuild then they end up being closer to the same price because the 3.0/3.2 P=C's seem to run at least a $1000 more for a set than the 2.7P+C's . (You can still get new Mahle 2.7RS P+C's for about $2000).

I think I would rather have a fresh rebuilt 2.7 than a used 3.0/3.2 with a lot of miles.

I guess the important thing at this point to help you make a decision is more info. You need to know if your P+C's are past their service limit. If your oil was changed regularly then they are probably fine.

One more thing. I don't know where you are located but here in California if I was faced with this situation I would ditch the 2.7 only because in Cali you would have to rebuild the motor with it's original smog equipment. This means thermal reactors, smog pump and all. That would be an absolute deal breaker for me. You can update to a later motor with it's smog equipment but you can't update an older motor with newer smog equipment. Sounds crazy but it's the law.

A rebuilt 2.7 with a good cooling system will last a long time. longer than 200k miles. The key is controlling temperatures. A good front oil cooler with a fan is a must for a long life.

[Crashly]

I hear you on the possibility of rebuilding the 3.0. My car has the front fender oil cooler. I don't believe that it has the fan. I will have to add one. Part of me leans to-wards rebuilding the 2.7 in order to keep it a numbers matching car. I really wish I knew the history of the motor. I live in Southern Ca so the smog is going to be an issue. The car is currently registered in Texas and does not have any of the smog equipment on it. I know that it originally came from the Monterey area and that It did have the 5 blade and thermal reactors up until 115K or so. I have a hard time believing that the top end made it that far without a rebuild. Currently there is not a hint of smog equipment on it. The only smog sticker is one that is on the drivers door jamb area that says that it does not have a catalytic converter. I am hoping that the smog sniffers do not know old Porsche's when I go to get it smogged. Hopefully when I register it in Ca it will show as a federal smog case rather than a Ca smog, due to the fact of the current registration in Texas.

[DohertyCM]

I rebuilt mine, Love the motor. I really think the 2.7 got a bad rap from guys who did know how to take care of the heat problem.
But when i rebuilt mine I upgraded cams, pistons and replaced valve etc. She runs like a top now and pulls really hard.

The easy way is to upgrade to a 3.2, but then again you will have to rebuild it also, you would be wasting time not rebuilding it before you put it in.

So you are in the same rebuilding boat....just out more money..

[Grady Clay]

Crashley,

Before committing to any course of action, I would do some diagnostics. Carefully inspect the sump plate and cut the oil filter apart. Do a cranking compression test and a cylinder leak test. Determine the oil consumption (quarts/1K mi).

Armed with those numbers I would talk to lots of builders. You will get varying opinions and estimates. The Forum can help you sort them out. Be aware there are a few in the ‘business’ of low-balling an initial estimate, one I’m thinking of has the same initials as Mickey Mouse, classic ‘bate & switch and worse.

Does your ’77 already have the plumbing for a front cooler? If so, what kind of cooler? If not add that to your budget. You also want to make sure you end up with the 245 mm 11-blade fan turning 1.82:1 the crank speed (you should already have the large diameter (134 mm) crankshaft pulley.

$4000 just for the engine rebuild without touching the P&Cs sounds about right to slightly low. Prudence would dictate budgeting for a new set of ‘73RS P&Cs. It would be wise to be prepared to an additional $2-3000 if you find something unexpected.

I recommend you investigate all available 3.0SC and 3.2 Carrera engines currently available. Talk and research what it takes to make the conversion. Investigate the costs involved with rebuilding those engines. It might turn out that, once disassembled, you may change your mind and decide on a later engine.

Regarding your Texas emissions. If this was originally a “California emissions” car, the numbers (VIN & engine) will reflect that. If you can pass emissions in Texas somewhere, do so and save the certificate.

A dead giveaway will be if the attachment points for the air pump look like it has been removed, the double pulley half on the fan, the opening in the rear tin and the rubber support for the pump. There are others.

I assume you have standard ’74 heat exchangers and muffler.

It might be useful to try and run your ’77 through a CARB inspection before you make a final decision. It probably won’t pass the tail pipe tests but you want to see what is said about the visual inspection.

Best,
Grady

[Crashly]

The hot compression numbers were in the 120-135 range. I do not know the oil consumption numbers as I just bought it. It has been sitting in a backyard for the last few years. My friend that owned it was deployed overseas and so It sat a long time without running. I only paid 5K for it and I was able to get it running with only a little bit of work. I did a cold leak down test and three of the cylinders were very dismal, in the 70% range. But this was probably due to a lot of carbon being on the exhaust valves. The car was stored about 1 mile from the ocean in very humid air which allows the carbon to flake off. The car starts and runs good however when I removed the exhaust springs to find the source of a clacking valve I found that the valve had around 1/8" of side to side movement vs the intake valves had almost no movement. The exhaust valve guide seals were also 100% destroyed and all that was left was the metal keeper that wraps around the valve all of the rubber was destroyed. I was hoping to get by with just a top end but from what I hear the 2.7 is doomed to pull a stud after you rebuild the top end, because of the fact that the studs have been disturbed. So far I can not find any evidence of time certs or case savers being installed. Basically all of the indicators point to the fact that at a minium the top end needs freshened up. I wish I knew the oil consumption numbers, but I dont. I was fortunate enough to find a rebuilder here in southern CA that is highly recomended and it is not Motor Miester. Tommorow I am going to drop by his shop and make the final arrangements to have him rebuild it. His over the phone quote was between 3600 and 4000. That would include a 1 year unlimited mileage warranty. He is from the old school and will probably be using oversize bearings. As far as I can tell that is ok. On my motor I already have the 11 blade fan and the front wheel oil cooler. The exhaust is a set of SSI's that originally came off of my 2.2 a few years ago. I know that the car had the thermal reactors to around 115K at which time they were removed and the eleven blade and oil coolere were added.