What have they done to my engine?
 

Some years ago I bought a nice US spec ´77 911S which unfortunately came without any papers or documentation. Through some amateur detective work, but mostly luck I have stumbled across the former owner and he had a pile of invoices from the owner before him. This is great news for me, since I like to know the basis of an engine before optimizing it (long term plan).

The invoices indicates an owner who has not worked on the car himself, but used three different garages for any small issue that has occurred. I guess that is a good thing. Most of the invoices are legible, but the biggest and most important for me is hard to decipher. It seems like it has gotten a new engine case, rod (possibly plural), something about piston, machine cylinder head, replace valve seals, and something about original valve (see 2nd paragraph)?

I would love to read words like time certs, but I do not find anything indicatingt that. Would not that be a common upgrade in 1999?

I know that these engines love to pull the threads on the head studs, especially the US models with the hopeless thermal reactors, but would´nt it be over the top to replace the whole case for that?

Are there any other possible incidents that can be read from this elusive invoice?


http://forums.pelicanparts.com/uploa...1590874927.jpg

Two things scare me about this invoice...

1. "Replace Case"
2. "John's Automotive" ... this name does not instill confidence. Can you look them up?

Morini,
That work was done 20 years ago. If the engine runs fine I wouldn't be worried at all.

Your concern around pulled studs is likely unfounded as the crankcase has probably been replaced with an aluminum one, not another magnesium one. What I would suggest you do is have a look at the crankcase casting number located just below the oil return tubes and post that number here so someone can confirm if your crankcase is a 2.7 or from a later car.

You can see the casting number I'm referring to here:

https://i.imgur.com/ISCOa2g.jpg

Cust supply back-up light switch
install switch $35

"Replace engine case + rod + main and _______
Machine cylinder head & replace valve seals + original valve

Replace sound insulation N/C
Replace rear sunroof seal $50
Cl. oil level gauge $35

My guess is that it threw a rod, blew a hole in the case, and had to have a cylinder replaced.
Whatever that means.

Agree with Sugarwood, though I know what a rod getting loose does from experience.

The single biggest expense is some $3,500 for a new case. The mag 2.7 case can't be replaced with the aluminum 3.0 case - the cylinder spigot and head stud spacings are different.

The only aluminum case which could be used would be the very early sand cast case. You could get those (all used) for under $1,000 back then, though they were much in demand for race motors. So at a guess this was a replacement case from Porsche, assuming they still had some in stock 20 some years after production of those cases stopped.

A good used motor would have probably been a better deal - lots of 2.7s were being upgraded to 3.0 - as I did in the late '80s after I had a valve head fall off.

$700 some dollars for gaskets?

What is the serial number off the case? A replacement case may be marked as a replacement or have a different number. This number will be to the right of the fan on a vertical web. There should also be a case type number on a horizontal surface near the serial number. Format nnn/nn.

Duh. The picture just loaded saying this exact thing. "Just below the oil return tubes you'll find the case part numbers. That will tell whether it's a mag or aluminum case."
I agree with if it runs and drives great, don't worry.

Replacement cases do not have a serial number from the factory. There is a blank where the serial number would be next to the fan housing. If you have a magnesium case, the casting number, under the engine where the case halves bolt together, should end with 7R.

Thank you for deciphering this, guys. You should be working in intelligence:-)

I agree. "John´s Automotive" is not very confidence inspiring and there is no information to be found on the web. On the other hand; after decades of spending foolish money on old cars and motorbikes I have met overpriced idiots in "specialist workshops" and wizards in backyard garages. Let´s just hope John is one of the latter and knew his way around old 911s back in 1999.

The engine has different numbers on the fan housing and on the left valve cover. Where the engine number normally is stamped (on the right side under the fan housing) it is blank, indicating a replacement case:

http://forums.pelicanparts.com/uploa...1591087341.jpg
http://forums.pelicanparts.com/uploa...1591087341.jpg

So I guess that I have a replacement magnesium 2.7 case and that the engine had a con rod failure already at 68 thousand miles (!) in 1999. The latest odometer reading on the invoices is 78000 miles from 2002. After that it was changed to km/t and not driven very much.

The car runs strong, but coming from a fast Euro 3.2 I had initially thought of upping the compression and changing the cam. I guess I´ll wait until the engine needs a major overhaul. The engine already has Carrera chain tensioners, SSI headers/Dansk muffler, 11-blade fan and all thermal reactor stuff removed, so it has had the most needed updates at some time.

Even without front oil cooler I never manage to get the oil temperature over an indicated 210 on full throttle in hot weather. 10 minutes of cruising home and it is down to 170, so it seems healthy.

BTW: When changing from 5-blade to 11-blade fan is also the fan housing changed? (explaining the different engine numbers)

Neither one of those numbers are the ones you need to figure out the case. The first one is the cam tower number. You need the case part number like the one shown above

I went from 5 blade to 11 blade and did not change the fan housing. There are a couple of different diameter fans so you need to get the right size.

The cam towers have their own numbers as does the fan housing.

Can you just take a picture of the numbers on the side of the block where Peter M. suggested?

Yes I see that the last picture wound not upload. I believe this is where the engine case number should have been?
http://forums.pelicanparts.com/uploa...1591172466.jpg

I have been searching underneath the engine as Peter M suggested, but have so far not found any number. Maybe it is obstructed by the headers.

Look at the cylinders where they meet the case. Weeping is a possible sign of a head stud problem. Most people check for loose head studs during a valve adjustment. Do you know when the last adjustment was performed?

If you don't see weeping, I wouldn't worry. If you don't know when the valves were last adjusted, I'd get that done. Tight valve clearances can damage the exhaust valves.