Has my engine been rebuilt? Can you guess the mileage?

[Tippy]

My '87 3.2L engine was supposedly rebuilt about 5 years ago (no documentation) when the turbo was added.

I know the engine had to at least had the top-end pulled down because of the flat-top pistons and one timing chain had been replaced.

After teardown, I was surprised at how good the main/rod bearings looked and the gears of the IMS and crankshaft's distributor drive gear.

Only one bearing for the IMS showed brass.

My question is this,

1) does it look like it was rebuilt within 5 years and
2) how many miles would you guess it has on it?

[euro911sc]

From what I have read and researched the rub showing on the IMS bearings is typical and happens in the break-in period. So I would not be too concerned about that. My 3.0 had about 90k and showed no wear on the distributor or IMS gears. I'm sure someone will chime in with a 'My 200k mile engine showed no wear...' kind of comment as well. I think if you do not have some kind of oiling issue or spun bearing you may be looking at normal

Keep in mind, I have only 1 engine under my belt so I'm mostly speaking from research I've done here and not personal experience.

Best regards,

Michael

[Tippy]

Originally Posted by euro911sc

From what I have read and researched the rub showing on the IMS bearings is typical and happens in the break-in period. So I would not be too concerned about that. My 3.0 had about 90k and showed no wear on the distributor or IMS gears. I'm sure someone will chime in with a 'My 200k mile engine showed no wear...' kind of comment as well. I think if you do not have some kind of oiling issue or spun bearing you may be looking at normal

Keep in mind, I have only 1 engine under my belt so I'm mostly speaking from research I've done here and not personal experience.

Best regards,

Michael

Thank Michael!

I assumed this motor, the way they are built, wont show much wear for many, many miles.

I figured it would be too hard to tell.....

[Flat6pac]

Intermediate shaft bearings ALWAYS show wear to the top from the tensioners pulling upward.
Take a main bearing and turn it over. If it has a Porsche 930 part # its probably from the factory build, If its not a 930 # its probably NOS which is the same items but not from Porsche.
Meaning someone has been there

[cgarr]

119751 on the bottom end.

[Tippy]

Originally Posted by Flat6pac

Intermediate shaft bearings ALWAYS show wear to the top from the tensioners pulling upward.
Take a main bearing and turn it over. If it has a Porsche 930 part # its probably from the factory build, If its not a 930 # its probably NOS which is the same items but not from Porsche.
Meaning someone has been there

Thanks, I will take a look later.

Originally Posted by cgarr

119751 on the bottom end.

Bottom end of what cgarr?

[otto in norway]

When I opened my engine, it looked pretty good, considering it was almost 30 years old, and never opened. It showed the copper on the intermediate bearing and main bearing at the flywheel, but all the other was in good shape. I opened it at 80 000 miles.
I guess the break-in can give you some wear on the intermediate shaft bearing...
Anyway, the main bearing are probably good for at least 160 000 miles. So once they are broken in, the wear will happen very slowly..!
a pic of my block:

[88911coupe]

I opened mine at 167k and the main bearings were still in spec(!). There was some wear on the IMS bearing, similar to what's seen above.

[Tippy]

Originally Posted by otto in norway

When I opened my engine, it looked pretty good, considering it was almost 30 years old, and never opened. It showed the copper on the intermediate bearing and main bearing at the flywheel, but all the other was in good shape. I opened it at 80 000 miles.

Some observations comparing mine to yours; my case is very bright, lustery silver inside, yours appears a little more grayish (could just be the oil used). My IMS gear is very bright, lustery silver compared to yours too, same as the case. The thrust bearing in mine shows no more wear than the other mains compared to yours.

Mine sounds like it may of actually been rebuilt before. Thanks Otto for the pics!

Originally Posted by 88911coupe

I opened mine at 167k and the main bearings were still in spec(!). There was some wear on the IMS bearing, similar to what's seen above.

Hmmh....well, I could see the mains being in spec but compared to Otto above, my insides appear shinier and more aluminumy, lustery, silver.

The wear shown on the IMS bearing is superficial, no lip had developed. But, who knows without documentation.......

[Tippy]

Ressurecting this thread.

My case did not have anything around the perimeter (sealant) between the halves.

I would assume this points to the cases have never been seperated?

[burgundyben]

Your case did have selant, you might not have spotted it but it was definately there.

[Tippy]

Originally Posted by burgundyben

Your case did have selant, you might not have spotted it but it was definately there.

Really? The factory uses sealant too?

It looked like nothing was there and in the picture the mating surfaces look clean to me.

[304065]

Factory 574 is laid down in an almost invisible layer. But it's there.

[Tippy]

Originally Posted by john_cramer

Factory 574 is laid down in an almost invisible layer. But it's there.

Ah I see.

[lindemans]

It is not uncommon that 3.2s still run very well beyond 150.000 mls.
My specialist however claims that almost without exeptions, engines with 125.000 mls. show substantial wear on its bearings (rods and crank). That is his experience from re-doing engines.
So any engine with that mileage showing flawless bearings is very likely rebuilt already.

My 3.2 is due next winter; I am anxious to see what it will look like in there.
It now has 150k on it and oil consumption is a bit on the rise. After a long period idle in traffic jam, it does produce a bit of smoke that reminds one of James Bond kind of features......

[Tippy]

Originally Posted by lindemans

My specialist however claims that almost without exeptions, engines with 125.000 mls. show substantial wear on its bearings (rods and crank). That is his experience from re-doing engines.
So any engine with that mileage showing flawless bearings is very likely rebuilt already.

Hmmm.............cant really get a good consensus one way or the other.

[lindemans]

On the other hand: your engine is what it is.

Is it very relevant whether that is due to a recent rebuild or not ?

After all, you need to do what needs to be done and can leave what can be left anyway....