Splitting Case Question

[arbita1]

If I was to split the case. And assuming for the moment that everything inside was in good condition. Could I get away with simply resealing and new rod bolts/nuts? Or does more stuff have to be replaced regardless of condition?

[Flat6pac]

Look at the bearings, they tell the story. If the mains are clear of dirt scratches so the rods will be also. If you look at some of my engines I explain opening the case to see whats there and the condition as part of doing the top end and studs.
I usually change the intermediate shaft bearings, the chain ramps and all the seals. When I move the bearings I mark them exactly where they go, right and left, 2 through 7. Thats exactly where they go back to after case cleaning.
Rod bolts are holding, why change them but if you are spending the money for the bolts you might as well do the rod bearings..but then why stop there....

Bruce

[earossi]

I am where you are today. I split the case last night and found that everything in the "tomb" APPEARS to be fine. Obviously, I need to pull the crank and have it fully inspected. But, assuming that everything is fine, there are a number of parts that need to be replaced. At the very least are all the seals that are affected when you choose to split the case. These include the crank, rear main, seals for the oil pump, and any other seals that are "dislodged" when you elect to split the case.

Also, when you split the case and inspect all the bearings...,.....do you elect to go back with the original bearings which are OK upon inspection?

So, for me, even though the tomb seemed to be fine, I have elected to replace all the bearings involved, simply because coating at this stage is not that big an issue and since to be safe versus sorry, you need to elect replacing the existing seals.

[Walt Fricke]

The only seals you really have to replace are the little O rings which go on the case through bolts. Some, if not all, of these get squished on installation. I've saved a few which looked more or less OK in case some day I don't have enough new ones on hand (I bought a package of a hundred or so a few years ago, but I've been into my motors a couple of times since).

Everyone likes to replace the seals at both ends of the crank. Both can be replaced without opening up the motor, but the flywheel seal calls for pulling the motor and flywheel, so not easy. The #8 bearing seal can be replaced without pulliing the motor, so there is less risk taking a chance that the old one, if not leaking, will do fine.

The oil pump and oil cooler seals do not need replacing unless they are hard and brittle. I've reused these several times on one or the other of my motors. They are captured, so they aren't going anywhere. I've not seen them lose their length, so on reinstall they will be compressed again.

Bearings are a tough one - I have several bags of "good used" ones, but can never find it in my heart or wallet not to put in new ones. I've got a new motor which may need to be disassembled entirely with only some dyno time on it, and I'd be very inclined to leave those alone. I just took apart a 100+ hour race motor. Bearings were so good I marked each as to where it went, just in case. I've been thinking to contact the coating places to see if they will coat a used bearing. Then I bought new bearings. One more bag of old bearings in the collection.

Maybe I ought to start replaciing chain ramps. I've busted a few old ones when prying them off - the clips on the one pin seem to get brittle. Broke an old one putting it on as well. Never had one fail in the motor (but see the post from a guy who found one of the pins holding the chain housing ramp in place in his crank sump). Amazing.

[afterburn 549]

Minimum Depends on time and miles.. (and your compulsive disorders LOL)
Engine Bay detail At least!
At a 100000 I would think new chains , sprockets and ramps .Depending on which engine it is there. Some modification ought to be addressed "while there" (Esp 2.7 cases )
Also
Clutch disk?
T/O Bng?
Cams deserve inspection
Crankshaft polished?

[arbita1]

Thanks all.

Bruce...that is a great idea to check the main bearing to determine the condition of the rod bearings. This way I wouldn't have to take them apart.

This engine had 205k miles on it. So I don't know how realistic I'm being. Maybe just hopeful. However, I'm sure ive read a bunch of times here before where someone split the case only to find everything was still on great shape.

[afterburn 549]

Why R U considering spiting it then ? (if nothing is amiss )

[Packet82]

If the bearings have 205k on them, replace them regardless. They're not terribly expensive and it's worth the peace of mind. You should probably have the case cleaned and the oil squirters cleaned out while everything is apart. I'd also have the crank polished and magnafluxed just to make sure there aren't any hairline cracks that may be a problem.

I don't know if you can get away without having the rods machined, but I had mine reconditioned and balanced while it was apart.

[Sboxin]

Well....I have to say something about opening the case...

In a 1992 964 w/115K we found the main bearings are OK, but had a #5 rod bearing
starting to fail - photo below. The Intermediate shaft bearings were worn as others have said
happens most of the time and needed replacement.

We needed to micropolish and magnaflux the crank along with balancing the crank and rods and pistons. The rods were also reconditioned and big hole recut. ARP rod bolts were installed.

IMHO...all used engines are unique situations...just sayin'

Regards,

[Packet82]

Here's what mine looked like:



142k on it. Needed all new bearings. Crank was scratched and ended up needing to be replaced. Some PO apparently decided never to change the oil. I ended up having to have the cams and rocker arms redone as a result too.

At 205k it's well worth splitting the case and doing a bottom end overhaul. You might find it in better condition, but I wouldn't be expecting it.