Intermediate shaft bearing prematurely worn on a 964

[sam_james30]

Hi

I’ve been doing a top end rebuild of my 3.6L 964 engine. Unfortunately due to dropping a woodruff key into the crank case I’ve had ended up splitting the case to retrieve it, D’oh!

I was going to simple reseal the case although I’ve found that intermediate shaft bearing seem very worn:



Although the main bearings seem ok:



Any idea why the intermediate shaft would have warn out so long before the main bearings?

Thanks

Sam

[cgarr]

For some reason that bearing seems to go rather quickly on all these engines.

[dtw]

^ This. Pretty typical wear of all the engines I've been into over the last several years - including very healthy, low mile ones.

[nocarrier]

Has anyone considered having these bearings coated?

I was wondering if a coating would help, hold up, or not be worth it on these bearings.

[MBruns]

That's very common, I see this more on current engines with the pressure fed tensioners than I ever did with the early style. Race springs have an effect as well but those engines are apart at shorter intervals, as far as coatings go there is not enough clearance for any coating worth doing without grinding the I/S journals as the coatings are around .0004 in. thick per brg. I have not seen a failure just wear into the copper.

Mike Bruns JBRacing.com

[Flat6pac]

I know when I open an engine that the intermediates need changing..
Bruce

[sam_james30]

Hey

Thanks for the help guys. I'm shocked as I had never meant to open the case up thinking that all the bearing would last for a very long time.

I’m going to replace the intermediate shaft bearing and leave the rest. This project started with a simple tune up, then I found a few snapped head studs, then I ended up opening the case!!!!!!

One other quick question, I hope it’s related enough to tack on the end, I’m over in the UK and having trouble finding LiquiMoly engine assemble lube per Wayne book. Do you think this stuff will work as well:

GRAPHOGEN MOLY COMPOUND 125gm

Thanks again.

S

[Walt Fricke]

S - I suspect Graphogen will work, as will either of the two other compounds a quick click of the seller's website revealed. I use Torco assembly lube, and it has worked fine for me. I think this is like case sealants - there are several which work, and some builders, be they professional or just owners, get particularly attached to one or the other.

All they really have to do is stay put until the engine's oiling system does its thing.

I've generally had good results with a combination of a magnet on an extender and turning the motor this way and that on an engine stand to get it to disgorge the bits which have jumped into it. Though I never pull the Woodruf keys without stuffing a red rag or two into the opening. The left side is especially insidious in this regard, as it slopes inward.