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Internal Disaster

8K views 6 replies 6 participants last post by  JJU9507 
#1 ·
A few years ago, we built a 460 for a Cobra replica using mostly Kaase furnished parts. We used the internally balanced stock crank, .010 under, locally ground and balanced, Kaase provided Comp cam and lifters, P51 heads, valves and springs, roller rockers, H beam rods, Kaase provided .030 over Diamond pistons and rings, locally bored, Mallory distributor, roller timing chain and sprockets. Standard oil pump with a Milodon pan.

The engine ran very well but had a few problems. We never got the rings to seat or the valve guides were passing a lot of oil as it would consume a quart about every 500 miles.

It also had a very strange issue with the distributor stability. At exactly 3000 rpm, the timing would go all over the map. We finally wired the advance weights closed and handled the advance by electronic means. I posted this issue to the forum then, but never got an answer.

In all other respects, it ran really well, lots and lots of power.

A recent visit to the sports car track was fun, but when we finished, the engine would not hold oil pressure at idle and a lifter was ticking. Uh Oh.

Teardown found lots and lots of ferrous debris everywhere. Load halves of the main and rod bearings were into the copper, with signs of scoring almost on every other engine part.

The real mystery is the crankshaft AND camshaft thrust bearings showed disastrous wear. The crank thrust faces are ruined on the rear face, and one side (cannot remember which at the moment) of the cam thrust plate (Kaase part) was worn well over .050". The top compression rings appear totally worn out.

We suspect that we lost oil pressure in the turns of the track and did not realize it and this might explain how things started to go bad, but we have not a clue why these thrust areas saw so much trauma.

I feel sure I left out some critical piece of information, but maybe you can help us with what I have provided so far.

Thanks in advance.

Harry
 
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#3 ·
Harry built this engine for me. The car has a Tremec tko600 tranny and we used the plain (non-roller) Danny Bee bronze cam thrust plate with a Comp roller cam. The cam end play checked fine at engine build. After we locked out the mechanical advance in the distributor the vibrations broke off the stops, so we removed the springs and weights and welded the advance mechanism at zero advance. The distributor has worked fine ever since. The bronze drive gear shows normal wear. The oil pump is a Ford Performance high volume pump with heavy duty drive shaft. The engine had 12k miles at failure.

Bruce
 
#5 ·
I retired from Continental out of CLE in 08. Wow, has it really been that long. My machinist/engine builder hasn't really gotten into it to figure out what's up. And, it's too hot here in southern NM to reinstall it, so he has it on the back burner for now. I'll post what we find, when we find it. We definitely need a crank, lifters, bearings and rings. If we turn out to need much work on the rods, I may just go for a forged stroker kit. Too much is never enough, right?

Bruce
 
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