Locost82
|
 posted on 17/8/05 at 08:01 AM |
|
|
Cam followers and Crank end float!
Quick overview
1 of my 8 cam followers has worn away to around half it's original length and destroyed the cam in the process! NICE!
I'm replacing the cam in the engine and noticed considerable end float in the CRANKSHAFT, around 1/8th inch. This is obviously outside the
design tolerance. Does anybody know whether the wearing away of the cam follower could have led to the destruction of the crank spacer, or are the 2
unlikely to be linked? I was thinking of contaminated oil.
|
|
|
|
|
James
|
| posted on 17/8/05 at 08:12 AM |
|
|
What engine?
Cheers,
James
------------------------------------------------------------------------------------------------------------
"The fight is won or lost far away from witnesses, behind the lines, in the gym and out there on the road, long before I dance under those lights."
- Muhammad Ali
|
|
|
Locost82
|
| posted on 17/8/05 at 08:32 AM |
|
|
Good point!
1300 x-flow Locost Racing engine.
It's gone from minor to major endfloat in about 10 races.
|
|
|
viatron
|
| posted on 17/8/05 at 09:49 AM |
|
|
When you say half its length i take it you mean from the end that the pushrod sits it? In which case i would check the rocker on that follower, cant
remeber ever seeing one wear on its length, they normally wear on the od of the follower or wreck the bore that the follower sits in.
Mac
|
|
|
MikeRJ
|
| posted on 17/8/05 at 10:49 AM |
|
|
quote:
Originally posted by Locost82
I'm replacing the cam in the engine and noticed considerable end float in the CRANKSHAFT, around 1/8th inch. This is obviously outside the
design tolerance. Does anybody know whether the wearing away of the cam follower could have led to the destruction of the crank spacer, or are the 2
unlikely to be linked? I was thinking of contaminated oil.
I suppose it's possible, but unlikely IME. The crank thrusts are only under any serious pressure when you have you foot on the clutch, as if
they have worn that badly from contaminated oil, the rest of the engine is almost certainly scrap metal.
One possibility is that one or more of crank thrusts were fitted backwards. This means a steel-steel bearing surface, and will very rapidly score the
thrust face on the crank. I've seen this happen several times, and the crank is nearly always scrap.
|
|
|
Bob C
|
| posted on 17/8/05 at 11:24 AM |
|
|
My mate's chevanne had this much crank movement when he pressed the clutch.
Amazingly, he drove it for years without any trouble.......
Bob
|
|
|
Locost82
|
| posted on 17/8/05 at 11:32 AM |
|
|
Viatron, the cam follower has worn from the cam end. The mushroom part of the follower is no longer there!
Bob C, I removed and replaced the thrush washers when I rebuilt the engine over the winter, looks like that could be the culprit!!! Out of interest
is there an easy way to make sure they're fitted the correct way round?
|
|
|
Locost82
|
 posted on 18/8/05 at 08:45 AM |
|
|
DISASTER
It was the thrust washer. Appears to have been thrown out and did a quick lap of the engine, destroying the cam follower, before depositing itself in
the sump. Result: new cam and followers, new crank, less fun money in the bank.
Bugger!!!
|
|
|
Nitroustoy
|
| posted on 18/8/05 at 12:06 PM |
|
|
Locost82,
Thrust washers are fitted with the steel back against the block and cap, the bearing surface goes against the crank.
Make sure all four are the correct way round oil grooves too crank.
|
|
|
