| Re: [GMCnet] Noisy Lifter [message #107719] |
Mon, 06 December 2010 19:45  |
Gary Casey
Messages: 448
Registered: September 2009
Karma:
|
Senior Member |
|
|
I guess before I got my shorts all twisted worrying about the worst, I would
verify that it is just a single lifter or a lot of them. Does it go "tick,
tick, tick" at idle (single lifter) or does it go "ticketty, ticketty ticketty"
(multiple lifters)? It is unlikely that low oil pressure will result in just a
single lifter leaking down just as it is unlikely that several lifters will fail
at the same time. I've never heard of a typical stuck lifter (one that goes
tick, tick tick and not bang, bang , bang) causing damage to the cam. The
impact caused by a stuck lifter is on the flat "heel" portion of the lobe where
the contact stress is very low. The part of the cam that sees the highest
stress is at the tip and that is not affected by the stuck lifter. Certainly a
single stuck lifter is something to think about fixing, but not something to
cause you to immediately tear things apart and spend lots of money. Sometimes
they even fix themselves - something to look forward to :-)
Gary Casey
From: Wayne Barratt
If it turns out to indeed be a lifter as your friends suspect, I would be first
concerned that your engines oil pressure is too low.
You may not hear it when the motor is cold , the oil is thicker and the pressure
higher, but as it warms up it may get noisier as the oil heats up and thins..
Low oil pressure at idle (less than 7 psi) will cause them to clatter, but as
the rpms rise they may quieten as the oil pressure rises to at least 35 to 40
psi @ 2,000 rpm.
Lifters can clatter through the plungers getting stuck due to dirt, or incorrect
manufacturing tollarences causing them to bleed down continuously.
If it is indeed the lifter, dont keep driving it like that or it will eventually
damage the lobe(s) on the camshaft.
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
