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Posted: Thu Aug 11, 2011 9:44 am
by plastic orange
Tax is free for my minor as it's a historic vehicle
I've tried replacing rockers - I've got 3 good sets - one as new, but it's made no difference, so I'm now at a loss. It will tick over all day sounding quiet, but rev it hard and it sounds like a bag of nails. The noise comes and goes, so I guess it is an oiling problem of some sort, but gauge doesn't indicate anything untoward - and I've tried another gauge too.
Pete
Posted: Thu Aug 11, 2011 7:26 pm
by v8rob
That sounds like lifter pump up to me and a valve is hitting a piston, what cam and valve springs are you running?
Posted: Thu Aug 11, 2011 7:41 pm
by Opel-V8
3 good sets, just send one set to Denmark.
Regarding oil pressure, how much should it lie on with warm, and cold engine, in psi or bar?
Posted: Thu Aug 11, 2011 8:12 pm
by Opel-V8
It doesnt sound implausible, but I got it not when the engine gets some rpm. only when the engine was hot.
but the last few days i havent heard the sound, weird.
But perhaps in Pete case.
But when I think about it, if a lifter is pumped over then the valve can of course not close completely again.
it should not couldt happen? or may it?
Posted: Thu Aug 11, 2011 9:22 pm
by plastic orange
v8rob wrote:That sounds like lifter pump up to me and a valve is hitting a piston, what cam and valve springs are you running?
I just changed from a standard cam to a hurricane cam a short while ago. Heads were off a while back for new head gaskets, valves and stock springs - no sign of anything untoward. I fitted composites instead of tins and skimmed 25 thou off to compensate. Tick was there before and after.
Pete
Posted: Sun Aug 14, 2011 7:51 pm
by v8rob
plastic orange wrote:v8rob wrote:That sounds like lifter pump up to me and a valve is hitting a piston, what cam and valve springs are you running?
I just changed from a standard cam to a hurricane cam a short while ago. Heads were off a while back for new head gaskets, valves and stock springs - no sign of anything untoward. I fitted composites instead of tins and skimmed 25 thou off to compensate. Tick was there before and after.
Pete
Just out of interest what kind of rpm are we talking here? much over 5500 on stock springs you will be getting into valve float problems allowing the lifters to pump up, maybe worth doing a test reving your engine to set rpms, and see where the ticking starts?
Posted: Sun Aug 14, 2011 7:56 pm
by v8rob
Opel-V8 wrote:It doesnt sound implausible, but I got it not when the engine gets some rpm. only when the engine was hot.
but the last few days i havent heard the sound, weird.
But perhaps in Pete case.
But when I think about it, if a lifter is pumped over then the valve can of course not close completely again.
it should not couldt happen? or may it?
Your right the valve wont close properly if the lifter has (pumped up), depending on how you set your pre-load on the lifter determines how much (pump up you can get), if i am building a fast road/track/race engine i will only put a max of 20thou preload on the motor, stock road engines can take much more as lifter pump should not really happen, but if you have 60thou pre load, and the oil pressure is over coming valve springs you suddenly have a cam with a 100thou more lift than you had before!