What would cause this
Discussion
In search of my slight single tick I discovered a rocker shaft pad with a very small and offset wear pattern. 
The one on the right. After approx 10000 milea
I took off the rocker and there is some wear in the bore. It was oily before I cleaned it up.
The shaft seems fine (very slight scratch but cant feel a ridge at all
Top of valve
Just ordered a new genuine LR rocker to fit to existing shaft
The one on the right. After approx 10000 milea
I took off the rocker and there is some wear in the bore. It was oily before I cleaned it up.
The shaft seems fine (very slight scratch but cant feel a ridge at all
Top of valve
Just ordered a new genuine LR rocker to fit to existing shaft
Edited by WokingWedger on Friday 17th March 16:35
Edited by WokingWedger on Friday 17th March 16:40
Edited by WokingWedger on Friday 17th March 19:12
Just a guess, but that pedastol looks like is been moving under load. If, for example that particular pedastol wasn't correctly torqued, it would allow it to 'walk' under load and cause those markings, it may also cause the outer-most rocker to act against the valve off square - causing the irregular wear pattern on the pad. The base of the adjacent pedastol is normal, so the issue can only be isolated to that particular shaft bolt.
All the pedestal bases look the same ( unlike the old spares I have). Looks to me as if they have been rough milled ( very rough) by the engine builder !
Could it be a poor seal between pedestal and head allowing oil to leak out before getting to the shaft and rocker ?
That may explain the rocker bore wear but what caused the poor contact patch at the valve stem, or could that be due to the wear in the rocker
Could it be a poor seal between pedestal and head allowing oil to leak out before getting to the shaft and rocker ?
That may explain the rocker bore wear but what caused the poor contact patch at the valve stem, or could that be due to the wear in the rocker
WokingWedger said:
...
???
They are all Aluminium !
Can't do much about position ! End of shaft !
http://www.powersperformance.co.uk/store/slug/stee...
Make of it what you will. He advised if you switch to steel change them all.
Perhaps check hydraulic lifter
My take is the pedestal base is so poor (because of walking?) that the rocker has had its oil supply rationed and given rise to the rocker bore wear at its bore load point as you see from pic 2. This added free play allows the rocker tip sideways giving that uneven contact with the valve.
fausTVR said:
My take is the pedestal base is so poor (because of walking?) that the rocker has had its oil supply rationed and given rise to the rocker bore wear at its bore load point as you see from pic 2. This added free play allows the rocker tip sideways giving that uneven contact with the valve.
I agree if the rocker wasn't getting its proper oil supply then that would cause wear and in turn perhaps explain the odd contact patch with the valve.Anybody seen this odd contact patch due to worn rockers before ?
I can't see how the pedestal can 'walk' anywhere, it's held by a great big bolt done up to 30lbft
The base of the pedestal is flat but it looks like it has been machined or scraped (as with done by scraper-old hand tool)
It is difficult to see if the top of the valve stem is flat.
Should I dress the valve top in anyway? I don't want to have to remove it and I don't want to go through the case hardening, so perhaps leave it and fit new rocker and check wear pattern after a few miles.
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