426 eating cams and camchains. need help.
Posted September 11, 2007 - 02:45 AM
Posted September 11, 2007 - 05:33 AM
What do you mean "waste"? Are the journals worn? If so, how much? Galled? How did the cam chain fail? What does the crank side cam gear look like? Maybe post up some pics of the failed parts to help us evaluate. I don't think too much oil in the bottom end would cause the clutch to not work properly...not enough, maybe. Can you 'splain how the clutch behaves? Also, how many miles or hours are on the rebuild and how did you repair the head damage?
Right off the top of my head I's say one of the oil passages is partially blocked. You need to get the oil, under pressure, to the head to give the journal bearings in the cam a film of oil to roll around in. If there's not enough pressure, you will get metal on metal contact. You also won't get enough oil volume up top to splash lubricate all the other parts. Could also be that if you changed the head or barrel that the oil passages in the head, gasket, and barrel, or barrel, gasket and case aren't properly alighned. Rare to get a manufacturing quality defect like that these days, but it can happen...
That's one thing yu really didn't have to worry about with pingers is cleaning the oil passages after machine work or motor damage...of course, you did have to worry about radiusing the edges of ports...
Posted September 11, 2007 - 08:00 AM
If the Cam Caps were incorrectly torqued previously then they may be distorted causing a too tight or too loose situation allowing the cams to deform the Head.
Exactlly what parts were replaced?
Posted September 11, 2007 - 08:47 AM
The original cylinder head had camshaft to cap clearance pretty much out of spec, and journals were worn. In а few riding hours after rebuild it seems to do the same thing with new head, also stretching the cam chain. Cam caps are torqued according to the manual. Checked oil pump - within specs.
My idea was that for some reason on high rpms oil is coming from the frame faster than it gets back from the lower end, causing an excessive oil level in lower end and emtying the oil tank. At some moment all oil gets into the crankcase causing a lack of oil supplied into the head. I think this is also a reason for a draggind clutch that does not disengage completly, but it works ok if I dont push bike hard, or let it idle for some time.
Posted September 14, 2007 - 09:59 PM