any ideas please?

[martinsaunders06]

whilst driving to a show on saturday my LDT 465 1C motor started to make a strange squeak type noise from the rear upper end of the rear cyl head. On removing the rocker cover it turned out that the oil feed to lube the rocker assembly was minimal and the noise was one push running dry of oil in the rocker ball socket and squeaking. we stripped the complete rocker shaft to check for restictions and it was ok. The actual oil pressure is ok at 60psi hot at 1200rpm and the front cyl head/ valve/rockers is being lubed perfect= its just the rear rocker gear that is dry.?.does anyone have any ideas as to why the oil flow to the rear head/rockers is being resticted when rest of engine is fine. The oil has been changed regular and there appear to be no build of carbonised oil deposits within engine?
many thanks martin

 

[NDT]

Must be a plugged passage thru the block or head. I would pressurize the oil gallery with compressed air with the engine off and rocker shaft removed, and see if you can force a wire down the passage and dislodge the blockage.

 

[martinsaunders06]

thanks for your reply, i blew thro the oil galleries with air and not sure but it may be slightly better but i did notice that the surface area of the cyl head below the rocker posts was certainly awash/wet with oil as if the oil flow was leaking around the rocker posts before it had time to get up into rocker shaft. The rocker posts do appear to have a mark/scribe type line thro their centers = is possible they are cracked?.Has anyone ever known rocker posts to crack and cause this sort of fault??
many thanks martin