02/02/10
Problem: A 265 Chrysler modified engine build had been fitted and the mechanic reported noisy roller rockers at start up.
The engine had a medium performance hydraulic cam and roller rockers, good springs and pre-loads had been checked.
Camshaft bump was detected in the diagnosis so a thrust button was installed into the front cover.
The next issue that we had was a broken distributor gear some 300 kms later.
I rang for assistance and the advice was that these nylon gears are reliable. The gear had split, another distributor went in and the engine then came to us with low oil pressure. Our gauge measured less that 10 psi at idle and would not go above 25psi at 2500 RPM.
Cause:
This engine had only done 600kms. The engine strip established that the broken gear had partially blocked the pick up pipe screen. Added to this were badly worn camshaft bearings at No. 2 & 3. A dry start with the new engine has been agreed to as the cause from start up, the owner has covered our costs and is chasing his mechanic for payment.
It has also been agreed to that the most probable cause for the broken distributor gear was a camshaft that was jumping around in very worn cam bearings.
Cure: New rod and cam bearings. More education for mechanics who operate without a master pressure gauge. The mechanic involved said that oil “came out when he removed the pressure switch” so he believed things were fine.
And the oil pressure is now 55psi at an idle speed of 750RPM
Hedley James