03 BLACKOUTSSS

iTrader: (3)

2 in 1000 miles to be specific. Here is some background. 427 built by a "professional". I don't know much of the details, its my fathers engine. I do know that at around 400 miles, it developed a tick, which quickly progressed into a knock. Drained the oil, metal EVERYWHERE! Pulled the cam, the very rear lobe (exhaust on #8, IIRC), cam lobe had serious wear as well as the lifter, which was ground down about 3/16". The cam that was installed was kind that required the zinc additive, if that means anything to anyone.

Second cam goes in, lifter replaced, same specs, same everything, same situation. About 400 miles in, metal all over the oil and same lifter / lobe grinding issue.

All pushrods were checked and correct, its a hydraulic flat tappet setup, the only thing that hasn't been checked yet is the integrity of the valve springs.

Anyone have any insight into what is happening and how to fix it?


Before the suggestions to take it back to the builder, thats not an option. Ive already told him to do that, but the motor is in a 69 Vette that was just painted. He won't send the car to the builder and risk it getting scratched.

blown 04

iTrader: (1)

are you running the engine between 2000-3000 for a while at first start up? you said your using the zinc additive right, i also like to use shell rotella 15-40 in the begining.
how about the valve springs, are they really heavy on seat pressure?

probuilder1

iTrader: (6)

My only guess would be the valve spring since everything else has been changed.

silverz28camaro

iTrader: (20)

Regular oil now days is crap...even diesel oil is better with more zinc additive to prevent wear. Zinc is only bad or 02 sensors and catalytic converters. thats why oil doesn't not have it now....all emmsissions reasons.

Also as stated above run the engine at higher rpms when first started. The high rpms will help oil the cam lobes.

If the motor was built with high performance springs and higher ratio roller ockers that puts more load and wear on the flat tappet lifters and cam lobes.

If it were me and I was spending the money to have ANY motor built I would go with a roller converstion cam. this helps eliminate any cam lobe wear issues.

silverz28camaro

iTrader: (20)

I would also like to know what are the cam specs and what ratio the rockers are. And what EXACT oil are you using?

03 BLACKOUTSSS

iTrader: (3)

break in was done as per builder instructions.
regular oil and zinc additive.
not sure where the rpms are at.
valve springs are dual, kinda high pressures because of the high lift cam.
rocker arms are stock ratio.
full roller conversion is in the works, with the second cam being smoked already.

silverz28camaro

iTrader: (20)

Roller cams are the best, you can go with less duration and more lift and get better street manners from it. Good luck man!

schino

iTrader: (14)

sucks to hear, my cousin was having similar problems with his big block, it ended up blowing a hole through one of the pistons i guess from running lean? hopefully roller setup will solve your problems

1Bear

iTrader: (1)

It’s hard to say what you have going on here, shy of tearing into and figuring it out. By the design of the oiling system of the Mark IV style engines, oil moves up behind the rear cam bearing via an annulus groove on the ’67 and later blocks, while the ‘65/’66 models used a cam with a grooved rear journal and no. 5 cam bearing with additional oiling holes. You can use a cam designed for ‘65/’66 models in a newer block without any issues, as the newer style cam bearings will essentially seal off the groove in the cam, but you cannot do the reverse by installing a newer style cam in an older block without machining the rear journal for the groove or you will starve the lifters and top end. I highly doubt your builder would have miss-matched components here, as getting the older parts is not exactly commonplace anymore and the fact that you appear to only have issues with bearing and one lifter. The oil galley feeding the lifters shouldn’t be plugged, as the oil passes from the rear towards the front, so if the galley was plugged it would effect all the lifters on the bank that was plugged. The reason your builder is suggesting a zinc additive is due to the newer shelf oils being restricted in the amount of zinc and phosphorous that new oils can have in emissions applications. This reduces the amount of protection you have, especially during break-in when the components are running at an higher temperature. One last thing, not knowing your cam spec’s, but taking into consideration that you said “high lift cam and dual valve-springs", I would recommend that you remove the inner valve-springs during break-in to lessen the pressure on the cam and lifters. Replace the inner springs after break-in and before you test out what a healthy 427 can do. Whatever the case, throwing cams and lifters at it won’t make the problem go away and you will probably end up with more scratches to the paint leaning over the fenders doing the job over and over again.

Even after break-in, I would continue to use either a zinc additive or an alternative oil designed for performance applications.

Suburbazine

Since your application is calling for an oil with zinc or zinc replacement, I would recommend using Pentosin in your application. We use this oil in cars that require zinc or matching properties in the oil. (it's expensive though)

Other than that, the other fellers in here have already given out all the good pointers.