[Dante Garofani]

I have a couple of questions about two components on my engine. The engine was professionally rebuilt approximately 4k miles ago so all the parts are relatively new.

First: I recently replaced the lifters with Rhoad’s type. I primed, installed and set the lash to one half after reaching zero. Started the engine with the valve covers off to ensure oil flow through the push rods and all checked out fine. Ran the car on and off for a week to tune the carb and always heard the same noises - a racket of lifter noise on start-up that got better as things warmed-up.

The tough part about these lifters is not knowing what is normal “ticking” and what is abnormal lifter noise.

After two weeks I took the car down to the local strip and made some passes to finish off the carb tuning. On the final pass I heard a valve train sound that was way-off and a notably rough idle. I connected the vacuum gage and saw the needle bouncing the the “rhythm of the tick.” Pulled the valve cover off and found the #4 intake push rod end-ball mashed into the rod body and the companion exhaust rocker and one inch of push rod from the ball down blued from excessive heat. All lock nuts were right where I set them as I marked them against the stud.

Question: Is this a case of a collapsed lifter? What could overheat one rocker assembly?

Second: During said test period, I noticed a random spike on my tach which coincided with an engine miss. This was totally random and sometimes occurred in clusters and others just once or twice. I’m using the stock distributor with a Mallory Unlite retrofit. The coil is a Pertronics, all connections are clean and tight, all spark plugs, wires, cap & rotor replaced twice.

Question: Is this a case of spark scatter or too much vertical play in the distributor?

Thanks for any insight. The real frustration is I just got the nitrous installed and I can’t pull the trigger until I get these gremlins out of my engine.

[Dante Garofani]

I have a couple of questions about two components on my engine. The engine was professionally rebuilt approximately 4k miles ago so all the parts are relatively new.

First: I recently replaced the lifters with Rhoad’s type. I primed, installed and set the lash to one half after reaching zero. Started the engine with the valve covers off to ensure oil flow through the push rods and all checked out fine. Ran the car on and off for a week to tune the carb and always heard the same noises - a racket of lifter noise on start-up that got better as things warmed-up.

The tough part about these lifters is not knowing what is normal “ticking” and what is abnormal lifter noise.

After two weeks I took the car down to the local strip and made some passes to finish off the carb tuning. On the final pass I heard a valve train sound that was way-off and a notably rough idle. I connected the vacuum gage and saw the needle bouncing the the “rhythm of the tick.” Pulled the valve cover off and found the #4 intake push rod end-ball mashed into the rod body and the companion exhaust rocker and one inch of push rod from the ball down blued from excessive heat. All lock nuts were right where I set them as I marked them against the stud.

Question: Is this a case of a collapsed lifter? What could overheat one rocker assembly?

Second: During said test period, I noticed a random spike on my tach which coincided with an engine miss. This was totally random and sometimes occurred in clusters and others just once or twice. I’m using the stock distributor with a Mallory Unlite retrofit. The coil is a Pertronics, all connections are clean and tight, all spark plugs, wires, cap & rotor replaced twice.

Question: Is this a case of spark scatter or too much vertical play in the distributor?

Thanks for any insight. The real frustration is I just got the nitrous installed and I can’t pull the trigger until I get these gremlins out of my engine.

[PONTIAC DUDE]

I hope your not using "Stock" rockers?

[Injunjoe]

The bluing of the rocker and pushrod sound like an oiling problem. That is the only thing I could figure would get both of them. There is a possibility that the oil is getting up the pushrod but not into the socket where the rocker ball is running. I would closely inspect the rocker ball and see if there are signs of a lack of oil such as galling of the rocker ball. I am not positive but I would think that if there was enough heat to blue the rocker and 1 inch of the pushrod that there was extreme heat in that one rocker, and that heat has to originate somewhere and the best bet is in the rocker ball. If it is truly blue it is up around the 450-500 degree point. I had no problems running "Stock" rockers on my 455 at all, I ran them for about 3.5 years and one day ran across a good deal on the Comp roller tips and picked them up. When I pulled the factory rockers off the engine I could see no signs of over heating at all. Another question for you, can you see the valve stem, what condition is it in, is there any discoloration similar to the rocker and pushrod? Could this be due to guide friction?

[ May 20, 2002, 12:14 AM: Message edited by: Injunjoe ]

[Dante Garofani]

PDude, They're not stock rockers. 7/16 BBC studs, CompCams magnum roller tips, and CompCams push rods.

InjunJoe, The valve stem and tip look good. It's fairly clear that the heat source is in the grooved rocker ball area. I just cannot figure out why this one rocker is burning-up when the oil flow at idle and 1500 RPM (what a mess) is equal to the other non-affected rockers.

I know the term "collapsed lifter" gets tossed around a bit and was wondering if a lifter failure could result in this type of damage.

For my benefit, what are the best hydraulic lifters and push rods for a Ram Air IV set-up?