Howdy all,

I just finished installing my rebuilt 455.
Bored .30 over with Sealed Power Pistons.
Speedmaster Aluminum Heads
Cometic .27 head gasket
Elgin 1141 P cam 234/244 duration 520/542 lift
Correct length pushrods- can’t recall length
roller tip rockers 1.6 lift.

I degree’s the cam to 106- couldn’t get it to 107.
I adjusted the rocker arms using the simple method of zero lash, rotate 90, zero lash rotate 90, two full rotations. Then tightened preload by 3/4 turn.

After running the engine for a break-in period, my number 1 exhaust arm was knocking. After removing the valve cover I discovered the pushrod was out of adjustment, as in 1/4” lash. I have readjusted, but am wondering if this is possibly an indication of loosing a cam lobe? The engine runs well, but I am at a loss for why this valve was so far out of adjustment.

Any thoughts?

 

If you use that method, assuming you have adjustable valve train, then you have to make FOUR full revolutions adjusting zero lash every 90 degrees.

 

Maybe that was an issue. I felt like 4 90s was one full rotation, the another 4 90s was a second full rotation. I guess I thought those 2 full 360 rotations would run through all the cylinders enough to take out lash at every valve before adding preload.

 

You can always just use the exhaust open, intake close method.

 

When in doubt, cut the filter open.

If there is something in the engine eating itself, that’s where you will find the debris.

 

Thanks, drained the oil. Oil looked great, ran a magnet through just to see if there were any particulates, and literally not one speck of metal. Smells a bit of gas, but I’m thinking that’s a timing issue to chase down? I also need to adjust the carb a touch?

 

Fix that right away. Diluted oil will hasten cam wear.
Fix timing first, then make sure your throttle blades aren’t cracked open excessively to retain an idle. That’ll effect idle circuit operation.

 

A magnet in the oil is not the same as cutting open the filter. There are lots of parts in an engine that can wear that aren’t magnetic.

Cut open the filter, then you can be reasonably sure the engine is t eating itself.

 

I’ll get after that filter! Appreciate the advice

 

Agreed. Planning to ensure my cam is degree’d properly. I’m pretty sure I nailed it on both the intake and exhaust degree. However, my brain is telling me I swapped the exhaust/intake numbers. Strange how the brain plays tricks once there is an issue. Pretty sure I got it right, but… The car idles great, throttle response is so much better than the old Delta 88 block. That rocker arm knock and loose pushrod just has my “worst case scenario” brain working overtime. I guess I also need to get at least one 45 degree plug wire for that #7 plug. The current boot has to be zip tied to the brake booster line to keep it from interfering with the steering.

Funny how upgraded parts always seem to require alterations. Kind of wish I just went with a standard cam, rocker arms, and valve covers.

Here’s to hoping by the extra HP will smoke away my regrets!