New cam...loud clacking lifters. ???

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I had the same type of noise once, I decided to put an mp 508 cam in a stock 72 360, I took a peek at the valvesprings, some prying, etc, and the were overtaxed of the point they were almost "sticking"and kind of popping open. Could have been disastrous lol. Put some stiffer springs in, after that it was fine.
 
Lift is relevant along with duration. the cam that did the damage you see in the pic I posted was a Lunati 60302. Intake valves hitting. That valve had 265/220 duration with a .475" lift and 112 LSA. The cam in question is a Comp XE268 268/224 duration .477" lift with a 110 LSA. Its not looking good.

I would see if you can pull some plugs and get the piston at or near TDC and take a peak thru the plug hole and see if you can see any marks on the piston tops. You have to remember, when you rolled it over before it ran, the lifters were fully collapsed and you would not have had any binding. This is why you use a shimmed up hydraulic lifter to check Piston to valve issues. You bent 4 P/R running break-in, NOT GOOD.
 
MRL Performance said:
Lift is relevant along with duration. You bent 4 P/R running break-in, NOT GOOD.
Click to expand...

Add to that mix cam TIMING. We don't know how you installed this cam, and cam timing affects interferance issues. Closest valves get to pistons is NOT at TDC
 
i had same issue on a stock 318 that i swapped in a cam out of a blown up 340 i had .the valve was touching so lightly it was almost like a scratch on the pistons .i ended up just grinding some reliefs with just a small grinder . not the best way but ran fine after. good bluck
 
Absolutely......it would just be of some surprise to me to see that type damage done from such a mild cam. Just goes to show how important checking those clearances is to every single application. It should never be taken for granted.


MRL Performance said:
Lift is relevant along with duration. the cam that did the damage you see in the pic I posted was a Lunati 60302. Intake valves hitting. That valve had 265/220 duration with a .475" lift and 112 LSA. The cam in question is a Comp XE268 268/224 duration .477" lift with a 110 LSA. Its not looking good.

I would see if you can pull some plugs and get the piston at or near TDC and take a peak thru the plug hole and see if you can see any marks on the piston tops. You have to remember, when you rolled it over before it ran, the lifters were fully collapsed and you would not have had any binding. This is why you use a shimmed up hydraulic lifter to check Piston to valve issues. You bent 4 P/R running break-in, NOT GOOD.
Click to expand...
 
MRL Performance said:
Lift is relevant along with duration. the cam that did the damage you see in the pic I posted was a Lunati 60302. Intake valves hitting. That valve had 265/220 duration with a .475" lift and 112 LSA. The cam in question is a Comp XE268 268/224 duration .477" lift with a 110 LSA. Its not looking good.

I would see if you can pull some plugs and get the piston at or near TDC and take a peak thru the plug hole and see if you can see any marks on the piston tops. You have to remember, when you rolled it over before it ran, the lifters were fully collapsed and you would not have had any binding. This is why you use a shimmed up hydraulic lifter to check Piston to valve issues. You bent 4 P/R running break-in, NOT GOOD.
Click to expand...


x3.
 
A Friend lent me an inspection camera today... I pulled three spark plugs and looked into three chambers... we saw nothing but three solid black piston tops... I'm ordering stock rockers, 901-16 springs, retainers, seals, keepers... does anyone know how many lands the stock valves would have? I will do the springs first, then the rockers to find out the real culprit!! Next winter I'll look at 302 heads and better manifolds...( If things hold together.) maybe a rebuild. thanks again....
 
its not that the piston is hitting the valves hard its that the springs don't have enough force to get the valve out of the way fast enough and is taping it back up. or it might be being forced back up due to the compression. it can't be checked by just turning the engine over by hand. it happens when the engine is at a fair amount of rpms.
 
rexduster said:
A Friend lent me an inspection camera today... I pulled three spark plugs and looked into three chambers... we saw nothing but three solid black piston tops... I'm ordering stock rockers, 901-16 springs, retainers, seals, keepers... does anyone know how many lands the stock valves would have? I will do the springs first, then the rockers to find out the real culprit!! Next winter I'll look at 302 heads and better manifolds...( If things hold together.) maybe a rebuild. thanks again....
Click to expand...

Really hope you get it working man! Good luck, I know how frustrating trouble shooting can be
 
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