valve to piston contact

[P.I.S_7.3]

Recently pulled my engine for blown head gaskets. Decided to tear it down all the way. I noticed 5 cylinders had valve marks on the pistons. Also my cam is totally wipednout. 4 lopes are wiped and so are my lifters.

I run diesel innovations pushrods with comp 910s shimmed about as tight as you can go.
So my question is what do I do to prevent this on the rebuilt motor?

 

[Magnum PD]

Correct valve recess, piston protrusion, decked pistons, not too much taken off block and heads, I got .066 cometic head gaskets.

 

[P.I.S_7.3]

Well the motor was all original. So everything shouldve been in spec. The only thing I can think of is the 910s arnt strong enough. I mean I only have 238/200s and a 38r

 

[Magnum PD]

No cracked springs? High rpms?

 

[P.I.S_7.3]

Springs are all good. Rpms maybe.

 

[P.I.S_7.3]

I used a .060 shim when I installed them

 

[P.I.S_7.3]

I measured every one of them as well

 

[Magnum PD]

May not have been enough.

 

[obspsd]

This Is.Why I Have Factory Pushrods. I'd Rather Bend A Pushrod Than Damage Something Else

 

[obspsd]

Which I Have Never Done And My 910s Aren't shimmed

 

[GreenF350]

What kind of RPM's were you turning? I am contemplating the 910 springs as well and whether or not they are the best choice for me.
-Aaron

 

[P.I.S_7.3]

I hit 4000rpms a few times. I keep hearing the factory pushrod arguement but it just doesn't make since to me.

 

[dentexpowerstroke]

I run factory pushrods as well. Truck has seen 4k rpm 65psi of boost haven't bent one yet. Is it both valves contacting. Could have a stupid amount of back pressure floating the exhaust valve.

 

[TyCorr]

Could the damage have occured in the engine before? Such as the motor was ran with tuning and/or injectors before the valvetrain was upgraded??

How much boost were you making with the recent setup?

 

[lincolnlocker]

Haha, every time I hit 3800rpm with the dually I bent a stock PR... got pics somewhere with all my pistons showing valve marks and all cracked.

live life full throttle...
load it like a box car, drive it like a stock car

 

[ghohouston]

Time for some head porting while theyre off

 

[backwoodsboy]

I hit 4000rpms a few times. I keep hearing the factory pushrod arguement but it just doesn't make since to me.

Not saying it is right or wrong, but the idea is that the factory push-rods act as a mechanical fuse. You always want the weakest link in any system of components to be the cheapest and easiest to replace.
You see it a lot in industrial applications/marine/agricultural applications. Say you have a output shaft that would cost $50k to replace. You make this shaft two pieces, with a shear pin (mechanical fuse) holding the two pieces together. The shaft has been tested to fail at 24,000 lb-ft of torque while the shear pin has been designed to fail at only 22,000 lb-ft. In the event that the system is shock loaded, the shear pin will fail before the shaft does, meaning you only have to replace a $50 pin instead of a $50k shaft.
In the case of a valve-train, the push-rod will yield before you beat the hell out of your pistons, valves, and camshaft.

 

[P.I.S_7.3]

It may be possible that the damaged happend before I added springs but that would literally be 75k miles ago. One lifter has a huge flat spot on the roller and I doubt it would have made it this long.

Also you can see where the rockers arms beat the hell out of the valve stems and mushroomed the ebds out

 

[P.I.S_7.3]

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[P.I.S_7.3]

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