i was wondering if anyone might know what my problem might be?my 355 tpi keeps breaking the vavels off at the keepers.they r stock valves but everything else isnt.cam is .520 / .515 lift i have the alluminum heads,rollers rockers,cromoly push rods,345lb springs.could it be the dampners inside the springs causeing coil bind?its broke 2 exhaust and 1 intake all at differant times and on differant cycinders.im curious to know if any one else has seen this and what they did to corect the problem.thanx

 

I'd suggest looking for witness marks on the top of the guides, and on the coils where they would touch if they were binding (or slapping against each other due to harmonics).

 

Did you do your research, and check all clearances, before settling on the parts used? Did you test-fit and check clearances while assembling? Or was it just kind of thrown together using what was to hand.

 

i got the cam from comp cams and went with the spec sheet for my upgrades.i think i might have to much lift for the stock alluminum heads.the 1.6 ratio rockers give it just a little to much lift.i got shorter push rods and got the strongest ones i could get.one of the previous times i broke a valve it also snaped the pushrod and the lifter also came apart.and the valve seal was smashed.i do believe i will take them heads to the machine shop and get them valve guides machined down alittle.what do u all think?

 

I think you should inspect and MEASURE everything carefully and find out what's wrong before doing ANYTHING.

Don't take em out of the box yet. Once you get the actual source of the problem identified, get yourself an adjustable push rod, and MEASURE for the size you need. More than likely, you actually need LONGER ones, but you can't possibly know what the right length is without MEASURING.

A clue emerges...

Yet another clue might be contained in telling us what springs springs you used... what part # are they? (nothing else please, just a part #) What is their EXACT MEASURED installed height? What other MEASUREMENTS of parts and clearances do you have?

Have I mentioned MEASURING things to see what's going on? That would be a good idea too.

 

Agree with this measured response.

You are destroying various other parts in the valvetrain, including valve seals. This would indicate they are getting smooshed by the retainers, which then go on to impact the valve guides, and break whatever the next weakest part in the chain happens to be.

If you've got 520 lift cam and 1.6 rr, you are throwing 555 lift at heads that probably max out around 480-ish. Can't end well.