Broke a brand new Crower Enduramax lifter

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Broke a brand new Crower Enduramax lifter

Post  bosshoss on August 17th 2016, 12:42 am

Installed a brand new set of Crower .903 bushing style lifters in my 598 this year.

25 runs in total. picked up a couple thou extra lash after two runs on Friday. During the third run on Saturday pretty sure it let go while on the converter at the starting line.

by the time I got in to it, cam is destroyed, one pair of lifters and a couple pushrods.

This is a C460 head deal with offset intake lifters and 3/8 pushrods. The lifters are machined to allow clearance for the pushrod but they are very close. maybe too close.

It appears that the intake lifter failed when the tower/extension piece that the tie bar attaches to snapped off the main body which of course allowed the lifter to begin rotating which is never a good thing.

I am going to assume that I was not diligent enough during initial assembly and missed the fact that the lifter body was contacting the pushrod resulting in a stress fracture of the hardened material....

Anyone else with a different perspective?


Last edited by bosshoss on August 17th 2016, 6:13 pm; edited 1 time in total (Reason for editing : corrected push rod diameter 3/8 not 7/16)
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Re: Broke a brand new Crower Enduramax lifter

Post  Scott Foxwell on August 17th 2016, 9:09 am

You can mock up another cylinder, or look at other lifters and push rods and see if there is contact to verify but sounds like you figured out the problem.
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Re: Broke a brand new Crower Enduramax lifter

Post  Frank Merkl on August 17th 2016, 2:58 pm

this is what you need to do

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Re: Broke a brand new Crower Enduramax lifter

Post  bosshoss on August 17th 2016, 6:14 pm

Thx frank. Crower said they thought clearance should be .030 does that seem legit?
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Re: Broke a brand new Crower Enduramax lifter

Post  Frank Merkl on August 17th 2016, 7:43 pm

I check with a .020" feeler gauge threw the full travel
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Re: Broke a brand new Crower Enduramax lifter

Post  bosshoss on August 17th 2016, 9:30 pm

ok thanks. I was getting .010 but must have missed something on #8
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Re: Broke a brand new Crower Enduramax lifter

Post  whatbumper on August 17th 2016, 10:21 pm

I was just sitting here picturing those little 3/8 pushrods flexing around like wet noodles banging everything around them. Get that sucker fixed and back racing.

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Re: Broke a brand new Crower Enduramax lifter

Post  Frank Merkl on August 17th 2016, 11:40 pm

3/8" is all I've ever used(.135" wall) , and on the intake pushrods they only have .030" clearance it the head and there's never any witness marks on them
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Re: Broke a brand new Crower Enduramax lifter

Post  Frank Merkl on August 18th 2016, 2:47 am

and we spin it ! with the .970"/.940" lift cam, were 1080 lbs over the nose and we let the motor go to 87-9300 rpm on the 1-2 and the 2-3 shift
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