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Post by bluredvision on Apr 3, 2019 20:08:11 GMT -5
I'm in the process of refreshing an old motor for derby, new bearings, rings gaskets, etc.... Ive got an issue the the crank end play. My dial indicator shows .027 end play, the norm is supposed to be .003-.010. is this okay for derby? or do i need a new crank?
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Post by smashford on Apr 3, 2019 20:25:21 GMT -5
Can't you get a thicker thrust bearing
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Post by bluredvision on Apr 3, 2019 21:09:55 GMT -5
not that i am aware. Big block mopar, from what i understand if the endplay is over .015 the crank has be be built up and machined or replaced.
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owen11x
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Ford makes it, Chevy shakes it, Mopar breaks it!
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Post by owen11x on Apr 4, 2019 6:40:31 GMT -5
I had one sbc that the crank had been bumper tapped a few times and I could move the crank pulley a pretty solid 1/4" and I never had any issues what so ever. Ran it a few times in bone stocks. It was a bone stock engine and a sbc at that so I didn't care about it lol It's hard on bearings I'd sure think
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n8
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Post by n8 on Apr 4, 2019 7:25:19 GMT -5
I have a small block chevy that had a similar amount of play. I assembled it anyways, and it is still running four years later. I am sure there is a downside to having that much end play, but I haven't seen the effect of it yet.
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Post by klicky96 on Apr 4, 2019 17:41:46 GMT -5
For derby use, you'll probably never notice it. For daily use, you'll probably go through a couple transmissions before figuring out what's wrong. In my honest opinion, if it were mine, I would call my local engine shop and talk to them about it. Theres gonna be a fix somewhere for it.
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Landshark007
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Post by Landshark007 on Apr 4, 2019 18:32:05 GMT -5
Your belts and timing chain mains an rods should keep it good it can't go to far
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Post by barn78 on Apr 4, 2019 18:35:31 GMT -5
For derby use, you'll probably never notice it. For daily use, you'll probably go through a couple transmissions before figuring out what's wrong. In my honest opinion, if it were mine, I would call my local engine shop and talk to them about it. Theres gonna be a fix somewhere for it. BINGO breaking pumps and taking names |
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Post by klicky96 on Apr 4, 2019 19:32:59 GMT -5
Your belts and timing chain mains an rods should keep it good it can't go to far It'll go far, far enough to destroy a pump in a trans. Or far enough to destroy a block from the crank walking. That timing chain wont do anything to keep the crank aligned, and there is too much forward and aft play on the journals for them to hold the crank, hence the reason of a thrust bearing. If it was only to run a few derbies, then yeah, run it. But if you're going as far as breaking it down and doing a refresh, then obviously it's worth doing right the first time. The choice is yours, and you might not ever notice a problem. But if it were me building it, I would make sure it was perfect. I wouldn't want to put the effort and money into an engine for it to fail because I skimped on what I thought wouldn't be a big issue. That could be the difference between winning $5k or winning nothing. |
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Deleted
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Post by Deleted on Apr 4, 2019 20:11:32 GMT -5
If you got plenty of time to fix it,fix it...if the derby is this Saturday...SEND IT!
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Post by scottgropp on Apr 7, 2019 10:16:43 GMT -5
Can't make a determination on this until you add rod side clearance measurement. If rods can't move on the rod journals as much as the the crank floats in the mains, they will bind, twist and grind. The oil shield can't protect them from that.
Transmission and timing chain issues are secondary to rod issues.
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