Day one and I've already got problems...
03-23-2008, 06:22 AM
#1
Day one and I've already got problems... Well I finally got everything all ready to start putting my motor back together yesterday so I was all excited to get cracking on it. Unfortunately that excitement didn't last long...
I went to get started on the bottom end and things were going well. I check my main bearing clearances and they were spot on (.0020-.0022). So then I put moly lube on the bolts, coated the bearings in assembly lube and began tightening to factory spec. I got all of the mains torqued down and then grabbed the crank snout and began to turn it over a few times to make sure that everything was still smooth, here's where the problem starts. The crank turns over perfectly smooth for 3/4 of the rotation, then on the last 1/4 turn it tightens up on me a little. Not a ton but definitely noticeable. So I think dammit, seriously, a problem already? I began pulling caps off trying to isolate the problem. I pull the number 5 cap in the rear of the motor and turn it over. Same problem. So i reinstall it and pull number 4, working my way towards the front. Same problem with the crank tightening. So I reinstall number 4. Then I pull number 3, the thrust bearing in the middle. Bingo, problem solved. The crank turns over smoothly for the entire rotation. I also notice that the bearing is not sitting smoothly in the cap. It seems to be pushed up slightly on one side. What do you guys think? Is there a chance that the bearing is slightly tweaked? They are brand new bearings. And it's not the crank. I had it mic'd and polished when I had all of the other machine work being done and it turned out great. I don't know. Any help would be great!
Thanks guys!
I went to get started on the bottom end and things were going well. I check my main bearing clearances and they were spot on (.0020-.0022). So then I put moly lube on the bolts, coated the bearings in assembly lube and began tightening to factory spec. I got all of the mains torqued down and then grabbed the crank snout and began to turn it over a few times to make sure that everything was still smooth, here's where the problem starts. The crank turns over perfectly smooth for 3/4 of the rotation, then on the last 1/4 turn it tightens up on me a little. Not a ton but definitely noticeable. So I think dammit, seriously, a problem already? I began pulling caps off trying to isolate the problem. I pull the number 5 cap in the rear of the motor and turn it over. Same problem. So i reinstall it and pull number 4, working my way towards the front. Same problem with the crank tightening. So I reinstall number 4. Then I pull number 3, the thrust bearing in the middle. Bingo, problem solved. The crank turns over smoothly for the entire rotation. I also notice that the bearing is not sitting smoothly in the cap. It seems to be pushed up slightly on one side. What do you guys think? Is there a chance that the bearing is slightly tweaked? They are brand new bearings. And it's not the crank. I had it mic'd and polished when I had all of the other machine work being done and it turned out great. I don't know. Any help would be great!
Thanks guys!
03-23-2008, 01:01 PM
#4
Teching In
Join Date: Sep 2007
Location: Winnipeg, Canada
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did u inspect that bearing to make sure that while installing it, there was absolutely no dirt, or foreign mass on it? its really easy to get just even a small piece of dirt on it while installed, which could bind up?
just an opinion.
just an opinion.
03-23-2008, 02:01 PM
#6
And brad, I'm taking it tomorrow to get the crank and mains checked for clearances again. They were checked once and came out fine, but I'll have them looked at again.
I just figured if the bearing was tweaked at all it would straighten out when I torqued it down. It's a softer material than the cap.
