I'm in the process of my first top to bottom rebuild. Last year my 04 mtn viper got sick when it had an exhaust port leak on the Mag side which I thought caused a burn-down. The prior owner had stripped out, and broke studs on the Mag side exhaust port. His remedy was to not restud but just jam some bolts in which I believe caused the burn down since you could almost sneak a penny between the port and the manifold.
I've got everything ready to go for the rebuild. However, I had not measured the crank tolerances until tonight. After taking measurements I found out it's all within specs except the Small End Free Play of the connecting rod. #1 and #2 are close. They measure .045" and .049" respectively when the tolerance is .04" So probably good enough for them. Now #3 (Mag side) reads .80"
The crankshaft itself is straight as a laser. Not even close to the tolerances. However I'm wondering if this Small End Free Play is acceptable realistically. And if not, could this have contributed to my burn-down? Another reason why I was asking was because the Mag side piston had obvious signs of burn down on top but the skirt was cracked at the bottom toward intake side. Can the skirt crack just as a result of the burn-down? I would think so but I'm not sure.
Bearings are all fine, checked each and every roller. And I can't feel any radial play in any of the bearings. All are smooth as silk. I cleaned the cases and crank three or four times and I believe I got everything out. I'll still probably clean it once then oil it again before install if I use it.
Do you think this crank is ok to put in with the Small End Free Play out of spec?
I'd appreciate any thoughts on this. Thanks in advance.
I've got everything ready to go for the rebuild. However, I had not measured the crank tolerances until tonight. After taking measurements I found out it's all within specs except the Small End Free Play of the connecting rod. #1 and #2 are close. They measure .045" and .049" respectively when the tolerance is .04" So probably good enough for them. Now #3 (Mag side) reads .80"
The crankshaft itself is straight as a laser. Not even close to the tolerances. However I'm wondering if this Small End Free Play is acceptable realistically. And if not, could this have contributed to my burn-down? Another reason why I was asking was because the Mag side piston had obvious signs of burn down on top but the skirt was cracked at the bottom toward intake side. Can the skirt crack just as a result of the burn-down? I would think so but I'm not sure.
Bearings are all fine, checked each and every roller. And I can't feel any radial play in any of the bearings. All are smooth as silk. I cleaned the cases and crank three or four times and I believe I got everything out. I'll still probably clean it once then oil it again before install if I use it.
Do you think this crank is ok to put in with the Small End Free Play out of spec?
I'd appreciate any thoughts on this. Thanks in advance.
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IMO:
The specs + tolerances provided by the manufacturer are for Max allowable wear to provide a reliable, quiet, trouble free engine.
Knowingly installing a crankshaft that does not meet the manufacturers maintenance specifications seems unwise to me as it compromises all the work and money already invested in the rebuild.
There is only one way to do any job...the right way!
Get the crankshaft rebuilt.
JM.02c
Bob
The specs + tolerances provided by the manufacturer are for Max allowable wear to provide a reliable, quiet, trouble free engine.
Knowingly installing a crankshaft that does not meet the manufacturers maintenance specifications seems unwise to me as it compromises all the work and money already invested in the rebuild.
There is only one way to do any job...the right way!
Get the crankshaft rebuilt.
JM.02c
Bob
I ended up remeasuring the Small End Connecting Rod tolerances again and the #3 (Mag side) connecting rod was .065" which is still out (.04" tolerance). The other two were right at the tolerance. #2 being .040" and #1 (PTO side) .039"
I believe the first time I measured them just a little off from where it should have been measured. But effectively the same result anyways.
I know the ideal thing is to have the crank reworked but I'm wondering if anyone has ever run a crank like this before and whether they had issues or not. Just trolling for some experiences to draw from.
I do appreciate the input Sideshow. Thanks.
I believe the first time I measured them just a little off from where it should have been measured. But effectively the same result anyways.
I know the ideal thing is to have the crank reworked but I'm wondering if anyone has ever run a crank like this before and whether they had issues or not. Just trolling for some experiences to draw from.
I do appreciate the input Sideshow. Thanks.
I will warn you the crank's from the factory are not even straight. I would recommend sending it to Hauck Power Sports in Rice Lake Wisconsin. I had A crank I sent out to A good machine shop in Minnesota for A rebuild. I decided to do A big bore and Sent it to Hauck and found out my rebuilt crank was junk and one rod was bent.
Wow that bites! I have a dial indicator and I made a jig to do all the measurements. Amazingly the run-out at the ends and all the bearings in between were at .0002" and .0001" The tolerances for ends was .0012 and everything in between was .0016"
So it may have been worked on prior to me owning it but it's a very straight crank.
The Big end side clearance of the connecting rods was .015" for all of them. The tolorance is .03" So those are also really good.
It's just that one Small end free play that is out. And it's doing bad things to my mind!!!! It's a tug-a-war between the good and the dark side!!!!
So it may have been worked on prior to me owning it but it's a very straight crank.
The Big end side clearance of the connecting rods was .015" for all of them. The tolorance is .03" So those are also really good.
It's just that one Small end free play that is out. And it's doing bad things to my mind!!!! It's a tug-a-war between the good and the dark side!!!!
There are definately a lot of sleds out there that have crankshafts with out of spec tolerances far greater then yours and they are running just fine...LOL....the trouble is you are thorough enough to have checked yours!
You now can't apply the "what you don't know can't hurt you" theory.
You now can't apply the "what you don't know can't hurt you" theory.