Another myth put out to pasture

[tubman]

OK. I have been looking all over the internet trying to find what the acceptable run-out should be for a flathead crankshaft. Very surprisingly, there seems to be no information on this. Just about everything I looked at said that proper bearing clearances are much more important than run-out. The one place I did find some actual numbers were on snowmobile forums. This is typical of what I found :

"I have heard between 2.5-3 thousands are factory spec so the question is how far does one let the crank get out of spec before repair? 4-5-6? What is a good measure to tell when the crank is on its last legs or could benefit from some preventative maintenance."

I have owned a few snowmobiles, and all of them had a red-line of over 10,000 RPM. From this, I have to believe that "less than .003" would be more than adequate for a flathead. Therefore, I stand by my initial statements.

I have spent some time and money determining these facts, which I believe will benefit the majority of members here.

I hate to have to say this, but unless you guys can come up with some solid, verifiable numbers, "37 Coupe" and "Kube": stay out of this thread; you have nothing to add but negativity, and that hurts everyone.

[bbrocksr]

Originally Posted by tubman

OK. I have been looking all over the internet trying to find what the acceptable run-out should be for a flathead crankshaft. Very surprisingly, there seems to be no information on this. Just about everything I looked at said that proper bearing clearances are much more important than run-out. The one place I did find some actual numbers were on snowmobile forums. This is typical of what I found :

"I have heard between 2.5-3 thousands are factory spec so the question is how far does one let the crank get out of spec before repair? 4-5-6? What is a good measure to tell when the crank is on its last legs or could benefit from some preventative maintenance."

I have owned a few snowmobiles, and all of them had a red-line of over 10,000 RPM. From this, I have to believe that "less than .003" would be more than adequate for a flathead. Therefore, I stand by my initial statements.

I have spent some time and money determining these facts, which I believe will benefit the majority of members here.

I hate to have to say this, but unless you guys can come up with some solid, verifiable numbers, "37 Coupe" and "Kube": stay out of this thread; you have nothing to add but negativity, and that hurts everyone.

Are you saying that only posters that agree with you can post on your thread?
Bill

[tubman]

Originally Posted by bbrocksr

Are you saying that only posters that agree with you can post on your thread?
Bill

Not at all. Read my post again; If they have any proven, verifiable hard information, they are very welcome to post. We don't need any unverified opinions or off the wall theories. I spent a bunch of time and money determining what I did; I only ask that they do the same.