Fred_Katz@ci.sf.ca.us wrote:
> Mike,
>
> Yes! I went through that in the last month. It's necessary to replace the
> jackshaft bearings because the hot-tanking will destroy the old ones.
>
> Order/buy all the components up front before the rebuild, so you won't get
> delayed during the rebuild. (Some parts are getting hard to get.)
>
> My U20 motor was really gunked up not only because it was dirty to begin
> with, but it sat for over 20 years in my garage. But that isn't the only
> reason to hot-tank it. That will clean out a lot of rust crud in the water
> jackets, as well as contaminants elsewhere. The caustic solution will
> destroy the pressed-in jackshaft bearings. Another thing I found out, is
> you need to hone the cylinder walls before installing those new piston
> rings. Do not re-use old rings. I found out after I hot-tanked, so I had to
> do extra work to clean the sanding particles from doing the honing.
>
> Have a machine shop press in the new jackshaft bearings. Also have them
> polish up the crankshaft journals, and do any required head valve work. One
> thing to watch out for - don't force the jackshaft into place. One of my
> jackshaft bearings was a tight fit, and I had to polish it in the
> interference areas to get it within proper clearance. The machinist assured
> me this was okay as long as you don't take off too much material.
>
> Here's another tip I got. Use an old radiator for the first 200 miles. Then
> install a recored radiator. Leftover gunk from the rebuild will clog part
> of the radiator. Might as well clog it before a recore, and not clog a
> newly recored radiator! Fortunately, I have both old and recored radiators
> on hand, but you may not.
>
> Fred - So.SF, Calif.
> BADROC
>
> >
> >I haven't heard anyone mention when to replace the jackshaft
> >bearings. I'm rebuilding the motor now and need to know if its
> >necessary.
> >
> >Mike
> >Hayden Lake, Idaho
Thanks Fred,
You confirmed what the machinist said. I do have an extra radiator
actually I have four 2 liter radiators. I don't know were they all came
from. I was going to fast track this in order to make it to Vancouver in
September. Now I think I'll just do it right; I have received a bunch of
info. from list members and also Mike Kerr.
Mike
Hayden Lake, Idaho
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