15 years ago, when I bought my TR3A, I found that the #1 crankpin journal
was deeply scored and nicked due to a piece of the timing chaiin tensioner
going through the oil pump, through the oilways and lodging in the
connectiing rod bearing shell, thereupon scoring the crank with every
revolution. I removed the connecting rod bearings nad carefully stoned the
scoring on the crankpin, using a small, fine, sharpening stone. The car has
run fine ever since. I would recommend the stone rather than a file. Under
no circumstances should you use a Dremel tool. And, I agree with David's
comments on break in.
----- Original Message -----
From: "David Massey" <105671.471@compuserve.com>
To: <Eganb@aol.com>
Cc: "[unknown]" <tr8@mercury.lcs.mit.edu>; "[unknown]"
<british-cars@autox.team.net>; "[unknown]" <Triumphs@autox.team.net>
Sent: Thursday, September 28, 2000 9:25 AM
Subject: Decision on TR7 Bearings from Hell
>
> Message text written by INTERNET:Eganb@aol.com
> ><snip>
> >After a closer look at the scratches and burr on my TR7s crankshaft, I'm
> >going to rely on my trusty Dremel and yards of Crocus cloth to smooth out
> >these blemishes caused by my carelessness, instead of pulling the crank
> >which
> >I have neither appropriate space or cash to do, but would probably end up
> >being a heck of a lot quicker.
>
> Don't go in there with a dremel tool. It takes away material too fast and
> if you use a stone the stone dust will get everywhere. Use a small, fine
> tooth file to take off the high spots only. The dents and low spots will
> not cause a problem but trying to make it smooth by taking away material
> that is the proper diameter will be counterproductive.
>
> >What I do have is plenty of time and sweat-equity to put into the
project,
>
> >and for you who are still interested, a couple of additional questions:
> >
> >1. I finally got the #1 bearing out by taking the camshaft caps off and
> >raising it enough to reduce the chain tension. The upper bearing slid
> right
> >out. My question is whether the chain is suppose to be so bloody tight,
> and
> >is there an adjustment I should be looking for?
>
> There is an automatic adjuster and if it indexes while the cam is loose
you
> may have to pull the front cover and reset it.
>
> >2. My strategy is to clean up all the scratches and burrs, then spray a
> >couple of gallons of WD40 over everything to clean out any grit, then put
> in
> >some extra new shells on the bearings that were scratched, turn the
engine
>
> >over several times by hand, and then take the caps off again to see if
any
>
> >scratches appear on the shells. What do you think?
>
> Again, don't worry about the scratches, just the burrs.
>
> >3. After I reassemble everything, including brand new bearing shells, I
> >thought I would leave the sparkplugs out, and pull the car in gear to
help
>
> >the engine get "broken in" without the heat and pressure of actually
> running.
> > Maybe pull it for a couple of miles, then replace the oil and filter.
> But
> >then I thought maybe this would cause accelerated wear because the engine
> >wouldn't be running at its normal temperature, so the oil might not be as
> >fluid. Thoughts?
>
> There really is no "break in" as there is when new rings are fitted. When
> I re-bearing'ed my TR6 I just filled the crankcase with a low viscosity
> oil, drove the car until warm and changed the the regular stuff. And I
> changed the filter, too.
>
> >Of course, just to be safe, anybody got a spare crank they don't need?
>
> If you wind up pulling the crank you can no doubt get it turned. I doubt
> the damage is more than a few thousandths deep.
>
> Good luck
>
>
> Dave
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