> 3) Oil seal replacement is a given right?
I'd say so, yes. The only exception, IMO, would be if you decide you can "get
away" with not pulling the engine and are willing to live with a possible small
leak from the rear main seal (which can't be changed with the engine in the
car).
> Does this require mainshaft regrinding?
Depends on whether you're talking about replacing with a stock-type labyrinth
(metal) seal, or the rubber seal that many vendors offer. The rubber seal
requires the crankshaft (the mainshaft is in the gearbox/transmission) to be
ground. There's also a long litany of things that can go wrong with the rubber
seal, for example, see
http://www.socaltriumphs.org/docs/mainseal.htm
> 4) How do you calculate horsepower from the piston bore size (all other
> things being equal). For example, how much does going from 86mm to 87mm buy
> you?
It doesn't always follow, but a reasonable first approximation is the ratio of
displacements, which is also the ratio of bore area. (87/2)^2 / (86/2)^2 = 1.02
or about 2% more. The increase in compression ratio probably helps more than
the increase in displacement, but the CR can be increased without increasing the
displacement. And, with today's gas, you can't go too high on CR.
You probably know this, but JIC, your TR3 most likely had 83mm liners
originally.
> And what is the reasonable limit to how large a bore you can use without
> too much overhead? I've heard of 89mm bores, but do these require special
> machining, etc?
The 89s don't require the block to be machined but are very thin where they fit
into the block, and are not recommended for the street.
> Assuming I
> don't get powder coating where I shouldn't, is there any problem with powder
> coating any of the external surfaces of the engine.
AFAIK, the only problems are practical ones, like are the racks in your oven
strong enough to support an engine block. I wouldn't think 400F would be enough
to cause problems with the cast iron warping, but I've not tried it myself.
Good luck
Randall
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