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Re: TR3 engine rebuild

To: <triumphs@autox.team.net>
Subject: Re: TR3 engine rebuild
From: "Terry Smith" <terryrs@adelphia.net>
Date: Fri, 8 Apr 2005 20:03:13 -0400
Todd wrote:

> Is overhauling the engine something that I may get in over my head with, 
> or will
> proper care, planning, and sheer determination get the job done?  (BTW, 
> we're
> talking about a '59 TR3A).

Hi, Todd.  I didn't see a response, so I'll jump in.  I rebuilt my '59 TR3A 
engine 12 months ago.  It was my third engine rebuild.  The first time, my 
father guided me.  The second one I did alone.  It does take a fair amount 
of mechanical aptitude, and willingness to be patient and follow a manual 
that you can trust.   You need a reliable machinist to evaluate your crank, 
block and head, and press any bearings (i.e., your cam bearings) in and out. 
The machinist can then tell you what size main and rod bearings you need to 
buy (i.e. standard, 10 thousandths under, 20 thousandths under, etc.)  I 
would also let them do the valves for you.  I also sent my carbs off for 
rebuilding to Quantum.  Others on the list, like Randall and Fred, can do 
these more complicated procedures, I'm sure, but they're fairly complex for 
first timers to get right.  Read the archives on this list for info on the 
best water pumps to buy, and so on.

> 2)  I've seen piston and liner sets advertised anywhere from
> about $425 (British Parts Northwest) to over $800 (Roadster Factory). 
> What's
> the difference between and good set and a bad/mediocre set, and how much
> should I care?

I do advise not to skimp on the internals.  Again, read the list archives, 
but ISR that AE and Mahle are the best.  Parts houses have sales at 
significant savings.  The quality of the materials and whether the piston, 
sleeve, and rings are built as a set for perfect fit makes a difference IMO.

> 3)  Oil seal replacement is a given right?  Does this require mainshaft
> regrinding?

Your crankshaft will most likely need regrinding anyway since most cranks 
are out-of-round after certain number of miles (albeit my first engine 
rebuild only needed polishing).  You have a choice between the standard seal 
or the upgrade seal which does require regrinding to a special spec.  I 
think it's about $100.

> 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?  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?

I've read about this in the archives somewhere.  If I remember right, 87 mm 
gives you about 2.3 liter, whereas stock was about 1990 liter, something 
like that.  I worried (with absolutely no basis) that 89 mm might give 
cylinder walls a bit too thin, which might exacerbate a tendency for tractor 
engines to overheat.  ...But then, with an upgraded water pump with hooked 
vanes, and other careful attention to engine details, that probably isn't a 
problem.

> 5)  Powder coating.  I'd like to powder coat as much as possible. 
> 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.  I'm thinking in terms 
> of
> warping due to heat, or other problems to be aware of.

Fred?

Terry Smith  '59 TR3A  (Body still off.)
New Hampshire 




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