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RE: TR3 and TR4 Motors

To: <pleask@mailhost.wlc.com>, "Michael Thompson" <miket@urgrgcc.edu>
Subject: RE: TR3 and TR4 Motors
From: "The Brooks'" <TR3A@worldnet.att.net>
Date: Sun, 9 Jul 2000 22:32:49 -0400charset="iso-8859-1"
Cc: "Triumph List" <triumphs@autox.team.net>
Importance: Normal
Mike and Pat,

I did the same thing with a nicely powder coated TR4 front plate too.  I
knew they were different, I just sent the wrong one out to FT and didn't
catch it until it was in my TR3, but wouldn't bolt up.  <argggg!>

I will be posting the differences, with pictures, on the New Jersey Triumph
Association's web page soon.  I need to scan the pictures I took of each
front engine plate, with a tape measure present across the mounts.  They
are easy to tell apart, IF you know what to look for.

Pat, aside from the front plates and the clutches (which affects the sleeve
the TO Bearing rides on) the blocks, internals and ancillaries are
virtually all interchangeable.  Some things, like the 4A exhaust manifold
will bolt up to the engine, but you will need a custom exhaust system to
get it the rest of the way to the rear of the car.  The 4A's HS6 carbs come
with a different intake manifold than the 3's H6's. but they can be swapped
out together if you wish.  The valve covers will fit either engine, but may
be "inappropriate" for that car, if originality is important to you.  See
what you want to use then post back to the list and we'll be able to keep
you from doing some of the stupid stuff we have already done ourselves.

Jack Brooks
Hillsdale, NJ
1960 TR3A TS69032LO
1974 Norton 850 Commando Roadster

>  Hi Pat,
>  I have dropped a TR4 motor into a TR3. Everything is the same except the
>  front mounting plate. Some of the ancillaries are different. ie intake,
>  exhaust, valve cover. In 1984 I found out the hard way that the
>  front plate
>  was different. I rebuilt this nice TR4 engine, painted nice and
>  was lowering
>  it in and the front engine mounts would not mate. So out it
>  came. The real
>  pain of it was, the plate sits behind the timing chain, so all
>  of that had
>  to come off to exchange it for my old TR3 plate.
>  Cheers,
>  Mike Thompson
>
>  ----------
>  >From: "Pat" <pleask@mailhost.wlc.com>
>  >To: "TRlist" <triumphs@autox.team.net>
>  >Subject: TR3 and TR4 Motors
>  >Date: Sun, Jul 9, 2000, 8:03 PM
>  >
>
>  >
>  > I have a frozen motor for my 1957 TR3A TS33154 (Project car).
>  >
>  > I have a spare motor from my TR4A Parts car (Motor is also is
>  sad shape)
>  >
>  > I know that the TR3A motor was 1991cc and the TR4 was 2138cc
>  - correct ? (In
>  > most cases)
>  >
>  > The diff in size was the sleeves.. no ?
>  >
>  > My question is: How compatible are the two motors if I find
>  something in my
>  > '3 motor is no good ?
>  >
>  > TR4 motor number is TS13959E
>  > TR3 motor number is TS81530F
>  >
>  > Thanks all !
>  > Pat
>  >
>  > PS: You have all been a great bunch and a wealth of
>  information and help..
>  > thanks.
>  >
>  >
>  >
>  >
>


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