In message <951031125834_8797681@emout05.mail.aol.com> writes:
> Hey there all,
>
> I know this is a Triumph list and all, but I was wondering if anyone had any
> ideas where I might find a harmonic dampener / front pulley assembly from a
> MGB engine. I'd prefer a cheap (as in nearly free) one.
>
> I've been told that this is what is used in the British Frame and Engine kit,
> and since I have to go up to the machine shop cause I screwed up my cylinder
> head anyway, I thought I'd take a spare crank up there and see if they could
> adapt it for me.
>
> Scott Tilton
> In Richmond Virginia
> with "winter projects" all over the place.
Sigh
It was my impression that the harmonic dampener whose characteristics matched
the TR crank came off an earlier MG but I do not know for sure.
The dampener kit that British Frame & engine sells includes the dampener, a
special made aluminum water pump pully, front oil seal and a fan belt. The
dampener requires use of a narrow belt. You need to locate a narrow pully for
the generator (from every othe rLucas generator in the world). You will need to
use a different front oil seal. You can not use the mechanical fan with this
modification, so unless it is for a full race car, you will need to add an
electric fan (10" fan works on this radiator). Unless you want to machine a
water pump pully, I would suggest going for the entire kit.
Of course I recommend balancing the drivetrain and nitriding the crank in
addition the the dampener.
For those of you who haven't a clue of what we are talking about.....
The crank of the TR2-4A engine does not come with a harmonic dampener like most
engines. The harmonics are such that the cranks have been known to break at the
base of the flywheel flange if you spend much rime over 5000 RPM. The factory
race & rally cars that used this engine were redlined at 5000 RPM. Balancing
helped, and nitriding the crank helped more, but the destructive harmonics were
still there. A few years ago some people (I believe from Racestorations Ltd in
the UK) got access to the BL crank harmonic test records. They compaired the
TR's crank harmonics with those from other cars and found a match in an older
MG. That MG came with a dampener to decrease the crank harmonics.
They put that dampener on the TR crank and I have heard rumors of fully
prepaired harmonic dampened TR engines running at 7000 RPMs (I'm redlining my
engine at 6000 RPMs and have picked a cam that runs out of steam at 6000 RPMs
but has a large flat power platu before going down, and am having the DCOEs
jetted to run out of steam at about 6300 RPM). Racestorations started offering
a harmonic dampener kit for the TR2-4A engine. British Frame & Engine in
California has a close relationship with racstorations and offers it too.
Frankly I wouldn't bother with a harmonic dampener unless you plan to rev over
5000 RPM. If you have a fresh, balanced engine with nitirded crank, non-stock
cam, header, 87mm pistons, shaved head & such maybe it makes sense. Its handy
if you are frequently doing autocrossing and don't expect to be looking at the
rev counter while negotiating the cones of your doing track racing. But then
again you could use a rev limiter.
TeriAnn
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