On Sat, 4 Jan 2003, Richard Seaton wrote:
> Doug,
Hi,
Just trying to fill in some blanks...
> There was a cam difference in about '73, to a milder cam.
The change was in 72, around CC75000.
> Exhaust manifold change to two 3 into 1.
This change was with CF1 ('73).
> Narrow spacing on the head. I think this is only on '69 TR6's, but I'm not
> sure.
This change was for 72 also. Figure CC75000. Note: this change brought the
"PI" head to fed. spec. cars.
> Sometime the intake was changed to a straighter flow to the head, I'm not sure
> when this took place.
CC75000.
> "long" crank for '69's and TR250's, This long area is the machined part that
> connects to the flywheel. There for the flywheels are different too.
I'm not sure when this change occurred, but it was before CC50000 for
sure.
> Prettier bumpers on the pre-74 or 73.
I agree.
> Brass bushing in the earlier transmissions, not sure when they changed to
> steel.
Supposedly they changed for CF12500, but I've had several boxes apart that
were above this number that used brass. The latest TR6's def. had the
steel bushings (75 and 76)
> A type O/D (2nd, 3rd & 4th) for early 6's, J type o/d (3rd & 4th).
Yep.
> Trailing arm brackets changed One notch inner and two notch outer for up to
> CC61570. 3 notch inner and 2 notch outer from CC61571.
It's good to know this.
> A few distributor and carb changes.
Almost every year is slightly different!
> alternator changes
Early cars had the Lucas ACR17, that later cars have the Lucas ACR18
> water pump pulley differences
Early cars have narrow belts and single pulleys. They switched to 1/2
belts, not sure when, but figure CF1. The later cars with air pumps (75
and 76) have a double pulley water pump for the air pump.
> Sorry I can't give you the commission #'s when the changes occurred, but you
> can look in the Moss or TFR catalogues for that.
But don't take the catalogue information for granted! Some of the info is
very valuable and some is almost completely wrong! Use the catalogs as
guidelines but be prepared to order other stuff than what you think you
have.
Welcome to the world of owning 40 year-old-cars! Quirky ones at that.
> I think the only performance differences are the camshaft, intake and
> exhaust manifold changes. This is what you are really wanting to know isn't
> it?
There are internal engine changes too. Like diff con rods, the valves and
valve springs. There's lots of little changes even durnig a production
year!
> Not to mention the 1969 TR6's just look better than the latter ones!!!! LOL
> I'm sure I'm setting myself up for feedback on this one!
I'd tend to agree with this, but some of have later cars and are quite
comfortable with the appearance...
If we're looking for recommendations, my preference is 72. It's the last
of the early chassis (a-type O/D, basic suspension stuff) but has the
later engine (with early rods!) so its got better performance potential.
IMHO, if you want a driver that also can double for autocross, etc., then
the '72 is just about ideal (if it is all original).
> Richard Seaton
> '69 TR6 CC27413L(O)
But I like all TR6's and I even like TR6 inpsired cars (like TVR2500's).
Good luck deciding.
rml
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