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Triumph TR3 - trannys in TR-3As

Today I was looking in books and at the two TR-3a trannys. One is TS 69283, a thin bell housing with no strengthing gussets (TR-2?). The other is CD 30199 (a TR-6, circa 1970?).
If the latter is a 6 trans, that would be 4-synchro and more bullet proof.
Are there any gear ratio issues or speedometer issues that need to be thought of? My thoughts are to run a TR-4 set of pistons and liners in the 3 block and do whatever else can be done to gain hp without making the car not a streetable car. Highway and mileage are concerns.
An o/d would be first choice, but there isn't one on the floor.

I would go with the 4 synchro box since you have one. You can get 87 mm piston/liner kits, too. Maybe bigger. I'll remember the name of the TR hot rod place overseas, maybe, so you can drool over their mods. TSI (?) is kind of performance oriented. Search the net for TR3 The's a real work of art.

With my 1991 cc engine, I consistently get better gas mileage (about 5% better) than my TR3A friends who have 2137 cc engines. I checked this out on several long trips in convoy with other TR3A drivers. We all had overdrives.

Don Elliott
Don Elliott

Sounds like I do have a 6 tranny, and the 1991cc liner kit would be the way to go. My last 3 had a 4 engine in it, and I liked that.

In 1988 when I was doing my car, I bought the 1991 cc parts. On the phone with Peter Hepworth in Yorkshire, England, he had to go looking to see if he still had a set for 1991 cc. A day later he had found a 1991 cc set in his cellar and he told me that it had to be the last set in existance. So you may have to go with the 2137 cc kit.

Don Elliott

What would those kits be in the Moss catalog? They are listing several but by mm instead of ccs.

While I wrote above that maybe I got the last set of 1991 cc parts, that was the statement made by the supplier. That may have been true when I bought them in 1988 but I see today that they are listed in recent suppliers' catalogues.

In my engine with 1991 cc displacement, the diameter of the pistons/liners is 83 mm across. The next size available is 86 mm which I guess applies for the 2137 cc engine in the TR3B, the TR4 and TR4A. 2137 cc was also available as a special option for the TR3A for those who wanted to enter speed events.

The 3 works TR4s that ran in the 1964 Shell 4000 Rally from Vancouver to Montreal had 1991 cc engines, an option as well from the factory so the TR4s would be in the 1500 cc to 2 liter class. The TR4 of Barry Martin with stock 2137 cc displacement had to compete in the same class as all the V-8 muscle cars with 5 and 5.5 liter engines. I did that rally, navigating in a Renault R-8 with 1100 cc displacement.

Today, there is also the 87 mm option which would give closer to a 2.2 liter displacement. There are racing options available from BFE in Temple City, Calif and from Racetorations in UK that can provide 2.5 liter displacement. But these are not just drop-in liners. I believe that machining work is needed in the block.

Don Elliott
Don Elliott

87 mm liners are still drop-in sets. It's the 89 mm ones that need machining. Mine are actually 87.2, which is like 86 mm bored over by 0.040". I got the set without rings and was then able to source the rings from Deves.
If I recall back when I was hunting around a few years ago there were a number of manufacturers for these things. In fact the least expensive set I have seen is 85 mm for $4xx US, actually for Ferguson tractors but will also drop right in. Though maybe people don't want to get quite that rustic with their TR.
J. S. Wallace

Thanks guys. An old mentor used to say "The only substitute for cubic inch is cubic dollars." So, the 89s are tempting. Then again, I am not planning on racing, just cruising, so mileage would be something to shoot for.
IF one went for the 87s, that shouldn'tbe too far off from what a TR-4 engine in a TR-3 would do for mileage it would seem.

Chris-I think the 87mm kits are probably the most popular replacement. Not only do they increase the displacement, but also bump up the CR to about 9.24 with the TR3 head. My best mileage was about 28 mph with overdrive. I don't know if it was a result of the big bore kit, but the car ran pretty hot, especially when the outside temp was over 80f. Maybe I will see you at the Montgomery Park swap meet in April.
Berry Price
BTP Price

I think you'll be perfectly happy with 86 or 87 mm pistons. The cubic dollars for 89's and the machine work would be logarithmically illogical IMHO. These are not underpowered cars, they were built to go 100 MPH. And on a bad road, the suspension can feel a bit spooky compared to modern cars.

As an aside to this, the 86 mm pistons and liners in one of my 3's came from a TR4. The shop I bought them from was near an airbase, the airman wanted 87 mm, so they replaced 86 with 87, nothing wrong with the used ones I got. I hope he was pleased with the performance increase he got. That car runs plenty strong, and I assume my TR4 has 86 mm also, it seems to have more power than either of the 3's, maybe because it's well broken in. The other 3 has 87 mm (Mahle brand, I believe). I never drive the cars back to back, but they all have plenty of power and torque.

Don's mileage may be related to his ability to tune the motor and not having brakes that drag, or even his driving style, compared to his trip companions. Or, like my 4, his car is well broken in.

You probably caught it in the other thread, but the place I never thought of is Revington. They really drive their cars.

This thread was discussed between 06/02/2006 and 16/02/2006

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