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TR2/3/3A tr3 or 4 motor?

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BillJoBob

Senior Member
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I have an engine in the rebuilding process. I was wondering how I could determine exactly when this motor was made and if it was a larger tr4 motor or not. I have the numbers off of the block and they are as follows:
CT40531E
P244
301435

Any info about these numbers would be a great help.

Thanks!
 
Where it becomes more important is when you go to install it. The front plate on a TR4 motor is wider across the motor mount tabs than the TR3 motor. they can be interchanged on the block, but you need to know that you have the right one before the timing gears, chain and front cover go on, because they don't interchange when you go to drop the motor in the frame of the car .
 
Thanks Fellas for the info. What is the piston size difference of the tr4 as compared to the 3? I have two or 3 blocks and another head and crankshaft as well. IYO, should I use this tr4 motor or go with the original set up?

Thanks again!
 
I think the 3 is 82mm, the 4 is 88mm. Might be wrong though.
 
By now, I wouldn't trust the number on the side of the block to tell you ANYTHING about what pistons & liners are inside. "Standard" for the TR3 was 83mm, while standard TR4 was 86mm. But both were available new with the other size, and 87mm replacements have been not only common but typically cheaper for many decades now. The chances of finding an engine with the factory liners in it are pretty small, IMO.
 
I just got a liner kit that is susppose to be a NOS 83mm. Still in original boxs and has the parrafin type sealer over it. Haven't measured it yet to make sure but if anyone is interested PM me.

Marv
 
Thanks Randall and Jim,
So what would be the size of the motor/ hp rating with 87mm pistons. Is it safe to say that installing this block would not hurt the overall value of the car for resale? We are not building a concourse car and our main objective is to restore, drive and eventually sell and begin another.
Thanks for all the info! You guys make restorations a lot less stressful!
 
TR3driver said:
By now, I wouldn't trust the number on the side of the block to tell you ANYTHING about what pistons & liners are inside. "Standard" for the TR3 was 83mm, while standard TR4 was 86mm. But both were available new with the other size, and 87mm replacements have been not only common but typically cheaper for many decades now. The chances of finding an engine with the factory liners in it are pretty small, IMO.
Click to expand...
Possibly worth noting is the fact that the pistons and liners could also be 85mm as used in the Standard Vanguard and the Standard-engined Ferguson tractors, although it's not very likely. Even less likely would be the 80mm pistons and liners from the Standard Ensign.

I'm not sure I'd make as broad a statement as you, Randall, about the chances of their being "factory" original pistons and liners. Although many of these cars saw serious mileage and abuse leading to rebuilds, I'll wager almost as many didn't and would still have factory-original components.
 
On anything but a painfully correct restoration, oversize liners aren't going to hurt the value at all (assuming they don't make it overheat). Even a Pebble Beach judge does not measure the cylinder bore!

The 87mm liners take it out to a whopping 2188cc
grin.gif
Don't have any hard data on power, but the factory claimed that going from 83 to 86 bought another 5 bhp, so I'd guess 86 to 87 might buy another couple of ponies. The advertised increase from 83 to 86 was less than the change in displacement, indicating that breathing is becoming the limiting factor. However, more torque is always welcome, even if it doesn't bump the peak power number up by much (and the torque will go up in proportion to displacement).
 
BillJoBob said:
Is it safe to say that installing this block would not hurt the overall value of the car for resale?
Click to expand...
I just realized that I mis-read this question.

I don't know how much it would actually change the value, but there are some buyers that would notice the engine number, and be less interested because it was clearly wrong. I'm certainly not one of them, and in fact I will be doing much the same thing to TS13571L at some point (since I want to keep driving the original motor while I build up a "hot rod" motor to replace it. But there are some who do care, and the wrong engine number would cost you points at a TRA concours competition (not sure about VTR offhand).
 
IMHO , only the people who want a concourse car would be effected. I would say maybe 33%
??
 
Andrew Mace said:
I'll wager almost as many didn't and would still have factory-original components.
Click to expand...
Well, I wouldn't care to take either side of that bet, Andy. But so far, the majority of TR3/4 engines that have come my way have not had the original liners in them. There was one TR3 that did appear to have 3 of the original pistons in it, but it was a low mileage car (with extreme rust issues). TS39781LO already had 87mm liners in it when it came to me in 1984 (and needed them replaced), as did the TR3A my Dad bought back in 1974 or so (don't know the engine/commission number offhand, but likely somewhere in the TS50k range). Ditto the wrecked 3A I bought for parts around 1982. The TR3A I had before that might have had the original pistons & liners in it, but was grotesquely worn out (bearings worn into the copper backing); and as I recall, an 87mm liner set was actually cheaper than just replacement pistons & rings. (At the time, JC Whitney carried the liner sets, but not the individual components.)

I've not been into TS13571L yet, but from the way it runs (and the PO's statements), I'm confident it has been updated as well. It may even have a bit of a cam in it, as it tends to lope at idle for no apparent reason.
 
Just another point regarding the TR4, but used in a TR3 vehcile. When I did mine, in addition to changing the front plate, I had to pull the plug and install a side draft tube for crankcase ventilation (I was using SU carburetors). This set up was standard on TR3 and early TR4's, but when Triumph went to Zenith's in the mid 60's, they eliminated the use of an open draft tube and went with a close ventilation system.
 
One more question on this topic gents... Are the liners and/or pistons marked or labeled to signify sizes? My TR4 motor appears to be original and unmodified and so I want to replace the liners and pistons with the same size parts. Thanks!
 
My observation has been that original pistons were not marked as to size but any oversized parts are so marked. Don't know about liners. If in doubt, measure I suppose.
 
Geo Hahn said:
If in doubt, measure I suppose.
Click to expand...
:iagree:
I've not found either "standard" or oversize pistons & liners to be marked except for the factory 'grading' letters and even those can't always be found.
 
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