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TR2/3/3A TR3 pistons/liners?

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59Rob

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Hi, I'm new here but not new to TR's, bought mine in 1978. Something went on it about 10 years ago and it just sat and the motor ended up seized. Needless to say I'm as embarrassed as I am unhappy about that development.

So it's time to tear it down and rebuild it and I have a question about the replacement piston/liner kit. There's the stock 83mm and I saw the bigger 87mm set for WAY more money and was wondering if it was worth the extra cash.

To further confuse me I received an e-mail from Moss Motors regarding a 20% off sale and they have another 87mm kit that says alternative? not sure what that means but the price is about the same as stock. so basically there's an 83mm and an 87mm for around $400 and another 87mm for around $1000. what gives??

Thanks for any help
 
hopefully someone will chime in on the specifics, but in my opinion, you get what you pay for! if there is a 600 dollar difference on one set they must be better quality, well in most cases

Hondo
 
I didn't pay any attention to the Moss flyer, but looking at their web site I see piston & liner sets in 83mm, 86mm and 87mm; all for around $400. The 87mm set is described as "alternative", because they also have a part number for the AE brand set (which is no longer available).

Then there is an 8<span style="text-decoration: underline">9</span>mm set listed on a different page, for $800. Although their description is somewhat lacking, I believe this is basically a "racing only" kit with forged pistons, custom-made liners, etc. The high price is partly due to the increased quality (for example, forged pistons are stronger but cost substantially more than cast) and partly due to the low-volume custom nature of racing parts.

BTW, I believe it also requires a special head gasket, which is not mentioned with the liner set.

Unless you are going racing or your wallet is too thick, I would suggest any of the $400 sets. The 86 or 87mm sets will give your engine some extra torque, but also increase fuel consumption and the potential for overheating. If you don't make any other changes, the larger liners will also increase the compression ratio, which may require using premium gasoline.

That said, I'm planning to build a "fast road" motor with the 89mm liners, Larry Young cam, 4-2-1 header, TR4A valves, HS6 carbs and some mild head work. I'm hoping the result will be similar to a hot motor I built back in the 70s that was a real hoot to drive. But it also had a tendency to break driveline parts, so I wouldn't recommend it to everyone.
 
JerryVV said:
Which Larry Young Cam?
Click to expand...
His TR270 grind:
https://www.tildentechnologies.com/Cams/TriumphCams.html

It's something of an experiment IMO, doesn't seem like enough duration to me, but I trust him to know a lot more about camshaft design than I do. Supposedly it has steeper ramps than other cams do (taking advantage of the rather large lifters in the TRactor motor) so the effective duration is bigger than other "270" cams.

Sure do wish I had had sense enough to keep the timing card for that cam I ran back in the 70s, but I have no idea what happened to the timing card and the car got crushed when I wasn't looking.

PS, the vintage racers seem to really like Larry's 298 cam, but the power band of 4000-6500 rpm seems like more than I want to run on the street. I still hope to drive this car to work every day!
 
59Rob said:
Something went on it about 10 years ago and it just sat and the motor ended up seized. Needless to say I'm as embarrassed as I am unhappy about that development.
Thanks for any help
Click to expand...

Welcome to the asylum... Just for curiosity's sake, have you tried to free the motor, ala the Marvel Mystery Oil piston soak, etc...
 
Duration is what interested me. I have an original "D" Cam and it's 284 I think. I'm told that's about as much as you want for the street. Of course it also needs some higher compression as well to work the best. My engine is done to Kastners book with 87's and .090 off the head. It's tired but still runs pretty good and good power up to 5000 rpm with a nice kick at about 3200 up to mid 4's. Fun stuff. I'm giving serious thought to the 89's too as it will get rebuilt this winter. I'm pretty sure that I can solve the head gasket issues too based on a friends solution that is working.
 
TR3driver said:
JerryVV said:
Which Larry Young Cam?
Click to expand...
His TR270 grind:
https://www.tildentechnologies.com/Cams/TriumphCams.html

It's something of an experiment IMO, doesn't seem like enough duration to me, but I trust him to know a lot more about camshaft design than I do. Supposedly it has steeper ramps than other cams do (taking advantage of the rather large lifters in the TRactor motor) so the effective duration is bigger than other "270" cams.
Click to expand...

I'm waiting to hear from someone who has it installed. I chickened out on my last rebuild after fitting it and wound up using the BPNW performance cam they have instead. Larry's has a lot of lift (sorry can't quote what it is from memory) - I wasn't at the point of coil bind on the valve springs but it was close.

And to get back on track, the $400 sets are good I think, last one worked well for me at least - I went with 87 mm.
 
I'm with Kevin, try to free the engine, it might save you the pistons/liners altogether. I bought my TR3A with a seized engine and managed to get to spin by putting it in fourth gear and rocking the car back and forth. Of course do spray the cylinders first as suggested.
 
I have a '58 TR3A and an 87mm pistons and liner set. It uses the standard head gasket with no problem because it is only 86mm +0.040" or standard TR4 and 4A bore size.

The car is noticeably more powerful than the 83mm version and since mine has been running okay since 1988, I don't think you're going to have any issues as long as you have the Rad flow tested and clean out the crud in the block when you change the liners.

89mm liners will need a special gasket, but I'm told by Pete Cox (quality control at Moss) that there is a further worthwhile gain in bhp and torque and that the optional fast road cam works well with it.

I'm building an 87mm bore engine with a Kent fast road cam and will report back when it's running if anyone is interested.

Ash
 
Thanks for all the replys guys, much appreciated!

We've been trying to free it for some time now, it's been soaking for six months so I think we can pretty much rule out freeing it up. We'll be pulling the motor soon and once the head is off I'm sure that will seal the deal.

I just figured if there's a 20% off sale I may as well get in on the deal.

Cheers
 
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