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TR2/3/3A My first new pistons(1970)

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mctriumph

mctriumph

Jedi Knight
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Spring of 1970 my POS 59 Tr3 needed new pistons/liners. Warshawsky's catalog had a set listed for 90 bucks
so I blew the budget and got a set. Crawling in the gravel of the "house " I shared with my BFF, I did an in car overhaul
of the old girl, as best as such things can be done, under the shade tree. When installing the pistons , I put plenty of STP on the
bearings and for good measure a dollop on the piston rings too. This thing had had the head shaved a fair bit and
at a guess the compression was a lot!
Ran great, but the rings NEVER seated ! Turns out rings must be installed dry ! Burned as much oil after as before.
Mad dog
 
I have heard stories about people using scouring powder (Ajax in the UK, Comet in the US) for rings which don't seat. Seems extreme, and I don't know if I would risk it !

I saw another post from you where you say not to oil the rings when rebuilding. I hear you, but I would hazard a guess that many will disagree.
 
auprichard said:
I have heard stories about people using scouring powder (Ajax in the UK, Comet in the US) for rings which don't seat. Seems extreme, and I don't know if I would risk it !

I saw another post from you where you say not to oil the rings when rebuilding. I hear you, but I would hazard a guess that many will disagree.
Click to expand...
 
Rebuilt an MGB 1800 engine many years ago.
Ran beautifully. Gave it back to the customer.
Came back a week later it was smoking its nuts off. Turned out he had left it just sitting in his drive idling for hours on end.
Needed a strip down, bores honed new rings
 
The dry piston ring trick is from THE Guru and famed race engine builder Kent Prather. Enough said.
I have seen the Ajax trick work like magic on a big Healey,Freshly built engine smoked endlessly. 10 minutes
later it didn't.
Mad dog
 
mezy said:
Rebuilt an MGB 1800 engine many years ago.
Ran beautifully. Gave it back to the customer.
Came back a week later it was smoking its nuts off. Turned out he had left it just sitting in his drive idling for hours on end.
Needed a strip down, bores honed new rings
Click to expand...
Was this with dry rings or oiled rings or he just ran it idling for too long?
 
Drive for at least 30 minutes, revving from 2500 to 4000 rpm.You are of course running a premium
breakin oil( like the pro's ) for the first 100 miles . Then you change the oil and filter, to your regular
oil of choice making sure you add ZDP to protect the cam/lifters.
Mad dog
 
All I can say about Ajax and dry is...OUCH!! I am sure both would work to seat rings, but you are taking a lot of miles out of the engine doing it.

The TR uses plain cast iron rings against a steel cylinder. You must break them in old school. After getting the engine running, take the car out on a decent, not busy road. Get up to 4th gear and floor it to 60mph. Once reaching 60, let off the gas and coast back down to 25-30mph. Do this about 10-15 times and you should be good to go. The full throttle accel loads the rings against the cylinders and heats them up. Coasting sucks oil into the rings, lubricating and cooling them.

This is not my idea...it is straight out of the older service manuals, and is long forgotten from before modern chrome moly rings and special cylinder wall coatings to promote ring sealing. The engine must be loaded to seat the rings. If they are not loaded early in their life to seat, then the cylinder will glaze over and they will never seat. The fix for non seating is to take the engine back apart and re-hone the cylinders. Then immediately do your seating drive.
 
The end of the piston story was these poor old slugs got re-used a few years later, in HP"s tr3.
After he smashed it up and scrapped the carcass, Don W. put it into his Tr2. Then 35 years on ,
when Don's Tr2 got a frame up, the numbers matching motor went back in. I got the core
which hid under a bench till It was scrapped. BUT I still have the pistons!! after 50 + years.
Mad dog
 
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