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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - TF Aerolite STD piston wanted

I know it’s a long shot, but I’m calling out for one replacement, used or new, Aerolite TF 72mm STD piston and rings. My best guess is the edge of #4 piston crown was chewed up by alumimun schrapnel after a blower self destructed. Top ring survived but the #2 ring, land and oil ring didn’t. Fortunately, the bore, head & valves look fine. The Aerolite pistons seem to be sold exclusively by Moss and it has the skirt cavities that provide heavy reinforement that traces back to the old German Mahle pistons. They want $450 for a piston & ring set. If I have to, I‘ll probably settle for a set of 4 conventional slit skirt pistons for $250, but I prefer the Aerolite. I have another set of them waiting to go into a 1250 XPAG. Know of any kicking around?
I got a 1250 piston in & out the bottom of another engine past the stock crank but the 72mm piston is too large to work by the beefier Moldex crank. I think I'll try dropping the crank out with the engine in the car.
Jim Northrup
jrnorthrupsr@Yahoo.com
JIM N

Jim
Would it be worth contacting Moss and asking if they can supply a single piston/ring set.
William Revit

I gave that a try since there was nothing to loose.
They don't have any broken sets and won't separate any from a set.

I'd have bet money that'd be the answer. There's one oversized pistons set they discounted $2000 since it is missing one 2nd compression ring.
JIM N

There's a set of 3 new (std size) on ebay today for $175

auction #364544830187
J Stone

Turns out, 2 pistons had broken lands. #4 cyl had about 1 1/2" of land broken between compression rings. The top ring was intact which is odd. #4's second ring was fractured and the oil ring was pinched/damaged, likely when that piston started to seizing. That cylinder was already down 20 lbs of compression and burning oil. #2 cylinder had about 1 1/2" fractured, too, but the rings were all good. I now think there was no foreign material that bound up in #4 and have to think the ring lands were the cause and not the effect. The 1250 Aerolites I'm installing in another engine have compression rings 0.090" thick and similar dimension lands but these 1500 rings are down farther from the top so there isn't too much room- rings only 0.0625" and about the same for the lands. The chunks of lands were sheared off sharply along the inner corners of the ring grooves, like a brittle fracture.

I'd known the engine was smoking a touch but ran fine with one ailing cylinder. I planned a teardown but we were limping it to our MG Club's Champagne Brunch when it started slowing down and smoking worse. We were stranded halfway there and missed the festivities (there went our $50, too). A buddy picked us up and we returned to the TD with our box truck and tow dolly. There was downpour, the night before, from the tail end of that week's hurricane. When we pulled in front of the MG, the truck's front end buried down into the muck down to front bumper and the right dualies were buried up to the axle. It was listing badly, too. An hour and $125 later, the wrecker had us out and we parked in the garage at home. Ironically, it ran just fine from the house to the shop for rebuild.

When it started siezing, we were only doing about 50mph and the temp was a nice, cool 190F, where the thermostat fully opens. This engine barely has 1000 miles on the Aerolites and I don't believe there were any highway miles on them. We've only burned premium in it and never had a hint of pinging. There’s no telltale deformation at all from detonation, especially since the top rings were all intact. My last TD engine teardown had 3 broken top rings but that had a good 20,000 miles of supercharged driving on regular gas, and still ran well with just a hint of oil smoke and pretty decent compression.

I scored a set of pistons from Abingdon Spares for a paltry $250 and fortunately, they're NOS with a date of 30/08/91. The make is not disclosed but they’re 3 ring, full skirt construction with the sunken stiffening ribs in the skirts like the original TD pistons. The rings are 0.080” thick and lands about the same. I had to measure skirts to figure out pin offsets. The STD is the only markings and one piston reads STD towards the front of the engine and three are facing the rear. I double checked the 1500 Aerolites and they are symmetrical, no offset. Hopefully, it’ll all be buttoned up this week and I hope to never see these pistons again.
JIM N

J Stone,

Thanks for the heads up. They're not STD but 30 over. There's a 30 stamped on the top and the box parts number indicates 1250 +0.030 on Moss. "3 030" and "1 020" are penciled on the box so I wonder if that was a mixed set for some obscure reason. I needed 72mm STD 1500 pistons. Am very happy I scored a good set from Abingdon at a low price.
JIM N

Try Egge Machine in California. They should be able to make whatever you need.
Steve Simmons

Hi,
I might have a single std XPAG piston for you or do you already have one.
Contact me at erikvanhardeveld@online.nl
Erik
Erik van Hardeveld

This thread was discussed between 24/07/2024 and 20/09/2024

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