MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

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 - Timing Chain Tensioner

Well, the engine should be back from the machine shop soon and I have begun to evaluate my other engine parts and fittings. I was inspecting my timing chain tensioner and since this is my first restoration, I don't know what is acceptable and what is not. Attached are several photos showing wear in the tensioner assembly. Should these parts be replaced?

Thanks for any help you can give,
Jim Smith TD17744




JV Smith TD17744

Last photo

JV Smith TD17744

Doesn't look too bad to me, so long as there isn't excess slop.
Steve Simmons

Should run another million miles if you are going with stock cam & springs.

If high performance cam and springs, I have recommendations.
JIM N

Jim,
Your comment interests me. I am installing one of Len Fanelli’s fast road cams and roller sets. Engine will be 0.100” over and CR about 8.5:1

No racing, just want better performance with new 4.3:1 rear end

Advice?

Jim
JV Smith TD17744

The tensioner foot and spring are relatively inexpensive. Especially since you are going with some higher-output parts, I would change them both.

Tom Lange
MGT Repair
t lange

With a roller lifter cam installed in a fresh rebuild, while initially rolling engine over with the starter (no plugs), there was a strange noise eminating from the cam chain cover. After removing it, I could see the high pressure springs on those steep slopes were snapping the cam forward, whipping out all the slack, maybe 5-10 degrees. The cast iron tensioner foot was bouncing violently against its housing. I recorded it on video but can't post it here. I've read about broken tensioners and can see why. It seemed to quiet once oil pressure built up, but there was no way to visualize it with the cover off as oil was slinging everywhere. Some say the tensioner builds up oil pressure, but that's not the case as the chain oiler hole in the foot leaks it out as fast as the tiny hole supplies it. It DOES provide some hydraulic dampening, though, to tame it down.
My first reaction was to buy a new chain (German iwis) and sprockets. The slack was cut about in half, but the action didn't completely disappear.
My next move was to slip a couple of hydraulic seals in behind the foot to take out the rest of the slop. The chain and tensioner settled right down.
Am I concerned? I wouldn't have bought two more cam sets if I were.
Could I maybe have stuck in a weak, incorrect spring? I doubt it as of all the springs that came out, that's the one that fits best in the tensioner. Anything stronger would exert excessive force on the chain, in my opinion.

It reminds me of one of my favorite drag racers, Sneaky Pete Robinson. He put his dragster on a chassis dyno with timing wheels on both of the 427 Ford SOHC motor cams and came to the conclusion the exhaust events were retarding 4 degrees at high revs from the long chain network, leading to blower explosions. He replaced the chains with gears.
JIM N

Not wanting to sidetrack the thread but…Those SOHC 427 side oilers had a long ar*e chain! Those were and are awesome engines to hear running. We had a local drag racer that was running vintage SOHC in his 55 T Bird running on a 8.50 index bracket racing back in the 70’s. It was a handful and fun to watch.
W A Chasser

Thanks,
I think I'll just put in a new tensioner assembly.
Jim
JV Smith TD17744

This thread was discussed between 06/02/2022 and 21/02/2022

MG TD TF 1500 index

This thread is from the archives. Join the live MG TD TF 1500 BBS now