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TR2/3/3A My TR3 engine problems

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sammy

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I posted earlier about a source for rebuilt engines, but I have done some further investigations since then, but I still am stumped about the source of my problem.

Some background: Last week, my father (TR3 owner from 1958 until 2000) and I were driving my TR3 and all of the sudden a loud knocking was heard from the engine. We didn't see anything and limped a mile home.

Originally I though it was the transmission and I pulled it and started the engine, but the noise was still there. I pulled the clutch disc and the noise was still there. I pulled the oil pan and didn't see anything out of the ordinary. No metal fragments in the pan.

Here is where I get stumped. With the spark plugs out of the car, the flywheel turns smoothly when the starter is engaged and there is no metallic hammering. When I put the plugs in, the metallic pounding comes back. In addition, when the plugs are in and the starter is engaged, the flywheel moves forward and back a noticeable amount (as seen from sitting in the driver seat). This movement corresponds to the knock.

What could be causing this flywheel motion (and the associated noise) when the plugs are in, but not when the plugs are out of the car? I think I can rule out the starter since it was not engaged when the noise first appeared.

I will truly appreciate any advice you can give me.
 
Someone might want to correct me if I'm wrong, but isn't this a symptom of the dreaded thrust-washer failure?
 
Disconnect the battery, pry the ring gear back (the flywheel) then go up front and do the same with the crank pulley. Measure the amount of movement. If it is much more than a thick fingernail, I will concur with SammyB. You may have major damage! Surprised you didn't see anything in the pan, like little pieces of thrust washers. With the pan off, you can see the thrust washers by pulling the rear crank bearing retainer, at least in my TR6. Has this engine ever been overhauled?


Bill
 
If the thrust washer just wore or broke and fell out, the surfaces where they ride are probably still OK. Take off the pan, use your workshop manual and investigate this further. It is quite possible to replace the thrust washers in place from below.

Don't freak out (yet) and do not try to start the engine again until fixed! The pounding sound will eventually ruin the block!
 
[ QUOTE ]
What could be causing this flywheel motion (and the associated noise) when the plugs are in, but not when the plugs are out of the car?

[/ QUOTE ]

I agree with others... Sounds like it might be thrust washer related, but the severe knocking seems to indicate more than just your typical worn thrust washers.

When you have the plugs out, the engine cylinders have no compression, and there is very little stress on the crank. With the plugs in, you have compression and everything is under more stress and more likely to move in directions that it shouldn't move (the back and forth crank movement you're seeing).

Have you actually inspected the main (I think the center main is the only one you can get to with the engine in the car) and rod bearings? That would be my next step.
 
Thanks for the help so far.

The engine has been overhauled at some point. I know this because I did pull a connectring rod bearing and it was oversized by .010. I did put the torque wrench on the front and middle bearing cap bolts and they were properly torqued.

As of right now, I guess I need to see what I can access below to get to the thrust washers. I won't be able to touch the car again probably until next weekend. Any additional suggestions would be greatly appreciated.
 
Hi Sammy it sounds like to me that you have a broken piston. Try turning the engine over with the spark plugs out and look inside through the spark plug holes and watch the pistons. While you are watching the pistons from on top, also periodically look up from the bottom to see if the crankshaft motion coincides with the piston travel. The flywheel movement might be just the crankshaft being forced back that is if the movement is not too much. If I remember right the trust washers are only on the middle cap, so I guess you could drop the middle main cap and replace the trust washers while the crank is still in the vehicle. Never done it before, but I do not foresee a problem. If the problem is a broken piston and you are cheap (financially challenged)like me, you might find a piston on ebay or some other likely source and slip that puppy back in.
sp53
 
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