TR4/4A TR4 Engine noise

[autoheart]

So it's either start antipsychotic meds, or figure out this noise. Here's the story, sorry for the length...

Engine rebuild last fall due to a knock from excessive crank end float - found a bad spacer and replaced it - this noise is different. Ground the crank and installed new bearings, upgraded rear main seal, replaced timing chain and tensioner, etc. Did not get into the cylinders, pistons, rings, etc since compression was good and burns little oil.

Now there's a "whacking" noise that sounds like it comes from the front of the engine. Not there when cold, and almost inaudible at idle up to around 2000 rpm. Loud from 2000-2500, then seems to ease up above that. Doesn't seem to be related to load. I've been all over the engine with a stethoscope but can't seem to locate it. I really have no clue, except maybe (just maybe) I screwed up the connecting rod bearing caps...

Anybody a "car"diologist who can help with this?

Joel

 

[AltaKnight]

its' tough to diagnose descriptions of noises.
If you didn't do any work on the pistons/cylinders and you didn't do any head work then we can likely rule them out
If it sounds a deep/heavy noise then it's probably time to spend some more quality time under the car checking the reinstallation of the crankshaft and bearings. You did make sure the caps were on the correct rods and the right way round?
The only other thing comes to mind is the timing chain tensioner, the TC can make a devil of a noise if it's flopping around not to mention damage.
Have you driven the car with the engine under load or is it still in your garage following the rebuild?

 

[autoheart]

Thanks Graham. As I tried to imply, I wonder if I messed up the cap/rod matching. It's one of the mistakes I can't exclude. Would that fit the description? It is on the road; I don't think the noise level is any different under load than not. I'm pretty sure, based on the stethoscope and the quality of the sound, that it's not the timing chain. I could drop the pan and check the rod caps...

Joel

 

[poolboy]

See if the crankshaft damper (pulley) is loose on the nose of the crank.

 

[vivdownunder]

Disconnect the fan belt to prove it isn't in the generator, water pump or fanbelt itself.

Wide fanbelts with inside cracks can make metallic noises like a broken timing chain tensioner.

If it has the fan, check a blade isn't fatigue cracked and about to part company.

A deep clunking sound from the front could be camshaft end float. No big problem as it's more annoying than urgent.

Viv.

 

[glemon]

I started to put a rod cap on in the wrong place once, when I startef to torque it down the motor not longer wanted to spin, I figured it out before I scored anything, did the motor spin relatively freely as you put things back together?

 

[LBCs_since_1988]

The only other thing comes to mind is the timing chain tensioner, the TC can make a devil of a noise if it's flopping around not to mention damage.

I second that! It happened to my TR4A. Noisy. I thought it was my water pump but it turned out to be a broken timing chain tensioner.

 

[karls59tr]

I had a similar noise that sounded like serious engine internal problems on my 3. it turned out to be that the "key" on the water pump shaft had worn a 1&1/2" groove inside the pulley housing causing the key to bang back and forth in the pulley! Take the belt off and see if you can move the pulley back and forth on the shaft.

 

[MadMarx]

Question:
As we are talking about NOISE.
Why not making a recording of that noise and publish it to youtube or elsewhere?
Better than guessing is hearing.

Cheers
Chris

 

[autoheart]

Ha! I am *so* excited.... It was the fan belt after all... When I did the engine I had to replace the water pump after I noticed the noise and it persisted, so I knew the pump itself wasn't the culprit. And in conjunction with the rebuild I put a new fan belt on (one of the "cogged" ones from Moss). Anyway, I just loosened the tension on the fan belt and it went away! I can make it come and go, so I'm sure that's what it is...or at least something it rotates on. I'm just overjoyed I don't have to go back into the engine...

I love this list. Thanks everyone.

Joel