A friend brought his MGA over because he said the engine made a rattling noise. Like marbles in the engine.
He told me that he just had the engine rebuilt and has had this noise since.
After listening to it it has some serious noises. They don't seem to sound like rods or crank bearings. However it does sound like a cam rattle and or valve train. Thought I would adjust the valves just to be sure. They were slightly loose but adjusting them didn't help.
I guess my question is:

Is the cam chain adjuster automatic or can it be manually adjusted? Does anyone have any ideas on upper noises an MGA might make?
I have a TR3 and am not familiar with the particulars of the MGA.

Make sure it isn't the generator or water pump. I'd remove the fan belt altogether to be sure.

Thanks... that's my next step. Really hard to believe a newly rebuilt engine could make a such rattling sound. Hope your right and it is as simple as the WP or Gen.

MGA's have a rivited front pulley on the crankshaft. Its not a upper end noise but check it with the fan belt off and see if thats where the noise is comming from. Also when installing a new timing chain tensioner it need to be activated. There is a small bolt that needs to be removed and a small probe or allen wrench inserted and turned. This will release the spring inside. Then the bolt gets installed and the lock tab gets bent over in 2 spots. I hope this helps! Bob

It's been years since I fettl'd with an A engine so I can't recall how the fan is bolted to the pump hub... BUT: with a B engine the fan has rubber grommets and short sleeves at each of the four bolts. If the grommets aren't installed or are in poor condition the noises it makes sound like the engine is coming apart at the top end.

Can you not get your hands on a stethoscope or long screwdriver to listen to pump, generator etc. to isolate the region the noise is coming from?

EDIT: Bob's suggestion and info regarding the chain tensioner needs to be considered too.

Can the chain tensioner be adjusted with everything assembled? Does anyone know of a good service manual for download?

Tensioner is spring loaded and needs to be "activated" as Bob says, on installation.

There's this: Bentley Press

Not aware of a downloadable manual, tho.

I doubt it is the chain tensioner not unlathed, I took a engine aprt one time foir a rebuild, it had been smoking and was worn, but the guys was drivng it, took the timing cover off, it was a lte model MGB someone had converte to a double row and put a new tensioner on it, but they never released it, guy had been driving like that for years

I have a sound stethascope, but a mop handle can work just a swell, move it around to different location, and see if you can pin-point the area where the rattle is, you'll be surprised at how well that works.

Does the sound diminish or disappear upon pressing the clutch pedal? If so culprit is not in engine but throwout bearing.

Well have check all outside items. No help on removing belt, pushing clutch, adjusting valves.
Now going inside as deep as I can with out taking out the engine.

Saw a V12 Jag engine that was "professionally" done that made noise. Someone had left a piece of wire in one of the cylinders. Amazing how much noise it could make being banged around and the tiny dents it left in that chamber.

Removed the head to see what is going on. Not sure if this is an issue but the pistons have an "F" on top which I think means "F"orward. If so they are facing the wrong direction. The other thing I see is that there are two verticle lines embedded into the number 2 and 3 cylinder wall. Probably from not checking the ring gap.
Have thoughts that perhaps the rods are facing the wrong direction maybe hitting something inside the engine.
Will update as soon as I find more to list

On a MGA and early 3 main MGB the rods have offsets where they attach to the crank.(2 types of rods in there) I have never tried to install them in the wrong bores. I would think if the rods were in backwards they would probably not clear the cam. Bob

I believe the "F" is the grade of piston fit.


mark

What do you mean by "fit". Where would you find this information?

http://mahleclevite.com/p_heavyduty_engineparts.asp

I believe i have seen this somewhere...cant find it now. But basically pistons are graded by measuring their size very accurately, and then assigned a grade.

I just talked to a guy who used to run an LBC shop. He said that "F" is for reference to front and rear. That if the pistons are on the rods correctly the rods have to go in the right direction. This allows the rods clear the inside surfaces. May be my noise source... Let's hope.

not the first time i have been wrong, i stand corrected.

But i do recall looking thru a site *somewhere* that had piston listed by grade of fit....


mark

As i remember the grade mark is in a diamond stamp also.I have not seen these on repro pistons just factory ones. I look forward to the answer to this problem when it gets sorted out! Bob

Well after getting the above post information back to the guy who owns the car, he has called the place who rebuilt the engine. They are willing to repair and correct the mistakes at no cost. The owner has cancer and I wanted to resolve it as soon as possible. So he has time to enjoy the car in case his prognosis (spelling) is poor.
Will have to ask them if my findings were the problem and the corrects done to resolve the problem.