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MG MGA - Engine has unusual ticking noise

Guys,
Yesterday, as I was arriving at work the engine in the MG developed a distinct ticking noise. I went out at lunch time to check it out. Pulled the valve cover off and observed/listened to the valve train. The rockers and such seemed fine. The ticking seemed to be coming from the right side near the front of the block. Ticking definitely speeds up with RPM increase. To be safe I had it transported home on a roll-back. Somehow they managed to knock my muffler off, so the exhaust is so loud I couldn
G T Foster

Gerry, Assuming that you are using the "right side" of the block to indicate the side with the distributor--the right side as seated in the driver's seat, that pretty much limits what is in that area. The distributor, the oil filter, the tachometer drive, and the dipstick are on the right side of the engine (as I remember it--do not remember exactly where the tachometer take off is as it has been a while since I looked at an MGA engine). Using your mechanic's stethoscope around these areas should give you an idea where the sound is coming from.

On the left side of the engine are the tappest, pushrods, and cam shaft. A sticky tappet or bent push rod might cause some form of clicking sound with mechanical tappets being noted for this even when in good condition. Both the use of a stethoscope and the measuring of the rocker arm/valve stem clearances would be in order.

One of the more commonly found causes of a "clicking" sound is the stretching of the timing chain. Called "timing chain slap", the times I have encountered it I heard it as a clicking sound somewhere near the front of the engine. Again, the stethoscope is your friend and will allow you to hear more accurately where the sound is coming from.

These are the common things causing a clicking sound. One very uncommon cause, which I have only seen once, was the loosening of a big end of a connecting rod. This caused a sound, heard as a "clicking sound" as one bolt had loosened slightly and the lock tab had broken. But, this was some 40 years ago on a Mark II Sprite and I have not seen a similar instance since then. But, worth keeping in mind if you do not find the cause elsewhere.

Les
Les Bengtson

Is it "all cylinders speed" or "single cylinder" Answer might help others diagnose.
Les, Tach drive is on the LHS (camshaft side)
Might be a leaking exhaust gasket. Had this on my V*lv* and it was v much like piston slap, or small end noise.
Also, does it get louder with rpm or load ?
Art Pearse

Gerry, another place you can look is your generator. If you have commutator problems, usually the contact sectors will come loose and you can get a fairly loud clicking as the brushes come into contact with the raised commutator contacts.
Mike Parker

I think the same as Mike - the only time I had that type of sound - I was 100 miles from home - drove all the way home and tried to ignore it. When I finally found the source it was one of the bolts holding the dynamo had come loose and the armature had rubbed against the back end plate making it unusable. I was amazed that it still produced a charging current. It cost me the price a 2nd hand dynamo (15)-cheers Cam
Cam Cunningham

Yeah Cam, that WAS the voice of experience speaking.
Mike Parker

While you are in there checking things out, Check out the riveted pulleys on the generator and crank. They have been known to breate this type of noise.

Chuck
Chuck Schaefer

Thanks for the input..
Yes, it's the distributor side of the motor. It does get louder with RPM and it does appear to be a single cylinder type of frequency. My ear tells me it's coming from about the number 1 cylinder. The alternator is a fairly new unit and appears solidly mounted. One of the first things I will do (after I reattach the muffler) is run it without the fan belt. At the club meeting tonight it was suggested that a broken piston ring could cause a noise like this. Time will tell....
Thanks,
Gerry
G T Foster

Gerry,
I don't think you have a problem with the alternator, I thought you had a generator.
Mike Parker

Gerry, pull the plug wires one by one and see which cylinder it is - noise should reduce if it is big end or small end play. It does not sound like valves.
Art Pearse

Gerry, if the ticking noise is coming from the front lower part of the engine near the timing chain cover it could be the oil thrower disc catching on the inside of the timing chain cover. I had the same ticking noise on my 1600 when the oil thrower disc disintergated. It's a failry easy and cheap fix. Use a stethoscope on the front of the timing cover and see if the ticking is coming from that area. It could also be a worn out timing chain tensioner causing the chain to catch on the oil thrower or something else.

Good luck,

Andy
Andy Preston

Dip stick touching the crank....?? Pull dip stick out and see if there are any rub marks on it...just a thought. Had it once in a non MG car, rotated the dipstick and all fine after that.
Peter Steyn

Hi Gerry. Location of noise is sometimes hard to pinpoint. I had a similar ticking, which turned out to be an extremely worn out carbon clutch release bearing. My noise sounded like it was coming from the front of the engine also. The clutch still worked fine, and Could still shift the gears without grinding....Glenn
Glenn Hedrich

A common problem with "B" series engines is no. 3 cam lobe/follower "clicking" or "ticking" away. My repeated attempts to overcome this (with my two MGA's) have not been successful in the long term. I do not know the reason but suspect that perhaps this area must be in a "shadow" that does not get as much oil as other cam lobes, thus additional (slight) wear and reduced "cushioning" of the cam lobe/ follower impact. Admittedly the cam is on the "left" side of the motor but the exact source of the noise is difficult to pinpoint. There does not seem to be any detrimental affect on the life of the engine and is mainly audible at idling. Might not be the answer to the query but just my experience.
Barry Bahnisch

Well,
I don't know if this is good news or bad news, but the ticking has mysteriously stopped. Was going to troubleshoot it Friday night. When I started the engine, no ticking occurred. I let it warm up, drove up and down the road, no noise. What now? I'm a bit nervous to drive too far for fear there is a problem lurking....Aaarrraaaghhhh!

GTF
G T Foster

OK Gerry, go back through the suggestions above and rule out those that cannot cure themselves!

Seriously though, it sounds like you need to drive it more (the equivalent of your trip to work) to get it to warm up fully.

It could have been a leak from the exhaust to manifold (sometimes sounds like a ticking) that was fixed when you fixed your exhaust (If you redid the front).

Neil
Neil McGurk

This thread was discussed between 03/11/2009 and 09/11/2009

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