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 MGB Technical - Mild rattle in area of mid-engine

I have a '72 1798cc B-GT which I have owned since a few months old.I can hear a mild rattle or tinkling sound in the area of the mid-engine. First thought it was tappets, but now advised it is not and could be the cam followers. Doubtful as they were changed 3,000 miles ago. Now thought to be possibly the camshaft. Oil pressure is good at just above 60psi but informed this has no connection to the camshaft. Car runs very well. I have heard that some cam followers can wear quite quickly, or not be the best quality so hoping this may be the case. Any advice and opinions much appreciated, as somewhat worried at what I may be looking at, or harm I could be doing to the engine of this much loved car.
JP Mitchell

The followers are the tappets!! Tinkling might be the timing chain/tensioner. Noises in engines are notoriously difficult to pinpoint.
Allan Reeling

As Allan said, plus, why were the tappets changed? Normally, if either cam or tappets is bad, both are bad and are replaced together.
Both are usually worn out on any BMC engine after about 50,000 miles. or much sooner if neglected or stored under conditions where condensation forms.

FRM
FR Millmore

At the end of the day, if oil pressure is good and the engine is running well then sometimes one has to wait till a new development. But as has been said, Cam, and followers( the little buckets thingies that lie in the chest of the engine behind the inspection panels.)and sometimes push rods need to be changed together. The timing chain will rattle as the slipper wears which provides chain tension,is another noise. You dont have big end knock or little end knocks which is a whole new ball game. Get an experienced person to listen, but it is difficult to diagnose on sound alone. It's not picking is it? MIke
J.M. Doust

Tinkling does sound more like timing chain - assuming it isn't the cooling fan grommets! Valve gear is more like a heavy tap, shove an old feeler gauge tween rocker and valve stem one at a time to find which one. New cams and followers *will* wear rapidly if you use the later API-rated oils like SM.
PaulH Solihull

Gentlemen,..many thanks for your advice. Probably best to follow J.M of Queensland and just take it easy and watch how things develop. Right now the car is running nicely. Thanks again.
JP Mitchell

My experience is that a tinkling or "jingle bell" sound comes from something loose. Frequently, this is with the exhaust system which can transfer noise through the pipe(s) and make a loose exhaust flange sound like an engine problem.

As to general diagnosis, the use of a mechanic's stethoscope, with its probe which can be held to various areas of the engine, is of great assistance. Held to the timing chain cover, it quickly allows you to diagnose timing chain slap. (The only time I had this problem, it sounded more like a grinding noise--as the chain ground against the inside of the timing chain cover, not a tinkling sound.) Another good diagnostic tool is the doctor's form of stethoscope which has the bell shaped end (not the pad, although one having both will work if the system is switched to the bell). This forms a directional microphone which can be pointed to various areas of the engine, allowing you to more clearly determine where the sound is coming from.

Les
Les Bengtson

This thread was discussed between 28/08/2011 and 30/08/2011

MG MGB Technical index

This thread is from the archives. Join the live MG MGB Technical BBS now