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MG MGB Technical - Engine making clicking sound
I have a strange clicking tinkling sound coming from my mgb engine, after having had it tuned on a rolling road, at about 2500 rpm, which disappears under acceleration. I have been told by a classic car restorer that it is not mains, big ends or piston slap, but rather is in the valve train. He then took £995 off of me to change the rocker shaft and camchain and tensioner, but no change in the sound. He now thinks that it may be worn valve guides - and it does burn a bit of oil on the overrun. He isn't getting another penny however! Any ideas from you clever folk as to what it might be?
Regards and thanks
|r j symons|
|Worn fan grommets can make a - possibly - tinkling sound. Run it with the fan belt off and see what happens.|
I've never heard of worn valve guides making a noise - smoke after a period on the overrun or idling yes. However if you get smoke *during* the overrun, then something is quite badly worn. Possibly also rings/bores, so do wet and dry compression tests as well.
Use a listening stick (long screwdriver) on the valve gear.
Diagnose, diagnose, diagnose before spending money. Especially with him ...
|Hi Rich, if you come down and say hello one day we would have a listen for you. I wasn't aware of any noises when you were on the dyno? You should have come back if you were worried you are always welcome. I can't see how it came to £995 to do r/shaft chain and tensioner.|
Paul is spot on with worn grommets on the water pump pulley, they can be very clattery.
Another favourite is the spacers rattling in the K&N filters or even the heat shield vibrating or touching bodywork.
Test filter spacers with engine off and thunp top of filter plate with hand, usually, if loose you will hear a rattling sound.
|Peter Burgess Tuning|
Many thanks for your replies. Paul - I will have a look at those grommets when I get a minute, and many thanks for your advice! And Peter, nice to hear from you again - I will certainly pop down sometime to take advantage of your ears! It started to tinkle on the way back from the dyno session (nothing to do with you, I know!) and has got worse since. Still pulls well though. I have had to reconnect the engine breather to the carb stubs as the smell of hot oil vapour was a little too strong in the cabin for me! And no, I couldn't see how rocker shaft and camchain and tensioner would cost that much money either - never again!
|r j symons|
Also have a tinckle at idle that goes as the revs rise, had a quick look last night after been out for a couple of hours and the carb overflow pipes are touching the back of the air filters. Need to have a look again and either shorten the flexi hose that connects the float chamber to the overflow pipe or fit some split hose to the pipe to prevent it touching.
|The overflow pipes can be close to the backs of the filters. The end of mine are virtually touching the carb ports, which gives a 1/4" or so gap between the bend and the filter base. If yours are closer than that you can probably cut a bit off the end of the pipe as well as shortening the hose to allow the two ends to almost touch.|
|Cheers Paul all done and sorted this morning another job fixed|
i had a simular noise from my b once. changed all the things you are talking about but still did not solve the problem.mine used to make a rattling noise as you changed up in every gear. did not find out what it was until i rebuilt another engine and put it in the car then stripped old one to have a look. the top piston ring on every piston was broke. don't know how or why but thats what it was ,.wasnt burning any oil.
|To be honest Bob the rings usually break when you remove the pistons from the engine because of the wear lips at the top of the bore.|
|Peter Burgess Tuning|
This thread was discussed between 15/09/2016 and 17/09/2016
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