Engine Clatter

[davew1949]

Can anyone describe what little end clatter sounds like? My '65 Mog has reasonable compression, is full of oil and seems to go well, but is deafening when warm and revving a little. It clatters like mad and sounds like a hammer drill. However if I feather the throttle so it's neither pulling nor being pulled the sound goes quiet(er). Doesn't seem to make the noise when still though. I suspect this might be the small end bearings, but is there a way to tell without stripping the engine? Thanks in anticipation. Dave

[linearaudio]

More likely big-ends
A light rattle may well be the timing chain shot- they can make an awful noise when off-load.
You can get an idea of big/little end by taking the plugs out, turning each cylinder just over TDC so the piston is being dragged down the bore, then trying to push the piston down with a suitable rod/screwdriver through the plug hole. Takes a bit of a delicate hand, but you can feel a movement then a stop if there is serious play! Much easier to do the same with the head off, which is itself a simple task. Check the timing chain first, though!

[PSL184]

Sounds more like big ends (mains) to me..... Drop the sump and take the centre cap off (the only one you can do with engine in and its always the first to go).....

[linearaudio]

Hmmm...Like to agree with PSL about the big-ends, not so sure about the mains! Unfortunately the rear main also gets a hard life, and isn't so easily accessible. If it is mains making a deafening row then by this time you are looking at a crank grind and undersize shells (mains start as a low clatter, particularly on first start-up of the day), and get slowly worse. Big-end clatter increases much more rapidly! Big end rattling will possibly get away with just new shells.

[MarkyB]

Shot big ends will lead to no oil pressure, does the oil light work?

I'd suggest tappet adjustment and timing chain replacement as long as the oil light isn't coming on with the engine running.

[bmcecosse]

It's certainly not going to be 'little ends' - where did you get that idea?? It will be crank bearings - big ends and mains. As others have pointed out - you need to lift the engine and exchange the crank for a reground one with new bearings. And fit a new oilpump - and check the oil filter parts are all present and correct.

[davew1949]

Thanks one and all for the info. I have been told it's probably not big ends as the oil light works (i know that isn't definitive) and no rumble on start-up. Thought it might be little ends as it's a bit higher up the frequency range than a rumble. Seems i might be wrong in that department though.

Looks like I have a bit of work to do - oh well that's what keeps me so young and attractive to women.

Thanks for all the hints,
Dave

[MarkyB]

Checking the tappet clearances isn't exactly hard labour

[davew1949]

You're absolutely right Marky, checking tappets isn't difficult. I did that quite recently so I'm pretty sure my "little" noise isn't tappets. I have a feeling it is a bit more "challenging". Still that's what winters are for isn't it?
DaveW

[IslipMinor]

Dave,

Where do you live? Is there someone from this forum that could have a listen to the engine?

[davew1949]

Hi Islip, I live on the Bromley - Kent area. If there is anyone knowledgeable in the vicinity who could have a listen that would be great.
Cheers, DaveW

[bmcecosse]

You described this as 'clatter' - which is what has led us all to suggest bearings......but is it perhaps timing chain 'rattle' or more simply - 'pinking' from over advanced ignition timing? An obvious help would be an oil pressure reading (THE essential extra before ALL others) - or as Richard suggests - a second opinion.

[Neil MG]

You described this as 'clatter' - which is what has led us all to suggest bearings......but is it perhaps timing chain 'rattle' or more simply - 'pinking' from over advanced ignition timing? An obvious help would be an oil pressure reading (THE essential extra before ALL others) - or as Richard suggests - a second opinion.

Agree absolutely, it might even be tappets!