Severe Knocking - A10 Road Rocket

[Brucie64]

Hi bsa-bill,

Thanks for your input, lordy lord...I wasn't aware there was a sleeve that sits on the crank, I removed the primary side locking nut, large spring, engine sprocket locator bush type thing and the engine sprocket itself. Does the whole assembly also sit on another sleeve?

Regards
Bruce

[bsa-bill]

Hi Brucie
I refer to part 67- 1134 in the pic as the sleeve, maybe it's what you term the engine sprocket locator bush type thing in which case you have it off

[Brucie64]

Hi bsa-bill,

Nope, looking at your diagram I am now thinking I may have left the sleeve on when attempting to wiggle the crankshaft up and down, I can't remember taking it off (there's old age for you).

The "engine sprocket locator bush type thing" I was referring to was actually 66-1135, I just couldn't remember its correct name.

I will check tonight when I get home from work for sure and report back, lets hope the sleeve is still on and I don't have a drive bearing issue after all.

Thanks again for all your help, most appreciated.

Regards
Brucie

[duTch]

 I also had a thought earlier, if you ccrank nut (67-1137) was done up tight-tight...?

[Brucie64]

Hi duTch

No it wasn't done up particularly tight to be honest, it obviously wouldn't have come off due to the split pin though. It shall be a bit tighter when I put it all back together again. What's your thoughts on this?

Cheers
Brucie

[duTch]

 Is there any gouges in the chaincase outer? If it's been loose, it'll try and machine its way to freedom and make a racket

[muskrat]

That might be the problem. If the nut wasn't tight end float would be compromised and get louder the "less tight" it becomes. The nut should be tightened to 65ft/lb = tiger tight. Do it up and check it all again (easier if you leave the spring off to check it all).
Cheers 

[RichardL]

Brucie:

It seems that there is a lot of dancing around the very real possibility that what you have is a spun rod bearing. Here is a link to a video I sent off to SRM asking about a noise in my engine back in 2007, I think.  https://www.youtube.com/watch?v=T9grUuIEzM0

What SRM said was: "Don't start it again, it needs to come apart." What I found was a spun bearing which I have come to blame on not having cleaned out my sludge trap before rebuilding the engine. Everything I know I learned by doing wrong, twice. 

As a side note, the Jaguar that I briefly mention in the video was sold off so I would have room to rebuild my engine a second time (and also because I had had it for 25 years with very little progress since installing the Chevy engine).

Richard L.

[RichardL]

Let me add, I completely support and understand the idea of ruling out everything else possible before splitting the cases.

Richard L.

[trevinoz]

I guess the big ends need a look see now.

[muskrat]

I watched the video and kept shouting at the screen, STOP, STOP .
Trying to diagnose a noise that we can't hear, half way round the world is a challenge.
Cheers

[Butch (cb)]

Let me add, I completely support and understand the idea of ruling out everything else possible before splitting the cases.

Richard L.

By chance, and as an aside – my pal is bidding on a Moto Guzzi V50 on ebay at the moment. The bike is a mk III but with a mk II engine, and in a separate sale the vendor has listed a working mk III engine. Story is that the original bike started making some ‘orrible clattering noises and so he sourced and fitted a  good second hand engine. The noise persisted and was the found to be due to loose bolts in the rear drive box. So not directly relevant in this instance, but a good pointer to getting a reasonable diagnosis before going too mad.

[Topdad]

Only goes to show "Never assume - it will make an ASS out of U and ME..... but how often do I forget this simply adage, Bob

[RichardL]

I watched the video and kept shouting at the screen, STOP, STOP .
Trying to diagnose a noise that we can't hear, half way round the world is a challenge.
Cheers

B,b,but, there IS audio on the recording and some obvious clanking that turned out to be something serious, as SRM apparently perceived. I like to think they have/had heard many A10 engines in trouble with similar sounds. I DON'T' like think, nor do I believe, that SRM was just trying to assure that I would buy a new gasket set from them. The bigger issue, I tink, is that we don't have a recording of Brucie's noises. It is going to be interesting whe Brucie unearths the actual problem.

Richard L.

[duTch]

 I had another thought too, that due to  the loose nut, the cush cams wouldn't have the necessary tension on them and so they could be slapping against each other...to add to the effects of the escape plan...
 I had a busted spring last year, and it was doing something weird but I can't remember what, but it made me investigate.
Thing is, I don't like the replacement spring- it's a few mm shorter than the old one and also ~3mm larger diameter, both of which have reduced the pre-load, so sometimes when I startup, there's a bit of clunking going on that I attribute to same lack of correct pre-load....