Classic cars forum & vehicle restoration.

[47Jag]

Stuart,

This is why I suggested you got a speed reference. From what I saw of your original video I felt that it was faster than crankshaft speed and so it seems. You were getting two strikes per rev. Wouldn't the simple solution be to take a number 9 knocking stick and re-profile the baffle? Looks like GONEPS got it spot on.

Art

[Stuart2u]

Hi Art

Having been under again for a further closer inspection, I suspect that when the engine was assembled it was noticed that a lobe and or a big end bolt was striking the baffle. This resulted in the grinding work on the offending lobe. The other three lobes have not been assaulted in this way.

Not sure about the big end bolts as the split pin is fitted in an unusual way, to my mind, in that one 'tail' is wrapped over the end of the bolt end (see picture). This method in itself extends the length of the bolt by the thickness of the pin. If they had been striking the baffle to cause the gouge marks I would have expected damage to one or both of the split pins, but as you can see they are fitted tightly in place and show no signs of any contact. Maybe the bolts were shortened at that assembly stage.

On that basis if the bolts are not now striking the baffle, it could be that the lobe is still the offending striker but I cannot see where it might be catching as the entire curve of the lobe is ground to bright metal with multi faceted angles.

I have already changed the split pin arrangement on the big end bolts so that the pin tails wrap around the flats of the nut making sure that the tails do not twist around into harms way. Is my way correct or is the way pictured the recommended way?

I thought about 're-profiling' the baffle, but am just a little concerned that once I start banging at it, it is going to twist out of shape elsewhere. Would it really matter if the offending areas were cut out?

I am guessing that the baffles purpose is to stop oil surging around the sump under high speed cornering and acceleration!!!!!!Would a couple of holes make a difference?

Stuart

[Penman]

Hi
What are the odds that it is the split pin ends?
I know the loops goes into the castellation but I was told to do them 90 degrees from that and wrap the tails round the nut rather than over the thread end.

I have been told the RR have their split pins made with a 90 degree twist so that the loops go in to the slots and you can still wrap the tails round the nut

Another alternative is to use proper locking wire.
_________________
Bristols should always come in pairs.

Any 2 from:-
Straight 6
V8 V10

[ukdave2002]

Hi Stuart

hopefully you have found the source of the noise the baffle plate scores do look fresh.

I don't think your engine has had liners fitted, its difficult to be certain from the picture.

Most M8 engines haven't needed liners yet, as the bores wear much less in relation to crank journals, many engines would only need a rebore every other rebuild, I think pistons are available up to +50" thou, so in theory engines may only need liners after 10 rebuilds

Keep us posted

Dave

[Stuart2u]

I cut out an irregular shape encompassing the two gouge marks....without cutting through the edge of the baffle. I folded the edges over a little to try to maintain rigidity. I also re-routed the split pins so that they securely wrap around the nut flats.

Everything went back fairly easily. Fired her up and..............................NO NOISE!!!!!!

A big thank you to every one who contributed to resolving this.

Stuart

[Rosco663]

Excellent result Stuart It's always good to see the forum coming together and providing assistance with all things mechanical. It has been an extremely good resource to me in the past as I'm sure will continue to do so in the future8)

Cheers
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Rosco