Engine Knocking....

[Denis Sweeney]

Tried retarding the timing and had backfiring on the engine overrun, by the time I’d advanced the timing to stop the backfiring I was pretty much back where I started from.
Tried shorting out each plug individually and in each case plenty of sparks on the screwdriver and the engine died a little in each case, so I assume the plugs all ok.
Tried listening to the engine using a large screwdriver as a stethoscope, could not hear any knocking at the block or top head and neither on the crankcase at tickover or high revs, but she was standing still.
The dynamo and distributor gears sounded a bit rattley.
The carb does sound a bit sucky when I rev the engine and there is a distinct pause before the revs kick in.
But again driving her today she was pulling well once the timing was advanced back to where it was.
In ignorance I’m inclined to think it is electrical, but ignorance is blind!!

[Ruairidh Dunford]

The purpose of shorting the plugs is to take the load off each rod in turn to see if the knock disappears - this will give you an indication if it is one of the rods causing a problem.

Earth the top of the plug hard down on the head to stop it sparking and causing you further excitement.

[Denis Sweeney]

Ruairidh, little did I know, how little I know, about the little I know………..

[GCD]

Ref your first post - Had this sort of knock from my Mk2 Ruby - it was the grease nipple on the propshaft front UJ brushing the hand brake bracket, which was a bit on the loose side.

[Lowbarn]

Virtually all my knocks disappeared when I properly tightened the flywheel.
The problem was that the flywheel nut ran out of thread before catching the flywheel. 
Solved with a structural washer. 
Richard.

[Denis Sweeney]

An update, having failed to gain any improvement and Ruby sounding decidedly rough in higher gears, I took Ruby to the local A7OC East Kent meet and after many heads under the bonnet one brave but knowledgeable soul suggested a trip out in her, on return declared, cam end float, which had been mentioned on this thread.
Yesterday I removed the Ali casing over the cam timing gear and with a large screwdriver between gear and casing and was able to visibly see the cam timing gear move back and forth. I struggled to get a feeler gauge to the centre to carry out an exact check end float but a crude check with the feeler gauge between the gear edge and casing showed about 20 thou movement back and forth, a tad more than the .002” max.
So it looks like an engine out job, unless others no better………
On the positive side it will allow me to attend to a number of other minor issues that had appeared over time.
Interestingly I checked back over my orders/receipts from when the engine was rebuilt and nowhere can I see mention of cam bearings being replaced, other parts relating to cam were purchased but no bearings, so the ones in Ruby are those already in the engine?
I have noted Ruairidh’s post a few years ago referring to a Peter Lawson article in the grey mag, but if there are any do’s and don’ts I should be aware of, please feel free to advise.
Cheers

[John Mason]

Hi Dennis, Some time ago (I can’t find it on the forum at present) Hedd Jones put something on about removal and installing a camshaft without removal of the tappers and cam followers. If yours can be done in this way it should save a lot of stripping down although if I remember correctly the engine has to be out of the car.

John Mason.

[John Cornforth]

Hi

I appreciate that too much camshaft end float is not a good thing, but can someone explain quite why this makes an engine sound/run roughly ? I assume that 20 thou isn't enough to make the cam lobe sides clash with anything ?

When I rebuilt my engine years ago the end float was 4 thou. OK, I thought, i'll take it apart and correct it. After a couple of hours of failed attempts to get the gear off the end of the camshaft, I gave up and settled for 4 thou instead of 2. Should I have persevered ?

[John Mason]

I found the easiest way to remove the camshaft gear off the shaft was to put the shaft in the vice loose with only the gear stopping it falling through to the floor. Then placing two pieces of wood under the gear each side of the shaft to prevent damage from the vice. Then with a further piece of wood on top of the shaft to prevent damage struck it sharply with a hammer to break the taper.he presto it was off.

John Mason,

[Ian Williams]

It makes noise because as the loads reverse on the helically cut cam gears the cam shaft slams backwards and forwards clattering and also scattering cam timing