A10 RGS spec engine clicking noise

[Evan91b]

Right, so I've removed the rocker box and the noise has disappeared. So I'm thinking definitely valve train. Are the cam followers able to be removed with the head and barrels in place? Because mine come up against a stop, I was only using the suction of the push rod in the cup to pull it up, but it hits something metal and has a similar sound to what was happening, but I belive that would be much greater than the full lift position.

Rockers are free to move although one is slightly stiff if rotating well past the full lift (down position). Springs appear good aswell and no bent push rods.

Evan.

[Evan91b]

*Another update*

Removed both timing covers and the camshaft gear but was loose but the lock tab stopped it coming undone much. Was only less than a flat of course and can be seen after tightening compared to the lock tab. The pulley is tight on the key way so perhaps this could have been the issue?

Also the gear to the right (idler I think it's called) it has end float in and out when the casing is on and the dynamo pulley. There weren't any spacers or shims on anything. But I can't see that causing the noise.

Evan.

[chaterlea25]

Hi Evan,
If the camshaft moved inwards the lobes may have tangled with the adjacent follower , spacings are quite tight  in there
You would need to lift the cylinder to inspect the followers
The cam gear is pushed against the casing bush face by the breather top hat and its cork washer , the cork washers come in different thicknesses as it needs to be compressed a little on fitting.
The idler gear end float is usually taken up by a cork washer between the dynamo sprocket and the casing

John

[Evan91b]

Hi Evan,
If the camshaft moved inwards the lobes may have tangled with the adjacent follower , spacings are quite tight  in there
You would need to lift the cylinder to inspect the followers
The cam gear is pushed against the casing bush face by the breather top hat and its cork washer , the cork washers come in different thicknesses as it needs to be compressed a little on fitting.
The idler gear end float is usually taken up by a cork washer between the dynamo sprocket and the casing

John

Thanks for the Info John,
I did a bit of temporary adjusting and fitted a piece of rubber behind the dynamo pulley to remove the end float (gasket set was wrong so need some Cork washers). This had cured the noise and seems much better now. I had removed all the play in the rockers first and this pretty much stopped the clicking too so I knew then it was at the idler gear.

Hopefully when the new gaskets get here I can re fit and test. Push rods were a pain to get right, not sure how I can do that with gaskets and sealant on there. I've heard there's some metal gaskets for the rocker box?

Evan.

[Minto]

Copper rocker box gaskets all day long, contact TT John on here, about 18 quid a set, bloody brilliant!

[chaterlea25]

Hi Evan
I do not think the idler/dynamo drive was the cause of the "pinging"
It had to be the camshaft that was drifting over to "pick up" the adjacent follower and then when the pressure came on it slipped back into place dropping the valve onto its seat

John

[Evan91b]

Hi Evan
I do not think the idler/dynamo drive was the cause of the "pinging"
It had to be the camshaft that was drifting over to "pick up" the adjacent follower and then when the pressure came on it slipped back into place dropping the valve onto its seat

John

I suspect the camshaft had made things worse because the noise had got a lot worse after I rode it yesterday. Then after tightening the camshaft nut and turning it over, the noise was still very faint. With no shim or washer behind the dynamo pulley the noise can be heard, but take up the end float and it goes away. That's why it pointed me to this? With the camshaft nut nipped up there doesn't seem to be any end float there unless it's very minimal. But when the nut was loose there was movement which I assume was the knocking and as you say too.

Evan.

[Colsbeeza]

Hi Evan,
I re-checked my cork idler seal two days ago and took detailed measurements with a vernier, as I had the dynamo sprocket off. The cork was still in good nick. They come at about 4mm thick, so need to grind it down a bit. I trimmed the cork down on my bench grinder and finished it with sandpaper to 3.1mm.  I have attached my calculations, and a picture of my cork "dolly" - the nearest bit of dowel from an old pine chair. It measures 15mm diameter, and the cork was a nice firm fit on the dowel.  It pays to allow a little bit extra for some compression. It took up all the endfloat ( I had a fair bit - 1.2mm ). Other owners say if the cork is too thick, it will disintegrate under excessive compression. Also oil or grease lightly for some lube for startup. If you do a Forum search, I know a couple of perfectionists have machined the cover to take a proper seal - a modern engineering solution. The cork solution is satisfactory if the right thickness. Check that the idler pinion is firmly keyed to the shaft and hasn't moved outwards. I will also post this in a more relevant section on Idler Seal.
Col

[Evan91b]

Hi Evan,
I re-checked my cork idler seal two days ago and took detailed measurements with a vernier, as I had the dynamo sprocket off. The cork was still in good nick. They come at about 4mm thick, so need to grind it down a bit. I trimmed the cork down on my bench grinder and finished it with sandpaper to 3.1mm.  I have attached my calculations, and a picture of my cork "dolly" - the nearest bit of dowel from an old pine chair. It measures 15mm diameter, and the cork was a nice firm fit on the dowel.  It pays to allow a little bit extra for some compression. It took up all the endfloat ( I had a fair bit - 1.2mm ). Other owners say if the cork is too thick, it will disintegrate under excessive compression. Also oil or grease lightly for some lube for startup. If you do a Forum search, I know a couple of perfectionists have machined the cover to take a proper seal - a modern engineering solution. The cork solution is satisfactory if the right thickness. Check that the idler pinion is firmly keyed to the shaft and hasn't moved outwards. I will also post this in a more relevant section on Idler Seal.
Col

Hi Col,

Thanks for the diagram and the explanation, that will definitely help me for eliminating that end float and not guessing the thickness :)
Mine had no Cork seal and didn't leak any oil into the dynamo pulley cavity at all, so I'm wondering how the Cork can hold up to the constant rotation without being lubricated constantly? I will probably soak it in oil at least but I can't see it lasting too long if nothing comes through the bush.

Evan.

[Swarfcut]

 Evan. No mystery. The idler shaft bushes have scrolls directing oil towards the gear. Outer bush scroll form is constantly pushing any oil from the idler gear back, away from the dynamo chain cavity, and there have been replacement  bushes fitted  with the bush scroll  running the wrong way, resulting in oil transferred to the chain cavity. Inner and outer bushes are identical in dimension, the way the scroll runs is the difference.

 Dynamo chain runs in grease, and as Col suggests, a dab of lubricant on the cork washer will prevent friction burn on start up. Once  the grease warms the cork will be happy bathed in the goo, sticking to the back  of the pulley boss and rotating against the inner timing cover under light compression enough to prevent  endfloat on the spindle. Crude, Effective, Cheap.

 In less enlightened times this cork washer was dismissed as an ineffective oil seal, and you can bet many engines were rebuilt without it. But to find these simple assembly errors on your new purchase can't be a good omen. Hope I'm wrong.

 Plenty on the Forum about cam followers. I searched  "Cam Follower Noise" on the Entire Forum, lots of pictures showing mechanical mayhem and basic assembly procedures. You'll see what holds the followers in place. Reprofiled cams and followers carry a risk of the followers contacting their  centre locating dowel and side retaining screws at their limit of travel on the back of the cam. At this stage what's in there is a complete unknown.

 "GB is not OK" I chanced upon, a saga of a good man's fight with the powers of evil. Eventually with a happy ending but which taxed the perceived wisdom of a good few contributors.

 Swarfy.