Axial slop in my new cam gear to new cam adjusting plate

(Mossback) #1

Good Day, I spun a cam adjusting plate inside an old gear and bought two new items to replace it. These are the older style with a bunch of little teeth that mesh together. There is slop between the two pieces in the radial (the direction they turn) direction. I figure this is a bad thing as movement will cause wear quickly considering all the load on those parts. I think I will heat the adjusting plate up with a torch and smack it in an attempt to make the outside diameter of the gear grow a little bit and fit in the outside gear better. What say you?

(Robin O'Connor) #2

Is the problem with the cam plates or the cam gears?
If there is no conernible wear on the ‘new’ items you purchased then it is more likely to be the cam gears, would be the first time I’ve heard of it.
Not sure about belting the plates to swell them up, it could work.

I’m surprised they managed to spin if they were bolted up I can’t see them ‘working’ against the teeth unless they aren’t torqued up correctly.

(Mossback) #3

Both pieces are new. My car is a 120 and I think it jumped as there were no circlips installed on the gears, although nothing was out of position when I took things apart. Cheers, Henry

(Robin O'Connor) #4

I always take out the circlips once the cams are locked up, they perform no useful purpose IMHO and can release themselves into the bowels of the engine and then into the oil pickup.
Do you mean that both the cam wheels and the plates are new and they have slop? Is it that much af a problem? The radial movement must be in the region of .001deg certainly not sufficient to alter any timing of the cams I would have thought. And as I said, once the plates are torqued up they are not moving under normal circumstances.

(Lee140FHC) #5

I’m having trouble understanding the problem here. The only way anything can “jump” is if there was a tremendous amount of slop in the chain…or…if the serrations on the cam plate were completely worn away AND the outer edge of the plate was no longer exerting enough clamping force to hold the sprocket tightly enough to the cam flange, allowing the sprocket to migrate around the flange.

Also, once the cam plate is properly torqued to the sprocket, the serrations do nothing…they are there to hold the cam in proper timing as the cam plates are tightened…the outer edge of the plate does the “clamping”.

(Robin O'Connor) #6

Have to agree. Seems strange so interested to hear the OP’s response.

(Peter Crespin) #7

So has anyone ever heard of a competently-installed circlip causing problems? Why remove them? The faster the engine spins the more firmly they seat. (NB radial play is not in the turning direction)

(Phil.Dobson) #8

it is possible that the plates are not actually properly engaged. it take a little patience to get them to mesh completely. if they are meshed they DO NOT MOVE. whilst the circlips serve no purpose once the plates are bolted up, then …‘if it was good enough for jaguar its good enough for me’ they stay in!

(Mossback) #9

Thank you for your input and advice. The outer sprocket and inner adjusting plate are both new and sitting at my desk, playing with them there is notable play on the serrations. This discussion prompted me to bolt the assembly to a cam shaft and, Poof, the play is gone!
My old arrangement was definitely spinning on the serrations. I don’t remember the bolts being loose on the camshaft but stranger things have happened. The serrations or clamping gave up while cranking the car over to start it in the garage.

Cheers, Henry (now I can put this all back together with some confidence this Saturday)

(Lee140FHC) #10

You have checked that valves were not bent due to improper cam timing? And sure, once everything is bolted together there will be no play…but that should have been true even with “missing” serrations.

(Robin O'Connor) #11

It’s not the ‘competently fixed’ items that come loose its the ones that arn’t seated properly that can go wandering.

(Mossback) #12

Oh yes, Two intakes bent, but I think they got bent when I dropped one of those anti rattle washers down into the abyss and after a roundtrip Albuquerque to Scottsdale, it worked its way into the chains before getting deposited into the pan. Put the chain right for the son’s wedding, but it was noticeably down on power. Now I’m putting all new gear on. Pulled a couple valves out of an old head and the cylinders hold with solvent in them, so it’s going back on.

Cheers, Henry Morrison, Albuquerque, NM

(Peter Crespin) #13

Agreed. So why write “I always take out the circlips”? You presumably do yours properly and so did the PO or you’d have nothing to remove?

(Robin O'Connor) #14

Just taking out the possibility that I screw up :slight_smile:

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