Worn distributor drive gear - cause or effect?

[v8alligator]

All,

I know I am resurrecting a old thread here but need some help as we are going through dizzys and cam gears weekly.

Rover 3.5 EFI Low compression V8 completely standard.

Was running really well. good oil pressure no noises what so ever.

Few weeks back we changed the front timing cover due to a split in the casing.

Engine fired up instantly and oil light went out but after a hour of running it stopped. Investigation showed the drive gear on the cam had stripped its teeth and damaged the dizzy drive also.

Fitted a new gear (making sure the oil grove was in the right place) brand new genuine dizzy fitted at the same time) Engine fired up and ran for 20 miles or so.... and then stopped.

Just pulled the dizzy out and the gear on the camshaft and dizzy have stripped its teeth again?

Any one have any ideas on what would cause this issues. Is it a blocked oil way? or am I looking at a cam shaft thrust related issues?

Appreciate any pointers.

Thanks

Bryan

[DaveEFI]

Was there evidence of plenty oil on the gears?

[sidecar]

In my humble there are really only two things that will kill the gears in such a short space of time, the first being excessive load on the gears, the second being mis-alignment of the gears. (This is of course assuming that they are at least getting some lubrication!)

The load on the gears can only come from two places, the oil pump or the dizzy itself. So does the dizzy turn freely when it is removed from the engine? Also using a pump priming tool how hard is it to turn the oil pump? I know that the load caused by the pump is a hard thing to gauge but it should not be 'mega' hard to turn.

With regards to mis-alignment of the gears I have seen them wear out when the camshaft bearings have worn but I must admit it would still take a while for this to cause the gears to completely wear out.

[mgbv8]

All,

I know I am resurrecting a old thread here but need some help as we are going through dizzys and cam gears weekly.

Rover 3.5 EFI Low compression V8 completely standard.

Was running really well. good oil pressure no noises what so ever.

Few weeks back we changed the front timing cover due to a split in the casing.

Engine fired up instantly and oil light went out but after a hour of running it stopped. Investigation showed the drive gear on the cam had stripped its teeth and damaged the dizzy drive also.

Fitted a new gear (making sure the oil grove was in the right place) brand new genuine dizzy fitted at the same time) Engine fired up and ran for 20 miles or so.... and then stopped.

Just pulled the dizzy out and the gear on the camshaft and dizzy have stripped its teeth again?

Any one have any ideas on what would cause this issues. Is it a blocked oil way? or am I looking at a cam shaft thrust related issues?

Appreciate any pointers.

Thanks

Bryan

The oil light means nothing in this case I'm afraid. You either have Zero oil to the gears or some really excessive strain on the gears.
What do you mean by the "oil groove being in the right place" ?
It sounds like you are not getting any oil from the front cam bearing to the dissy drive cog.?
Are you sure that the woodruff key on the cam is the right one? If it is the right one are you sure that its not fitted with one end cocked up to block the oil flow?

Perry

[DEVONMAN]

I agree with Perry that you should check the oil supply to the gears.
To avoid doubt, the fat part of the spacer should be at the front and the oil groove in the gear should face to the rear.
Also check that the camshaft can be moved by hand backwards and forwards as far as the slack in the chain will permit you.

But the clue may be in the fact that you changed the front cover. Did you check the running clearance of the oil pump. This may be too tight and causing drag on the shaft which goes up to the dizzy.

Denis

[v8alligator]

All,

Thanks for the replys and sorry for the delay in responding (been away on holiday)

There is defiantly oil over the dizzy drive... it was flooded in oil when removed so am 100% confident its not that.

I would say that the oil pump is tighter then normal to spin and when the Dizzy is clamped in makes the problem worse.

I have loosened (1/2 turn) the oil pump cover fixings and this has allowed the oil pump to spin more freely

So the questions are:
1) Is there different oil pump gasket thicknesses?
2) Are there different oil pump gear thicknesses? I know there are 2 types early and late but thought this as to do with the male or female dizzy drive.

Thanks

[DEVONMAN]

I have found a few different thicknesses in aftermarket gaskets.

You really need to do a feeler gauge check on the running clearance of the pump. Aftermarket gears can also be out of tolerance. The gears when new in a new pump housing are normally 2 thou proud of the face of the housing.

With a gasket of compressed thickness slightly greater than 2 thou, the pump will then have some running clearance.

eg. A 10 thou gasket would give 8 thou running clearance if the gears are 2 thou proud of the housing.