Timing gears.

Geoff

Can anyone give me information on timing gears please. I am working on a '38 Terraplane Roadster, that has a '42 motor. This is the only one in the country, as we never got any new cars in after 1939, until after the war., hence I hae no experience of this particular model. My query is - will the cam gear from a '48 8 cylinder match the crank gear in the '42. I do have a pair of '38 gears, but this means I have to change both over, and it's a bit of a contortion to get a puller in to remove the crank gear.

Geoff.

Huddy42

Geoff,

Some '42 Hudson's had the 20% timing gears installed, mine had a fibre 20% when I purchased it from Hal, this should be stamped on the gear itself.Is the gear solid ? or does it have spokes.??



Does the crank gear have numbers stamped on it, the 20% gear should be 166310.



I think the 14 1/2% number would be 150566 or even 162165 not 100% sure on the 162165 though.



Replacement with the Aluminium camshaft gear used by Hudson was 165907 for the early 30's models as sets only.



Les.P. Down Under.

Geoff

Gday Les. The crank gear is 162165, and I have an alloy gear from a '48 8 cylinder, which is 165958. I need to know if these are compatible, as I have been caught out before with mismatched gears that howled like a banshee! Regards,

Geoff.

Huddy42

G'Day Geoff, I have never found any info on how to tell which is 14 1/2 % and which is 20% gears.



According to my parts book the 162165 crank gear suits 1941-42

The 165958 suits all 46-47, BUT, when did they change from the 14 1/2% to the 20 %



As I said in my previous email my '42 had a fibre 20% cam gear,I have always believed that ALL 20% were Aluminium, so there lies a new question.



Les.

Geoff

So we are still in the doo-doo!!! One of our club members changed his gear over on a '38, and it had no backlash and made the engine knock. Changed it back, and the knock disappeared, so he obvioulsy had the wrong gear which altered the valve timing. You will be aware that if the valve timing alters things start colliding internally. The engine I'm working on has a mysterious knock, which is definitely not con rods or pistons, (can't eliminate by shorting plugs), and the valve timing is way advanced, even though the gear marks are meshed correctly. The inlet valve opens around 12 teeth b.t.d.c. I have just replaced the two centre rods, which has obviously altered the internal clearance slightly. I reckon it has a mismatched set of worn gears, as I can see definite heavy wear on the fibre gear on the front of the tooth on one side and rear of the tooth on the other.. It is a solid fibre gear, so there is no possibility of the centre having moved. The plot thickens. Can anyone else enlighten me as to whether a 1942 crank gear is compatible with a 1948 cam gear? Or can anyone supply me with a correct 1942 cam gear?

Geoff.

Jon B

Small point (and this is not answering your basic question, so you may disregard). You said 'solid fiber gear'. I thought that all the fiber gears had a metal hub. This is the same metal hub which, because of wear and stress, actually broke away from the outer fiber gear causing the timing to change. Except when (for some reason) the two halves of the gear would re-align, at which time the engine ran perfectly.



But I assume that if there was such a break, you would have noticed it with the gear out of the engine.

Geoff

I have two gears here which are solid fibre including the hub, but no part numbers on them, and they are both worn considerably, so not worth the risk of installing in case the teeth give out. I need a matched set of gears.

Geoff.