Joined: Sep 2017 Posts: 24 Threads: 4
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Hi all,
after a successful Drive It Day outing yesterday I was checking the old girl over and I've lost the damper cap from my OM type carb.
Looking on Burlen's site it's not clear whether I should have a vented or un-vented cap, and I can't remember which type was fitted to mine. I can't remember seeing a vent hole in the cap, but not sure. Is anyone on the forum running a pre-war type 1" OM? If so, would you be kind enough to see if yours has the little vent hole, or not, in the brass damper cap and post a reply.
Also, anyone got any cunning ideas for stopping these things vibrating loose other than loctite?
Best wishes and thanks for any advice.
Robin
Joined: Aug 2017 Posts: 1,341 Threads: 34
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Location: Cheshire
Car type: Race Ulster, 1926 Special, 1927 Chummy, 1930 Box
Get an unvented one. If it doesn’t run properly you could always drill a hole in it.
Alan Fairless
Joined: Aug 2017 Posts: 1,474 Threads: 26
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Location: North Yorkshire
29-04-2019, 10:03 AM
(This post was last modified: 29-04-2019, 02:35 PM by Steve Jones.)
Yes, as Alan says. Don't Loctite. Give it a slight nip up with water pump pliers or similar.
Steve
Joined: Aug 2017 Posts: 935 Threads: 22
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Location: Near Cambridge, UK
Car type: 1928 tourer (mag type), short chassis Gould Ulster
I am not good on SU type letters, but does the OM have a damper? If it has I think there won't be a hole.
Robert Leigh
Joined: Aug 2017 Posts: 2,748 Threads: 31
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Location: Auckland, NZ
Without hunting out my hoard, surely whether a dashpot or not, now or originally, must be a vent of some sort. Unless of the 1960s type with diagonal vent to air cleaner formed into the round body.
Joined: Sep 2017 Posts: 24 Threads: 4
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Thanks for the advice folks.
I like Alan's idea regarding the vent hole. Why didn't I think of that!
To answer Robert's question. The OM has no damper/ dashpot. The cap on these carbs is just a cap.
(I.e. no attached damper as in the later post-war SUs on minis etc).
Best wishes
Robin
Joined: Aug 2017 Posts: 265 Threads: 1
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One of my cars is prone to having its SU cap unwind. Fixed by cutting a short length of cycle inner tube and slipping it over the neck of the dashpot.
If your bicycle tyres are the wrong size I would think the finger from a redundant rubber glove might work.
Regards,
Stuart
Joined: Aug 2017 Posts: 425 Threads: 30
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Location: Wellington, NZ
It's great these old SU bits are still available and the cost of the parts is reasonable but their international postage rates are terrible! I just bought a couple of ball ends, a 6 inch rod, two throttle shaft levers and a couple of new dashpot screws and postage to New Zealand was 25 quid!
I looked at using one of the UK forwarding services but it worked out to be much the same since if you post to a UK address you get charged the VAT. That offset any postage savings.
Simon
