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Mounting alloy carb mounts.
Posted: Mon Nov 04, 2019 4:05 am
by Sundowner
Several months ago, while I was still a member, I bought a set of the clubs alloy carburettor mounts for my SPRINT.
I'm now about to fit them and I was wondering what sort of tension I need to put on them considering the 'O' rings?
I expect that they can be over tensioned?
Any tips?.
Thanks & Cheers,
Rob
Re: Mounting alloy carb mounts.
Posted: Wed Nov 06, 2019 9:32 pm
by marshman
Just fitted the club ones to my Sprint - the rubber ones were badly split and leaking air making it impossible to set the carbs up properly. I tightened them right up so that there was no gap. Must admit I didn't use a torque wrench I just did the bolts (mount to manifold) and nuts (carb to mount) up evenly in stages to ensure the gap closed up in a parallel fashion. You can "feel" when contact is made between the mounting faces. I guesstimate the torque to be around 15 to 20 ftlbs.
Make sure you get the throttle linkage connecting bar back in the right way round otherwise you will have to take the carbs off again to turn it over as it was 180 deg out! (Don't ask! caused a bit of head scratching followed by some cursing)
Roger
Re: Mounting alloy carb mounts.
Posted: Thu Nov 07, 2019 12:36 am
by Sundowner
Thanks for answering Roger.
The reason I asked was that I'm fearful of over tensioning them and splitting the 'O' ring.
I guess with a coating of a suitable rubber grease and being gentle, it should be OK.
Thanks again,
Rob
Re: Mounting alloy carb mounts.
Posted: Thu Nov 07, 2019 9:53 am
by tony g
O ring grooves should be sized so that they push into the groove under tension when completely flat. Treat then as if there was just a metal to metal fit so the bolts are tight.
Tony
Re: Mounting alloy carb mounts.
Posted: Thu Nov 07, 2019 10:16 am
by Sundowner
tony g wrote: ↑Thu Nov 07, 2019 9:53 am
O ring grooves should be sized so that they push into the groove under tension when completely flat. Treat then as if there was just a metal to metal fit so the bolts are tight.
Tony
Thanks again Tony,
Rob
Re: Mounting alloy carb mounts.
Posted: Thu Nov 07, 2019 10:28 am
by marshman
tony g wrote: ↑Thu Nov 07, 2019 9:53 am
O ring grooves should be sized so that they push into the groove under tension when completely flat. Treat then as if there was just a metal to metal fit so the bolts are tight.
Tony
Absolutely right, and those in the club alloy mounts do. As I said just make sure that everything is tightened evenly to ensure a nice even compression all the way round and no pinching or bunching of the 'o' rings.
Roger