9 replies to this topic

[AStarker]

1275 Clubman
1986

I have a modified 1275 clubman which I don't drive it very often so it stands for 2 to 3 months at a time. Latley it starts no problem after the usaul 4 or 5 pumps of the accelorator but unless the throttle is kept open and blipped it refuses to idle, this happens even after its warm. It's fitted with a Weber DCOE 40 and a Kent road/rally cam, mini spares head with high lift rockers and Mini Spares variable timing belt.

Originally I suspected it was the idle jets and progression circuits, so I clened the carb & jets with carb cleaner. Thereafter I thought it may be the sandwich plated between the carb and manifold was letting air in so I relaced this. I recently also put in a new coil and condenser so it can't be the ignition. I cant test the timing as its revving to fast to keep it running but the dwell angle is spot on.

What I have found is that if I fill the float chamber by poking the float down it does then idle but then cuts out. The float is currently set at 8mm with a 15mm stroke. I dont think its the pump (electric SU) because at high revs the car fgoes like a bomb.

I have thought about trying the test of spraying engine starter to check for air leaks but if anyone has any other ideas I would be bery gratefull to hear them.

[dfmini]

I used to have the same problem as your with my Weber (no idle).
That was a problem with the body of the carburettor being not proof.
One very small piece which blank a hole in the idle circuit was missing. It was on the top of the body' carb.
I drilled, and used a small "non headed bolt" to fill the hole.

the chance of being the same problem is very small, but it took me few months to find out, so worth telling you.

(hope you understand my froggy english)

[robsrallymini]

I've got a 45 weber on a rally spec engine and mine ticks over at 1400rpm, if you try to slow it down it
just cuts out, this was set up on rolling road and the carb is fine.What does yours tick over at?

[AStarker]

Thanks for the replies guys. It used to tick over (very lumpily because of the cam and steel flywheeel) at arond 600 RPM. I have looked for missing blanking plugs on the carb body but these seem fine.

I have bought a can of engine starter and will see how I get on this weekend....

[01smartc]

At least ... with a weber maybe more like 1400rpm

Chris @ Smart Performance

[bmcecosse]

Why on earth would it wear the camshaft out ????????????
I assume the idle jets are clean ?
Have you cleaned the emulsion tubes? Could be coated in 'varnish' from fuel evaporation with the car standing unused for so long.

Edited by bmcecosse, 04 February 2011 - 05:44 PM.

[dfmini]

No chance of having a good idle at 600rpm with this kind of engine.

I have a smooth idle now with my 1293 (286 camshaft + Weber 40) but at 1000-1100 rpm

[AStarker]

Thanks - I hadn't thought of wearing the cam lobes however the car should idle lumpily. Once I get it right I will increase the idle. I found that with a can of engine starter sprayed around the manifold it idled no probelm, so I removed the inlet mainfold and checked the surface, not great so I mounted it in a milling machine and flycut it true. I had to remove at least 25 thou to get it completely true. Problem is I didn't have a new gasket handy. Will get one and fit it this weekend. I have cleaned all the jets a couple of times but will do it again if I don't come right when I put it back on.

[Dusky]

No chance of having a good idle at 600rpm with this kind of engine.

I have a smooth idle now with my 1293 (286 camshaft + Weber 40) but at 1000-1100 rpm http://www.theminifo...O_DIR#/wink.png

What jetting do you use for that setup?

[cal844]

Thanks - I hadn't thought of wearing the cam lobes however the car should idle lumpily. Once I get it right I will increase the idle. I found that with a can of engine starter sprayed around the manifold it idled no probelm, so I removed the inlet mainfold and checked the surface, not great so I mounted it in a milling machine and flycut it true. I had to remove at least 25 thou to get it completely true. Problem is I didn't have a new gasket handy. Will get one and fit it this weekend. I have cleaned all the jets a couple of times but will do it again if I don't come right when I put it back on.

As long as the engine is run in there wont be any accelerated wear.

Idle: 1000-1500 rpm cold

On my friends race engine(vauxhall C20XE 'Redtop') running twin 48s the car wasnt running(would 'hunt' for fuel at anythingbelow 1000 rpm)

I stripped and rebuilt the carb, gave it all an ultra sonic clean, the car now runs like a champ... Too quick at pick up even from idle