Running Roughly

[El Rob]

I have recently bought an ex race car S4 Elan. I have run it once before and have been able to drive it. It performed with no problems. After stuffing around for a couple of months and getting organised, putting a new exhaust on it(extractors back), I have been trying to get it running again. I can get it started but it runs very roughly, will not rev at all and fuel droplets come out of the Stromberg openings (taken plenum off). Can anyone give some advice? Is there a valve closing issue enabling pressure to get back out the Strombergs?
I am not sure how much has been done to the engine, only that it it was described as a "strong race engine"

thanks for any help,

Rob

[oldelanman]

Hi Rob and welcome to the forum.

If the engine was running OK before and the only thing you have changed is the exhaust, I would suspect the carburettors.
With Strombergs it could be an air valve sticking, no oil or incorrect oil in the dashpot dampers or stretched/holed diaphragms.

As you have the airbox off it's easy to check the air valves - remove the dampers by unscrewing from the top of the covers and then lift the air valve piston with your finger through the intake. It should slide freely up and down and drop smoothly onto the bridge of the carb when you let it go. Ideally both should drop at the same rate. To check the diaphragms you will need to remove the covers from the top of the carbs but, unless there is an obvious tear, deterioration is not that obvious and you would be best to replace them anyway - they are readily available. If all is OK, reassemble and top up the dashpot dampers with oil - various views on what oil to use but engine oil should be OK.

Finally, before you try to start it again, I would remove the plugs and give them a clean as well, in case the misfiring has fouled them up. I guess it could also be that as the car has been used for racing it has hot running plugs fitted which don't like running cold - I'm no expert on this but others on here will be able to advise on whether that's likely or not. You could try a more "standard" plug if that's the case.

Hope this helps.
Best regards,

[GrUmPyBoDgEr]

Welcome from me too Rob & I hope you get your Car's running problems sorted soon.
I appologise for being an old Cynic but I'm having a problem with a Race Elan being fitted with Stromberg Carbs.
Most Racers choose to use the Weber variant due to the better full throttle performance.
What sort of competition was your Elan used for & is the source of your information on the History of the Car reliable?
Along with Oldelanman I'd go for a new set of Plugs as the 1st option.

Cheers
John

[m750rider]

Before you start messing with the carbs I suggest you ensure that ignition and timing are correct. Spark plug change won't hurt, but probably won't solve blowing back through the intakes. Set the timing with the engine at idle and then make sure it is set correctly at full advance - you should be around 32-35 degrees BTDC. Once you know that is right you can begin to trouble shoot the fuel system.

[oldelanman]

Before you start messing with the carbs I suggest you ensure that ignition and timing are correct. Spark plug change won't hurt, but probably won't solve blowing back through the intakes. Set the timing with the engine at idle and then make sure it is set correctly at full advance - you should be around 32-35 degrees BTDC. Once you know that is right you can begin to trouble shoot the fuel system.

Worth checking the ignition timing for sure but if Rob has only changed the exhaust since the engine was last running OK I can't see that it is likely to be far out. Having said that though it maybe the distributor clamp is loose and the timing may have been disturbed while working around the engine.

Regards,