Been away for a few days so not had chance to do anything to it. Going to get out tomorrow & hopefully get the rings bedded in
So been out this morning & got her warmed up. Then Did the hard acceleration from 2000 rpm up to 4000rpm. Then deceleration back to 2k rpm. Did it 5 times. Drove it normally for a few miles & then repeated it under load full throttle to 4k then deceleration another 5 times. Hopefully bedded the rings in. She pulls ok. Think I still have jetting issues though. Idle is still erratic. Also if i blip the throttle wide a few times i get the occasional backfire. Also overun rpm back to idle takes a fair bit longer than it should. Carb butterflies are shutting correctly so am i rich or lean?
Not by much though. Too check your main jets are the right size or there about. Go on a long dual carriage way, get it up to a speed of say 60-65 for 5 miles or so. Turn key off, pull over, IN A SAFE MANNER. Then check a plug colour. You don't check plug colours while doing SHORT IN traffic driving as the plugs wont be clean . Or fit an AFR Gauge and work with that.
Like the AFR gauge idea. Where can you put the lambda probe though? Will sticking it up the silencer work. Or do you need to modify the silencer to take it. I suppose ideally you need 1 in each exhaust with twin carbs?
It depends on the exhaust. The 4 into 1 aftermarket collector types are easier. Some of the Vintage speed exhausts have a bung hole each side for thr probe. Basically it has to tap off gas in the exhaust about a foot or more from the tail pipe. Having changed the cam then backfiring and bad idling may be the new normal.
Just been for another longer run. Pulling fine but won’t idle. It seems worse the hotter it gets. When I pull up it’s missing & trying to stall. If i knock it into neutral (auto) and give it a quick rev it is racing before it drops to an uneven idle.
Can’t think where I could have. New manifolds & gaskets, it was the same with the previous manifolds. New base gaskets. I have tried disconnecting the servo hose and just fitting another balance pipe in its place. Still contemplating refitting previous engine as i am getting racked off with it now.
The idle screws are further in than they should be to get it to idle. Meaning the throttle flaps are further open than they should be to obtain a normal idle speed. With the snail attached each carb is pulling about 15kgh when it should be about half that, due to the flaps being further open. Don’t know why it won’t idle with normal opening of the flaps. Seems i can’t get it to idle on the idle circuit. Both carbs have been cleaned out & float heights checked etc. The carbs worked perfect on idle on the previous 1911 engine I removed.
Have you double checked that you don't have a blockage in the idle circuit? It only takes a tiny bit of fuel line. with a blockage in the idle circuit it might be pulling fuel through the mains and over fuelling. Might not be but would explain the symptoms. It should do most of its low RPM running on the idle circuit.
..how did you check it?..you sure there’s no vacuum leaks at the servo or did you check the servo hose all the way to the front?..the only way to do it really is with the smoke tester.. Wysłane z iPad za pomocą Tapatalk
..think to bed them in properly you need to do at least 1k miles and then recheck compression again if still low put some oil into cylinders and see what happens.. I’ve only done that on mine and Im even more puzzled now..I’ll start new thread on this tho.. Wysłane z iPad za pomocą Tapatalk
..those spark plugs look pretty much like mine..little bit rich I guess.. Wysłane z iPad za pomocą Tapatalk
RPM dropped roughly the same amount when pulling each lead off so I don’t think its a particular cylinder causing a problem.
The carbs ran fine on the previous 1911 engine & idle was smooth. I have not been able to get a smooth idle at all on this engine. I know it’s slightly bigger on capacity & has a C25 mild cam, didn’t think changes are that radical. It seems the 34ict’s just don’t work with anything other than a standard cam.
I run an Engle 110. Mine is a type 1 engine though (1641). It took me quite a while and a big bag of mains and airs to get it running right. I had a lot of issues with it ticking over on 3 cylinders at idle. Once all the fuelling was sorted it was fine. I agree though that over running is usually timing. air leaks will stop it ticking over. Brake cleaner is great stuff for spotting air leaks.
I can borrow the smoke tester from work & check for possible leaks, however there was no leaks with the other engine in. I am pretty sure its fuel related but why does it get worse when the engine gets hotter? Its as if the throttle is partly stuck open, then revs drop & it starts missing & shaking.
..well no help here Im affraid but it looks like we are in the same club..pretty much symptoms on my engine..the only difference’s never stalled.. ..I also recon its fuelling/cam related problem.. Wysłane z iPad za pomocą Tapatalk
