Chris14SR
18-07-05, 12:02 AM
I've got a 1300 with a 1.2 head and t40 dcoe carbs. I've just got the car back from having the following work done - head gasket replaced, cylinder head skimmed (it was already very highly skimmed so the compression is now ridiculous, although I'm not sure exactly how much. the company said there was nothing more that could be taken out of the head), new camshaft fitted (was running a 300 degree cam, but it was knackered, the lobes were showing serious amounts of wear so I've gone for a brand new piper 285 cam kit to give a little more oomph at the bottom end), full carb clean and rebuild, and a rolling road setup. Oh, and a new Weber throttle linkage as the old one was one of the front mounting types with the swingarm on a spindle, rather than the pulleys on springs like the proper Weber ones.
In many ways the car is running nicely now, and increasing the throttle gradually shows smooth acceleration and generally smooth running. Very nice. For this reason I dont' think the other problems are likely to have shown up throughout the rolling road setup. Increasing the throttle sharply causes the car to misfire, starting with a slight misfire but becoming extremely bad, to the point of losing power and slowing down. I have a feeling this is either the ignition timing or a fuelling/jetting issue.
It's also incredibly ropey on idle, far worse than it was before I gave the car over. Sometimes it's idling very high (1500-2000rpm) and other times it just drops and stalls. It's like suddenly it loses fuel and cuts out. It's also become a bit of a pig to start in the mornings, taking anythign up to 10 attempts, sometimes coughing for a few seconds, firing a few cylinders then dying. Eventually it coughs more and more, and then finally starts properly.
I don't think this is really the fault of the tuning company, as they don't generally deal with carbed cars, and it's always been a bit of an ass with it's idle and starting, but you would have thought that a milder, unworn cam would make it idle better and start smoothly, instead the opposite is true.
Giving 1/2 - 3/4 throttle, the car picks up superbly through the entire rev range, with smooth acceleration. Any more or less than this and it seems to have difficulty.
I'm pretty much at a loss as to why this is happening. I can only think that perhaps the new throttle linkage is set slightly out for the idle, or that perhaps in cleaning the carbs, something inside now has some residue that's causing unreliable operation under full throttle.
This is a shame, because the car is extremely powerful for a 1.3, showing 115bhp on the rollers, a figure I believe to be completely accurate based on how it's been performing up till now. I just want to be able to put my foot down again and for the car to accelerate like it should.
Oh, one last thing, when I depress the clutch say to stop at a roundabout, if the revs die quickly as if it's going to stall, and I stamp on the throttle, it'll stutter and die, whereas if I slightly press on the throttle pedal, it'll rev higher.
Any thoughts would be greatly appreciated. I plan on taking it to someone else to get a professional second opinion on this, but I'd also like to hear what other people think.
Cheers
Chris
In many ways the car is running nicely now, and increasing the throttle gradually shows smooth acceleration and generally smooth running. Very nice. For this reason I dont' think the other problems are likely to have shown up throughout the rolling road setup. Increasing the throttle sharply causes the car to misfire, starting with a slight misfire but becoming extremely bad, to the point of losing power and slowing down. I have a feeling this is either the ignition timing or a fuelling/jetting issue.
It's also incredibly ropey on idle, far worse than it was before I gave the car over. Sometimes it's idling very high (1500-2000rpm) and other times it just drops and stalls. It's like suddenly it loses fuel and cuts out. It's also become a bit of a pig to start in the mornings, taking anythign up to 10 attempts, sometimes coughing for a few seconds, firing a few cylinders then dying. Eventually it coughs more and more, and then finally starts properly.
I don't think this is really the fault of the tuning company, as they don't generally deal with carbed cars, and it's always been a bit of an ass with it's idle and starting, but you would have thought that a milder, unworn cam would make it idle better and start smoothly, instead the opposite is true.
Giving 1/2 - 3/4 throttle, the car picks up superbly through the entire rev range, with smooth acceleration. Any more or less than this and it seems to have difficulty.
I'm pretty much at a loss as to why this is happening. I can only think that perhaps the new throttle linkage is set slightly out for the idle, or that perhaps in cleaning the carbs, something inside now has some residue that's causing unreliable operation under full throttle.
This is a shame, because the car is extremely powerful for a 1.3, showing 115bhp on the rollers, a figure I believe to be completely accurate based on how it's been performing up till now. I just want to be able to put my foot down again and for the car to accelerate like it should.
Oh, one last thing, when I depress the clutch say to stop at a roundabout, if the revs die quickly as if it's going to stall, and I stamp on the throttle, it'll stutter and die, whereas if I slightly press on the throttle pedal, it'll rev higher.
Any thoughts would be greatly appreciated. I plan on taking it to someone else to get a professional second opinion on this, but I'd also like to hear what other people think.
Cheers
Chris