GT6 isues compression?
Discussion
Hi guys
driving into college this morning my car developed a issue where when putting the clutch down or at a stop idling the revs will drop and the engine will cut out. It was running hotter than usual and if trying to idle i had to play with the choke to stop it stalling.
when i got to college i lifted the bonnet to have a look see if anything was leaking etc, no leaks but there was little petrol in the see through petrol filter, i found a mate who is more knowledgeable on cars than me, he reckon it might be a gasket or loosing compression, there is no mayo on the oil filler lid, but when i took it off while the engine was running there was a noticeable drop in the revs
any ideas please?
driving into college this morning my car developed a issue where when putting the clutch down or at a stop idling the revs will drop and the engine will cut out. It was running hotter than usual and if trying to idle i had to play with the choke to stop it stalling.
when i got to college i lifted the bonnet to have a look see if anything was leaking etc, no leaks but there was little petrol in the see through petrol filter, i found a mate who is more knowledgeable on cars than me, he reckon it might be a gasket or loosing compression, there is no mayo on the oil filler lid, but when i took it off while the engine was running there was a noticeable drop in the revs
any ideas please?
Possibly an air leak in a bit of tubing somewhere. I had this problem one day in my Spitfire and looked up a solution online and that's all I could really find. All I did to fix it was make sure the hose connections were ok (and it's never done it again). I suspect that in fact it was more to do with the fact that I was sitting in traffic, however!
If it's struggling to run and pulling the choke out makes it better you know a couple of things.
1) It's running lean when it's struggling to run - pulling the choke richens the mixture.
2) It's probably not a fuel supply issue - if the float chambers were running low/dry there wouldn't be any extra fuel to go in when you pulled the choke. If it happens again quickly grab a screw driver when you stop and whip the front float chamber lid off - it should be more or less full.
I'd guess the same as greeneggsandham, an air leak. I'd start by looking at the breather tube(s) that run from the engine-side of each carb to the rocker cover (depending on model) - I've had these perish on my Spitfire. Because these are engine-side of the carbs any air getting in here won't pull any more fuel through the carbs, weakening the mixture.
Take them off and give them a really good check over, beending them to see if any splits open up. If they are fine you can try adding some jubile clips to make sure they are a good tight fit to the carbs/rocker cover too.
1) It's running lean when it's struggling to run - pulling the choke richens the mixture.
2) It's probably not a fuel supply issue - if the float chambers were running low/dry there wouldn't be any extra fuel to go in when you pulled the choke. If it happens again quickly grab a screw driver when you stop and whip the front float chamber lid off - it should be more or less full.
I'd guess the same as greeneggsandham, an air leak. I'd start by looking at the breather tube(s) that run from the engine-side of each carb to the rocker cover (depending on model) - I've had these perish on my Spitfire. Because these are engine-side of the carbs any air getting in here won't pull any more fuel through the carbs, weakening the mixture.
Take them off and give them a really good check over, beending them to see if any splits open up. If they are fine you can try adding some jubile clips to make sure they are a good tight fit to the carbs/rocker cover too.
OK guys I will check those things
It had been stood for a few days possible even a week.
I had topped the carbs up the day before the run to college
The pipes around the carbs are new
It ran fine on the way home, but is still running hot in comparison to what it was before the service, its now running just over half on the temp gauge is that ok?
thanks guys
Hot running would be associated with a leaning of the mixture, you want to be a bit careful as you can damage the pistons.
What do the spark plugs look like? Is it 'pinking' under load?
Could be the ignition, a richer mixture is easier to ignite or possibly the coil is breaking down when the car gets hot. Would be worth checking.
As for where it should be on the temp gauge, well, that varies from car to car. If it's different to what it used to be, that indicates a potential problem. You didn't overfill the dashpots did you? When you put the piston things back in you should start feeling resistance when they are about an inch or less (check!) from the bottom.
What do the spark plugs look like? Is it 'pinking' under load?
Could be the ignition, a richer mixture is easier to ignite or possibly the coil is breaking down when the car gets hot. Would be worth checking.
As for where it should be on the temp gauge, well, that varies from car to car. If it's different to what it used to be, that indicates a potential problem. You didn't overfill the dashpots did you? When you put the piston things back in you should start feeling resistance when they are about an inch or less (check!) from the bottom.
Edited by varsas on Thursday 13th October 14:07
Cerberosa said:
sparkplugs are new as its just had a service, and no the dashpots were not over filled, havnt got round to sorting the problem yet, been doing my "easy to fit" servo but thats done now
I was asking more because it might give an indication as to what the problem is. See here:http://www.spark-plugs.co.uk/pages/technical/diagn...
If the problem is so bad that the plugs show anything other then 'normal' (a bit of black around the threads is OK) I personally wouldn't be driving it until I had it fixed as more serious damage could occur. If the plugs do show normal (check after a decent drive) that suggests to me it's an ignition problem. Might be worth squirting WD40/carb cleaner/whatever around the pipes etc to check for air leaks?
Edited by varsas on Saturday 22 October 17:25
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