prelude1980
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| posted on 13/4/10 at 11:30 AM |
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Help Needed - Cylinderhead
i have 2l blacktop zetec, i'm trying to tune it on megasquirt. but when you look down the inlet on cylinder 2 when the engine is running you can
see it light up, i've tried adjusting the spark table up and down but with no effect other than make the engine run rougher than it is.
any help much appreciated
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
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cd.thomson
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| posted on 13/4/10 at 11:32 AM |
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incorrect cam timing or you have the HT leads mixed up?
Craig
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prelude1980
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| posted on 13/4/10 at 11:37 AM |
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i've checked the timing and it's right to megasquirt. ah with the leads i think i have. is there a diagram showing the correct way?
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
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prelude1980
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| posted on 13/4/10 at 11:42 AM |
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just checked and the leads are on correct.
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
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cd.thomson
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| posted on 13/4/10 at 11:45 AM |
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no, incorrect cam timing not spark timing. Is there any possibility the cambelt has slipped or that the cams could have been fitted incorrectly?
Also the inlet valve could be sticking open, has any work been carried out on the engine?
Craig
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MikeRJ
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| posted on 13/4/10 at 11:52 AM |
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Weak mixture will cause this, partially blocked injector perhaps?
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Fatgadget
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| posted on 13/4/10 at 11:57 AM |
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Not timing surely..otherwise ALL ciylinders would exhibit the same symptoms no?
My prognosis given the symptoms is either a duff injector or manky spark plug...swap them around and c the outcome.
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prelude1980
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| posted on 13/4/10 at 12:11 PM |
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quote:
Originally posted by Fatgadget
Not timing surely..otherwise ALL ciylinders would exhibit the same symptoms no?
My prognosis given the symptoms is either a duff injector or manky spark plug...swap them around and c the outcome.
I've had the plugs out and they are all good and clean with the same gaps. i'll try swapping the injectors around.
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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prelude1980
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| posted on 13/4/10 at 12:12 PM |
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quote:
Originally posted by cd.thomson
no, incorrect cam timing not spark timing. Is there any possibility the cambelt has slipped or that the cams could have been fitted incorrectly?
Also the inlet valve could be sticking open, has any work been carried out on the engine?
sorry i misunderstood. the cams seem correct, the head has been smoothed out a bit and the inlet port matched to the inlet manifold
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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prelude1980
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| posted on 13/4/10 at 12:39 PM |
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i just swapped the injector over with another cylinder but it's still doing the same thing
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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atspeed racing
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| posted on 13/4/10 at 12:48 PM |
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Do a compression test
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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prelude1980
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| posted on 13/4/10 at 01:01 PM |
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i'll have to go get a tester for that. but assuming that test comes back ok. what's next.
if the test comes back and the pressure is low, is that piston rings?
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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Mal
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| posted on 13/4/10 at 01:30 PM |
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Is this the first time of running the engine since wiring it for Megasquirt?
If so you may have the wiring for cylinders 1&3, then 2&4 incorrect in relation to the coil pack connections.
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Mal
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| posted on 13/4/10 at 01:32 PM |
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Correction to the above post
Is this the first time of running the engine since wiring it for Megasquirt?
If so you may have the wiring for the injectors to cylinders 1&3, then 2&4 incorrect in relation to the coil pack connections.
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prelude1980
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| posted on 13/4/10 at 01:38 PM |
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no this isn't he first time the car has been run, i've just upgraded the inlet side from a diy manifold to a st170 one, although i'm
starting from scratch on the tuning
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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prelude1980
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| posted on 13/4/10 at 01:39 PM |
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also i'm using simultaneous firing so that shouldn't matter
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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prelude1980
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| posted on 13/4/10 at 03:14 PM |
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just a small update been messing with the car more, the throttlebodies aren't balanced and adjusting them is helping although the balancer i got
is crap so need to get another one
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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Chippy
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| posted on 13/4/10 at 04:17 PM |
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Sounds to me like either a sticking inlet valve, or the tappet have been wrongly adjusted holding the valve open just a tad. Does the Black top have
hydraulic lifters, if so then that one in over pumping. My opinion, for what it's worth! Cheers Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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prelude1980
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| posted on 13/4/10 at 04:20 PM |
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It has solid lifters, how would you fix a sticking valve?
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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MakeEverything
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| posted on 13/4/10 at 05:48 PM |
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quote:
Originally posted by Chippy
Sounds to me like either a sticking inlet valve, or the tappet have been wrongly adjusted holding the valve open just a tad. Does the Black top have
hydraulic lifters, if so then that one in over pumping. My opinion, for what it's worth! Cheers Ray
^^ What he said ^^
If you can "See" into the cylinder, then the valve is open! It should be closed. Either that or you have a seriously hot inlet valve,
and some worrying detonation going on.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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MakeEverything
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| posted on 13/4/10 at 05:55 PM |
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quote:
Originally posted by MakeEverything
quote:
Originally posted by Chippy
Sounds to me like either a sticking inlet valve, or the tappet have been wrongly adjusted holding the valve open just a tad. Does the Black top have
hydraulic lifters, if so then that one in over pumping. My opinion, for what it's worth! Cheers Ray
^^ What he said ^^
If you can "See" into the cylinder, then the valve is open! It should be closed. Either that or you have a seriously hot inlet valve,
and some worrying detonation going on.
Or the overlap on that cam for that cylinder is incorrect, but you say you havent changed it?
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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prelude1980
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| posted on 13/4/10 at 05:57 PM |
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quote:
Originally posted by MakeEverything
quote:
Originally posted by Chippy
Sounds to me like either a sticking inlet valve, or the tappet have been wrongly adjusted holding the valve open just a tad. Does the Black top have
hydraulic lifters, if so then that one in over pumping. My opinion, for what it's worth! Cheers Ray
^^ What he said ^^
If you can "See" into the cylinder, then the valve is open! It should be closed. Either that or you have a seriously hot inlet valve,
and some worrying detonation going on.
mmm well i'm looking at the throttlebodies when they are closed and can see it light up behind, but after playing with balancing it has gone. so
i'm hoping that's what it is, just bought a carbtune so will tune properly and see what happens.
Usually something simple and my inexperience showing
[Edited on 13/4/10 by prelude1980]
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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MakeEverything
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| posted on 14/4/10 at 07:16 AM |
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Dont dismiss it though.
The carbs will have a vacuum to lift the gizmo inside. ideally, i think id be taking the head off to have a proper look, but i know that takes time,
effort and money!
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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rusty nuts
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| posted on 14/4/10 at 08:54 PM |
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No need to take the head off to check for burnt/sticking valves! Do a cylinder leakage test and check/adjust the valve clearances
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prelude1980
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| posted on 14/4/10 at 08:59 PM |
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well if it still acts odd after i've played with the balancing and fuel/spark. i'm gonna start looking at removing the head or checking
for a sticky valve, really not keen on that just yet. but thanks for the suggestions, this weekend will soon tell what i need to do..
Fingers crossed
Speed has never killed anyone. Suddenly becoming stationary... that's what
gets you.
https://www.topcashback.co.uk/ref/dodd1980
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