Discussion
Hi all
I'm currently building a cobra and have come abit stuck. My chevy v8 engine appears to idel ok, alittle rich, but i need to set the timing because once i put the gearbox into drive, the revs drop and engine stops!
i've checked and cant find any vacum leaks so i assume that seeing as the timing is out this is why the engine wont hold correctly.
Is there anyone out there who can help with the timing and setting the engine and carb up correctly?
thanks
Jason (waterlooville)
I'm currently building a cobra and have come abit stuck. My chevy v8 engine appears to idel ok, alittle rich, but i need to set the timing because once i put the gearbox into drive, the revs drop and engine stops!
i've checked and cant find any vacum leaks so i assume that seeing as the timing is out this is why the engine wont hold correctly.
Is there anyone out there who can help with the timing and setting the engine and carb up correctly?
thanks
Jason (waterlooville)
Get a timing light, find the timing reference point on the front pulley, as long as it's visible you should be able to get the timing somewhere close. If all else fails just retard it until it barely runs and then advance it by 20 deg or so and it should run OK. Or if you really don't fancy that sort of thing, yellow pages for a local mobile mechanic.
GreenV8S said:
Get a timing light, find the timing reference point on the front pulley, as long as it's visible you should be able to get the timing somewhere close. If all else fails just retard it until it barely runs and then advance it by 20 deg or so and it should run OK. Or if you really don't fancy that sort of thing, yellow pages for a local mobile mechanic.
Sorry , Thread Hijack
Checked the timing on my mates Stag last week, the haynes stated 14Deg BTDC
What really threw me was ,this was on Number 2!
Just seems unusual.....
antonyj said:
Checked the timing on my mates Stag last week, the haynes stated 14Deg BTDC
What really threw me was ,this was on Number 2!
Just seems unusual.....
What really threw me was ,this was on Number 2!
Just seems unusual.....
Presumably the timing marks were positioned accordingly? Does seem very unusual not to time it from #1 though, did the manual say why they timed it against #2?
Was this engine running OK before or is it a new build?
If a new build then you may need to change springs in the dizzy to get the advance to come in at the right point.
If it has not been changed then you may only need to set the initial advance correctly.
The max advance on some small block Chevys can be as high as 52 Degrees but it must come in at the right point.
Steve (also in Waterlooville)
If a new build then you may need to change springs in the dizzy to get the advance to come in at the right point.
If it has not been changed then you may only need to set the initial advance correctly.
The max advance on some small block Chevys can be as high as 52 Degrees but it must come in at the right point.
Steve (also in Waterlooville)
GreenV8S said:
antonyj said:
Checked the timing on my mates Stag last week, the haynes stated 14Deg BTDC
What really threw me was ,this was on Number 2!
Just seems unusual.....
What really threw me was ,this was on Number 2!
Just seems unusual.....
Presumably the timing marks were positioned accordingly? Does seem very unusual not to time it from #1 though, did the manual say why they timed it against #2?
Exactly , when I tried to use No1 I got no reading as such, but perfect using number 2. Never seen it before.
OK thanks Steve
i have 2 dizzys, although one of the housing is cracked, so its pretty usless i think.
the engine was runnig fine after the rebuild, ive taking it our of my old vette and it was ok in that, so im guessing ive set it up wrong some where, im just a little stcuk as to how to correct it?
i have a mate coming over on weds who builds and races minis so hopefully he can help!
i have 2 dizzys, although one of the housing is cracked, so its pretty usless i think.
the engine was runnig fine after the rebuild, ive taking it our of my old vette and it was ok in that, so im guessing ive set it up wrong some where, im just a little stcuk as to how to correct it?
i have a mate coming over on weds who builds and races minis so hopefully he can help!
sheepy said:
What causes it to die: The act of pressing the clutch pedal, or after selecting a gear, re-engaging the clutch (I'm assuming it's manual)?
His first line says 'Putting it in drive' which makes it an auto.
The drag of an auto will pull the revs down but I suspect there may be more than ignition in this equation.
Steve
steve_d said:
sheepy said:
What causes it to die: The act of pressing the clutch pedal, or after selecting a gear, re-engaging the clutch (I'm assuming it's manual)?
His first line says 'Putting it in drive' which makes it an auto.
The drag of an auto will pull the revs down but I suspect there may be more than ignition in this equation.
Steve
well .....
i had the dearbox and engine rebuilt about 15months ago. It used to be in a corvette. and they both ran fine!
so, the engine and gear box was removed and i decided to put them into a cobra which i am currently building.
Nothing else has changed, expect that i have had to re-wire all the engine and gearbox, and during the this time the dizzy was changed, so i need to time the engine back in and make sure all the vacums are correctly installed etc. This is why i think i have a problem.
Does it sounds possible?
I've spoken to a guy a corvette kingdom and hes suggested the timing is all well out and hence engine not preforming like it should. I know NOTHING and i mean nothing about setting this up, hence i have some help tomorrow coming over, and short of that, ill have to get a mobile mancanic out!
unless you good peps can see someone else i should be doing.
i had the dearbox and engine rebuilt about 15months ago. It used to be in a corvette. and they both ran fine!
so, the engine and gear box was removed and i decided to put them into a cobra which i am currently building.
Nothing else has changed, expect that i have had to re-wire all the engine and gearbox, and during the this time the dizzy was changed, so i need to time the engine back in and make sure all the vacums are correctly installed etc. This is why i think i have a problem.
Does it sounds possible?
I've spoken to a guy a corvette kingdom and hes suggested the timing is all well out and hence engine not preforming like it should. I know NOTHING and i mean nothing about setting this up, hence i have some help tomorrow coming over, and short of that, ill have to get a mobile mancanic out!
unless you good peps can see someone else i should be doing.
As I see it, the options are:
Torque converter shagged
Air leak (inlet manifold)
Dizzy installed 1+ tooth out
Ignition module / coil dodgy
ECU / speed sensors (does it have an ECU???)
Idle speed too low
(There may be others too, I just can't think of them)
Does the engine rev happily whilst just sitting there?
Does the engine temp stay steady or continue to climb if left idling?
What happens if you give the engine a (little) bit of gas as you try to engage drive? (be careful!!)
Does R make any difference to D?
If it revs happily, and doesn't try to overheat whilst just sitting idling, I'd think the timing wasn't too far out. Also try spraying something like carb-clearner or wd-40 around (but not into) the throttle-body and inlet manifold to see if the idling stumbles (would indicate an air leak).
If the engine does have an ECU, there could be all sorts of possibilities, best calling an expert or auto-electrician
Also check the condition of the rotor-arm and dizzy-cap. My MG eats these, and the symptoms just before it dies are that it idles but has no power.
Sheepy
Torque converter shagged
Air leak (inlet manifold)
Dizzy installed 1+ tooth out
Ignition module / coil dodgy
ECU / speed sensors (does it have an ECU???)
Idle speed too low
(There may be others too, I just can't think of them)
Does the engine rev happily whilst just sitting there?
Does the engine temp stay steady or continue to climb if left idling?
What happens if you give the engine a (little) bit of gas as you try to engage drive? (be careful!!)
Does R make any difference to D?
If it revs happily, and doesn't try to overheat whilst just sitting idling, I'd think the timing wasn't too far out. Also try spraying something like carb-clearner or wd-40 around (but not into) the throttle-body and inlet manifold to see if the idling stumbles (would indicate an air leak).
If the engine does have an ECU, there could be all sorts of possibilities, best calling an expert or auto-electrician
Also check the condition of the rotor-arm and dizzy-cap. My MG eats these, and the symptoms just before it dies are that it idles but has no power.
Sheepy
thanks sheepy
got an update, i was told some of my vacum hoses were not quite right so i've changed these around and now the will hold in drive
the engine ticks over lovely at idel no problem, temp climbs up to running temp then steadies off. the engine isnt quite running smoothly in drive, but it is runnig now, so i will sort the timing out tomorrow night and take it from there, hopefully this will sort out all my problems and ill be away! or atleast up and down the drive way! lol
thanks for all your help and advice everybody, if it all goes wrong ill be in touch! cheers again
ja
got an update, i was told some of my vacum hoses were not quite right so i've changed these around and now the will hold in drive
the engine ticks over lovely at idel no problem, temp climbs up to running temp then steadies off. the engine isnt quite running smoothly in drive, but it is runnig now, so i will sort the timing out tomorrow night and take it from there, hopefully this will sort out all my problems and ill be away! or atleast up and down the drive way! lol
thanks for all your help and advice everybody, if it all goes wrong ill be in touch! cheers again
ja
I know on efi LSx chev engines you have to get the PCM to add more idle air via the IAC control so it idles ok in an auto.
Timing might help, but you might need either more rpm out of gear than in. Or if you have efi you need to add more air in (open throttle a little) to deal with the load.
Also applies to fans, power steering loads etc.
Maybe your converter has a lower stall speed than before? So you need a higher engine airflow to handle the extra load. Assuming your vacuum etc is all ok.
Timing might help, but you might need either more rpm out of gear than in. Or if you have efi you need to add more air in (open throttle a little) to deal with the load.
Also applies to fans, power steering loads etc.
Maybe your converter has a lower stall speed than before? So you need a higher engine airflow to handle the extra load. Assuming your vacuum etc is all ok.
OK guys
thanks for all your advice
this is gonna sound stupid, but it turned out to be, the vacum hoses which i said i got mixed up and the engine wasnt running on all 8 cylindars!!! i had 2 maybe 3 spark plugs out!
Being totally new to this i couldnt tell, but a mate, listened and we sorted it all out.
Once the spark plugs were replaced she started up and idel no problems, no shaking and sliped into drive lovely! Hell i even spent the next 20mins driving it up and down my road .... just to test it!
Anyway thanks for all the adivec and help, i know a little more now so hopefully this wont happen again!
Ja
thanks for all your advice
this is gonna sound stupid, but it turned out to be, the vacum hoses which i said i got mixed up and the engine wasnt running on all 8 cylindars!!! i had 2 maybe 3 spark plugs out!
Being totally new to this i couldnt tell, but a mate, listened and we sorted it all out.
Once the spark plugs were replaced she started up and idel no problems, no shaking and sliped into drive lovely! Hell i even spent the next 20mins driving it up and down my road .... just to test it!
Anyway thanks for all the adivec and help, i know a little more now so hopefully this wont happen again!
Ja
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