Jumped timing, Distributor?
Thread Starter
Racer
Joined: Oct 2006
Posts: 378
Likes: 20
From: East Hampton CT
Jumped timing, Distributor?
Greetings Everyone!
I hope everyone here in the NE is handling the cold weather with good spirit.
My '87 vette 4+3 is not starting.
Situation:
I pulled into a mall parking lot, semi-agressive and then let off the gas (no wheel spin). Once my foot left the gas pedal the engine shut down.
I have spark, but I appears sporatic??!?! Sporatic as I took a spare spark plug hooked it to the #1 wire and when I cranked the engine is would spark randomly. Example- It would provide a series of sparks and then once or twice.
I think the distributor gear is worn out and has caused my timing to jump.
Please let me know if you think I should look at any other causes.
Thanks and wish me luck
I hope everyone here in the NE is handling the cold weather with good spirit.
My '87 vette 4+3 is not starting.
Situation:
I pulled into a mall parking lot, semi-agressive and then let off the gas (no wheel spin). Once my foot left the gas pedal the engine shut down.
I have spark, but I appears sporatic??!?! Sporatic as I took a spare spark plug hooked it to the #1 wire and when I cranked the engine is would spark randomly. Example- It would provide a series of sparks and then once or twice.
I think the distributor gear is worn out and has caused my timing to jump.
Please let me know if you think I should look at any other causes.
Thanks and wish me luck
Drifting
Joined: Sep 2005
Posts: 1,867
Likes: 3
From: Pasadena Maryland
Bring the timing mark up to TDC and look at the rotor, it should be close to 1 or 6. Get someone to crank it over while you watch the rotor spin. If the spark is intermittent you should see the rotor stop for a moment while the engine is cranking. If the rotor spins continuously you should get continuous spark? Do you have a check engine light? Also, the timing chain can jump time.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
kalister1 made a good post. Also, just as I did yesterday, you can remove #1 plug and bring the piston to TDC (timing mark at 0* on the HB). Take the cap off and note the orientation of the rotor. If not at #1 or #6 then it has jumped time. Check all the connections at the dist. Take the ICM out and have it tested at Autozone.
Just some thoughts.
Oh, I understand you state you have intermittant spark, but do you have the ref pusles to the injector connectors?
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Hook up a timing light and have someone spin the engine while you see where the timing really is.
May be something else instead of timing.
SBC's don't ususally jump timing at the the distributor. I've personally never seen one do it there. Not saying it's impossible, just not likely.
It's normally the timing chain and gears that wear to the point where the chain will get a tooth off. When this happens the result is called 'jumped timing'.
In this case, the valve timing will be way off as well as the ignition timing.
May be something else instead of timing.
SBC's don't ususally jump timing at the the distributor. I've personally never seen one do it there. Not saying it's impossible, just not likely.
It's normally the timing chain and gears that wear to the point where the chain will get a tooth off. When this happens the result is called 'jumped timing'.
In this case, the valve timing will be way off as well as the ignition timing.
Burning Brakes
Joined: Jan 2006
Posts: 847
Likes: 0
From: Colorado Springs CO
Or a loose distributor causing the unit to move over time and loose timing. I had to lock tight and use a lock washer on the nut. Just an idea.
I just notice someon else pointed this out. duh
I just notice someon else pointed this out. duh
Last edited by Ttime; Feb 9, 2007 at 06:09 PM. Reason: I need to read the thread closer! Spelling errors too
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Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Look down the hole at the cam gear that drives the distributor gear. If the dist gear is hurt bad, the cam gear likely is too. A new distributor gear will not last long on a worn cam gear.
The cam gear puking puts a tremendous amount of metal in the oil which heavily scuffsthe piston skirts and cylinder walls.
You do not want to shred another gear if you can avoid doing so.
The cam gear puking puts a tremendous amount of metal in the oil which heavily scuffsthe piston skirts and cylinder walls.
You do not want to shred another gear if you can avoid doing so.
