Timing degree
Thread Starter
Safety Car
Joined: Dec 2004
Posts: 4,071
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From: San Diego CA
Timing degree
Alright got the carb and distributor on the '81 changed out. Don't have the vaccume advance hooked up yet because all of the parts stores closed before I remembered to get a hose for that. According to a mechanic friend of mine said I can just hook that up to the little vaccume outlet on the front of the carb (Edelbrock 1904 aka M4ME Q-jet).
Anyways the real question is what do we set the timing to? It's at 10 degrees right now, my buddy thinks it needs to probably be at 6. What do you guys say?
Anyways the real question is what do we set the timing to? It's at 10 degrees right now, my buddy thinks it needs to probably be at 6. What do you guys say?
Drifting
Joined: Sep 2004
Posts: 1,532
Likes: 4
From: Fairview Heights Illinois, near Saint Louis MO, STL C3 Shark
Mine has total of 36 with the following settings (note, NOT stock springs/weights in distributer)
16* initial Timing
20* centrifugal in at 3000 rpms
======================
36* total at 3000 rpms.
Anything less than 16* initial and it is a DOG. My "book" for my 76 wants it set at 8*........
16* initial Timing
20* centrifugal in at 3000 rpms
======================
36* total at 3000 rpms.
Anything less than 16* initial and it is a DOG. My "book" for my 76 wants it set at 8*........
Thread Starter
Safety Car
Joined: Dec 2004
Posts: 4,071
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From: San Diego CA
Out of curiousity, what's your method to getting a 36 degree total, lars?
We're doing it with the cheapo timing light and slowly twisting the distributor then locking it down, with the vaccume advance disconnected.
We're doing it with the cheapo timing light and slowly twisting the distributor then locking it down, with the vaccume advance disconnected.
Safety Car
Joined: Oct 2004
Posts: 3,725
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From: Minnesota
Thread Starter
Safety Car
Joined: Dec 2004
Posts: 4,071
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From: San Diego CA
Originally Posted by jdmick
I'm using an aftermarket HEI from Procomp, and I don't have a set of soft springs.
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Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
Then you have to rev it up past 4500 rpm to get the total. Just install some soft springs to get the full advance in by 2500 and set it to 36.
Race Director
Joined: Sep 2004
Posts: 11,874
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by Kalway
Alright I'm going to sound like a total newb right here but I'd rather sound like a newb than be an idiot.
Where would I get some soft springs locally?
Where would I get some soft springs locally?
Drifting
Joined: Sep 2004
Posts: 1,532
Likes: 4
From: Fairview Heights Illinois, near Saint Louis MO, STL C3 Shark
Mine wouldn't work right with the new springs and old weights. I couldn't get 36 total no matter what. With the NEW SPRINGS AND NEW WEIGHTS it worked out perfectly.............. NEW WEIGHTS and STIFF SPRINGS got me exactly 36* at 3000 rpms, and maintained my 16* intial setting. Starts every time, runs strong.
So, don't just arbitrarily through away the new weights. Experiement with them because you might find that they ARE useful.
So, don't just arbitrarily through away the new weights. Experiement with them because you might find that they ARE useful.
Thread Starter
Safety Car
Joined: Dec 2004
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From: San Diego CA
What brand distributor are you using?
Oh and I better double check.
I hook the vaccume advance up to the little vaccume port on the front of the carburetor right?
Oh and I better double check.
I hook the vaccume advance up to the little vaccume port on the front of the carburetor right?
Last edited by Kalway; Jun 28, 2005 at 09:56 AM.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
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From: At my Bar drinking and wrenching in Lafayette Colorado
Kalway -
Get Mr. Gasket part number 927 or 928. Do not use the weights in the kit. Use the two gold springs on your HEI. This will give you full total advance under 3000 rpm and you can safely set the total by rev'ing the engine up until the advance pegs out.
Lars
Get Mr. Gasket part number 927 or 928. Do not use the weights in the kit. Use the two gold springs on your HEI. This will give you full total advance under 3000 rpm and you can safely set the total by rev'ing the engine up until the advance pegs out.
Lars
Thread Starter
Safety Car
Joined: Dec 2004
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From: San Diego CA
Do that with the vaccume advance disconnected, right?
Oh how exactly can you tell if it's at 36 degrees? The marks only go up to 12 and 8
Oh how exactly can you tell if it's at 36 degrees? The marks only go up to 12 and 8
Last edited by Kalway; Jun 28, 2005 at 04:30 PM.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
Easiest method: Use an adjustable timing light. Available from Sears for $69.
Alternate method: Measure the circumference of your harmonic balancer and divide by 10. This is the distance to measure clockwise (seen from the front) from your existing timing mark to get to 36 degrees. You can then use a standard timing light and shoot the new line to line up with the "0" mark on the tab.
All timing settings are always performed with the hose pulled off the vacuum advance control unit.
Alternate method: Measure the circumference of your harmonic balancer and divide by 10. This is the distance to measure clockwise (seen from the front) from your existing timing mark to get to 36 degrees. You can then use a standard timing light and shoot the new line to line up with the "0" mark on the tab.
All timing settings are always performed with the hose pulled off the vacuum advance control unit.
Thread Starter
Safety Car
Joined: Dec 2004
Posts: 4,071
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From: San Diego CA
Genius... By the way, I can tell this carburetor has been sitting around for awhile. The throttle response keeps getting better and better. For awhile it would sort of bog down when you punched the gas and slowly rev up. Now it's giving me more immediate response.
One of these days I'll have to send her down your way lars, or you could visit San Diego
We'll probably do the final tweaking of the timing this weekend. Right now I'm gonna re-break in this carb.
One of these days I'll have to send her down your way lars, or you could visit San Diego
We'll probably do the final tweaking of the timing this weekend. Right now I'm gonna re-break in this carb.