Timing help
Thread Starter
4th Gear Member
Joined: Aug 2008
Posts: 1,676
From: Goodyear, AZ
Timing help
i have a 66 289.
lunati cam (61003)
valve springs
holley carb
stealth intake
msd mechanical advance dizzy
(with the factory heavy springs in it)
i CANT GET THE CAT IDLE BELOW 18 DEGREES ADVANCED. BELOW THAT IT BACKFIRES THROUGH THE CARB AND STALLS.
WHAT SHOULD MY TIMING BE AT.
i REPLACED THE BALANCER WITH A AFTERMARKET ITEM THAT HAS 3 SETS OF TIMING MARKS. I USED THE ONE THAT WAS SPECIFIED IN THE DESTRUCTIONS.
I KNOW THAT DAVE SANDBORN CAN ANSWER THIS,
lunati cam (61003)
valve springs
holley carb
stealth intake
msd mechanical advance dizzy
(with the factory heavy springs in it)
i CANT GET THE CAT IDLE BELOW 18 DEGREES ADVANCED. BELOW THAT IT BACKFIRES THROUGH THE CARB AND STALLS.
WHAT SHOULD MY TIMING BE AT.
i REPLACED THE BALANCER WITH A AFTERMARKET ITEM THAT HAS 3 SETS OF TIMING MARKS. I USED THE ONE THAT WAS SPECIFIED IN THE DESTRUCTIONS.
I KNOW THAT DAVE SANDBORN CAN ANSWER THIS,
5th Gear Member
Joined: Feb 2007
Posts: 2,688
From: Ramona, CA
Maybe you werent actually at O when you dropped in the dizzy.. Try finding tdc again and get it in there on the right tooth.. It sounds like thats what happend.. You may be soo far off that reading 18 degrees is actually 7.. Maybe..
6th Gear Member
Joined: Oct 2006
Posts: 6,417
From: Cork, Ireland
Hiya,
a) your harmonic balancer slipped and your timing marks are now completely out of whack
b) you have connected the vacuum advance to full vacuum on carburator instead of ported vacuum
to a)
pull #1 spark plug, then manually turn your engine to what the balancer syays where 0 defgrees is (your timing marks)
check if the piston actually is on TDC. You can check that with a long wire and rocking back and forth the engine. make sure the wire is long enough or bent, so it cannot fall in!
You won't get it very accurate. with a bit of practice you'll get it right to about 2 degrees.
But this way you'll know if your balancer is correct or if it has slipped
to b)
with engine in idle unplug the vacuum advance on carb side. If you hear it sucking there or can feel it sucking on the port then you used the wrong vacuum pickup on carb.
Check carbs manual which is ported vacuum. use that and block the other
Kalli
a) your harmonic balancer slipped and your timing marks are now completely out of whack
b) you have connected the vacuum advance to full vacuum on carburator instead of ported vacuum
to a)
pull #1 spark plug, then manually turn your engine to what the balancer syays where 0 defgrees is (your timing marks)
check if the piston actually is on TDC. You can check that with a long wire and rocking back and forth the engine. make sure the wire is long enough or bent, so it cannot fall in!
You won't get it very accurate. with a bit of practice you'll get it right to about 2 degrees.
But this way you'll know if your balancer is correct or if it has slipped
to b)
with engine in idle unplug the vacuum advance on carb side. If you hear it sucking there or can feel it sucking on the port then you used the wrong vacuum pickup on carb.
Check carbs manual which is ported vacuum. use that and block the other
Kalli
5th Gear Member
Joined: Feb 2007
Posts: 2,688
From: Ramona, CA
Hiya,
a) your harmonic balancer slipped and your timing marks are now completely out of whack
b) you have connected the vacuum advance to full vacuum on carburator instead of ported vacuum
to a)
pull #1 spark plug, then manually turn your engine to what the balancer syays where 0 defgrees is (your timing marks)
check if the piston actually is on TDC. You can check that with a long wire and rocking back and forth the engine. make sure the wire is long enough or bent, so it cannot fall in!
You won't get it very accurate. with a bit of practice you'll get it right to about 2 degrees.
But this way you'll know if your balancer is correct or if it has slipped
to b)
with engine in idle unplug the vacuum advance on carb side. If you hear it sucking there or can feel it sucking on the port then you used the wrong vacuum pickup on carb.
Check carbs manual which is ported vacuum. use that and block the other
Kalli
a) your harmonic balancer slipped and your timing marks are now completely out of whack
b) you have connected the vacuum advance to full vacuum on carburator instead of ported vacuum
to a)
pull #1 spark plug, then manually turn your engine to what the balancer syays where 0 defgrees is (your timing marks)
check if the piston actually is on TDC. You can check that with a long wire and rocking back and forth the engine. make sure the wire is long enough or bent, so it cannot fall in!
You won't get it very accurate. with a bit of practice you'll get it right to about 2 degrees.
But this way you'll know if your balancer is correct or if it has slipped
to b)
with engine in idle unplug the vacuum advance on carb side. If you hear it sucking there or can feel it sucking on the port then you used the wrong vacuum pickup on carb.
Check carbs manual which is ported vacuum. use that and block the other
Kalli
Thread Starter
4th Gear Member
Joined: Aug 2008
Posts: 1,676
From: Goodyear, AZ
I appritiate the info. However it is not vacuum advance. it is a Mechanical advance unit. My Balancer is new and it is keyed on the crank. it cant slip.
I will However use the wire and the markings. i left it sit and started working on somethig else and decided i would come back to it.
Tonight will be a good night to start again sice i am dropping it off the jack stands. Just finished a hydro clutch conversion. it was easy and i bought all the parts at an off road shop cheaper that i found them anywhere else.
Thanks for the help guys.
I will However use the wire and the markings. i left it sit and started working on somethig else and decided i would come back to it.
Tonight will be a good night to start again sice i am dropping it off the jack stands. Just finished a hydro clutch conversion. it was easy and i bought all the parts at an off road shop cheaper that i found them anywhere else.
Thanks for the help guys.
3rd Gear Member
Joined: Apr 2008
Posts: 939
From:
For a problem like this, it's best to back to the basics. Check the things you "know" are right. If you've never made a simple mistake, you just havn't worked on your car enough.
1. It's not uncommon for timing marks to be off. Usually caused by parts mis match - pointer, cover, or balancer. Like Kalli said, check TDC to make sure it's accurate.
2. Confirm that you have the correct wiring from cap to plug. It's pretty easy to get two wires switched, and you'll get exactly those symptoms. Check with the cam maker about the firing order.
3. Are all the plug wires properly attached to the plugs?
1. It's not uncommon for timing marks to be off. Usually caused by parts mis match - pointer, cover, or balancer. Like Kalli said, check TDC to make sure it's accurate.
2. Confirm that you have the correct wiring from cap to plug. It's pretty easy to get two wires switched, and you'll get exactly those symptoms. Check with the cam maker about the firing order.
3. Are all the plug wires properly attached to the plugs?
6th Gear Member
Joined: Oct 2006
Posts: 6,417
From: Cork, Ireland
See what the lads have to say above. more valid points there.
You say you have mechanical advance only?
did you block the vacuum canister on distributor, or is it a distributor without a vacuum advance?
In case you don't have or want vacuum advance make sure you have all ports on carb plugged.
Spray around with WD40 to make sure you're not pulling air somewhere where you shouldn't (vacuum leak). Check as well the hose for brake booster to manifold.
Block that one temporarly just for a test. Check on the PCV hose as well
You say you have mechanical advance only?
did you block the vacuum canister on distributor, or is it a distributor without a vacuum advance?
In case you don't have or want vacuum advance make sure you have all ports on carb plugged.
Spray around with WD40 to make sure you're not pulling air somewhere where you shouldn't (vacuum leak). Check as well the hose for brake booster to manifold.
Block that one temporarly just for a test. Check on the PCV hose as well
5th Gear Member
Joined: Apr 2007
Posts: 2,100
From: Texas Hill Country
These guys have good advise for troubleshooting. To answer one of your initial questions, your intial timing at idle with no advance should be around 6* for stock or as high as 10-12* for performance motors. If you are running really rich for some reason, you may need to run as much as 22-24* intial to not completely foul the plugs. I just went through that.:-) Now with a mechanical advance, when you rev the engine up you should probably be at full advance between 3000-4000rpm. The total advance should for stock should probably be around 32-34*. With performance motors, it may be 36-38*. To be save, I was start with stock settings and go from there when things are working. ti is not an exact science. Optimum timing will be different for almost every engine.
I would check the plug wires, TDC, and vacuum ports, like others have said.
I would check the plug wires, TDC, and vacuum ports, like others have said.