Is there a point of diminishing returns on timing advance?

crazypete · 06-20-2003, 10:59 AM

Just wondering because my vacuum advance doesnt work, so I'm compensating by advancing the base timing and I seem to have got it up to 24 degrees initial (46 total with mechanical) and I dont hear any detonation at all. It's cool too because the exhaust tone changed to a higher pitch almost. I have no noticable problems starting her hot. Should I keep going?

84gt347 · 06-20-2003, 11:25 AM

ordinarilay, that would be waaay to much total timing. I would go to the track and watch my mph. 34 is usually good, sometimes 36. I run 14 initial and 21 in the distributor and get my best results. I used to try 16 initial and my mph dropped by 2 mph.

crazypete · 06-20-2003, 11:41 AM

ok, so total timing should not generally surpass the mid 30's. As soon as I can figure out how to get that plate out of the distributor, I'll flip the weight guide over (it has a smaller channel, I believe) for less mechanical advance.

is 24 initial hurting me or helping me? Lets say theoretically that I have some possessed deamon car that shows no detonation at 34 initial and I rip out the mechanical advance so it runs at 34 degrees all the time. Would I want this or is less timing necessary for idle or emissions or low engine speed?

Thanks guys!

84gt347 · 06-20-2003, 11:57 AM

High initial timing or a locked distributor at a high rate of timing can cause cooling problems in street cars, and thats not a rule of thumb, but something to watch out for. If your not having any starter problems or detonation problems now, watch out for them under extreme driving conditions, most notably, heat. Imo, it is better to have a higher initial timing and less in the distributor. I use a msd and it is adjustable. I have a pretty high compression ratio and 16 initial seems to let my car warm up quicker than i like. You'll find what you like, with a little experimenting. I still say, at the track, you can monitor your mph and tell when the mph drop off is and you'll know more for sure where it runs best. Start low and eek it up a couple of degrees at a time till you max out mph and quit there. Stop right where it maxes out, and hopefully you will have a safe amount of timing. imo more than 36 may work and not detonate, but i'll bet 34 to 36 would get you the same mph in the quarter and be a safer setup.

andy669 · 06-20-2003, 01:38 PM

Too much timing can be masked by having too much fuel. My car runs best with the timing in the low 40's/high 30's. Although I cant say I have heard of someone running as much as 46. You might try taking some fuel out as well as timing.

Andy

crazypete · 06-20-2003, 02:20 PM

Is there any easy way for the average citizen to get the baseplate on the distributor off? I've been staring at it and it doesnt seem as if the paddle gear for the magnetic pickup is going to come off the mainshaft without serious prying. I gave it a few cautious prys with a screwdriver and decided that it's better if I dont break the paddle or deform the housing. It's an 85 distributor. Any suggestions?

06-20-2003, 10:59 AM	#1
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	Is there a point of diminishing returns on timing advance? Just wondering because my vacuum advance doesnt work, so I'm compensating by advancing the base timing and I seem to have got it up to 24 degrees initial (46 total with mechanical) and I dont hear any detonation at all. It's cool too because the exhaust tone changed to a higher pitch almost. I have no noticable problems starting her hot. Should I keep going? __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior

06-20-2003, 11:25 AM	#2
84gt347 Registered Member Join Date: Mar 2002 Location: sherwood Forest Posts: 291	ordinarilay, that would be waaay to much total timing. I would go to the track and watch my mph. 34 is usually good, sometimes 36. I run 14 initial and 21 in the distributor and get my best results. I used to try 16 initial and my mph dropped by 2 mph. __________________ 84 gt350 89 lx vert 92 lincoln lsc. All Forced ( one way or another)

06-20-2003, 11:41 AM	#3
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	ok, so total timing should not generally surpass the mid 30's. As soon as I can figure out how to get that plate out of the distributor, I'll flip the weight guide over (it has a smaller channel, I believe) for less mechanical advance. is 24 initial hurting me or helping me? Lets say theoretically that I have some possessed deamon car that shows no detonation at 34 initial and I rip out the mechanical advance so it runs at 34 degrees all the time. Would I want this or is less timing necessary for idle or emissions or low engine speed? Thanks guys! __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior

06-20-2003, 11:57 AM	#4
84gt347 Registered Member Join Date: Mar 2002 Location: sherwood Forest Posts: 291	High initial timing or a locked distributor at a high rate of timing can cause cooling problems in street cars, and thats not a rule of thumb, but something to watch out for. If your not having any starter problems or detonation problems now, watch out for them under extreme driving conditions, most notably, heat. Imo, it is better to have a higher initial timing and less in the distributor. I use a msd and it is adjustable. I have a pretty high compression ratio and 16 initial seems to let my car warm up quicker than i like. You'll find what you like, with a little experimenting. I still say, at the track, you can monitor your mph and tell when the mph drop off is and you'll know more for sure where it runs best. Start low and eek it up a couple of degrees at a time till you max out mph and quit there. Stop right where it maxes out, and hopefully you will have a safe amount of timing. imo more than 36 may work and not detonate, but i'll bet 34 to 36 would get you the same mph in the quarter and be a safer setup. __________________ 84 gt350 89 lx vert 92 lincoln lsc. All Forced ( one way or another)

06-20-2003, 01:38 PM	#5
andy669 Registered Member Join Date: Jan 2001 Location: Moline Il Posts: 901	Too much timing can be masked by having too much fuel. My car runs best with the timing in the low 40's/high 30's. Although I cant say I have heard of someone running as much as 46. You might try taking some fuel out as well as timing. Andy __________________ 88 coupe 91 LX NMRA Pure Street 5120

06-20-2003, 02:20 PM	#6
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	Is there any easy way for the average citizen to get the baseplate on the distributor off? I've been staring at it and it doesnt seem as if the paddle gear for the magnetic pickup is going to come off the mainshaft without serious prying. I gave it a few cautious prys with a screwdriver and decided that it's better if I dont break the paddle or deform the housing. It's an 85 distributor. Any suggestions? __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior

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