Cranking difficulty with advanced timing?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

slikside · 07-24-2014, 07:30 PM

I just advanced my timing from 8*BTDC to about 16*BTDC to try and get some better performance and fuel economy.

Now, when I go to start it, even cold, it struggles to crank over, similar to a heat soaked starter.

Should this be expected, or is something else going on coincidentally?

This is on a bone stock '72 350 C-10 with points ignition.

The throttle response is definitely better.

Thanks.

Prescott · 07-24-2014, 07:44 PM

Yes, it is predictable that the engine is fighting itself at 16 degrees. You could even blow a hole in one of your pistons. Try backing off to 12. It might behave a lot better.

slikside · 07-24-2014, 08:02 PM

Ouch! That would be bad. I'll do that.

slikside · 08-01-2014, 12:25 PM

Quote:

Originally Posted by Prescott

Yes, it is predictable that the engine is fighting itself at 16 degrees. You could even blow a hole in one of your pistons. Try backing off to 12. It might behave a lot better.

Finally got around to doing this (haven't driven in the mean time), and yeah, much better now...thanks.

GASoline71 · 08-01-2014, 07:02 PM

Bone stock engine and 16 degress is waaaayyyy too advanced. No "performance" to be gained. The neigborhood of 10 degrees will be fine... maybe even up to 12.

Gary

**bowtie72** · 08-02-2014, 09:07 AM

Your easiest upgrade for performance and economy would be a HEI dst. You will be amazed at the difference.

07-24-2014, 07:30 PM	#1
slikside Registered User Join Date: Jun 2010 Location: San Diego Co. Posts: 1,179	Cranking difficulty with advanced timing?? I just advanced my timing from 8BTDC to about 16BTDC to try and get some better performance and fuel economy. Now, when I go to start it, even cold, it struggles to crank over, similar to a heat soaked starter. Should this be expected, or is something else going on coincidentally? This is on a bone stock '72 350 C-10 with points ignition. The throttle response is definitely better. Thanks. __________________ 1972 Chevy C-10, SWB, Fleet, 350/350, PS, PB, HEI, mostly stock, Survivor.

07-24-2014, 07:44 PM	#2
Prescott Registered User Join Date: Jun 2013 Location: Prescott AZ Posts: 31	Re: Cranking difficulty with advanced timing?? Yes, it is predictable that the engine is fighting itself at 16 degrees. You could even blow a hole in one of your pistons. Try backing off to 12. It might behave a lot better.

07-24-2014, 08:02 PM	#3
slikside Registered User Join Date: Jun 2010 Location: San Diego Co. Posts: 1,179	Re: Cranking difficulty with advanced timing?? Ouch! That would be bad. I'll do that. __________________ 1972 Chevy C-10, SWB, Fleet, 350/350, PS, PB, HEI, mostly stock, Survivor.

08-02-2014, 09:07 AM	#6
bowtie72 Registered User Join Date: Mar 2007 Location: Colorado Posts: 363	Re: Cranking difficulty with advanced timing?? Your easiest upgrade for performance and economy would be a HEI dst. You will be amazed at the difference. __________________ 1968 SWB "Little White Truck" 1972 LWB LS 4l80 "Plain Jane!!"



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