Timing a 1957, dual four, hydraulic lifters.
07-20-2013, 06:14 PM
#1
Drifting
Thread Starter
Timing a 1957, dual four, hydraulic lifters.
I have a question on timing a 1957 with dual fours, hydraulic lifters, 245 HP, 1110891 distributor. The 1956 -60 Corvette Chassis Service Operations book printed back in 1960 says 1957-58-59 Dual Four-Barrel with Hydraulic Lifters should have 4 degrees B.T.D.C. My 1957 Owners Manual says on all dual four barrel carburetor equipped engines should have 12 degrees BUDC. Which is correct, 4 degrees or 12 degrees? I have been running 12 and I think if I retarded it to 4, it would not even run.
07-20-2013, 06:58 PM
#2
Melting Slicks
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2016 C1 of Year Finalist
I believe 10-12 degrees initial timing usually works fine.
4 degrees seems to low.
Of course knowing the distributor advance curve and all the other techi stuff will also help.
4 degrees seems to low.
Of course knowing the distributor advance curve and all the other techi stuff will also help.
07-20-2013, 07:32 PM
#3
Team Owner
My initial timing on my dual quad 270HP solid lifter motor is 12*...that is what the engine 'likes'...
07-20-2013, 07:57 PM
#4
Safety Car
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If the distributor has ever been rebuilt or modified there's a good chance that factory specs may longer apply. Keep in mind that whatever you add to initial you are also adding to total. The factory could specify initial advance because they knew exactly what total it would result in. Rebuilders often use "one-size-fits-all" parts and/or that distributor may have met someone like me in it's past 
. I can't speak of your particular distributor but the factory often used very different curves for high performance engines than the milder ones. The mild cammed engines had higher cylinder pressures that require a longer and slower curve. I'd start by setting total to about 36º and go from there.
. I can't speak of your particular distributor but the factory often used very different curves for high performance engines than the milder ones. The mild cammed engines had higher cylinder pressures that require a longer and slower curve. I'd start by setting total to about 36º and go from there.
07-20-2013, 08:48 PM
#5
Burning Brakes
Arthur,
Look up LARS and tuning, you can contact him and he will send you a nifty procedure of how to 'optimize' the timing on YOUR small block Chevy engine.
You ask if it should be 4° or 12° or ????? Those values mean nothing more than starting point. That was safe number for production line and for the factory components in 1957
Get a digital read-out timing light with BOTH degrees and rpm (side by side) they are about $50-70.
Read LARS, but in summary what you want is to have all mechanical advance in by 2500-3000 rpm, probably will be 34-38 degree total mechanical with the vacuum plugged. Some of my small blocks are 37, even 38 degrees mechanical advance at 2500-3000 rpm.
You will gain throttle response, torque and reduce engine temp. I do my buddies C-1, C-2's and they are amazed at the 'free' benefit of simply optimizing the timing.
There are many Lars posts out there, but so many are corrupted or counterfeit (with other's editing). Lars will send you one of his clean tuning documents
Joe
Look up LARS and tuning, you can contact him and he will send you a nifty procedure of how to 'optimize' the timing on YOUR small block Chevy engine.
You ask if it should be 4° or 12° or ????? Those values mean nothing more than starting point. That was safe number for production line and for the factory components in 1957
Get a digital read-out timing light with BOTH degrees and rpm (side by side) they are about $50-70.
Read LARS, but in summary what you want is to have all mechanical advance in by 2500-3000 rpm, probably will be 34-38 degree total mechanical with the vacuum plugged. Some of my small blocks are 37, even 38 degrees mechanical advance at 2500-3000 rpm.
You will gain throttle response, torque and reduce engine temp. I do my buddies C-1, C-2's and they are amazed at the 'free' benefit of simply optimizing the timing.
There are many Lars posts out there, but so many are corrupted or counterfeit (with other's editing). Lars will send you one of his clean tuning documents
Joe