Topic: Holley 750 DP w/auto tranny?
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
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Former Member
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Charleston AFB, SC - USA
Joined: 10/31/2007
Posts: 111
Vette(s): 1979 Cream Beige Coupe w/383 & 700R4
Just curious, what makes you sure the HG won't help? It should lower the compression at least a few tenths. I can't run race fuel, it's a DD and I'm not that rich haha. But when you say "it's the tune" what do you mean? I tried 2 sizes higher on the jets and a size smaller on the rods. The dist has the heaviest springs possible, and it does it even with the vac advance unplugged. I'm not sure what part of the tune could fix it?
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Lifetime MemberJOSH,, I FORWARDED TO NOSAL1 TO REVIEW, HE BUILT MY MOTOR AND COULD GIVE YOU BETTER INSIGHT.
Ping is caused by one thing. Heat. When you reach 2500 deg F inside the cylinder, you begin to get ping and knock. You also produce NOx at this point.
kstyer 2008-06-24 17:13:04
EGR valves are designed to cool the cylinder in regular engines. If you don't have one, and it's not likely, forget that part.
Alum cyl heads run cooler than cast iron, but that is a lot of expense and work.
Retarted timing runs cooler, to a point.
High octane burns cooler, but for a longer period of time. That helps
Cooling system temp should be kept as low as possible.
Higher compression promotes heat. Lower compression runs cooler.
Richer mixtures burn cooler than lean mixtures.
A good set of headers remove more heat, but allow more fresh air into the cylinder, which in turn could run hotter.
All of these things come into play with the tune.
Perhaps the first thing I would do with your car is try using some cooler heat range spark plugs.
Former Member
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Charleston AFB, SC - USA
Joined: 10/31/2007
Posts: 111
Vette(s): 1979 Cream Beige Coupe w/383 & 700R4
I don't have an EGR valve. I have alum heads. I've tried retarding the timing a ton with no success. I have longtubes. The plugs I have now are NGK R5672A-8. They're an 8 heat range with 35 gap. Do you think I should go even colder than that?
Josh,
As VETTERBOB mentioned we had a bit of a problem with the pinging of his 383 as well and as Bob stated he/we tried several carbs and went back to Edelbrock 800 CFM,however the relief came when we took it to another friend who had Sun distributor analyzer and set the distributor( i.e. setting spring tension with certain springs and balanced weights) up to a static timing of 26 degrees advance and have the mechanical advance increase to a total advance of 36 degrees at 2800 rpm instead of 3300 rpm.
You will have to take the car to a mechanic who has the distributor machine and also has a touch and feel for adjusting the carbs which may include him to change primary and secondary rods and jets in the carb..
I am sorry but there is no quick fix for the pinging problems.Bob's engine was the only 383 I built that had a pinging problem and I have built many,his was the first in Florida.
I do not know if this is any help,however may give you a direction to check out.
Sal C.
As VETTERBOB mentioned we had a bit of a problem with the pinging of his 383 as well and as Bob stated he/we tried several carbs and went back to Edelbrock 800 CFM,however the relief came when we took it to another friend who had Sun distributor analyzer and set the distributor( i.e. setting spring tension with certain springs and balanced weights) up to a static timing of 26 degrees advance and have the mechanical advance increase to a total advance of 36 degrees at 2800 rpm instead of 3300 rpm.
You will have to take the car to a mechanic who has the distributor machine and also has a touch and feel for adjusting the carbs which may include him to change primary and secondary rods and jets in the carb..
I am sorry but there is no quick fix for the pinging problems.Bob's engine was the only 383 I built that had a pinging problem and I have built many,his was the first in Florida.
I do not know if this is any help,however may give you a direction to check out.
Sal C.
Josh,
Also you will need to go to a cold plug or as cold as you can get depending on the heads.Early heads like Bob's would use AC R42 if you can get them and if you have later model heads (peanut plug instead of 13/16" plugs) AC R43 as opposed to AC R44 or an equal in aftermarket,Bosch,NKG,or any major brand other than Motorcraft(Ford Plug I have seen these used in Chevy engines and causes throwing up everywhere)Unfortunately Axcell does not have a cold header plug which I have used successfully..
Take care and good luck.
Sal C.
Also you will need to go to a cold plug or as cold as you can get depending on the heads.Early heads like Bob's would use AC R42 if you can get them and if you have later model heads (peanut plug instead of 13/16" plugs) AC R43 as opposed to AC R44 or an equal in aftermarket,Bosch,NKG,or any major brand other than Motorcraft(Ford Plug I have seen these used in Chevy engines and causes throwing up everywhere)Unfortunately Axcell does not have a cold header plug which I have used successfully..
Take care and good luck.
Sal C.
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
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