351 pinging
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Joined: Jun 2003
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From: Gilroy, Ca
351 pinging
I have a "pinging" problem due to a to high compression. The engine is a 351W w/ GT40 cast iron polished and cleaned up bowls, port-matched heads, GT40 intake, SVO 70mm mass air, SVO 65mm throttle body, SVO EGR high flow spacer, SVO EEC-1V processor, 30lb SVO flow matched injectors, SVO ceramic coated short tube headers, 3" single exhaust w/ 2 chamber flow master and high flow cat, Crane 1.6 rollar rockers, Crane roller cam #444112, .530 valve lift, 208-216 degree at .05 lift.
This engine on a dynajet produced 202 hp at 4500 rpm, 349 torque at 2750 rpm. Horsepower was flat +-5 hp from 3000 to 5200 rpm. On all pump gas (91 octane).
This is in an early Bronco so low end responsiveness is important. I believe my CR is 10.5 baised on best info I have. Cranking pressure is 185lbs. I want to run 91 octane premium. I'm getting tired of using 100 octane at $4.69 a gallon to keep it from "pinging". It runs great except for lack of top end pull 4000 up which probably is the cam.
I think my options are : 1) go to aluminum heads (as I've been told 10.5 CR is okay w/ 91 octane), 2) machine GT40 heads to (can this be done? and what drawbacks?).
If I go with #1, head choices are: GT40X, Brodix 5.0R 68cc, World Winsor lite, Canfield 65cc or ???
Sorry for the long post but want to give all info in the hopes of getting some good responses.
Thanks very much, Cary
This engine on a dynajet produced 202 hp at 4500 rpm, 349 torque at 2750 rpm. Horsepower was flat +-5 hp from 3000 to 5200 rpm. On all pump gas (91 octane).
This is in an early Bronco so low end responsiveness is important. I believe my CR is 10.5 baised on best info I have. Cranking pressure is 185lbs. I want to run 91 octane premium. I'm getting tired of using 100 octane at $4.69 a gallon to keep it from "pinging". It runs great except for lack of top end pull 4000 up which probably is the cam.
I think my options are : 1) go to aluminum heads (as I've been told 10.5 CR is okay w/ 91 octane), 2) machine GT40 heads to (can this be done? and what drawbacks?).
If I go with #1, head choices are: GT40X, Brodix 5.0R 68cc, World Winsor lite, Canfield 65cc or ???
Sorry for the long post but want to give all info in the hopes of getting some good responses.
Thanks very much, Cary
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Joined: Jul 2001
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From: Huntersville
351 pinging
Have you done any work on your timing curve? i have a 69 351W with c90e heads and am pretty sure this thing has close to 10.1 compression. I run premium also to keep the pinging done but I can use my timing to run it on regular, it just does'nt have the pep. I have been playing with running full manifold vacuum to my advance starting with a base timing of 12 btdc and pulling another 12 with the vacuum at idle. Seems to do better. Idles smoother, runs cooler, seems pepier. After I get off idle the vacuum pulls in more advance but not sure how much. The thing is once you're out on the road and hit a big hill and your vaccum drops so does your advance with keeps it from pinging.
I'll probably get flamed for this since everyone says to use ported but I have found a couple older articles explaining it and it seems to be working for me
Clint
I'll probably get flamed for this since everyone says to use ported but I have found a couple older articles explaining it and it seems to be working for me
Clint
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From: Gilroy, Ca
351 pinging
This things eec-iv controled and I don't think the distributor has a vaccum advance at least I don't see one.
The EGR is installed but no water ran to components and not hooked up. I asked the SVO tech guys if it would help and they told me no?
It doesn't throw any codes.
SVO tech guys said that my cast iron heads can onty handle aprox. 9.5 CR. and aluminum heads should be good for 10.5.
It would ping Hard from 1/2 throttle on. But runs great on 100 octane.
What about coating the combustion area?
Can I mill the combustion area to 68-70cc to lower CR to 9.2-9.5.
Thank for your help. Cary
The EGR is installed but no water ran to components and not hooked up. I asked the SVO tech guys if it would help and they told me no?
It doesn't throw any codes.
SVO tech guys said that my cast iron heads can onty handle aprox. 9.5 CR. and aluminum heads should be good for 10.5.
It would ping Hard from 1/2 throttle on. But runs great on 100 octane.
What about coating the combustion area?
Can I mill the combustion area to 68-70cc to lower CR to 9.2-9.5.
Thank for your help. Cary
Last edited by caryt; Sep 20, 2003 at 07:26 PM.
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Joined: Jul 2003
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From: Independence, MO
351 pinging
I need some more info, what kinda injection do you have SD or MAS AIR? HAVE you you had a chip burned for you set up a stock motor is one thing but when you change all this stuff a stock ecm wont cut it, with that many mods a number of things can cause pinging, Too hot of a spark plug, over advancing the timming, not enough pulse with on the injectors (comp chip), too lean. ect. ect. give me some more info about you system and what modle and may be we can help. DW
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From: Gilroy, Ca
351 pinging
Dw, Its got a Mass Air EFI, M-12071-C302 mulitport wireing harness kit , M-12071-G302 computer and mass-air meter kit all from the Ford racing catalog. Timing is set to stock 10btdc.
When I first talked to the Ford Motorsport tech guys they thought it was lean with stock 19lbs inj. So they recomended the 70mm mass-air meter M-12579-A-70 and 30lbs inj. I got a good deal on a set of flow matched 30lbs so I changed all. Did not affect ping.
I asked them if I should get a different EEC-1V module they said no.
I have tried to find info on chipping but haven't had much luck, Its a little confusing.
I will check spark plug #, I know rhat with the 76 race gas there is no color to the insulator.
Thanks, Cary
When I first talked to the Ford Motorsport tech guys they thought it was lean with stock 19lbs inj. So they recomended the 70mm mass-air meter M-12579-A-70 and 30lbs inj. I got a good deal on a set of flow matched 30lbs so I changed all. Did not affect ping.
I asked them if I should get a different EEC-1V module they said no.
I have tried to find info on chipping but haven't had much luck, Its a little confusing.
I will check spark plug #, I know rhat with the 76 race gas there is no color to the insulator.
Thanks, Cary
Posting Guru
Joined: Jul 2003
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From: Independence, MO
351 pinging
make shure your plugs arent to hot, a spark plug thats to hot will cause pinging (preignition), did you order the mas air calibrated for 30lb. injectors? you realy need to look in to a custom chip, you may want to contact WEBMASTER (KEN) @ MOTORHAVEN here on the forums, another thing is a adjustable fuel pressure regulator, if you tweak your fuel pressure you can gain another 10-12HP but everything else needs to be in order be fore you go there. DW
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From: Gilroy, Ca
351 pinging
DW, I checked the plug # autolite 764. Tried to get info on these but autolite site sucks. They cross-refenced to champion #rs12yc.
So I think these plugs are {race type} and to hot? Maybe thats my problem? Do you have a plug sugestion.
Thanks, Cary
So I think these plugs are {race type} and to hot? Maybe thats my problem? Do you have a plug sugestion.
Thanks, Cary
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Posting Guru
Joined: Jul 2003
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From: Independence, MO
351 pinging
Its always best to go with factory recomended plug and start from there, a plug thats to cool wont hurt any thing it will just eventually foul out, but if **** to hot and pinging it can cause engine damage, so I'd start with the factory recomended plug in a AUTOLITE brand gapped at about 0.040-0.045. DW
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From: Gilroy, Ca
351 pinging
Just checked some spark plug sellers on the web and they list, 94 f-150 lighting { closest to what I have?} autolite app764, non race version of what I have? Or the Champion 2408. I can't seem to find a chart to show the heat ranges availible to tell if these are hotter than normal?
Cary
Cary
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