persistent spark plug fouling
Thread Starter
Instructor
Joined: Jan 2015
Posts: 101
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From: Rochester NY
persistent spark plug fouling
Im having problems with my spark plugs.Ill start with what my engine is first. I have a Blueprint 355 engine with Edelbrock manifold and 650 carb. I have a DUI distributor with MSD wires. Everything is new. Im using Champion 792 with .045" gap(which is what they suggest using). Car runs kind of rough and has poor throttle response. I then tried to start again but wont because the plugs are wet and fouled.I tried tuning the carb so it wouldnt run so rich but i still get a rich condition. Any help would be greatly appreciated. PS. I tried to search this forum but could find anything.
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two things come to mind, float level too high and why are you running such a cold plug? A 792 is a C59YC. The heat range of 59 is recommended by Champion for engines with a 13.0:1 to 14.5.0:1 compression, see page 5 and 6 below.
https://www.gsparkplug.com/media/wys...ence_Chart.pdf
https://www.gsparkplug.com/media/wys...ence_Chart.pdf
Last edited by MelWff; Dec 16, 2018 at 10:49 AM.
Thread Starter
Instructor
Joined: Jan 2015
Posts: 101
Likes: 2
From: Rochester NY
Blueprint engines recommends these plugs and used them at the dyno, Also my compression is 10 to 1
- Cam Type: Flat Tappet
.480 Intake .486 Exhaust
229 Intake / 230 Exhaust duration
@ .050
Last edited by Japery; Dec 16, 2018 at 11:09 AM.
Thread Starter
Instructor
Joined: Jan 2015
Posts: 101
Likes: 2
From: Rochester NY
Iv tried other plugs that where in the hotter ranges at no avail. I bought a 7lb mech fuel pump,do you think i should use a fuel pressure reg? should I try diff. needle sizes in cab? Is carb to big?
Last edited by Japery; Dec 16, 2018 at 11:24 AM.
Le Mans Master
Joined: Dec 2006
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Im having problems with my spark plugs.Ill start with what my engine is first. I have a Blueprint 355 engine with Edelbrock manifold and 650 carb. I have a DUI distributor with MSD wires. Everything is new. Im using Champion 792 with .045" gap(which is what they suggest using). Car runs kind of rough and has poor throttle response. I then tried to start again but wont because the plugs are wet and fouled.I tried tuning the carb so it wouldnt run so rich but i still get a rich condition. Any help would be greatly appreciated. PS. I tried to search this forum but could find anything.
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Race Director
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Did you measure the fuel pressure, Edelbrock carb has a maximum of 6.5 psi?
Did you set the timing to what Blueprint recommends, 34 at 3,500 rpm?
Le Mans Master
Joined: Aug 2017
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From: Cool Northern Michigan
Ok, never mind. I really doubt this is a sparkplug heat range issue right now. You are flooding. And no certain sparkplug is going to help you.
Why are you flooding? IDK Raw fuel is entering unmetered some how, somewhere, some place. Just a few drip-drip-drips from the boosters or shooters will screw up everything.
Good Luck
Why are you flooding? IDK Raw fuel is entering unmetered some how, somewhere, some place. Just a few drip-drip-drips from the boosters or shooters will screw up everything.
Good Luck
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I agree...sounds like a carb issue. Need to fix that first. No way you should be fouling plugs.
That said...does it smoke? Can you post pics of plugs? Is there oil getting on them or just fuel fouled?
JIM
That said...does it smoke? Can you post pics of plugs? Is there oil getting on them or just fuel fouled?
JIM
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From: Long Island
I agree, I tend to thing it's the carb leaking or just too rich.
I had an issue last summer with dirt in the carb - kept the float from seating the valve and it dripped fuel into the carb...
I had an issue last summer with dirt in the carb - kept the float from seating the valve and it dripped fuel into the carb...
Last edited by BLUE1972; May 10, 2019 at 09:44 PM.