Plugs keep foiling up

[kennyhbh]

After 50 or so miles the plugs are foiled up. So bad i had a hard time getting home tonight from a car show. I just got the car ,so have no history its a Roush 402 sr. So far change out the plugs , adj floats,trimming ,. When engine has fresh plugs engine runs real strong! Starts right up ,water temp is good, but when plugs go bad, back fires after let foot off the gas, here it missing,ect. Any suggestions..

[Tommy]

Kenny,
When I had my engine rebuilt with higher performance in mind, the builder installed a set of cool plugs to assure there was no pre-ignition or detonation that could have caused real damage. These plugs lasted longer than yours (about a thousand miles) before fouling, but I got tired of messing with them. So I looked up the heat range data on them and got a set one step warmer. They have worked fine with no fouling. .... If I were you, I'd try plugs one step hotter and see if that helped.

[bobcowan]

What plugs are you using, and what do they look like when fouled?

[kennyhbh]

running auto-craft 605

[Gaz64]

A little more info on the engine would be helpful.

Foiled? You mean fouled, with fuel or oil.

Fouling from excessive richness, weak spark or too cold heat range?

What spark plug are you using? Compression ratio? Cam profile? Carburetor?

[RICK LAKE]

Kennyhbh Ken are you running an MSD setup?? If yes check the cap and rotor. The center of the cap probe is carbon and may have cracked off. You will get spark but ugly. Check rotor end for burn and make sure the steel point is tight in rotor cover. How do you have the coil mounted. If it is an oil filled one you want the coil vertical and if possible not mounted on the motor.
Next would be to check the fuel pressure regulator to too high a pressure. NO more than 5 psi is needed to run a motor. When you start running 6 psi and high the floats start to bounce and cause flooding when driving. Do you have black smoke coming from pipes? If so what color does it look. As others have said, gas is black, blue is oil, white is water. I would make sure you also that the correct PCV valve in the motor. It could be sucking oil instead of oil mist in motor. Leave pcv valve off motor and road test add rag to keep oil from sparying on motor and is if spark plugs go bad again. If not we need to check valve and possible blowby from the rings in the motor. May have a bad motor. I have seen bad camshafts and distributor gear problems in Roush motors. Pictures would really help here. Final checks make sure you the the correct gap for the plugs in this motor. Get a spark tester and make sure the spark is bright and strong. If you have a spare plug and vice grips and wire to ground plug you want that nice spark with the motor running. Start with fuel pressure first. Good luck. Rick L.

[bobcowan]

I'm not familiar with Autocraft. Do you man Autolite? If so, the 605 is a pretty standard copper core plug, with a #3 heat range. That plug is used in a lot of stock late model engines, and has a slightly shorter reach than you would expect (by 1mm) for a SBF.

As you increase the performance and power output, you usually decrease the heat range. Usually, 1 heat range per 75-100 hp.

But, getting back to the original question, what do the plugs look like when fouled? Are they oil or fuel fouled? A picture would be nice. I'd also like to see the back of the strap.

Also, what gap are you using? I'm not sure what static compression that engine has, but the gap should probably be something like .035"'ish.

[Dwight]

with the newer gas we burn today you will not get the same tan tailpipe color that we did in the 60's plus ethanol in our modern fuel it makes reading plug a lot harder.
Here is a good link to plug reading.




sparkplugreading

[kennyhbh]

Hi guys. change the plugs still having the problems. gap 55 . running msd. change out the cap and rotor . swap in a different 6al msd box . wont hold a idle have to keep pumping pedal keep it running, at higher rpm i can here it miss fire. side pipes are black carbon. also the plugs that i took out weren't filled with carbon.

[Got the Bug]

What do the plugs look like? Are they wet in any way? Any coolant loss lately?

You might want to try doing a compression test.

[bobcowan]

Originally Posted by kennyhbh

Hi guys. change the plugs still having the problems. gap 55 . running msd. change out the cap and rotor . swap in a different 6al msd box . wont hold a idle have to keep pumping pedal keep it running, at higher rpm i can here it miss fire. side pipes are black carbon. also the plugs that i took out weren't filled with carbon.

Gap is too big. Bring it down to about .035" or so.

So probably not too rich, and probably not oil fouled.

But you might consider going one heat range colder if they foul out that quickly with a smaller gap.

You could also consider cutting the ground electrode back like in a racing plug.

[Gaz64]

Originally Posted by kennyhbh

Hi guys. change the plugs still having the problems. gap 55 . running msd. change out the cap and rotor . swap in a different 6al msd box .
wont hold a idle have to keep pumping pedal keep it running, at higher rpm i can here it miss fire.
side pipes are black carbon. also the plugs that i took out weren't filled with carbon.

What carburettor?

Sounds like one or more blocked idle air bleeds.

Some pics would be nice.

As Bob has said, plug gaps are too big.

Never heard of your plugs either.

[kennyhbh]

We're are these idle air bleeds.

[Gaz64]

What carb do you have Kenny?

[kennyhbh]

Hi , Holley 770 street adventure .

[jhv48]

Before you start messing with colder/warmer plugs, determine whether the plugs are oil fouled or fuel fouled.

Different solutions to each of these. Plugs will appear black and could be damp and smell like gas if fuel fouled. Black and oily will be more problematic to solve.

[Gaz64]

Originally Posted by jhv48

Before you start messing with colder/warmer plugs, determine whether the plugs are oil fouled or fuel fouled.

Different solutions to each of these. Plugs will appear black and could be damp and smell like gas if fuel fouled. Black and oily will be more problematic to solve.

Correct.

Do not try to correct the condition you have with a hotter heat range spark plug.

For a street car, one range colder than factory spec is generally enough.

What camshaft specs have you got?

Give the idle air bleeds a shot of carb cleaner first and reassess.

http://members.tccoa.com/392bird/airbleeds.jpg

[kennyhbh]

Plugs are all dry with carbon around the ceramic ,but electrode is a light white tint color.

[RICK LAKE]

Kenny I have an FE with a complete MSD setup. I run ..050" gap with no problems. Same plug as from the 60's. This is what the MSD is designed to do. Bigger and hotter spark. You Never said did you replace the coil? Where is the coil located. How many ground wires do you have to the motor? What fuel pressure are you running? It sounds like you are dumping fuel. You have to try another carb if possible. If this is a fuel problem and it happens this fast,you are washing out down the cylinder walls. Quick check, what does the oil look and smell like? Do you smell gas in the motor oil?? If yes we found our problem with a bad carb or pressure being too much. Does your fuel lines have the little gauge to read pressure? THis carb looks like the old 650DPDF carb. Your Best bet may be to pull carb and get a float bowl kit and pull both ends. clean out and thing in the bottoms and check the float in a glass of water to make sure they float. clean the needle and seat on the intake and reassembly. Check float levels and reroad test. Pictures of your car would really help in trying to fix this problem for you. On some coils they have a resistor to keep the voltage down on oil filled coils. If you run them at the charging voltage, you can cook them over time or have the blow apart. Yes been there done this. I run "E" coil now. How far are you from NJ?? Rick L.

[kennyhbh]

Hi, Rick and other club members, re gap the plugs they were a sloppy 00.57' brought the gap down to a tight 00.50. Blew out the idle air bleeds ?i think they weren't clog. Oil smells like oil no gas.when i installed the rotor and cap I replaced the coil. I turn key car fired right up holds a idle. So guess the plugs were foiled up again. So I it's the carb. I'm thinking . Going to rebuild it. 1 question why extra ground wire. Coil is mounted to fiberglass inner fender.