Where's the smoke?

[Brainchild]

My truck has been fouling plugs for a while now.It's usually #1,and sometimes #7.Both on the drivers side.

The engine does not smoke.Maybe a little in the morning after sitting all night,but never after firing it up in the morning.I have switched gas stations 4-5 times,that didn't help.I can't see any reason it would foul a plug.Any ideas welcome at this point.

It's a 1969 350,flat top pistons,original spec replacement cam,HEI,AC R45 plugs.Q-Jet carb.That's about it.

[crazy longhorn]

Originally Posted by Brainchild

My truck has been fouling plugs for a while now.It's usually #1,and sometimes #7.Both on the drivers side.

The engine does not smoke.Maybe a little in the morning after sitting all night,but never after firing it up in the morning.I have switched gas stations 4-5 times,that didn't help.I can't see any reason it would foul a plug.Any ideas welcome at this point.

It's a 1969 350,flat top pistons,original spec replacement cam,HEI,AC R45 plugs.Q-Jet carb.That's about it.

"Wheres the smoke"? I asked myself that one time.....the 307 in my 71 had a fresh top end, & really sounded sweet(300hp 350 heads). We headed to southern Il, with my motorcycle loaded in back & she was running great, knocking down 15-16 mpg with a set of 3.73's! Not so good on oil tho.....that BIOCTH drank 3 1/2 GALLONS of oil from Rock island to Carbondale & back! On the way home the weather was good, So I rode the bike, & let the wifey drive the truck.....I never did see the smoke, but I could smell it(had to ride the bike ahead of the truck to keep the freakin oil spots off it!) Needess to say ,it was "shortblock time" the following week Best of luck, L

[mjrmn]

I would suggest checking the plug wires also--if the plugs are running a bit on the cool side because of a lack of power from the coil they could build up deposits that will not burn off

[Wootdog]

they can also do a copression foul or the wires could be the problem do comp ck.

[Green Machine]

Is it gas fouling(just black) or oil fouling(chunky brown/black) ??? Short drives in cold weather can contribute to fouling. Might try a little hotter plug and get the ones with the extended tips.

[Brainchild]

The truck has been together almost 2 years.It doesn't use much oil,leaks around the valve covers,I figure that's where most of it goes.

I am going to do a compression check today,and a voltage check to make sure I have a good 12v source.Maybe some new wires and plugs are in order as well.

I have seen engines smoke 10x worse than this one and not foul a plug,that's why I don't think it's rings or guides.Could be wrong though,it happens on occasion


Thanks

[Brainchild]

Compression is good,and 12v to the HEI.I replaced the wires,and plugs,we'll see how it goes this week.I did gain a little on the performance end,so maybe that was the problem

[Eddie H.]

Check that your intake manifold bolts are torqued properly. If they're a little loose, it can suck oil out of the lifter valley past the intake gaskets. I've seen this happen a few times, especially when using aluminum intake manifolds.

[Brainchild]

Well it made it a week before it fouled a plug.#1 again.

Plug was black fouled.

I did notice a little oil pooling on the intake,didn't check the torque on the bolts though.I'm using a stock intake and a Q-jet.I don't notice any loading or running really rich or anything,just fouls a plug every now and again.

Carb is off a buddys 76 4x4 with a 350,never had an issue on his truck,just swapped for a Holley.This has been an issue even with the 2 BBL on it.I swapped the 4BBL on a few months back.

MAybe I should just build a new motor,and forget it

[ChevLoRay]

My '69 has the original 350 block in it, with later heads. It had another intake, from the engine that the heads came from. With an Edelbrock 1405, it ran rich and would foul #1, before any others ever did. So, I kept a set in the truck, with the tools needed to swap one out.

Later, I changed the intake to an Edelbrock and the carb to an Edelbrock 1901. Still, the #1 would foul, but not as much. I tried different plugs, including AC Rapidfires in the R45TS type. Better, but not cured.

One day, after several months of a mysterious bout of sudden engine dying fits, it died and I had it hauled home. The HEI that was on it when I bought it, was about to be changed for an ACCEL unit, that was essentially a rebuild to their specs. Since that time, my engine has not fouled another plug.

My engine does get rid of some oil, as blowby. It comes out of the oil fill cap, and there isn't anything I can do, except rebuild it or replace it. The exhaust pipes are black, and sooty. The engine isn't running rich, anymore. So, I'm quite satisfied that the ACCEL HEI that I installed is the reason my engine isn't fouling the plugs, any more.

[truckdude239]

i always thought hei was suppose to have a good 14 volts to it? not 12

[MisterMan]

cheap plugs??? dont feel too bad, i found out my bad mpg was due to me dragging 3 dead. hehe...woops! starts first crank now too, also that $100 battery ought to do the trick.

[Steelawork'n]

I was also thinking the original intake might be worn and I was also thinking the HEI had some issues. Make sure you're gapping your plugs for the HEI ignition. If the gaps are too tight you could be burning the plugs up.

[1969owner]

try getting a hotter plug. or if you stay on its a$$, you could flood it, and it foul the plugs