Nice long engine question!

[tnichols]

I have recently rebuilt a 318, .030 over, isky cam(474) i think, stock 72 340 intake and headers. My aggrivating problem is it smokes. Smells like raw gas like way too rich, but I have tried three carbs with the same result.the heads are later heads that ive plugged the air injection holes on. unfortunatley, i did not rebuild the heads at the time, i have seen the engine run before the rebuild and did'nt smoke.It has been rich right from the start....fouled the plugs bad.it only has about 10 miles on the engine, if that...most of the time its just been cam break in and tuning. I guess the smoke could be some oil but smells like raw gas. Anybody know what I'm missing here?????????

[Lil_Bee_R/T]

I got someone you can cal to ask, this is his shop humber but dont cal till about 10am eastern.

Bill Richardson- 434-846-0043

[TL]

Mech. fuel pump leaks into the crank case?

[tnichols]

ok, i think im starting to get a handle on this...the smoke is white and im low on coolant.....intake seal? head gasket seal? both are new but i have alays had a hard time with intake sealing.could this be it, would water in the chambers cause it to smell rich?

[unclemike]

Could be you got a couple of things going on. A carb running rich becase of a ruptured power valve (Holley) or low vacuum from bad intake sealing. You didn't say what heads you're running but if its the 318 heads the ports might not be sealing properly with the larger runners in the 340 intake.

[Shaun]

What carb is on it? Is there water in the oil? How do the plugs look?Have you pressure tested your cooling system to check for a possible gasket leak?
Keep us posted.

[pishta]

White smoke is usually coolant and there is a sweet smell to it. Blue smoke is oil and black smoke is gas. Ruptured valve is a stinker, blown head gasket or intake gasket will both let water into the cylinders, making white steam/smoke and draining your coolant. Here is a Rube Goldburg (?) intake seal test. Pull the rocker shafts so all valves are closed. Drill a hole the size of a tire valve stem and mount one in the motor lift plate and bolt it on with a gasket to the intake manifold. pump some air in (or use a mighty vac with the shreader valve unscrewed and evacuate) the tire valve stem and look/listen for leaks. Alternately you could probe around the intake on an idling motor with a squirt bottle of water and listen to the idle quality, youll know when you hit the leak as the idle will change. Pressure test your radiator with an adapter and a bike pump and listen in the spark plug holes with a stethescope for cylinder leaks.

[Shaun]

A coolant system pressure tester is readily available at any auto parts store and is used for that and testing your cap. So if it's water,then that's how you find it.
Watch your water with your cap off to see if you have too many bubbles.
Let us know

[unclemike]

One other thing I remember is that the air injection heads were prone to cracking.

[tnichols]

Thanks for the help so far, i have changed the intake manifold gaskets today, like a few minutes ago, so I have not started it yet...for some reason it looks like i didnt put sealant around the water ports!!dont remember, but it looks like it was installed dry. I used some around them this time and I'll see. If this does not cure it....I'll follow the advice of pressure testing the system.these are later model air injected heads that were plugged.

[tnichols]

Oh, and another thing. im using a thermoquad, plugs looked pretty good considering how much it smoked!

[Rug_Trucker]

Originally Posted by tnichols

Oh, and another thing. im using a thermoquad, plugs looked pretty good considering how much it smoked!

They were "steam cleaned!"