Misfire Under Load

[Spyglass]

Originally Posted by FWB

that much oil consumption i would guess the intake is leaking. Can't help you with a recommendation for someone in Houston, i can recommend someone in San Antonio area.

I was thinking this too, I don't know much about the intake gasket configuration, could it be leaking into all cylinders at the same time?

[Spyglass]

Originally Posted by studebaker53

Does your MSD have a vacuum advance hose? Disconnect it and drive it.. Sounds like your distributor advance is not working properly.

I can certainly try this, but my greatest concern is the burning of oil and my gut feel is that the misfire is linked to the oil.

[patrickt]

Usually you see intake gasket leaks show themselves when your manifold vacuum is high, not when it is low. When you stomp it hard for full throttle, your manifold vacuum drops and the intake gaskets don't have to seal quite as much. But, you never know....

[Spyglass]

Originally Posted by patrickt

Yeah, maybe start out really simple by just disconnecting the PCV and put in a fresh set of plugs, forget the carb switch for now. That's a lot of oil going somewhere and, if you're really lucky, you've just got a big glob of it coming in the base of the carb through the PCV, then it hits the plugs, causes a misfire, then it burns it all off, scares the people behind you that you're on fire or something, and then it runs good for a while before it does it again. Maybe.

Assume I should leave the PCV in place and route the pipe from the PCV to a temporary puke bottle to catch any oil?

[patrickt]

Originally Posted by Spyglass

Assume I should leave the PCV in place and route the pipe from the PCV to a temporary puke bottle to catch any oil?

Don't get fancy, just pull it and plug it. If you built up that much crankcase pressure you'd be shooting your dipstick up through the hood.

[Spyglass]

Originally Posted by Danr55

Have you done a compression test on the motor?

Unfortunately I don't have a compression tester but would like to get this checked as this would give me indication regarding piston ring condition(s). That's why I'd like a recommendation for a good classic ford engine shop in Houston.

[LG57]

I can't say how good they are, but Bumberra's is in old town Katy and is a performance shop with a dyno and has been in business for quite a while.
I have a dyno sheet for my car done by them for a previous owner and the tuneup has been good.

[FWB]

Originally Posted by Spyglass

I was thinking this too, I don't know much about the intake gasket configuration, could it be leaking into all cylinders at the same time?

it can, when you stomp on the pedal you could draw oil from the lower intake runners, lots of splashing going on there with the lifters going up and down.
do you have any seepage on the front and back of the intake? at the corners where it meets the head and the block? does #1 and #5 plug look the cleanest?
do you or anyone you know own a borescope?

[Spyglass]

Originally Posted by FWB

it can, when you stomp on the pedal you could draw oil from the lower intake runners, lots of splashing going on there with the lifters going up and down.
do you have any seepage on the front and back of the intake? at the corners where it meets the head and the block? does #1 and #5 plug look the cleanest?
do you or anyone you know own a borescope?

I haven’t noticed any seepage from the front or back of the intake, but it is leaking a lot of oil and I haven’t identified where from.

I don’t know the cylinder numbering, looking from the front of the engine the left back and front right cylinder spark plugs have slightly less oil on them than the others. These two cylinders are next to the valve cover breathers, if that makes sense.

[Spyglass]

Originally Posted by LG57

I can't say how good they are, but Bumberra's is in old town Katy and is a performance shop with a dyno and has been in business for quite a while.
I have a dyno sheet for my car done by them for a previous owner and the tuneup has been good.

Thanks, I’ll check them out

[patrickt]

Originally Posted by Spyglass

... but it is leaking a lot of oil and I haven’t identified where from.

The easiest way to identify a leak like that is with UV dye. You can get a kit with the UV flashlight, a bottle of dye, and some goggles for next to nothing. I've used it many times both on oil and on gas leaks with my carburetors. It really works.

[jhv48]

If all 8 plugs look like the one in the picture, then you’ve got a set of fouled spark plugs. The blue smoke seems to point to oil fouling, but could be fuel too. Not going to run right until you either clean them or replace them. Are you sure they’re the right heat range for your engine?
It’s rare to see all 8 oil fouled at the same time because of a head gasket or intake gasket leak. rarely do both head gaskets or intake gaskets leak into all eight cylinders.

Those plugs will never run right in the shape they’re in. Replace them and then go for a ride.

You indicate that the engine runs better after two or three acceleration runs. That indicates that the combustion is trying to clean up the fouled plugs.

Have you noticed a decrease in your mileage recently?

Do you have an automatic choke on the carb? Is it fully open?

Do you only run a few miles each time you drive or do you get it up to temp and let it stretch it’s legs?

My suggestion is to replace the plugs and take it out on a twenty mile drive. Get it good and hot. Not stop and go driving. Freeway or mountain roads. Let it run and see if the problem goes away. Hard to diagnose if the oil is being consumed or leaking out if there is lots of oil on your floor.

[Spyglass]

Originally Posted by patrickt

The easiest way to identify a leak like that is with UV dye. You can get a kit with the UV flashlight, a bottle of dye, and some goggles for next to nothing. I've used it many times both on oil and on gas leaks with my carburetors. It really works.

Thanks, never heard of this, I’ll give it a try.