Gas fumes and empty gas filter. - '68 300

[mgm1986]

Thank you all. I was on the fence about blocking the crossover and this helped me make the decision. I will order a new pan and report back.

@david hill
I don't see any holes or cracks in the pan when I hold it up to a flashlight. Since I plan to replace the pan I am not going to worry too much about it. Although it is ironic the pan is rusting with so much oil covering it!

I will read up in the FSM but for those who have done it, should I use thread sealer on the intake manifold bolts?

Also, should I be concerned about the carbon build up around the crossover ports before I block it off with the new pan? If a chunk of carbon where to break off is it going straight back out the exhaust or will it possibly fall back into the cylinder and cause chaos?

 

[Omni]

mgm1986
Personally, I do not use any sealer on intake bolts. The sealing is accomplished when the manifold is torqued (35 ft lbs - I think). These bolts do not intersect any water passages (that I know of). I do not use the separate the gaskets that come with the valley pan. There have been discussions about this and it seems that they are used when aftermarket heads are installed. Do make sure that the threads on the the bolts and heads are clean. A tap/die set is a good investment. As per the FSM a light coat of oil on the threads help to insure an even torque.
I have no insight on the carbon. I would not think that engine destruction would result if it was left alone.

 

[Big_John]

Thank you all. I was on the fence about blocking the crossover and this helped me make the decision. I will order a new pan and report back.

@david hill
I don't see any holes or cracks in the pan when I hold it up to a flashlight. Since I plan to replace the pan I am not going to worry too much about it. Although it is ironic the pan is rusting with so much oil covering it!

I will read up in the FSM but for those who have done it, should I use thread sealer on the intake manifold bolts?

Also, should I be concerned about the carbon build up around the crossover ports before I block it off with the new pan? If a chunk of carbon where to break off is it going straight back out the exhaust or will it possibly fall back into the cylinder and cause chaos?

IMHO, that oil could be from a spill while putting oil it, but I could be wrong.

No sealant needed for the threads. They don't go into a water jacket.

I wouldn't touch the carbon. It's not hurting anything and the chances of breaking pieces off multiplies with trying to remove it. Anything that loosens up once you put it back together will simply blow out the exhaust.

 

[mgm1986]

Intake reinstalled with new valley pan with the exhaust crossover blocked off. I followed the fel-pro instructions on the install, silicone gasket maker on the ends only, used all four paper gaskets for the intake ports.

After a 20 minute drive there seems to be no oil escaping around the valley pan. As with any new gasket, time will tell if this is resolved.

I am having trouble with the throttle sticking; not returning to idle without a quick peg of the pedal. I suspect the cable isn't adjusted properly although the cable is pretty beat up so it might need a closer look and possibly replace it.

On a positive note, no gas fumes after the initial test drive which is what I was initially trying to resolve. Hopefully after a few more runs this doesn't reappear.

I also replaced the distributor o-ring and gasket while I had it apart. The o-ring was completely flat and oil was definitely escaping from the dizzy. When I reconnected everything I also connected the dizzy vac advance to manifold instead of ported vac on the carb. Such a big difference in idle quality and it seems to be more responsive to throttle input so I am going to leave it as is until I get time to reinstall the TQ that I have rebuilt and sitting on the shelf.

Thank you all for your input and guidance. I am hoping this is the last hurdle so we can enjoy the old girl over the summer before the next set of winter projects begin!

 

[mgm1986]

Had a nice 90 mile trip with the 300 Sunday and no smell of gas so I am hopeful this issue is resolved. I did end up moving the dizzy advance back to ported vacuum. What I noticed when it was connected to manifold vacuum, it hesitated when I pegged the throttle.

A few more kinks to work out but the smell of gas was a concern and this is resolved. Also, no oil around the distributor or on top of the valley pan so I am ready to tackle the next challenge.

Thank you again for all of your input and guidance.