Thread: Recent FE390 engine rebuild engine smoking problems solved I believe.

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Hello folks. I think that I finally figured out why my engine was burning oil and smoking so much after my recent rebuild. There appears to be 1 small thin port next to the #7 and #2 intake ports on the heads that when you look in them you can see the exhaust valves for those cylinders. There is also a port on either side of the intake that match up with these ports that seems to be some kind of possible air cooling passage for the intake. Not sure though. I also found a small hole in the intake that was letting oil into the passage via the lifter push rod hole. The passage was filling with oil and I think that oil was also seeping behind and getting sucked in behind the intake gasket at the port openings which in turn were being dumped into the exhaust port of #7 which was then getting blown out my exhaust. You could see the oil in the ports when I took the intake off. I'm not sure why there are no holes in the gaskets for these ports though. I do remember when I got this car most of the top end was in the trunk. When I went to clean up the parts, I'm pretty sure there were 2 thin pieces of metal stuck to the intake on the ports in question to cut them off. I'm ordering an Edelbrock Performer intake to replace this old Weiand but it also has those ports. Anyone know the best way to go about plugging these puppies? I'm not sure why these ports are even there if they are not to be used. As always, thanks for reading my post and offering your knowledge. Appreciate it very much.

I'd suggest you post a couple of pictures showing the ports you're describing, to be more sure of getting an accurate answer.

Exhaust crossover ports to aid in heating up the manifold when cold. You can usually get gaskets that block these ports off, but make sure that are metal block-off plates. Sometimes they are just the gasket material, and feel that these can burn thru.

If you are buying a manifold anyway, the Edelbrock 7105 Satin RPM Performer does not include this passage. Fel-Pro 1246 or 1247 should fit fine, just check which one for your application.

I saw a old video somebody posted a link to on here awhile ago and it told what the exhaust crossovers do, it said the crossover not only did warm up the plenum below the carb but actually kept it hot, the large dropplets of fuel (that we don't want) where suppose to drop down on the hot plenum (hot from the crossover) and they would vaporize by the hot surface and be sucked into the cylinder and then burn, probably needed more in yesteryear when carbs where everyday used. Anyway blocking the things off is usually done, edelbrock made cast aluminum plugs for some motors and I have heard of jamming aluminum foil in there packing it tight (Not my idea and I haven't done it) keep in mind thats exhaust and it gets really hot, I even thought of and heard of using some sort of refactory to help keep'em from leaking.