Oil leaking where tailpipe meets headders??

[eastcoastcivil]

I recently bought a 67 swb fleetside C10 with a rebuilt 350 4 bolt, edelbrock intake and a 600 performer carb. It sat for a year without being started at the PO and when I got it home it wouldn't start. The gas tank was really rusted bad inside so I put a new tank, sending unit, lines, fuel pump, fuel filter and cleaned the carb. I had it started for a little bit with the choke on and as it was warming up it started to run really hard and sluggish. a day later I started it again and it ran fine for 5 minutes and then sluggish again. When I gave it a shot of gas or turned it to half choke it would stall. The times when it would stay running when I gave it gas it wasn't accelerating like normal, it was really really sluggish. I then looked under the truck and noticed that oil was leaking from the connection at the headders and the tailpipe (right before the mufflers, and I mean a fair amount of oil). I checked the oil and it was a little bit too full but clean. Has anybody ever had this happen or know what might be the cause of this? Is my motor toast? Really really kinda down about this since I thought I was going to solve the problems with a clean fuel system and have it on the road this week?

[sandking]

Blow by. Probably bad valve seals/guides or valves. Pull the valve covers and inspect.

[sandking]

Also pull the spark plugs, I would bet they are black and wet with oil, which would cause it to run rough. Fouled plugs.

[eastcoastcivil]

Blow by? there is a fair sized puddle under my truck on both sides where the headders meet the tailpipes. Can the valve seals/guides or valves be changed by just taking the cover off or is this a job I should have a mechanic do? Also. can this be caused by the fuel push rod?

[eastcoastcivil]

Could it be the carb is running too rich and its not oil but gas?

[sandking]

You need to figure out if it is oil or gas first. If you need to get to the valve seals, its a fairly easy fix, but you have to remove the heads.
Pull the plugs, that would be the first place to look.

[ChevLoRay]

Blow-by is normal for my truck. I haven't seen it leak from the point you mention. If it was oil, I'd be inclined to think it wouldn't run. The oil would be thick and burnt. I don't believe it would/could leak. I would bet that the carb is running rich, and fouling the plugs. Pulling the choke out half-way cuts the air that it getting, which isn't enough for all the fuel that it is getting. Does the smell of the exhaust bring tears to your eyes? Is it smoky?

If it has a quadrajet, it's possible that the lead plugs in the bottom of the float chamber are leaking gasoline into the intake, flooding the cylinders and diluting the oil in the crankcase. Thin oil doesn't lubricate as well. Do you hear any knocking sounds, like wrist pins or bearings? Doesn't mean that it is the case, just a rhetorical question.

[Boog]

The last used engine I bought started great and idled great but when you rev'd the thing it smoked like crazy. I noticed wet drops under the truck while it ran. Turned out it was spitting drops of oil out the open headers. The engine had stuck oil rings on 4 cylinders. I had that one bored and built.

[Boog]

The last used engine I bought started great and idled great but when you rev'd the thing it smoked like crazy. I noticed wet drops under the truck while it ran. Turned out it was spitting drops of oil out the open headers. The engine had stuck oil rings on 4 cylinders. I had that one bored and built. If yours has sat for very long some piston rings may be stuck causing the oil to get by.

[eastcoastcivil]

It is most definitely gas. I am going to change the oil and check the plugs with a spark plug tester. I'm hoping I don't have to tear the engine apart but you gotta do what you gotta do. I'm hoping its not rings or seals, the truck did run for a bit when I bought it a month ago. Thanks for all the info.

[harshard]

From my personal experience, an engine that sets for that length of time in the elements , humidity ect. the oil rings -compression rings will break due to a thin layer of rust that builds up on the cylinder wall. This will cause you to burn masive amounts of oil. Check your plugs, this will tell you alot.

[mclairmo]

If the rings are stuck, try spraying wd40 or similar into the spark plug holes and see if that loosens them up. Also, dump a can of BG44K in the gas tank to help loosen stuck rings. Valve seals can be changed with the heads on. You just need a an air compressor and attachment for the spark plug hole so you can keep the valves from falling when you compress the valve springs and remove the valve keepers.

[mclairmo]

Also try rebuilding the carb. After a year with old gas in it, the carb and it's tiny orifices are likely all gummed up and all the rubber parts are junk now, probably all dried up. Also check for any vacuum leaks.

[69GMCLonghorn]

Nobody has stated what you probably already know... Regardless of the reason, that thing is a POWDER KEG waiting to go off! Be careful, ya hear? Or we could all see the first 67-72 truck and owner orbitting the Earth!!