Oil in Hemi's exhaust system

[AR67GTX]

I've been helping a friend try to get his restored Hemi Road Runner up and running. The Hemi was rebuilt and dyno tested and is stock except for a hydraulic roller cam, MSD distributor and the usual piston substitution for a clean up bore. Started it for the first time last week and seemed to be fine but had some fuel line leaks so just ran it maybe two minutes or so. Started it up yesterday to verify leaks were fixed and it seemed to start OK at first but as I was standing over the engine holding the throttle to keep it running it seemed to start loading up and I was having to hold quite a bit of throttle to keep it running about 1000 - 1200 rpm and every time I would relax the throttle it would start to die. Then smoke began pouring out both exhausts and filled the garage with smoke and it was running rough but not making any bad noises. Finally the smoke was just ridiculous and we let it shut down and I noticed a small pool of oil under the driver side. When I crawled under it there was oil dripping out of the driver side exhaust manifold and pipe connection. You could see where some droplets had been sprayed around the surrounding area. We searched and searched and found absolutely no sign of oil leaking above or anywhere else on the engine - definitely coming out of the engine in the exhaust. Unless he did so after I left we didn't have time to pull the plugs and it has PBs so that apparently means pulling the valve cover to get the rear one out.

Any thoughts? Considering the car only ran for maybe 5 minutes this was apparently a lot of oil through the engine and out the exhaust. But possibly it could have leaked into a cylinder(s) after the last start. The small puddle on the ground under the exhaust connection was about 5 inches diameter but I suspect a good deal of the exhaust innards are coated now. An intake gasket leaking from the crankcase was about the only thing I could think of that would pass that much oil that fast. But I guess valves, seals, etc are other options. I think he's a member on here but I don't think he or his wife post too often. Probably next Sat before he gets a chance to do any digging around in it except to talk with the builder.

 

[2059]

Well, you could touch base with the builder. That does sound like A lot. I'd pull the plugs, run a compression trst on all. Should be 160-180 # if I recall. I know it can take a bit for rings to seat but this sounds like a bit much....

 

[Ranger16]

I can't imagine a valve seal (or even a lack of) leaking that amount of oil.

 

[AR67GTX]

I can't imagine that or a broken ring either. That manifold to pipe connection is on a angle down to the ground and we weren't aware in the brief time we ran it, of an exhaust leak there - but for that much oil to run out on a sloping run from that connection and to leave about a 5 inch puddle on the floor - makes me think here is probably 3 or 4 times that much still in the exhaust if not more.

If that much oil had somehow settled into a cylinder after last weeks shutoff, I think it would be enough to have locked up the motor.

Looks like pulling the valve cover, plugs and running a compression test on the cylinder(s) is probably the next step. If nothing there then I'll suggest pulling the intake but he or his builder may have another plan. I hope it's something simple like an intake gasket. I don't know what's been milled on the engine. I gave a hand installing that monster engine and the thought of pulling the whole thing back out is almost to painful to think about.

 

[Moparstyle]

Could of been washing the cylinders down with fuel sounds like its really rich but i would be on the builders door step good luck

 

[Yatzee]

I would suspect your sucking oil past the intake gasket out of the valley. I've seen this before. If it is entering the combustion chamber, you must have one hell of a smoke stream coming out the exhaust

 

[Fran Blacker]

What Yatzee plus plug on bottom of intake or a crack. If intake comes off look it over.
Bought a manifold put it late evening didn't start car. Going to a show in am started it to hear a huge whistle. Start to feel around back of intake, somebody drilled one of heat tube bolt hole into a intake runner.

 

[AR67GTX]

It did become one heck of a smoke screen but it didn't smoke immediately upon start up. Took a minute or two to really get going. I noticed some smoke arises around the engine off of the exhaust manifold connection while I was holding the throttle but in the back ground others were hollering to get fans going and I didn't realize at first the amount of smoke at the rear until it began to drift up front where I was. When he figures it out I'll try to post back.

 

[WileE]

I'm puzzled. Is it burning by combustion ? Or external leak onto exhaust ? Two totally different things.

 

[Cranky]

It's common to suck oil from the lifter valley but generally it's not enough to pull it through the cylinder and into the exhaust to where it's dripping from it. If there's that much oil going into the cylinders to come out in liquid form from the exhaust, think I'd be looking elsewhere.....

 

[1967coronet440]

What cranky said, Sounds more like a leak onto the exhaust.

 

[AR67GTX]

Outside of motor and manifold were completely dry. We crawled all over it and under it and wiped our hands on practically every inch of it. The car is up on jack stands so we have good access. No oil externally at all - at bottom of valve covers, at oil pressure sending unit points, on manifolds above the flange, on the starter, on the starter wire harness, on the head surface, on the oil pan, on the bell housing, around the intake - none. The oil was leaking out of the manifold flange to the head pipe and the clamp flange was the lowest point so it was dripping off of it. It was also pretty gray and not like new oil - like it had been through the combustion chamber and sooty manifolds. Head gasket leak is always another possibility. We didn't examine the oil to see if there was any sign of coolant in it.

 

[lewtot184]

look at the spark plug tubes. are they sealed up? do the plugs fit properly?

 

[Cranky]

look at the spark plug tubes. are they sealed up? do the plugs fit properly?

That thought crossed my mind too but even if the plugs were just snug, would oil be able to get into the cylinders with enough volume to go out the exhaust and stay liquid?

 

[lewtot184]

That thought crossed my mind too but even if the plugs were just snug, would oil be able to get into the cylinders with enough volume to go out the exhaust and stay liquid?

my guess would be oil diluted condensation and not raw oil. if those tubes aren't sealing or have cracks oil will seep and pond around them. anybody do a plug change on a hemi and notice all the smoke on start-up due to the oil that ponded in the tube socket and drained in the cylinder? all hemi's should have the milodon tube seals installed. of course this is just an idea to look at.

 

[AR67GTX]

look at the spark plug tubes. are they sealed up? do the plugs fit properly?

The front three were dry. We could not see down the tube on the fourth one because of the booster/MC. Managed to get a finger about half way down inside and it was dry that far. It was getting late in the afternoon when things went wrong and I had to leave shortly afterwards.

 

[AR67GTX]

my guess would be oil diluted condensation and not raw oil. if those tubes aren't sealing or have cracks oil will seep and pond around them. anybody do a plug change on a hemi and notice all the smoke on start-up due to the oil that ponded in the tube socket and drained in the cylinder? all hemi's should have the milodon tube seals installed. of course this is just an idea to look at.

This needs to be checked when the valve cover is pulled - a possibility. We definitely lost a cylinder. Last week it started and ran and sounded almost just like my stock 440 due to the hydraulic roller. This week it sounded pretty normal at start but seemed to have issues within a minute or so of starting - wouldn't hold an idle, had to hold the throttle open to keep a fast idle, not running as smooth but running - probably only lost fire in one cylinder.

 

[eldubb440]

pcv and breather functioning?

 

[HEMI-ITIS]

The plugs will give the 1st clue.You said it smoked out both sides so it's pushing oil into the intake is most likely.

 

[not so famous bob]

Well, you could touch base with the builder. That does sound like A lot. I'd pull the plugs, run a compression trst on all. Should be 160-180 # if I recall. I know it can take a bit for rings to seat but this sounds like a bit much....

my first hemi , bone stock had 205- 210 pounds on every cyl. they did use plug seal tubes didn`t they? that would account for a start up smoke out, but shouldn't be dripping anywhere.
I would pull the heads in a heartbeat !