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Author Topic: 8V71 lub oil drips from exhaust  (Read 2213 times)

Offline Timkar

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8V71 lub oil drips from exhaust
« on: May 01, 2007, 07:06:03 PM »
Hi Guys I am sorry if you read this elsewhere, but I am posting it everywhere I can think of in case someone has a had a similar problem.
Really need any and all ideas here.I replaced the head(after
having it tested)put original injectors in, set valves, injectors and
was having oil come from the exhaust pipe on the side I had replaced.
Took rockers off, checked torque on injector hold down bolts. Reset
valve bridges, exhaust valves and then injectors. I still have lub oil
drips coming out of the exhaust (depending on revs about 1 drip every 3-
5 seconds) I picked up a set of valve seals and that is my next step
unless someone can think of something I am missing. Oil in crankcase is
new 40W and is clean. Oil pressure is good. I got the water leak
stopped by replacing the compression seals and gaskets, but now I have
the oil in the exhaust problem. The only place I could think of the oil
getting in is either through the valve seals or between the injector
and the tube. This was not happening before I changed the head, so I am
guessing it is not being caused by anything in the bottom end.
Cawston, British Columbia

Offline TomC

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Re: 8V71 lub oil drips from exhaust
« Reply #1 on: May 01, 2007, 10:54:50 PM »
Did you try driving it to burn off that oil?  Might be just residual.  Good Luck, TomC
Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.

Offline NCbob

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Re: 8V71 lub oil drips from exhaust
« Reply #2 on: May 02, 2007, 08:44:20 AM »
Many questions come to mind as I go over the components and the operation of the engine cycle...and I keep getting a hmmmmm.

Since you've done all this work it seems fair to believe that all was done correctly..soo we won't dwell there. As Tom C asked...have you brought the engine up to operating temp yet?  Are air box drains clear? If oil is clean and residue you are getting is black...might it be condensation from the muffler?

Methinks that, if possible, it would be a big assist to put the bus on the road for an hour at normal speeds
and check it again.  Valve seals?  Don't recall Detroit using them on exhaust valves but that might have changed with 4 valve heads.  We used to knurlize (Internally) them on the 2 valve heads. I'd think that the exhaust valve stems would get too hot for seals....but then it's been a long time since I've rebuilt one.

Keep us posted on the cure, please.

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Offline Sammy

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Re: 8V71 lub oil drips from exhaust
« Reply #3 on: May 02, 2007, 04:27:31 PM »
How are the blower seals and gasket?
How about defective oil ring, pushing a little oil into the airbox?
Open the airbox inspection covers, take a look at the rings, see if anything looks abnormal.
You must take it for a good run, get it up to operating temp, clear out the airbox.
How many miles is on your engine??

Offline Timkar

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Re: 8V71 lub oil drips from exhaust
« Reply #4 on: May 02, 2007, 08:18:26 PM »
Might have found the problem. It's been idling a lot lately since I changed the head, so I was probably getting a build up in the air boxes. I don't have plates or insurance on it right now, so I can't go too far. Realized as I was running it today that the slobber tube on the side I had just replaced had not been spitting while the other side was. Removed  tube and fitting and replaced them, then she was spitting. Took it down the driveway, turned around and made her work coming back up the hill. Parked it and it is still spitting a bit, but no where as much as it was. I'll get a permit in the next couple of weeks and take her for a good run. Hopefully that was the problem...A lot of idling and a blocked slobber tube. Thanks to all
Cawston, British Columbia

Offline pipes

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Re: 8V71 lub oil drips from exhaust
« Reply #5 on: May 02, 2007, 08:52:22 PM »
Hi Tim
The exhaust on the drivers side....on mine... is next to the radiator fan. when I run the engine once in awhile ,that side smokes more than the udder side (In cold weather) and I've had the idea that the muffler never gets hot enough to burn the goop out of it..............Is the problem on yours on the drivers side?                       Ken
Stanwood WA.. North of Seattle.
05 Eagle plus air bags.

Offline Timkar

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Re: 8V71 lub oil drips from exhaust
« Reply #6 on: May 02, 2007, 09:20:46 PM »
Hi Ken,
Yes that's the side. It's on the 73 Eagle I have..8V71N 5 spd. The 88 has an 8V92 with an Allison, Remember when I couldn't get one in Canada? Now I end up with two. The 73 will be going as soon as I get her fixed up.
Hope all is well with you...
« Last Edit: May 02, 2007, 09:25:23 PM by Timkar »
Cawston, British Columbia