Newly Rebuilt 4.2 is now oil smoking pretty badly

[RQCinLHT]

I got my engine machined recently and I did the assembly. I checked all my tolerances and clearances to be sure all was to spec, and it was. I'm a machinist by trade, and have a full set of mics and gages to check with ten-thousandths precision. No plastigage for me. The only thing I couldn't check however was my valve seals and valve guide clearances, I had the head work done by the machine shop. At fire-up and for a good week afterward, all was well. I had checked the plugs a week in, and they showed signs of good burning.

After I drove to the station and filled the gas tank full the next day, it has steadily been blowing oil smoke. It puffs a lot of it when I bump the throttle, and it blows a noticeable amount on steady RPM. You can hear a steady misfire due to the oil consumption. It started off slow, and then built up to what it is now.

Before this full gas fill-up, it has never been full since I bought the Jeep, and I'm not sure how long its been before that since it was gassed up all the way.

This stuff has me beaten down pretty good, it just makes no sense that it should be burning oil like this only 3 weeks into running on a fresh motor.

Is it possible that the mechanical fuel pump may have gone bad? Gulping engine oil thru the crankcase and feeding it to the carb? I also am wondering if the full tank maybe dissolved some crud into the tank, and now I'm burning it thru? I hope someone might have had a similar experience on this they can share.

 

[RQCinLHT]

I should add, I do have an in-line fuel filter between the pump and the carb, a see-thru yellow bowl. I don't see anything out of the ordinary in there, but I have not taken it apart yet

 

[Lumpy Grits]

Pull the spark plugs and 'read' them for oil contamination.
Then do a compression and leak down test.
I would stop driving it till fixed.
Are you loosen any coolant?
What does the engine oil look like?
LG

 

[mtnwhlr]

I think you thinking it is fuel is off the mark. Is the smoke blue "oil" or black "gas". Did you break it right to seat the rings?

 

[RQCinLHT]

The smoke is a light blue, not very dark. It's not black at all. This jeep isn't tagged yet, so haven't done much road driving except the county roads where I live. Whats your advice for seating the rings

 

[Lumpy Grits]

Blue is oil smoke.
With all do respect-Just because you are a machinist. That doesn't make you an engine builder. Different worlds.
Did you confirm oil pressure after start up and then again after warm up?
Please follow what I posted in post#3 to locate the issue.
How much gap did you leave in the rings, after fitting?
Good luck,
LG

 

[RQCinLHT]

Not sure how that's meant to help. Did not call myself an engine builder, just mentioned I have tools for precision measurement, not relying on cheap methods or "hoping" clearances are right on putting the bottom end back together.

At work right now, I'll have to check the build sheet for what i measured on ring gap. Whatever that range was, i was on the low end but was still in tolerance. I am going to do the compression check and leak down this weekend.

 

[mtnwhlr]

The smoke is a light blue, not very dark. It's not black at all. This jeep isn't tagged yet, so haven't done much road driving except the county roads where I live. Whats your advice for seating the rings

Read this I hope it helps.
http://www.google.com/url?url=http:...gglMAQ&usg=AFQjCNGeTt5X6L56lbwfJcKq0aEIp7ZBFw

 

[RQCinLHT]

Thanks for the help guys, I really do appreciate it. I am working on getting one of the CNC's squared away and running on a job right now, and once that's done and running, I'll be pulling the jeep into the drive (with the riding mower), and will then do the compression check. Autozone didn't have a leakdown tester kit, so I'm going to see what results the compression yields for now. As my luck makes it, the starter won't stay engaged to the flywheel due to 1/4 of so of some teeth missing, so I keep having to loosen the starter on its two bolts and move it in and retighten. I know, should've just replaced the flywheel in the beginning. Learned the lesson the hard way, but it's looking like I'll be I end up having to pull the engine back out anyway due to this oil consumption. I used cast-iron rings when I reassembled, and I had a .010-.012 gap across all compression rings. These are the ring set the engine machine shop got for me with the .060 over pistons. Just can't believe that these wore down in just 2 weeks to burning oil? The compression and leakdown will help tell the story.

For oil pressure, I can tell my gauge has some sticking problems, but it immediately pops up to 20 psi while running. Won't jump past that, seems like it wants to when I rev higher. I have an aftermarket engine coolant temp gauge (came with the jeep already), and it's registering off of the coolant inside of the intake manifold. It's been reading 210-230 with the engine fully warmed up, and I did put in a new thermostat, 195 deg.

I didn't learn machining by being perfect the first time on everything, took making mistakes and learning from them. I'm on the same track on this motor build, but it's still fun.

 

[hagar]

What oil are you using/burning ?

 

[RQCinLHT]

Valvoline 10w-30. Conventional

 

[RQCinLHT]

Just did compression test. Psi
1. 160
2. AMC 150
3. 145
4. 142
5. AMC 150
6. 145

 

[Lumpy Grits]

Re-torque the headbolts to the high side of torque spec.
Try another reading.
Think there's a possible issue with cyl 2&3.
Never-ever trust the OEM ele. oil psi gauge set-up.
20 psi is dang low.
How does the oil look?
LG

 

[RQCinLHT]

The oil looks good. I drained some off last night to check it out, and no signs of coolant in it. I just checked torque on the headbolts that are outside of the valve cover, and they're still at 105, no movement on them. The big problem now is, I can't get the starter to engage the flywheel enough to start the engine. I was able to get by on the compression check OK, but now that I've got the plugs back in and trying to fire up, the pressure it's pushing against is pushing it back away from flywheel. The flywheel teeth are worn no doubt, but none of them are missing completely. A handful of them have about 75% left, but most of them look mostly there? I can see on the bendix gear on starter that it's just glancing the teeth. Am I able to get an oversized bendix gear to counter this?

 

[RQCinLHT]

For timing, I've got it set at 6 deg before TDC @ 600-650 RPM, with vacuum advance disconnected and port plugged. When I hook the vacuum advance back up, it jumps to 24 deg before TDC.

I read that article on setting up a motor for first fireup, and it mentions setting it at 30 deg before TDC with vacuum advance disconnected. Man, that just goes against what I've read so far on what the recommended timing is

 

[Lumpy Grits]

Back off each head-bolt 1 at a time about 1/4 turn at most, and reset. Follow the std sequence for the bolt pattern. That's how a cyl-head is re-torqued.
Take it to the full 110 ft/lb setting with 1/2" dia. bolts.
LG

 

[PistolDave]

Is there any chance that the oil could be coming into the intake through a malfunctioning PCV system?



Not saying this is the case on your engine, but I have seen some pretty shoddy practices from local machine shops when it comes to head rebuilds. A friend of mine had a set of heads "rebuilt" by a local shop for a 351C Ford, and I don't know exactly what they did, but his valve guides leaked oil like crazy after they came back from the machine shop. They were actually worse than they were before rebuild. Maybe something to check before you write off the bottom end.

Dave

 

[mriplaybass]

You never mentioned how much oil you are using via dipstick level. Are you sure that the oil that is burning is engine oil. I also did not see what Transmission you have. What I am getting at, although unlikely, if you have an automatic Transmission and the diaphragm in the modulator fails, you can suck Transmission oil into the engine via the modulator vacuum hose. I completely emptied a Ford Transmission twice before I figured out what was going on. If you have a manual Transmission , this won't help you much.

 

[RQCinLHT]

The PCV hoses are not connected to the intake, they just vent right out the valve cover for now. The jeep has the 4 speed standard shift tranny. Once I get this starter problem solved, and I can get it to crank properly every time, I'm going to load it up on the trailer and take it to the shop I had do the head so they can see what this is doing.

 

[mtnwhlr]

You should have your PVC hook to a non ported vac.