360 Uses OIL! - way, way too much!

[carlos1a]

I didn't know who else to turn to for this one. This site seems to be the best for AMC information. I have a rebuilt 360 from 1976 in My CJ-7. The engine only has about 1500 miles on it, maybe less. I will use about a quart of oil every 200-300 miles, if that. I just cannot tell where it's going. There are no obvious leaks, al least not that much. I drove it about 20 miles until the engine was hot, parked it for 10 minutes and when I started it up again, there was a cloud of oil that seemed like I was fogging for mosquitoes.

Here's what the machine shop did:
baked block, cleaned it up.
bored cylinders .030, new pistons
ground crank main journals .020
ground piston journals .010
reassembled crank, pistons in block
rebuld heads
installed the aftermarket oil line to get oil to the rear main

I installed the new cam, lifters, timing cover, new timing set. I bought exhaust manifolds, cleaned them up and put them on in place of the rusty headers. The muffler that I installed seems to be too small for a V-8, but I put it on. Now I'm thinking that I should have double checked it for a V-8 engine. I cant see where a smaller muffler would cause it use too much oil so I'm discounting that for now. I'm concentrating on one small miracle at a time.

I tried installed the intake. But...

The aftermarket oil line was in the way. Damn, what next? I cut the valley pan gasket almost in half and re-installed everything and drove it for several hundred miles. Thinking this was a bad idea, after a few quarts of oil later, I removed the intake and changed the oil line to a smaller diameter, just to make room for the complete valley pan gasket and put it all back together again. I thought that the oil was going right through the intake and into the carb and burning in the cylinders. Now the valley pan gasket is complete. I have really good oil pressure, expecially when the engine is cold. It does drop some when the engine heats up. Even with the valley pan gasket intact, it still uses way too much oil.

It smokes mainly when it's started when warm or hot, last I drove it - I dont remember it smoking alot when it was cold after I changed the oil again. I used 10W40 this time.

Now it's at the shop. I asked them to try to determine where the oil is going, since I dont really know how or where or if it's burning. I asked them to check the valve timing to make sure that I dont have the chain one tooth off, because it runs rough when it's cold. The engine lopes when it's cold but when it was hot, the last time, it seemed to run smooth. It just uses too much oil! Arrrggh! I know that I followed the Haynes manual when I reinstalled the timing chain, I could swear that I did it correctly but I did not take a picture of it before I installed the timing cover so, I cant check it without disassembly. I need a certified AMC gear head to point me in the right direction. Any suggestions before I do something that I'll regret later?

Chip

[jeepsr4ever]

Chip, pull all lines off the carb taht are attached to the intake manifold, especially in the back of the manifold. Run it and see if the msoke goes away.

[tufcj]

Aftermarket manifold?

Even with the full valley pan, if the tin baffle from the bottom of the factory manifold wasn't transferred to an aftermarket manifold, it can pull oil thru the PCV system. Some get away with it, some can't.

A second question that came to me is how big is the cam? Factory valve seals will crush as lift approaches .500". You could have damaged the seals and be sucking oil around the valve stems.


Bob
tufcj

[JERSEYJOE]

Right on Bob, without the stock shield in place hot oil hits the intake and turns to vapor and gets sucket into the pcv. Blocking the exhaust crossover will relieve some of the problem since the intake will not get hot enough to do that.

[fifesjeep]

Was the engine broke in properly?... If not the rings maybe didn't seat properly... Did you have the vlave guides and seals checked or replaced? You never know.. there seems to be more and more shops cutting corners to profit an extra penny or two... 1 quart every 200-300 miles!!! WOW... you have to be throwing a smoke screen like on the game SPY-HUNTER!
I'm not certain but to me that seems like a lot of oil... and for it to be consumed through the pcv system that would definitely be noticeable... Pull the PCV Valve and look at it... If you have A lot of oil in it then you know that, that coulb be part of it... If you have the vac. lines hooked up wrong you could be drawing too much vac from the crank case.... It's ideal to have a negative pressure in the crank case but too much is bad! Let us know what happens or what they find... If they say it's the heads ie: Valve guides & Seals then they should fix it free because if they did the head work they should've caught it beofre they installed them etc... I'd also do a compression test and a bleed down test on every cylinder... Just to double check everything...

[carlos1a]

The intake manifold is the same one that I removed and I did make sure to re-install the baffle in place before re-assembly. I have a little less compression after the rebuild than I had with the stock setup. I attributed that to an aftermarket cam and the fact that all of the cylinders had more volume due to the .030" bore. I dont really have enough experience with these things to know how much the compression would decrease with the combination of these two factors.

With that much oil being used, I figured that I should see some signs of where it was going.

The shop that I took it to called on my cel phone this morning and left a message. I never take the doggone thing into work, the metal building cuts off celular service and kills the battery. I gave them my work number but they didn't use it. I'll know more of what they say tomorrow when I call them back. My fear was that they did not know exactly what to do with it, so they were not real anxious to get started. Thanks for the tips so far, I will keep you posted when I know something.

Chip

[fifesjeep]

By boring it you should gain compression, (Not much and depending on how much you bore it). Think about it... With the cylinder being bored and the piston being enlarged and the combustion chamber staying the same It'll be pushing more volume into the Combustion chamber Which will create a higher compression ratio (Like I said before not much depending on the bore).

[ironman_gq]

could be poor oil control by the rings. oil could be getting past the rings if they have the wrong end gap or weren't broken in correctly. don't know if a glazed cylinder would cause it but the shop could have put the wrong finish on the bores that would cause the rings to not seat properly and cause the low compression

[carlos1a]

They did confirm for me that the timing chain was properly set. Although I dont believe that I will take it back to them, ever. I'm not sorry that I took them it to them to confirm a few things, well worth it. Maybe part of my displeasure was a result of what I told them going in. I maybe expected it to run and perform like a computer controlled engine.

Anyway, back to the oil. I discovered that it has a bad PCV valve. I found out after I got it back from the shop, which is part of the reason why I know that they will never see any of my cars again. It does run better when it's hot but, worse when it's cold. Fortunately, it's not cold very often. I called the machine shop that did the work on the engine and was told that the valve stem seals they installed were the same type that they install in racing engines. They told me that there is really "no possible chance" that the oil was getting in past the valves. I have a few other things that I'll be looking for. I'm going to drive it down there soon and let them look it over. They seemed more than accomodating.

Chip

[carlos1a]

Ironman said "could be poor oil control by the rings. oil could be getting past the rings if they have the wrong end gap or weren't broken in correctly. don't know if a glazed cylinder would cause it but the shop could have put the wrong finish on the bores that would cause the rings to not seat properly and cause the low compression"

The shop said that the type of rings should not require much to seat. I didn't really know why. Is it realistic to say that 125 lbs compression is low considering that the cylinders were bored out .030"? I could look up the stroke and calculate the compression based on the stock bore and the .030 over bore just to see what the compression would have become. The oil ring, being the lower ring, could have not seated properly and it would not effect the compression, true?

Say for instance that the shop is correct and that the oil could not be getting into the cylinders past the valve stem seals, how can I be sure if the rings are seated properly? What can I do if they are not? I've heard of a few old fixes for this - what is the real way to do it, short of replacing the rings all over again?

Thanks,

Chip

[jeepsr4ever]

Yep thats too low for new rings.

[Goose]

well there are some simple symptoms to tell where your oil is going.. bad rings will smoke all the time a little.. valve seals etc will smoke after you decelerate (and when you start up in the morning..)Bad rings will also show up on the spark plugs and the exhaust will smell like burning oil.

(Unhip and old school I know, but what the heck)

[fifesjeep]

"The shop said that the type of rings should not require much to seat. I didn't really know why."

Chances are they used the regular cast steel rings.... which take less to seat due to the composition of the material used in the rings (soft) and of the cylinders, high Nickle content, (Hard).... If they used Moly rings.... they would take a little longer to seat due to the similar or like metals... (Both the moly and AMC blocks have high nickle content).

"Is it realistic to say that 125 lbs compression is low considering that the cylinders were bored out .030"?"

Absolutely man! Somebody correct me if I'm wrong but stock compression should be around 160?... With a cylinder difference of no more than 20psi? Hmmm, I'm going to have to dig out the books from storage and look it up now...

"The oil ring, being the lower ring, could have not seated properly and it would not effect the compression, true?"

Honestly, the 1st ring takes the blunt of compression etc, the second ring takes the remainder or the lesser of the compression that slips by the 1st ring... there's really not much seating for the oil ring... the oil ring is just that... the "Oil Ring"... it pretty much (forgive the crude description), picks up the oil, lays it down and wipes it up... Basically controls the oil film on the Cylinder walls... (I'm sure others will go into a more detailed and precise "How it works").

"Say for instance that the shop is correct and that the oil could not be getting into the cylinders past the valve stem seals, how can I be sure if the rings are seated properly? What can I do if they are not? I've heard of a few old fixes for this - what is the real way to do it, short of replacing the rings all over again?"

There's always a chance of something going wrong... "Murphy's Law" I have the positive seals etc on my 360... and my baby didn't smoke not even during the break-in... To check your rings to see if they have seated properly... (Without a visual confirmation)... You can do a compression check and also a leak down test... this isn't conclusive but it'll help narrow the possibilities. Well you have 1500+ miles on it... so basically your option would be to replace them... If you washed your cylinders, (Flooded the cylinders with gas pushing the oil out of the grooves and cleaning or removing the oil film from the cylinder wall)... Could also cause lower compression and excess wear!!! And seeing that the cylinders have a high nickle content and and they most likely used cast steel rings.. your rings probably have seen better days already!... But anything is worth trying.... You could always remove the coil wire... remove #1 spark plug, take some ATF/motor oil etc, dump a couple of table spoons etc in the cylinder have a buddy bump the motor a few times... then places your finger over the hole leaving a slight hole put a rag over it as well (To catch most of the fluid) and then crank the motor for 3 to 5 seconds or 2 to 3 compression strokes, (To push the fluids out).... Repeat this for every cylinder!!! It's worth a shot, exhaust all options and if you're still left with no idea/solution replace the rings.
Hopefully this helps... and if I've given some wrong info, people please jump in and correct me.

[dwg86]

I had the same problem with my 401 with an air gap manifold. I cut the intake gasket because of the internal line. The intake had a baffle under the pcv valve, but it was still sucking oil through the pvc(drained th oil pan in about 400 miles). I machined an aluminum plug for the pvc hole in the intake and bought a pvc grommet with a baffle (moroso it think) and installed in in the valve cover between the rockers for number 2 and 4 cylinder. No more problems.
401 .040 over, forged pistons, 10.5 with 1970 291C heads, custom ground reed cam intake dur 228 @ .050 512 lift, exhaust dur 232 @ .050 516 lift, harland sharp roller rockers, rollmaster billet timing set, machined for a thrust bearing and a teflon cam button($18.00 for the cam button from am racing in Canada).Milodon dual external oil line and high pressure spring(90 psi cold 40 psi hot 60-70 psi warm running down the road.

[carlos1a]

Ok, my 360 (The one that was using way, way too much oil) has stopped smoking on me for no known reason. My guess is that I hadn't broken it in long enough, not enough reverse pressure to get the rings to seal properly, whatever. I started driving it more. I drive it to work 2 to 3 times a week and I drive it almost exclusively on the weekends. I really concentrated in seating the rings. I decelerated at every opportunity going down small hills as much as possible. Now it doesn't smoke at all. I have not re-checked the compression yet. The oil is still going somewhere but I noticed that the right front of the engine has a few drips of oil on the garage after it sits for a while, and there is oil on the frame on the right side. So, it's leaking somewhere, I'll keep the oil level up while I drive it until such time that I can locate the source and correct it. It's not too inconvenient to add oil, I'm just happy that the smoke is gone.

I also have the Summit 8601 cam it mine, I noticed that there was another post relating to this cam. It lopes a little when it's cold but runs very smooth when it's warm. I may have a vacuum leak in the quadratrac that could add to the problem, I have not got that far yet. Not a big deal to me at this time.

Chip

[shfletch]

I went through the exact same problem with the 360 I put in my cj earlier in the year, except I was using 1qt every 100 miles. My problem was the pcv sucking oil through the manifold and into the carburator which oil washed the cylinders and the rings lost their seat. I was having major blow bye and could not get it solved. I pulled the pcv and vented the intake hole and still could not get the rings to seat.

After screwing with it for weeks and adding multiple catch cans, I pulled the engine back out and went through everything again fresh. When installing it back in I vented the intake manifold with a filter and added a crank case vent to each rocker cover to help with pressure. I am not running a pcv now and am having no problems what so ever with 2000 miles on it.

[fifesjeep]

My problem was the pcv sucking oil through the manifold and into the carburator which oil washed the cylinders and the rings lost their seat.

How does oil wash a cylinder?... When I had a coule of cylinders that had been washed (By Gas) I used oil to fix the problem...

[milnersXcoupe]

on assembly of the short block, if the motor is going in and being run right away - smear oil on the piston skirts and with clean cyl. bores > assemble 'dry'.

on start up > hold 2k to 2.5k RPM for 2 minutes.

the rings will 'cut' themselves in > no blow by .

if the engine will NOT be run right away, then lightly oil the rings. :!: :t: :shock: