Rebuilt engine, Drinking oil...

94 1L 5-spd. Bored 0.030 over, valve job, new valve seals, new pistons, rings, etc. Rebuilt from the ground up. Machine work done by a reputable shop, Assembly done by me, a reputable builder. Car runs like a top, compression is perfect, 210 across the board. At highway speeds 60+mph, a HUGE plume of smoke emits from the exhaust. It is caused by oil from the pcv system finding its way through the intake. New PCV valve, free flowing fresh air inlet tube, and free flowing pcv to intake tube. This much so far I know for a fact, so why is this happening?
The only thing I can think of, is that the aftermarket PCV valve is insufficient. I wouldn't be surprised at this, as last week I had to cut my own TB gasket because the aftermarket ones I acquired (3 different gaskets) allowed a sizeable vacuum leak at the mating between the TB and the intake manifold. Any ideas before I try a pcv valve from the dealer? I maintain a fleet of 20 of these cars, and this is the second car to have this problem. The other one is high mileage and I haven't gotten to inspecting the pcv system - But for all intensive purposes this engine is practically brand new!

-MechanicMatt

Matt, I'm kinda stumped on your 3qts a week... I wouldn't think that PCV would pass that much in a week. But as you stated, 210# in all 3 cylinders, rebuilt head and new rings. I have to assume the rings were fitted and installed properly being a fresh .030 over?

Funny story, My wife bought a van many years ago, I took it back to the mechanic found on the door sticker for some service and he kinda freaked out when I pulled up. After I started talking with him he pulls out a 6" stack of service records for the thing(no wonder he freaked eh ! Lol), the last one being where the previous owner had noticed low oil... and refilled it, it goes low again, refilled again... then calls the mechanic as they hear the engine knocking at a light nearby. They pull it into the garage and it's low on oil again. No leaks, no oil smoke. The Engine was toast. When they started to disassemble it they pulled off the valve covers and they were full of oil. All of the oil passages going back to the oil pan were completely closed off with sludge. Before this they never serviced the engine all of the service was to the inside electrical, brakes, driveshaft, rearend and transmission. This was during a period of 3 years and he figured they never changed the oil or filter just added oil. So we reaped the benefit of a new factory engine with darn near a new van from a dealer as they got it on a trade-in.

Not saying this is what's wrong, but seems kind of unusual with it being a fresh rebuld and all.

Good Luck,
RPG0

Well, I haven't actually measured the rate of consumption. I'm just trying to figure out why the pcv system is sending oil into the intake. I think I read somewhere that there is a problem in the heads of these cars with oil draining which might lead to a pooling of oil in the head eventually pouring it into the head?

Supposedly there is a little brass oil pressure reducer (orifice) that goes between the head and the block and mounts in the block. I am certainly no expert, but I would think that if that was missing, you'd have excessive amount of oil going to the top the cam/valve cover area and be causing what you see. I did rebuilt my motor a couple months ago, but due to a block issue, ended up installing a JDM myself for cheap.

just my 2 cents

91Caprice;
I was reading an interesting post on the teamswift board: http://www.teamswift.net/viewtopic.php?t=27274 Have you checked your oil pressure? Perhaps you are having a similar condition with very high oil pressure causing you grief by pumping oil into the head faster than it can drain??? There's another post over there regarding modifying the head gasket to insure that oil is freely able to drain back from the head http://www.teamswift.net/viewtopic.php?t=24773&start=0&postdays=0&postorder=asc&highlight= Maybe one of these issues will apply. Please let us know when you find a solution.

Here is what I found on the restrictor:

Cylinder Head Oil Restrictor On
1989-95 GM 1.0L Engines

Beware of some confusion on the cylinder head oil restrictor used on 1989-95 GM 1.0L engines. This engine uses hydraulic lash compensators in the cylinder head and the restrictor is used to control the amount of oil directed toward them. The confusion has been the correct location of the restrictor. Apparently some engines have it installed into the cylinder head and some in the cylinder block.

Regardless if the restrictor is screwed into the block or head, it also prevents excessive amounts of oil into the cylinder head area. If the oil control plug (restrictor) is not installed, the additional oil may overwhelm the PCV system and cause oil consumption.

When properly installed, this restrictor, Part #96051574, also acts as an anti-drainback valve and prevents lifter noise at start-up. This engine is made for GM by Suzuki and they also offer this restrictor under Part #11112-73001.

Here is the direct link:
http://www.rebuiltautoengines.com/suzuki-articles.html

Very interesting! Thank you guys for the information, gotta love these forums man. It may be a while before I post back with any findings as a few other geos have more pressing issues at the moment. But I will definitely let you guys know what works for me eventually. Thanks again!

-MechanicMatt

Matt;
Good luck on your quest. With 20 Metros under your care I'll bet you have learned a bunch about these cars and we look forward to hearing how you've solved various issues that have come up.

Well gentlemen, as promised, I'm back to report my findings with regards to my Metro with the fresh engine rebuild that was drinking oil like no other. After a slue of more urgent repairs on my fleet, I finally had time to take a closer look at said problem child. As it turns out, it was the aftermarket head gasket's inability to drain oil from the head back to the crankcase that was creating my problem. My solution, which has been covered by other forum members, was to use the old gasket as a template to cut larger drain holes in the new head gasket. The impressions left in the old gaskset allowed me to transfer the necessary size and shape holes to the new one using a cutting wheel on a die grinder. That simple! No more smoke at sustained high speeds, no more oil consumption through the intake PERIOD! After putting the poor metro through the ringer on the freeway, I parked it in the service area, popped the hood, removed the top half of the air filter housing, to discover an absolutely DRY air filter, DRY bottom half of housing, and DRY Throttle body. Thanks again for everyone's input.
-Matt

Matt;
That's AWESOME! Thanks for the update, I'm sure it will save a lot of time and effort not to mention frustration.

Greetings everyone, this is my first post here.

I have owned a Sprint and a Metro XFI previously,
and just bought a 92 Metro recently.

I am posting here because my Metro has a similar problem:
It is burning a great deal of oil, it goes through at least a quart every 100 miles; I have tried using thicker oils and a viscosity increasing oil additive and they are not effective.
It is definitely burning it, as it puts out constant bluish smoke.

The odometer reads 73K, and I tend to believe that it is 173K on the engine.
I do not believe this engine has been rebuilt or had major work done.
I just did a compression check, and all three cylinders registered solid readings of about 195.

I have pulled the PCV and it seems to work as it should.
There was some oil in the top of the throttle body when I first bought the car, but I tend to think this may be because the previous owner had overfilled the oil; it appeared to be close to a quart high.

With the solid compression ratings, I think I can rule out a problem with the rings and also with the valves and valve guides. My thinking has been that most likely I have one or more of the valve seals that have failed; due to the amount of oil consumption, I would guess that one has completely failed: like fell apart basically.

However from what I have read here, I am keeping in mind other possibilities, like the head gasket, and also I have read here about an oil pressure regulator? valve? that is mounted either in the block or head. I was wondering just exactly what would happen if this was not working? would the top of the head fill up with oil? and would the oil then back up through the PCV system and into the top of the throttle body?

I am going to start tearing it apart today, so I will let you all know what I see as I go, any suggestions or guidance would be greatly appreciated.

I am also going to replace the timing belt while I am at it, since I don't know when or if it has been replaced in the past, do Metros usually require anything else replaced along with the belt, like a tensioner or guide or something?

With the solid compression ratings, I think I can rule out a problem with the rings and also with the valves and valve guides. My thinking has been that most likely I have one or more of the valve seals that have failed; due to the amount of oil consumption, I would guess that one has completely failed: like fell apart basically.

However from what I have read here, I am keeping in mind other possibilities, like the head gasket, and also I have read here about an oil pressure regulator? valve? that is mounted either in the block or head. I was wondering just exactly what would happen if this was not working? would the top of the head fill up with oil? and would the oil then back up through the PCV system and into the top of the throttle body?


Extremely worn valve seals are definitely a possiblity to keep in mind, and I would look into these first. Since the time when I originally started this post, I have rebuilt 4 more metro engines. And along with the experience have gained the following insight: There is an oil control check valve that limits the amount of oil pumped into the head from the block. With the head and (head) gasket removed it should be clearly visible mounted in the block around the number 1 cylinder (if memory serves true). Now, the head gaskets are designed with this check valve in mind, and the drainback holes cut into it are small enough to keep adequate oil in the head for lubricaiton. When I first assembled the engine associated with this post, I had not included that check valve during assembly. This basically resulted in way too much oil going to the head, which the gasket was not designed to drain. Now I have on purpose built two engines this way, (without the checkvalve) but of course enlarged the drainback holes in the head gasket to compensate, and they appear to run much stronger than the other three engines I built WITH the checkvalve and un-modified head gaskets. None of the engines to date, drink oil through the PCV system.

I am also going to replace the timing belt while I am at it, since I don't know when or if it has been replaced in the past, do Metros usually require anything else replaced along with the belt, like a tensioner or guide or something?

No. Typically, just the belt is adequate.

MechanicMatt

thanks much for the response and clarification,

None of the engines to date, drink oil through the PCV system.


yeah, it didn't seem likely that that much oil could be running all the way back through the throttle body.

There is an oil control check valve that limits the amount of oil pumped into the head from the block.

I'm guessing that if this valve fails, it will fail open?
interesting modification that you did, doing away with the valve entirely= one less thing to go wrong.

How often have you encountered head gaskets that have gone bad with Metros? I have not seen much anecdotal evidence of this which again steers me towards suspecting valve seals on my car.

yeah, it didn't seem likely that that much oil could be running all the way back through the throttle body.

On the contrary, that is exactly what was happening in my case. Because I left out the check valve, and hadn't yet figured to motify the head gasket, oil was backing up in the head and flooding through the PCV system and into the thottle body where it then became part of the combustion process, and blew huge plumes of smoke out the tail pipe.


I'm guessing that if this valve fails, it will fail open?

The only way for this valve to fail is if it clogs or if its not there at all. If it clogs, the head looses lubrication. If its not there, too much oil will shoot into the head.

How often have you encountered head gaskets that have gone bad with Metros? I have not seen much anecdotal evidence of this which again steers me towards suspecting valve seals on my car.
[/QUOTE]
The only times I have seen head gaskets go bad on metros is with either old age, or overheating - the general causes of head gasket failure (in non-high performance vehicles at least). Aluminum is much more prone to failure through excessive heat cycling (than cast iron). An aluminum head, or an aluminum block for that matter has a given number of heat cycles it can endure throughout it's service life, until it becomes too soft to maintain a flat surface with the head gasket. At this point in it's life, the head and block become insalvageable, even machine work will only temporarily restore it's use. I could go on, but the point is, a head gasket does not just fail, and if it does, it usually will not cause oil consumption into the combustion chamber, at least not until long after it starts to manifest in other disturbing symptoms; such as coolant in the oil, oil in the coolant, water consumption into the cylinder, and compression loss across adjacent cylinders.

What I meant to suggest earlier, is that perhaps someone had assembled your engine incorrectly, as I had, by not installing the check valve into the block before installing the head. And seeings how your compression is strong, and a blown head gasket will not cause oil consumption as a solitary symptom, you are left with either A) the engine is assembled improperly B) you have bad valve seals C) your oil pump is over pressurizing the system (stuck pressure relief valve you mentioned earlier) and not dumping off excess oil back into the pan, or D) the oil drainback holes in the head gasket have become clogged with oil sludge from old age.

Also note, that when i said that none of the engines drink oil to date, i was refering to the engines after I had figure out the relationship between the check valve and the drainback holes. No checkvalve means you must enlarge the drainback holes. If you do not enlarge the drainback holes, you must install the chekcvalve. If you have no checkvalve, and un-modified drainback holes in the head gasket, you will get oil through the throttle body via the PCV system. I apologise if I'm a bit scattered, i really am trying to clarify lol its a bit late.

MechanicMatt

no you have been very informative,
just some normal slight misunderstanding on my part because of my ignorance.

It boils down to I guess the valve seals still being the likely culprit; I am just curious if it will be easy to tell if the seals are shot when I pull off springs/lifters, I have not run across a procedure to test them in my manual yet, I suppose I will be able to see gaps between the seals and valve shaft, or damage to the seals.

Well I pulled the head out this morning, I got it all out but have not got the springs out yet, I hope I don't have to buy some special tool to compress those springs, they are kind of submerged in there. I don't have any kind of actual valve spring compressor, I am hoping I can make do with a brake caliper vice-grip or wide mouth clamp. I am guessing maybe you can compress them with even a large socket, and maybe kind of shake the keepers off even if you can't really get at them? I'll see.

On a side note, I guess because of all the oil burning, the EGR port was clogged stem to stern. I also noticed carbonization on valve faces, top of chambers, and a little on the top of the pistons. The carbonization seemed worst in number 2 cylinder, which also seemed to have the most oil fouled plug when I would pull the spark plugs before pulling the head.

I also hope no one tells me its a good idea to go ahead and replace the lifters while I have it apart as they seem to run over $20 each.

I have been comparing prices and was quite surprised at how much cheaper Kragen/Advance auto was on a head gasket set, for the felpro and especially the beck-arnley. As far as I know they both make good gaskets so I will go with the beck-arnley cause its a few bucks cheaper; unless somebody has some horror story about their product.

if your just going to leave the valves alone and not lap them or grind them you can probably just put the head back on but if you do lap them or grind them you should replace the rings at the same time. they make a special tool for doing the springs on metros and if you can't get them in and out another way i can sell you the one i bought since i probably won't use it again. if you want it will sell it to you for $30 plus shipping. i decided it was just easier in the long run to replace the motor with a jdm one

okay I'll keep you in mind
but I don't plan on messing with the valves other than cleaning them

do lifters have to be put back where they came from like valves or does it not matter?
thanks

Keep your lifters with their bore. Have fun =)

MechanicMatt

found out after some googling that you don't need a special tool to get valves out on a Metro; you just take a big tool ( I used a screwdriver, there's nothing really fragile right there ) shove the spring down and grab the keeper- I used a needle nose and a magnet was helpful.

Then I could apparently see the seals from the top, do I have to knock out the valve stems to replace the seals? that's the way it looks.

I bought all the stuff I will need to reinstall head:
gasket set $90 with valve seals
head bolts $20
plus timing belt and seal $30

if I pull this off and can get maybe another 100K out of the engine it will be a score

I payed $400 for the car.

replaced all the valve seals last night, none of them were destroyed, but if you compared them to the new seals you could see they were stretched out a bit.

OK, so I am putting the camshaft back in last night, and my gasket kit has what is apparently the replacement for the camshaft seal- the doughnut seal at the passenger side end of the camshaft.
What I am wondering about is why does there seem to be a gap underneath the #3 camshaft holddown/bearing ( on the distributor end ), a gap that looks just like it could fit a seal about the same size as the one on the timing belt side.
Is that gap just there for oil to flow through?
and the only oil seal on that end is the O-ring on the distributor?
just hoping that there is not a seal there that I missed

There is definitely something to this oil drinking issue. I have a 96 metro which was using a quart every 40 miles. I removed the engine and disassembled it to find nothing to indicate cause of an oil consumption problem. What I did find was the number two piston and plug heavily oil fouled and a slightly bent exhaust valve. The stem seals seemed ok and the rings were fine. I was suspicious of the small hole in the head gasket which covered a larger hole that the oil passes through. This hole had some crud in it which could've been blocking it. Also, the little brass valve was installed and appeared to be functioning properly.
So my theory is that under high rpm/ load conditions such as highway driving more oil is pumped into the head than can escape and the level rises until it begins to get sucked out by the pcv system. Since the pcv outlet in the intake manifold is very close to the number two intake the oil is immediately sucked into the number two cylinder and is burned with the fuel.
Since I'd just purchased the car, it's possible the seller had installed an improper head gasket with a undersize oil hole which could cause this problem. Unfortunately, if i'd known all of this I could've gotten away with just replacing the head gasket and maybe a valve job and been back in business. If some of you are wondering why I pulled the engine it was because the clutch was bad too (broken pressure plate) and it made more sense to me to do everything this way.
I hope my findings may prevent someone else from going through all of this. Even so it was still worth it though up here in WA where gas is a ripoff $3.45 a gallon (thanks gov't).
Rich