utfan01ss

iTrader: (1)

So this week I realized how dumb I was thinking my oil pressure gage was faulty. Listen to this... So I built a brand new 355ci for my IROC, new Scat internals, LT4 cam, roller rockers, headers, etc... The motor runs great, nice and quiet, sounds great, etc.. I currently have about 3500 miles on it since putting it together. Well about a week ago my oil pressure gage started jumping up and down randomly. So I immediately think its the sending unit going bad. But should I check the oil just to make sure, nah, I just changed it 1500 miles ago. Its not leaking and doesn't smoke so its still full.

I go to O'Reillys and buy a brand new sending unit. Don't get a chance to change it due to other things going on for a couple days so I keep driving the car. It's ok, just a bad sending unit. Well I notice the valves starting getting noisy, like a sewing machine. So I think the valves are out of adjustment... pull the valve covers off and re-adjust the valves. Yep, oil is pumping out of the rockers, granted its solid black which is weird but whatever.

So I jack the car up and remove the drain plug from the oil pan. Maybe a quart of oil comes out.... thats it. So I'm immediately thinking.... DAMNIT! That explains the noisy valvetrain. I pull the oil filter and there isn't much oil in it either. Usually they are full when you do an oil change.

So I decide to fill it up with Mobil 1 synthetic and install a new filter. Lets see if the oil pressure gage works now, yep, 60 psi... and guess what. The engine is quiet again. I really hope I didn't screw something up, it had enough oil in it to pump through the rockers so maybe I didn't scorch a bearing. I've since put another 500 miles on it without an issue, fingers crossed.

My question is.... where the hell did all the oil go?????? There are zero leaks and it does not smoke at all. Now I haven't had it tuned yet so it runs a little rich. My uncle seems to think I'm getting fuel in the oil which is causing it to evaporate. Never heard of that before but ok, sounds legit. What do you guys think? Ever had this happen? I'm watching the dipstick like a hawk now...

afremont

First, fuel getting into the crankcase wont make your oil evaporate. You looked under the car and made sure it wasn't soaked back to the bumper? Three or four quarts in 1500 miles is allot. Pull all your plugs and look at them.

utfan01ss

iTrader: (1)

I didn't think that sounded right. Yeah, I looked all over for any sign of a leak and found nothing. It's got me puzzled, so tomorrow after work I'll pull the plugs and see what they look like. Any certain thing I should look for? I'm assuming if it was burning oil the plugs would be wet correct?

Thanks

afremont

They should show some kind of build up I would imagine. If you have a problem with one cylinder it will certainly stand out when you look at the plugs. If it's not leaking, then you must be burning it unless it somehow gelled up and stuck all over the inside the block.

utfan01ss

iTrader: (1)

Alright, makes sense. I think I'm going to do a compression test as well just to see if the rings are seating properly. But since this motor is fairly new still, I'd imagine it could take between five to ten thousand miles to fully break in correct? I'll pull the plugs tomorrow and see what they tell. Thanks for your help...

thunderstick

you say you built the motor... what did you do as far as heads and intake? any changes? and head gasket? use a different thickness? i had the same problem, am not 100% sure i found the cause of it yet, but i have a suspect. i was taking in oil in all cylinders at about a qt. every 500 miles or so, about the same as you. suspected (recently replaced) teflon valve seals, but apparently they were all good, got replaced again anyways. when i pulled the intake this time, it separated cleanly, was able to just peel the gaskets off like they never sealed. i don't know what the thickness of the original head gaskets were, but i had replaced them with a felpro .039 when i did the original rebuild. i don't believe gm used that thick of a gasket, so in the grand scheme of things, i "raised" the heads off the block by doing that and obviously when you raise them, you also move them farther apart and the intake might not seal properly because that area has been increased. so in my case, i put a .028 gasket on the heads this time, putting the intake back on by tomorrow, and hopefully will have it all back together by the weekend. can't say that was the fix to my oil consumption, but it was the only suspect i found when i tore it back down. and it may not be your problem, but if you did anything with the heads and intake, it might have an effect on your problem. i hope this helps and i hope mine is now fixed, but time will have to tell on that...

utfan01ss

iTrader: (1)

That's interesting, I bought a Fel-pro gasket set for my 89 L-98 which came with stock head gaskets and intake gaskets, which I used. I had the heads decked although the machine shop didn't take much material off. So after reading what you had to do I decided to take a quick look at my motor and see if I could notice any oil leaks. And I found one... which may be my issue.

If you look closely at this picture behind the thermostat housing next to the number 1 intake port you'll notice a small puddle of oil. Seems like the intake gaskets are leaking after all. Still confused on how that much oil could be burnt without any smoking but I guess its possible. Now, they make different size intake gaskets too right? Think I could find a thicker intake gasket and seal this up without having to remove the heads?

utfan01ss

iTrader: (1)

I removed all eight spark plugs and noticed one, the number 2 cylinder, was half white and half tan. Almost seems like its a dead cylinder compared to the rest of the plugs. All the others were solid tan around the electrode, which according to my book, is normal.

Could this be normal or do I have something going on with this cylinder? Almost seems like the fire is weak or something, not really sure. This pic is kinda hard to see but you can tell its half white and half tan. Any thoughts on what could be going on?

ASE doc

That one cylinder may be running a little lean. Weak ignition would leave more deposits, not less. If the engine is using oil, expect to find a white chaulky buildup on the plugs.

One thing I notice is you say you are running synthetic oil in the brand new motor. Synthetic oil should not be used for break in. It doesn't allow the rings and cylinder walls to break in. You need to run organic oil(preferably straight 30 weight, though 10w30 will work) for the first 1,000 miles. During this time, you need to perform the ring break-in procedure. This consists of driving up and down a steep hill where you can go up and down in second gear. Refrain from using the brakes as much as possible on the downhill, allowing the engine to hold the car back. This will accelerate ring seating. If this doesn't reduce your oil consumption, you may need to redo the crosshatch in the cylinders, replace the rings and start over. Also, are you sure that you installed the rings correctly? That the gaps are offset correctly?

utfan01ss

iTrader: (1)

I've got over three thousand miles on the motor, used valvoline conventional for the initial break in and just now switched to synthetic. I gapped the rings and installed them correctly, dot facing up and oriented in the correct position. Motor feels really strong so I believe the rings have seated. I have no smoke at all through the exhaust and it makes a good amount of torque.

ASE doc

Look for oil buildup in the intake, coming from the PCV make up air tube. This is a sign of high blow-by. Try running the engine with the PCV valve out of the valve cover and the make up air tube plugged. Look for an usually heavy flow of combustion gases from the valve cover opening.

thunderstick

intersting that your plugs all look normal, for the most part. mine were always fouled, BUT i also had an ignition issue and running rich condition that i also have to resolve, which will hopefully be corrected when i finish this top-end rebuild. what ase doc said about that pcv make-up tube is also true, and still part of the process i have to eliminate on mine, as well. one thing at a time... but when i hook everything back up, i am going to bypass that pcv make-up tube overboard at first to eliminate it as a possible oil supply in to the intake. btw, did you use thread sealer on the intake manifold bolts? that is an odd place to collect oil. usually it'll be found around the runner-to-intake area(s).

utfan01ss

iTrader: (1)

I checked my PCV system and didn't observe any oil coming from the valve covers. I removed the hoses, fired the car up and let it warm up... then revved it a few times but nothing came out. So I'm sure my PCV system is operating correctly.

I didn't use any type of sealant on the intake bolts when I put it together. I agree, it is an odd place to collect oil. I wiped it clean with some degreaser so tomorrow I'm going to drive it from Knoxville to Chattanooga then back and see if any oil is in that area.

Honestly it seems someone may have drained my oil, don't think I have any enemies. lol.. but my plugs look fine, it doesn't smoke, no leaks underneath anywhere and everything is brand new. Motor runs great too... I installed a high volume oil pump so my only thought now is maybe the intake gasket is not sealed, allowing some oil to bypass into the intake port. Not 100% sure though

thunderstick

oops. s'posed to... probly why you're pooling up w/oil there. let us know how the oil consumption goes on that trip. wish i could give you more info on mine, but as mentioned earlier, it's still going back together so i'm not going to know anything firm for a while yet...

ASE doc

If you had an intake leak from the crankcase into an intake port, it would present as a lean condition on any cylinder(s) affected by the leak. The engine would idle poorly. The area in the photo is more likely to collect coolant from a seeping thermostat housing gasket. The blow by test doesn't necessarily reveal oil or anything else but hot gases that may appear to be clear like hot air. The point of the test is to observe volume. On a stock motor in good health, I would expect to see very little volume. On a high compression performance engine, I would expect to see a bit more volume but it shouldn't be heavy. If you installed 1/16" low tension rings I would expect to see a fairly heavy flow, that's why low tension rings are used with a vacuum pump.

Since you are concerned about possible oil loss, my advice would be to check the oil daily for several days. This is a small effort to protect your brand new engine. This way you can track oil loss over those several days and confirm one way or the other whether you're actually losing oil.

utfan01ss

iTrader: (1)

That's interesting, my motor does have idle issues but there intermittent, come and go. That area in the photo is definitely oil, not coolant. I bet my intake is leaking. Sometimes my car idles at 1500 Rpms, sometimes at 900 and sometimes it won't idle at all. I was thinking it was the stock tune causing that but my cam isn't big by any means, just an LT4 hot cam. So it should idle.

I did a 500 mile trip and it went through a quart of oil. No leaks and no smoke. I did pull the PCV and notice it was wet with oil. Thinking about installing a catch can to see how much oil it pulls through it. Would that be a good idea?

Yesterday the car wouldn't idle at all, died each time I let off the throttle. But today when I went to Bristol for the street drags it idles fine all day. Don't get this thing









doc;5393398]If you had an intake leak from the crankcase into an intake port, it would present as a lean condition on any cylinder(s) affected by the leak. The engine would idle poorly. The area in the photo is more likely to collect coolant from a seeping thermostat housing gasket. The blow by test doesn't necessarily reveal oil or anything else but hot gases that may appear to be clear like hot air. The point of the test is to observe volume. On a stock motor in good health, I would expect to see very little volume. On a high compression performance engine, I would expect to see a bit more volume but it shouldn't be heavy. If you installed 1/16" low tension rings I would expect to see a fairly heavy flow, that's why low tension rings are used with a vacuum pump.

Since you are concerned about possible oil loss, my advice would be to check the oil daily for several days. This is a small effort to protect your brand new engine. This way you can track oil loss over those several days and confirm one way or the other whether you're actually losing oil.[/QUOTE]

utfan01ss

iTrader: (1)

Hope your oil issue got fixed. I'm thinking mine is leaking through the intake gasket. Going to pull it and install new gaskets to see if it helps. Gonna get the intake ported while it's off, need more top end anyway.

utfan01ss

iTrader: (1)

And ASE Doc, I used stock replacement piston rings btw. I did notice a small amount of steam come from the PCV hole though. My engine is at 10:1 compression... Would doing a compression test reveal anything ring related? Such as not sealing or seating correctly?

ASE doc

Rings that are not seated, but installed correctly and not damaged in any way, will still show good compression. The difference would be minor 10:1 motor should test at about 180 with a mild cam. The crankcase vapor test is a better test for this type of ring issue. Low compression on one or more holes would indicate an issue on those holes.

Don't be too concerned about a little steam. As metal cools it attracts moisture from the air. Then that moisture evaporates when the metal heats up again. If you're concerned about water infiltration from a head or intake gasket, just keep an eye out for white buildup at the top of the dipstick tube or around the oil fill cap.

I have made the mistake of switching over to synthetic oil before rings were completely seated. I have had some success switching back to organic oil and completing the ring seating procedure that I outlined for you. If the problem persists, you may want to try this. If you still can't get the oil consumption down where you're comfortable with it, then you would have to take a ball hone to the cylinders and replace the rings.

Good luck.

thunderstick

hopefully i'll know this next weekend... would've been done, but work, school, wife - you get the picture. just got plugs-n-wires to put on, couple odds-n-ends, and light her up. did you replace your intake gasket yet and if so, any luck with it resolving your problem?

hotrodjoe

I suspect oil control rings....broken/upside down or poorly seated comp rings. We've seen it where when the rings weren't seated the car could idle all day without issue, but when under heavy load, here's what happens: The pressure slips into the crank case, pressurizes the crankcase, and then the pistons that are on the intake stroke get extra air pushing UP into the cylinder....this pushes OIL up above the piston rings and then it burns on the power stroke. We didn't notice it at idle/low throttle position, but only on the highway. Also have seen where the blowby nevr went away because using Synth oil too soon makes the rings to NEVER seat. But I suspect a ring issue. Also, we once had Compression Gas getting into the Head Gasket oil passages...pressureized the crank case and was quite literally BURNING the oil up...the heat from the combustion gasses dried out the oil or something and it disappeared....we're still not sure if the compression gas was burning the oil up and drying it out or if it was somehow letting the oil get into the cylidner. The funy thing is that the plugs always looked pretty good since at lower RPM they cleaned up pretty fast. The only way we found that one was when we pulled the plugs after a 20 minute high speed run....we got off the highway ramp, killed it and coasted it into a gas station at teh end of the ramp....then popped the plugs.

thunderstick

my plugs were ALWAYS fouled, but part of that may have been from poor ignition...

cuisinartvette

Lets hope its not the rings upside down done that one before!

Id pull the intake off those leaks can be sneaky sometimes. Comes throught he bottom of the gasket usually.

My Gasket sells various thicker ones.

If your valve covers dont have bafffles you could be pulling it in through there.

SBC can take some abuse hopefully eveyrthing downstairs is fine (bearings and all.) if your oil pressure is good just drive it unless you feel like checking things out.