# Oil Consumption



## zrsteve (Aug 28, 2014)

I have fresh 389 Tri-power. During the 500 mile break-in the motor the used 1.5 qts of oil. Change out the break-in oil and have drove it another 439 miles, checked the oil and it was down 1 qt.

The motor isn't leaking oil, I'm not seeing any blue smoke coming out the exhaust but I did wipe my finger in the left exhaust tip and there is some type of oil sludge in the exhaust. I've pulled all of the plugs and although some of the plugs did have what appeared to be a carbon build up, it really didn't look abnormal.

Any ideas


----------



## PontiacJim (Dec 29, 2012)

This is a tough one to diagnose as it could be several things.

PCV line hooked up correctly? Any line connected to your valve cover? I have seen on aftermarket valve covers that on some engines the PCV/breather hose that connects to the valve cover is directly over a rocker arm. Splash oil gets sucked up and into the engine. These valve covers usually don't have an oil shield and the PCV line simply plugs into a rubber grommet on the cover. Just a thought.

You may use some oil during break in until your rings seat, but there are many opinions on how to break in an engine. Used to be you kept it under a certain speed for the first 500 miles. This is really not good because you have to seat the rings. If break-in is not done correctly, you glaze the cylinder walls and your rings won't seat so well and you may use oil. It is suggested that you need to both accelerate and decelerate to break in the rings. I found this:

"One of the aims of breaking in an engine is making sure the piston rings seal against the cylinder bores. That is done using gases emitted during running that force the rings outwards. That’s why it is good to provide high pressure initially. We’re recommending you don’t go over 3,500 RPM. As a rule of thumb, keep it below the halfway point of zero and the redline. At the same time, don’t baby the throttle, just be careful not to go over the aforementioned limit too often. While accelerating, do it with confidence, applying wide open throttle from low RPMs."

Pontiacs will consume oil if the heads are not prepared correctly. Oil gets pulled down the valve stems and goes into the engine. Must have the O-ring oil seals at the valve spring retainer and the metal valve spring "hats" that go over the springs and act as an oil deflector -which some do not reinstall. Must have good valve guides. Bronze inserts are best, but some shops will "knurl" the old guides as a quick fix or to save you money - not a good idea. Umbrellas seals on the valve stem guides can help keep oil out of the engine. And then there is the Viton stem seals which requires machining of the valve stem guides.

Other things it could be, but these would be last resorts: ring gap too wide, or a broken ring.

:thumbsup:


----------



## zrsteve (Aug 28, 2014)

PontiacJim said:


> This is a tough one to diagnose as it could be several things.
> 
> PCV line hooked up correctly? Any line connected to your valve cover? I have seen on aftermarket valve covers that on some engines the PCV/breather hose that connects to the valve cover is directly over a rocker arm. Splash oil gets sucked up and into the engine. These valve covers usually don't have an oil shield and the PCV line simply plugs into a rubber grommet on the cover. Just a thought.
> 
> ...


Thanks for the feedback PJ. As my knowledge of motors is limited, here's what I can tell you:

1. Yes the PCV valve/line is hooked up correctly.
2. As this car originated in CA it has the tube running from the valve cover to the carburetors. I needed to replace the original tube with an Ames aftermarket tube. This tube was in use prior to the rebuild.
3. The engine builder made the same recommendation about seating the rings, only his was a little more aggressive, vehicle in 2nd gear and at 2,000 RPM's mash the accelerator to 4,500 RPM's, let off and let the engine brake itself with compression. I've done this 4 times.
4. I've checked the compression on all cylinders. One cylinder at 165#, four at 170#, one at 173# and one at 180#. Rings seated?
5. As for the heads, not sure what was done but here's what's listed:
Pioneer brass extension plugs
SI valves 1.92/1.66 1-piece stainless valves.
Iron valve guides (.502 OD)
Hard "exhaust seats" installed.
SBI replacement (Ram Air III) valve springs installed.
Mill, drill and tap for screw in studs, canted valve head.
Heads resurfaced.

Your question about a line connected to the valve cover prompted me to examine the tube and hoses going to the carburetors. I did find the insides of these coated with oil. I measured 3.5" from the top of the rubber grommet to where the tape hit the head. The tube is inserted 2.75# into the valve cover. Was it sucking oil up and into the carburetors? Don't know, but I cut 1.5" from tube. I'll see if that helps.

Sorry for the long list, but thanks again.
Steve


----------



## chuckha62 (Apr 5, 2010)

Whoa... There's your problem. If your PCV is hooked up correctly and attached to your vacuum port at the base of the carb., then that should be okay. The other hose should run from a breather (with a filter inside) on top of one valve cover, and go to the base of your air cleaner. If it's at the base of the carburetor at a vacuum port, then it will very likely suck oil. I've never seen a hose inserted directly into the valve cover without a fitting and at that, it shouldn't be beyond the half inch or so required to secure it. Oil in the hose is a huge clue. Is there at least a baffle right below where it goes into the valve cover?

Your compression looks okay given the rings are still seating. Also, I agree with the 2000 to 4500 full throttle runs and back down. I always do this at least 10 times on a fresh build, then never leave it at a sustained RPM (like a freeway cruise speed) for the first 1000 miles. Always vary to RPMs. When you get 1000 miles on it, change the oil again and drive it normally.


----------



## zrsteve (Aug 28, 2014)

chuckha62 said:


> Whoa... There's your problem. If your PCV is hooked up correctly and attached to your vacuum port at the base of the carb., then that should be okay. The other hose should run from a breather (with a filter inside) on top of one valve cover, and go to the base of your air cleaner. If it's at the base of the carburetor at a vacuum port, then it will very likely suck oil. I've never seen a hose inserted directly into the valve cover without a fitting and at that, it shouldn't be beyond the half inch or so required to secure it. Oil in the hose is a huge clue. Is there at least a baffle right below where it goes into the valve cover?
> 
> Your compression looks okay given the rings are still seating. Also, I agree with the 2000 to 4500 full throttle runs and back down. I always do this at least 10 times on a fresh build, then never leave it at a sustained RPM (like a freeway cruise speed) for the first 1000 miles. Always vary to RPMs. When you get 1000 miles on it, change the oil again and drive it normally.


Yes the PCV valve and the tube are hooked up correctly. I have cut the tube so it only extends into the valve cover ~.75" and I have a wad of Chor Boy steel scrubber stuffed in the end acting as a filter.


----------

