# Issue with engine using oil



## timmyg (Jan 2, 2012)

Hello
Been a while since I posted anything. I have a 1970 HO 455 in my 65 GTO. I have a question that may appear to be a no brainer, but I want to ask some of you who are really up on the Pontiac Engine. My engine runs really strong, however it uses a lot of oil in my opinion. I have an 8 quart oil pan on the engine. In the period of driving the car modestly say a hundred or so miles, I am adding sometimes two quarts of oil or so. The Engine only leaks a small amount at the Rear Main Seal. The engine does not smoke while normal running is going on. However when I put foot into it it smokes to the point where I leave a decent amount of smoke in the road behind me. Also when I drive the car somewhere and turn it off for a short period of say 4-5 minutes when I start the engine it does not smoke, but if it sets for a half an hour or longer it will puff smoke out of both pipes. When the car sets in the garage for any amount of time between drives it does not smoke when I start it.
I am using the Valvoline 20-50 Racing oil Blend that has the Zinc in it.
The Tail Pipes do have residue in them that you can smear on your finger if you rub your finger in them. 
Compression is between 175 and 180 across all the cylinders. I realize that the compression does not affect the oil rings if they are bad but just wanted to point that out. I have had the engine apart before and all the cylinders looked good.
What I am struggling with is whether this could all be associated with the heads such as valve seals and or guides rather than the bottom end of the engine such as the oil rings. 
Any advice or suggestions on how to approach this issue would be greatly appreciated. I am knowledgeable with engines but i really don't want to go into the bottom end of the engine if i don't have too. Maybe this scenario will ring a bell with one of you who is more knowledgeable with the Pontiac engine than I am 
Thank You ,


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## 05GTO (Oct 6, 2004)

The problem may be a bad PCV valve.


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## timmyg (Jan 2, 2012)

A bad PCV Valve? How would that cause using oil and smoking to the degree I have described?


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## PontiacJim (Dec 29, 2012)

Here are my thoughts on this, and I may be wrong, but this is my experience on using a lot of oil on a new engine.

Did you have the heads rebuilt? You could be getting oil splashing on the valve stems and this is being introduced into the engine.

Pontiac heads have oil shields under the valve retainers/on top of the springs. Some guys leave these off ( which you can) if you have a big lift cam and there is a clearance issue. These do help with oil control and why Pontiac used them.

Did you install new valve guides or have them knurled? Sometimes a shop will knurl the valve guides to save money rather than replace them IF they are marginal and knurling will work. This is not the best approach as oil can still get down the valve stem and into the engine. New steel inserts can be installed and then reamed to bring back the factory specs with the new valves.

Did you have the umbrella seals installed on the intake side? If the valve guides were not cut down to use teflon seals, these are used on stock Pontiac heads and usually come with an engine rebuild kit. These wipe oil off the valve stem as the valves go up and down in the guides. In addition, there are the small rubber O-ring seals that go under the valve stem split locks which prevents oil from going through the split locks and running down the valve stem and into the engine.

Oil sealing on Pontiac heads is important and all three, oil shields, O-rings, and umbrellas seals should be used along with new valve guides. 

When I rebuilt my 400CI and assembled my heads, I won't tell you what I left out :nono: and found my engine sucking up oil, but it ran like a bear, and I could not figure it out........until later. 

Being the engine is still "new", the piston rings may have not seated and some oil could be getting past the rings. You don't want to baby the engine or the rings won't seal - they will glaze. Learned that one too. It is recommended that you want to do several hard accelerations and decelerations to allow the rings to operate under pressure and suction. Here is some info Engine Break-In Guide: 10 Tips to Help Properly Break in Your Engine - OnAllCylinders


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## BearGFR (Aug 25, 2008)

Which heads are you running... Pontiac cast iron or aftermarket aluminum?

Bear


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## timmyg (Jan 2, 2012)

Pontiac Cast Iron, I forget the casting number but when I originally looked it up they were listed as being used on the HO Engine.


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## timmyg (Jan 2, 2012)

The entire story with the engine is as follows:
I purchased the car and the owner had had the car in the garage for over twenty years. He said the engine was freshly rebuilt prior to the car sitting for the length of time that it did. When i got it the Rear Main Seal leaked pretty bad. I took the Engine out and redid the Rear Main Seal. Really did not help much. Ran the car for a while longer and took the engine back out and took it to a friend who has a long history of engine rebuilding and racing. Although he is a chevy guy and not that familiar with some of the pontiac tricks he said he looked at the oil rings when apart and they looked good and he did not see any sense in changing them although I wish he had since he had it all apart anyway. As far as the heads he didn't put new seals on the valve stems either. I remember him saying he had some concerns over using the umbrella seals and therefore I don't think they are on the heads. I could be wrong though. In his defense I only asked him to try to get the rear main seal from leaking and take a look at everything else while he had the crank out. I am of the opinion that it is the heads and the seals/valve guides. I believe if the guides especially on the intake side are worn and there is also issues with the seals that the vacuum on the intake side could pull oil down onto the piston and therefore smoke and use oil. Thoughts/opinions??
Thanks


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## 05GTO (Oct 6, 2004)

timmyg said:


> A bad PCV Valve? How would that cause using oil and smoking to the degree I have described?


Here you go;



> The most common problem that afflicts the PCV systems is a plugged up PCV valve or hose. Accumulation of fuel and oil varnish deposits and/or sludge inside the valve can restrict or even block the flow of vapors through the valve. A restricted or plugged PCV valve cannot pull moisture and blow-by vapors out of the crankcase. *The valve can cause engine-damaging sludge to form and the backup of pressure that may force oil to leak past gaskets and seals. *The loss of airflow through the valve can also cause the air/fuel mixture to run richer than normal, increasing fuel consumption and emissions. The same thing can happen if the pintle inside the PCV valve sticks shut.


http://www.doityourself.com/stry/3-signs-of-a-bad-pcv-valve


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## timmyg (Jan 2, 2012)

Yes, I understand the function of the PCV Valve and what happens when it malfunctions. This is not the case with my engine however to the degree of oil usage I am seeing. The PCV Valve is clear and working correctly. I appreciate your advice though. One other thing i did notice when I had the engine apart last time was several of the piston tops had a film of oily sludge on them. Not carbon but oily sludge. From Valves maybe, I am thinking??


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## BearGFR (Aug 25, 2008)

timmyg said:


> One other thing i did notice when I had the engine apart last time was several of the piston tops had a film of oily sludge on them. Not carbon but oily sludge. From Valves maybe, I am thinking??


I think you may be onto something there...
I'd begin to suspect both the valve stem seals and the valve guides themselves. 

Bear


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## geeteeohguy (Feb 2, 2008)

My thoughts: First off, do an engine cylinder leakdown test. I suspect your oil control rings are not up to task. You want less than 20% leakdown in every cylinder. Secondly, running 20/50 racing oil is a poor choice for a street driven car. Racing oils do NOT have the additive packages needed for street conditions and are not a good choice. They are meant to be run briefly and dumped. The valve guide advise was spot on, as well. But you are pumping oil at WOT, so I would suspect oil control rings. How is your engine blowby?


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## 05GTO (Oct 6, 2004)

The 3 leading causes of excessive oil usage are bad rings, a plugged PCV valve and bad or worn valve stem seals.

I agree with geeteeohguy regarding 20w50 especially in the colder northern climates. A better choice of oil for Maryland would be a 5w30 to provide immediate lubrication and less wear on the engine during the winter.

Just my humble opinion,


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