It likes a little extra oil.......

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MOPARJ

MOPARJ

What can I upgrade now?
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I believe a while back, I posted how my 6,000 mile 318, stock rebuilt heads, stock replacement pistons, and Comp XE268 cam was using some oil. As of late, it seems to be using a quart every 750 miles. I am using 10w40 with Comp Cams lube. Oil presure is good, the motor runs great, with plenty of power and the only smoke is when I am going down a grade on a freeway when I back off the throttle, or if I open up the secondaries. Even that is only a white/very very light blue (if at all). It will not do anything upon start up. There were no valve seal remnants under the valve covers and the oil looks great. the plugs were not black, but some were ever so slightly gray, maybe a bit of ash.

I will add that in those 750 miles, it is turning 3,000 rpm on the freeway 50% of the time.

About a two months, or 1,400 miles ago,I installed a Holley 650 DP on the motor. It seems since then, I have noticed the consumption. Maybe it is a coincidence. What I do know is that the power brakes and the PCV hose share the rear vacuum port on the back of the carb. Could the brakes be using more of the vaccuum and leaving little for the PCV to operate, thus causing my slight issue?

Or am I overlooking or overreacting to this consumption? Maybe I am looking in the wrong direction, as to me, this seems like a minor problem. Advice or comments are appreciated.
 
You might try omiting the comp additive, on the next oil change, to see if that helps. The additive is primarily geared toward cam breakin, but the basis is the extreme pressure additives. This might be affecting ring seal?

Have you tried a compression test, to see if it is ring based burning?
 
Backtobasics said:
You might try omiting the comp additive, on the next oil change, to see if that helps. The additive is primarily geared toward cam breakin, but the basis is the extreme pressure additives. This might be affecting ring seal?

Have you tried a compression test, to see if it is ring based burning?
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Not yet; I guess I havent been too frightened yet, based on the low amount of smoke and not tooo overly excessive oil consumption; yet it still uses some.

I have thought about the Comp additive as well. The last quart I added 150 miles ago was without additive, so maybe I will thin it out some.
 
Well, I just performed a compression test.

All 8 of the cylinders ranged from 128-139, with most being about 133. Not a big difference to signify ring issues, wouldnt y'all agree?
 
Well, compression sounds alright, but You're probably getting some ring blowby.

From what you described by letting off the throttle, I'd say you need to replace your Valve seals. This involves an on-head valve spring compressor and using air pressure to keep the valve closed.

I'd look into it.
 
along with the valve seals I would checkout the guides.some machine shops still believe in knurling the guides. compression test sounds like the rings are sealing decent.
 
Why isn't the power brake booster plumbed directly to the vacuum port on the intake manifold? The "sharing" seems odd to me.
 
Dusteriffic said:
Why isn't the power brake booster plumbed directly to the vacuum port on the intake manifold? The "sharing" seems odd to me.
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They are no longer sharing; I placed them both in their respective positions.

I wouldn't think the valve seals would be bad, as there is no smoke on start up and the there is no remnants under the valve covers, plus, the heads had no guides and seals put in about 6K miles ago. There is some clicking from the left cyl head and some from the right when cruising between 1,500 and 2,500 rpm on the hwy or road. I couldnt see how this would be slightly worn guides already. I am mainly attributing this clicking to the cam itself and the lifter (i.e. what others have described as the "sewing machine effect" from comp cam flat tappet setups; they are not the quietest).
 
if its a hyd cam I would check lifter preload and check the pushrods for correct height and clearances using .040 preoad as a base.also take the valve covers off and use a straightedge and check for equal valve height.better to fix it early than later,never assume. here to help,just ask.
 
mopar3762 said:
if its a hyd cam I would check lifter preload and check the pushrods for correct height and clearances using .040 preoad as a base.also take the valve covers off and use a straightedge and check for equal valve height.better to fix it early than later,never assume. here to help,just ask.
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Couldnt understand why the pushrods would be wrong, as I had them on before the rebuild and they were factory replacements from Mancini. The lifters were new units that came with the XE268 cam, and the springs are new comp units as well. Both should be compatable with stock length pushrods. No major milling was done to my knowledge. Revs to 5K just fine.
 
I have noticed a bit more smoke when the throttle is released after the motor was run hard for a moment, such as accelerating hard on the freeway. It is just the right side tail still. Nothing on startup or idling or normal driving, just when you let of the gas while driving and the amount depends on how hard it was driven.

I took the manifold off and valve covers and wiggled all of the valve springs around. No major movement there and no noises. I did notice that while I was inspecting the intake gasket that there was a very small break near cylinders 6 and 8 intake ports. It was hard, so I probably did not do that when I pulled the mani off. I wonder if this is just enough of a break to suck oil on deceleration and not cause any backfires or misfires. Again, the motor is running great. I noticed a quart low at 600 miles this time around. It was not like this when I out the motor in, so I am leaning towards intake gasket, rather than a ring or guide, because of the good compression and god running.

Whaddya think?
 
If your intake gasket was leaking oil into the ports that would explain it. Try installing it with a little smear of permatex on the gasket surfaces -
 
You may have answered your own question. If you didn't have the problem until you installed the Holley carb I would put the old 4bbl back on . If you installed a intake and carb at the same time the intake gaskets could be the problem. The carb could be too rich and washing the oil off the cylinder walls on hard acceleration or hard deceleration. As suggested I would drop the cam lube from the oil mix, the cam is broken in by now
 
I put 500 miles on the car this week. It was hot the entire weekend, well over 100. This is the first 500 miles since the intake gasket swap.
When I got home last night, I was pleased to notice that the oil level is still above the full line. My father was following behind me during a cruise yesterday and did not notice any smoke at all, if any, it was not blue. I am now running Valvoline 20w50 VR1 oil with no other additives instead of the Castrol 10w40 I was running with COmp break in lube.

So far, things are looking better.
 
MOPARJ said:
I put 500 miles on the car this week. It was hot the entire weekend, well over 100. This is the first 500 miles since the intake gasket swap.
When I got home last night, I was pleased to notice that the oil level is still above the full line. My father was following behind me during a cruise yesterday and did not notice any smoke at all, if any, it was not blue. I am now running Valvoline 20w50 VR1 oil with no other additives instead of the Castrol 10w40 I was running with COmp break in lube.

So far, things are looking better.
Click to expand...

Pls let me know after the next few 100 mls. I have the same oil consumption after my rebuilt and if this is only the Intake gasket that would be really great. Never spend a thought on this and was ready to buy Ede Heads...
 
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