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.

Cmon gentleman....

I need some opinions, 318 or not...lol...

If you're sure it's not leaking past the valve guides or valve seals it could be the intake gasket not sealing at the bottom. These will leak just enough at high vacuum to cause your problem. To eliminate the PCV as a problem just unhook it and block the port. Make sure the valve cover has a baffle under the PCV valve. One other culprit could be the piston rings failed to seat. When you first started the new engine was there any kind of carb problem that may have washed the rings?

I thought the brakes went to the manifold and the PCV to the carb...

What type of oil are you using? Conventional or Synthetic? The reason I ask is conventional oil has an inherent characteristic of being volatile. Meaning at normal operating temperatures, some components of the oil burn off or evaporate. Synthetic oil is resistant to this type of evaporation loss. Although, one quart of oil in 750 miles seems a bit excessive for evaporative loss. Regardless, it could be plying a roll in your oil loss issue. What does the oil look like? Such evaporative loss also increase the oils viscosity. What is the engines operating temperature? Is it higher than normal? Does the engine ever overheat?

Just a couple other possibilities to consider.

This motor never overheats. It stays right at 180 all of the time and rises to 195 in only the warmest of days. The oil looks great, not too thick. It is 10w40 Castrol with a bottle of Comp Cams lube. Maybe the lube is doing more harm than good at this point?

I didnt really wash out the rings at break in. Initially, there was some difficulty to get it started as the oil pump/dist gear was not set in correctly, but I didnt pump a bunch of fuel into it. As soon as I righted that issue, it fired right up and I broke it is for 30 minutes at 2,000-2,500 rpm, stopped to change the oil, then ran it some more.

I would anticipate worse running, misfiring, and more smoking if it were the rings, wouldnt you all agree? It has run great for 6,000 miles.

I wouldnt think the carb is pumping too much fuel in, even though it is large for a stock 318 (650 DP electric choke with #70 jets. I do not smell fuel in the oil. Should I back this back down to the Eddie 600 I have? It its fairly rich when it is cold; I can smell fuel in the exhaust, but it cleans up later.

There is a lot of 3,000 rpm freeway cruising for 40-50 miles at a time. Maybe with the lift of this cam and the stock heads, it is just burning more oil? I dunno.

No smoke on start up. If it is, I cannot see it, or it is just fuel smoke or very very light blue. I do not see any valve seal particles in the heads under the valve covers.

The smoke while standing on the throttle or when I am going down hill is minimal and only for the initial moment when I start either driving situation.

Went for another 40 mile shake down today. Only visibly saw a small bit of smoke when I jumped hard on the gas, otherwise nothing. I cleaned the plugs before I left; check again when I returned. They still look clean like they did when I checked them the first time.

I did look down number 8 cyl, which had the worse looking plug before I cleaned them. It even wasnt that bad, with a little brown oil on top of the piston. I know, if there is an issue, that it is on the right bank, as my father has followed behind me and noticed what smoke there was coming from the right side tail pipe.

Maybe the right cyl head wasnt as quality a job as the other and a valve/head job may be in line sometime in the future, not near future. I will go with 302s at that point, or milled 360 (smaller valve heads).

Sorry for the abundance of words; just trying to be descriptive.

-Justin

my suggestion would be to do compression & leakdown tests.

Would you think that I should unplug on of my bungs in my Performer intake and try to route in the brake line there and just run the pcv only to the carb and see how it does for the situation?

Also, say it was a malseated ring. Can it seat it self ne way or the other over time? If it is not a ring (which I doubt it is) or intake gasket, i am sure it must be in the right cylnder head. It may just need more work done to it than what was performed.

All and all, given the great running condition and small amount of smoke that is present when it does happen, does this sound like something that needs immediate fixing, or is it fine for a while and wont hurt anything?

Again, sorry for the questions....

Drove more today, pulled the plugs. Still, no black oil, if anything just a very very small amount of gray ash on the ends, but nothign more.

Oil still reads full after 200 miles since last quart added. Thinking about routing the brake vaccuum into the manifold and pcv to the carb tonight. Motor is running strong.

You're going to have to do a compression and leakdown test to be sure it's not a ring problem.

Ok..

I know how to do both, but what will each point to is the numbers are low? Only ring issues?

I would consider pulling intake to be sure it's sealed, or maybe for now, crank the bolts down to be sure they're snug.

Quote:

---

I would consider pulling intake to be sure it's sealed, or maybe for now, crank the bolts down to be sure they're snug

---

I had the same problem many years ago and my intake wasn`t sealing and it was sucking oil in from the valley. Have the heads been cut any? Mike

No, the heads have not been cut or shaved.

If it is an intake leak, it must be rather small, as it runs great, there is no detonation or rough idle (besides from the cam).