Oil Consupmtion

[MOPARJ]

My 318, near stock compression, Comp XE268 cam and Holley 650 DP now has 6,000 miles since its rebuild.

My oil consumption, with 10w40 and Comp lube is about 1 quart in 750 miles, mainly freeway driving at 3,000 rpm. Is this still acceptable?

All plugs look ok, except number 8, which was not oily, but has a bit of ash deposit on it. In following behind me, my father notices a very small bit of smoke when I get off the throttle, especially on the freeway and a tad when I jump on the gas. It is only from the right tailpipe. The motor runs great, lots of power. It is also a bit more prevalent when going downhill on the hwy with my foot off of the gas.

Does this sound like I am dumping too much fuel into the motor? The smoke is so hard to see that he cannot tell if its that blue to be oil. It does not smoke a bit upon start up or any other running condition. I am running 70 jets in the Holley.

 

[ramcharger]

If it's on deacceration, it would be from valve guides or leaky intake gaskets.

 

[Thrashard340]

Generally, 1 qt every 1,000 miles would be acceptable. You're a little on the high side for oil consumption.

 

[MOPARJ]

Generally, 1 qt every 1,000 miles would be acceptable. You're a little on the high side for oil consumption.

Yeah, its held pretty consistant.

Would dumping too much fuel into the motor from the 650 DP accelerate oil consumption? It does have about as lumpy of a cam that one would want in a relatively stock 318.I can live with this rate of oil drinking, as long as it does not get worse.

 

[dustertogo]

Yeah, its held pretty consistant.

Would dumping too much fuel into the motor from the 650 DP accelerate oil consumption? It does have about as lumpy of a cam that one would want in a relatively stock 318.I can live with this rate of oil drinking, as long as it does not get worse.

With the way you say it runs and all, sounds like you've mainly got a problem affecting #8 cyl. If it were a carb problem (too rich etc.) it would affect all and you would definitely notice other symptoms with running etc. You may want to do a compression and cylinder leakdown test on #8. Ramcharger may also be on to something with the intake gasket.

 

[MOPARJ]

I should reiterate, on behalf of the oil consumption that the motor is driven on the hwy at 70 mph (3,000 rpm), 65% of the time, as the cruises I go to are quite far from home.

 

[MOPARJ]

As of now, 650 miles= 1/2 quart low. Not too bad, eh?

After furthur investigating, the smoke is very little and only during deceleration or going down a steep hill or grade on a freeway at a higher rate of speed. If I sniff both tailpipes with the motor off, the right has a slight fresh oil smell, while the left does not. Again, running condition is great.

Could it be that when rebuilt, one of the valve seals (#8 judging by that plug), just didnt seat quite perfectly and is not broken, but just not properly seating, therefore slightly leaking some oil?

If so, is this a huge performance eater and will it cause any other damage?
Again, running wise, it is strong.

 

[dgc333]

Ash build up on just one plug is an indication of that cylinder burning oil. If the ash is evenly dispursed around the plug then it's likely getting past the rings. If it is predominately on one side of the plug it is getting past the valve seals.

 

[MOPARJ]

Ash build up on just one plug is an indication of that cylinder burning oil. If the ash is evenly dispursed around the plug then it's likely getting past the rings. If it is predominately on one side of the plug it is getting past the valve seals.

Yep, it was collecting on one side, hardened, not oily. I placed in another plug, although it is a 64 heat range, rather than 66. It has been in for about 150 miles. Still dry and looks ok.

The rest of the plugs are a bit white tipped, but otherwise great looking. It is not running lean, at least not at full throttle, as I see fuel smoke in the rear view mirror (some).

I am running 10w40 Castrol with one bottle of Comp Cams lube at each change. 6,000 miles now, 28-30 psi oil pressure at hot idle, 60 at speed.
180-190 temp at all times once warm.