Puzzled about oil

[carthur]

I have a 300E (90) and it uses oil, at a rate from what I can see, is 'normal' but nonetheless high in my view. (2 litres per 5000km or so...only car that Ive ever owned that viewed that as normal)

The other day I had to do the drive-clean test to renew the plates here in Ontario, and the results were, in the tech's words, "really decent" with HCs at 20 PPM and CO2 at .1% or something insignificant like that.

While I'm pretty happy with the emissions test results, my puzzlement is this: where does the oil that is being consumed go, if not burned out the cylinders/exhaust? Why would the HC value not be higher than "really decent"?

Thanks

CB

[Duke2.6]

Two liters per 5000 KM is about a quart every 1600 miles - not bad. It slips past the rings and valve guides. All engines have to consume some oil to lubricate the upper rings and valve guides, then is is consumed in combustion. Consider that in 1600 miles your car consumes about 80 gallons of gasoline, so one quart in 80 gallons is one part of oil per 320 parts of gasoline - an insignficant amount.

Up until I refreshed the cylinder head in my Cosworth Vega is consumed a quart every 200, but could pass the emission standards for a modern car.

The lowest oil consumption I have ever experienced in my 103 is a quart every 2000 even after the newest design valve guide seals were installed and, emssionwise, it has always been a lot dirtier than the CV.

Your emission numbers are very good. Many 103s are on the ragged edge of the HC limit.

BTW the 0.1% is CO not CO2.

Duke

[manny]

Two questions to ask:
What weight of oil are you using ?
Are you sure it is burning, not leaking ?
I find it hard to believe that you could use that much oil, and have a reading of 20 ppm hydrocarbons.

[carthur]

I find it hard to believe that you could use that much oil, and have a reading of 20 ppm hydrocarbons.

Manny,

Well to be honest, that's why I chose the thread topic I did...

I use 10w40 now (winter) and 20w50 in summer. Dumb lube shops only carry 10w30 so I have to bring my own...10w30 runs through this car twice as fast as 20w50. Might be time for fresh valve seals, now @ 165,000km on the clock

Thanks all

[tower]

Thought I would ask, as I do most of the maintenance on my "S" and "E" and looking for support on occassion. I'm in kitchener.

Tower

[Duke2.6]

Originally posted by manny

Are you sure it is burning, not leaking ?
I find it hard to believe that you could use that much oil, and have a reading of 20 ppm hydrocarbons.

My Cosworth Vega scored 18 and 11 PPM HC consuming a quart every 200 on a loaded two speed dyno test. Oil consumption usually doesn't have much effect on emissions if the catalytic converter is working well. The CV also has a pulse air injection system that pumps a lot of air into the exhaust to ensure that the converter has plenty of 02 to work with. The exhaust O2 reading was about 3-4 percent.

Without air injection high oil consumption could cause higher HC readings and possibly degrade the converter.

Duke

[carthur]

T.O. (beaches)...I have little in the way of tech skills, however!

[STORMINORMAN]

Pennzoil LongLife is my personal favorite, although Delo works just fine, too.

You may be pleasantly surprized with the improvement in your oil consumption.