1 qrt oil every 300 miles!

[Lit549]

Well,im still chasing my rough idle problem and in the process ive noticed im going through a quart every 300 mi and my fuel milage sux .The engine only has about 7k on it.No oil leaks,doesnt smoke,and pcv is working right with no oil sucking into carb(its dry in hose).Its 96 vortech with zz4 cam,600 eddy,and professional products intake..Could overtightening the rockers cauze this? How about intake gasket or maybe bad oil rings? The compression and leakdown test was good..Im stumped..Where is my oil going??Plugs are pretty clean,a few have oil on sprkplug threads (not from valve covers)..thanks in advance.

[Captkaos]

Was the motor rebuilt?  And the plugs don't have oil on them?

[Irish_Alley]

if the oil is on the threads its cause it leaked down onto them from the valve covers. this is a 96 engine with obdII?

[454Man]

Valve seals? mine has one cylinder valve seal that leaked from the get go... Check your plugs to see if they look like....

[Lit549]

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Travis Carter · Driver at Permian Crude
Number 7 had some oil on it pretty bad , BUT its only that bad if I go out and put my foot in itreal good.Like its getting oil in there worst at high rpm? And its in a 85 c10so know computer..Little history on the engine--ibought it from a local gm mechanic, he said itwas a warranty pulled from a truck in 96, he didn't state the issueit had just that it was basically a "new" engine.He is a respected mechanic locally..So, i bought it, installed a zz4 cam and we used the ls6 beehive springs with comp lifter( so no maching required on vortech head).Ok, we installed engine, ran it for 5 k mi and rings would not seat! We pulled it, my good close friend is also a mechanic and he tore it down and said whoever honed the cylinder didn't do it right and that's why they wouldn't seal.We went back with iron rings this time , installed engine and its been about 7k miles this time..Ive done compression test, leak down test, compression was all around 190 except for 1 and 3 which were 170, leakdown on all were 7%…Again , the #7 cylinder had alot of oil on plug after a hard run, normal driving it just has a touch of signs of oil, all the rest had dark spots(like dried oil) on the porcelins forever, now they are clean..What's baffling me is why doesn't it smoke? There is no leaks what so ever, and truck runs ok but not like it should in my opinion..Ive said it runs like a 305 since we put it in, put it does have a 308 gear so go figure..Long story but that's how its gone down, and ive chased my tail every since.Im knowlegable on cars and can do alot but this ones getting to me..
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[454Man]

Mine doesn't smoke one but with the valve seal leak, but  still  have to put in oil.

[Lit549]

Hmm,maybe thats it? I may just pull it and build a new ,on my own this time!

[454Man]

Our try changing the valve seal ... Hope you get it resolved

[Lit549]

How can i tell if its the valve seal??Replace them? ?Thanks man

[454Man]

Oil drips on the plug and looks like mine in the photo.  I change that plug everytime it starts to miss... Every 3 oil changes. I'm to lazy to do the valve seals in 100+ outside temps.:-)

[74 C-10 Shorty]

Also you get a puff of smoke when you start it up after sitting a while.

[Irish_Alley]

lit the reason i asked about the computer you stated it was a 96 vortec. in 96 is when gm made all vehicles obdII. and since your had (im guessing) cpi or at least a tbi, it would need a computer to run it has nothing to do with what year your truck is.

[Lit549]

Ya Irish,its a 600 edelbrock..Icarburated it,so no computer needed..But youare right..

[Irish_Alley]

lmao 600 eddy missed it, my bad

[Irish_Alley]

but like 74 said do you get a puff of smoke when you start up?