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Discussion Starter · #1 ·
im running a rebuilt dz 302 and i think that i might have an oil problem..at cold start my pressure is 50psi at idle,and will go up to 70 psi on rev...but when it warms up it drops to 20psi at idle but will go up to 40-50psi when reved up...ive read in here that that is some what normal...10psi per 1000 rpm...but does this hold true for the 302 solid lifter engines? what weight oil and type should i be running? thanx,david
 

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hey in any perf motor let alone a hot climate i would run at least 20w-50wt oil, this should be just what you need, goodluck
jake
 

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I wouldn't run a 50wt oil in any engine unless it was built with clearences to allow running it. Back in the day I would bet 30wt was used from the factory. I would run 10w-30 during your cooler months and 10w-40 in the heat of summer.

Modern engines run 5w-30 or 10w-30 and warn against using 20w-50. An old worn engine might live a bit longer with a 50wt oil because bearing clearences are greater. Same with a race ready engine that is set up loose to allow it to rev a bit quicker. Most small block builder shoot for the tight side of factory clearences so unless you know what's been done inside your mill, play it safe and don't go above a 40wt oil...
 

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Discussion Starter · #7 ·
thanx guyz...well i just changed it to castrol 20-50, then i just read djd's input..i think i will change to 10-40 just to be safe..the pressure now is 60-80 at 3000 rpm and 20-30 psi at a hot idle 750 rpm thanx again guyz....david
 

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20-50 castrol, assuming you are using dino oil, is pretty heavy. I use Mobil1 15W-50 and see 35 at idle and 70 above 3K rpm cold, and 30 idle/60 above 3K hot.

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Rick Dorion
69 RS Conv,355,Autogear M22,4.10's and I don't worry about stone chips ( yet ).
 

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15w-50 is 50wt just as 20w-50 is. The 15w will not thicken as much as the 20w in very cold weather. I don't know the temp ratings (it's been posted before though) but straight wt oil will thicken when cold, the multi wt will as well but stays usable in lower temps than straight wt.

David - how many miles on your engine? Do you know anything about how it was assembled?
 

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Discussion Starter · #10 ·
djd...bought the car about 6 months ago and have talked to 3 out of 4 past owners..the owner i havent reached yet is the one that restored the car...so not sure of the milage but rumor has it is a fresh rebuild...and it looks like it...clean exhaust,great performance,new paint,ect.my guess is that it has around 5,000-10,000 miles.. david
 

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I have about the same symptoms in my 302 on a fresh rebuild (balanced and blueprinted) about 10 years ago and about (guessing only as I have put about 3500 miles on in 4 years of ownership) 5-10K miles on the motor. I never worried because it seemed and had been confirmed normal to me. At first start in the cold I am at about 70PSI on the factory gage. Once it warms up at about 900 RPM Idle I am at 20-30PSI and at cruizing idle 2500-3000 I am back to 60-70 PSI. I am running Mobil 1 (10W50 I believe) here in Ohio.

Sounds perfectly normal to me.

Robert

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My 67 SS396 Chevelle
My 70 SS396 Chevelle
My 68 RSZ/28

Robert Stacho (a.k.a Mytmouse on Team Chevelle)
 
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