Oil For Old Small-Block Chevy

[Phishin]

My 1990 Chevy K1500 has a 350TBI that is NOT roller. It's flat.

 

[SteveSRT8]

I owned a 1995 GMC vandura 3500 with a flat tappet 350 in it.

 

[Coprolite]

I see what you are getting at. I haven't had a 350/327 since I had 2 motors for my old Vette about ten years ago. I was thinking that you were referring to version 1.0, while Chevrolet probably got up to version 1.43(arbitrary number) when all the variations are counted up.

Originally Posted By: Matchlight

Originally Posted By: Coprolite

I would go for PU or PP 5w30 or M1 0w-40. Your '90 350 is nowhere near the first generation of 350 engines. The first one was introduced in 1967.

You are correct, however the overall design and layout of the engine was the same from 1968 to 1985 at which point they added things like a one piece rear main seal, roller cam shafts and some other minor things. 1967 was the odd ball of the 350's because it used the earlier "small" bearing journals and cartridge oil filters. All of the small-block V8's from 1955 until LT1's were introduced in '92 were refered to as the generation 1 small-blocks, at least by GM. Heck, they continued to use the "1st generation" up through the 2003 model year vans.

 

[440Magnum]

Originally Posted By: Matchlight

Yes, most if not all production small-block Chevy's were using rollers starting in '85 I believe.

Not the pickup truck versions. I was surprised by that too, never having messed with a SBC newer than late 60s until recently. Ford and Mopar went roller on their smallblocks for all applications in the mid 80s, but Chevy only did so for the high performance versions in the Corvette and F-bodies. The trucks remained sliders through the 90s.

 

[[RT] ProjUltraZ]

Originally Posted By: Matchlight

You know the "oil university"? The guy who wrote heavily endorsed the idea of using 20 over 30 weigth oils, and in general was talking about backing off the viscosity according to the oil pressure.

but did you check oil pressure 10psi/1000 rev or 50 psi at 5K when the oil is warmed up? even it reaches 50 at 5K i wouldnt use it tho

Originally Posted By: Matchlight

has huge oil pressure with 5w30 when you start it up in the morning. Even in the summer, the oil pressure practically pegs upon start-up. Cruising it highway speeds, it's up there almost at 80 psi, which is the limit of the gauge.

do you really have only a dummy gauge? i thought the C4s had oil press gauge. All oils are 5 to 10X more viscous at start up. shouldnt be driven at high revs (say over 3.5K in your car) before the oil is warmed up. that's your hot psi at idle usually around 19 or 20 psi i would think in your car, and coolant temp at normal operating temp

 

[Matchlight]

Originally Posted By: 440Magnum

Originally Posted By: Matchlight

Not the pickup truck versions. I was surprised by that too, never having messed with a SBC newer than late 60s until recently. Ford and Mopar went roller on their smallblocks for all applications in the mid 80s, but Chevy only did so for the high performance versions in the Corvette and F-bodies. The trucks remained sliders through the 90s.

I had a class last night, so I couldn't go poking around in my SB Chevy interchange manuals to see what the facts are, but I stand corrected. The Corvettes always got the new stuff first, followed very shortly behind (usually one model year)by the Camaro's and Firebird's. The Caprice platformed, full-size cars used small-blocks, but I believe the only one of those that got the rollers are the police interceptors. The G-Bodies also used SB's, but they used the 301's (Pontiac, discontinued in the early '80's), 305's (Chevy/Pontiac) and 307's (Buick/Olds). I believe, not sure if it's concrete fact, but starting in 1986 all SB Chevy blocks got grooves cut in the top of the lifter bores to accept either the rollers or the flat tappets. That was the improvement that I was speaking about that happened in the '85 to '86 time frame. Did all SB Chevy's use rollers starting at that time, no. I made a blanket statement that was not correct, so instead I bloviate in long posts to clarify myself. I woudn't surpised if the trucks used flat tappets all the way up to '95 when they came out with the Vortec induction systems.

 

[Matchlight]

Originally Posted By: [RT

ProjUltraZ][quote=Matchlight]but did you check oil pressure 10psi/1000 rev or 50 psi at 5K when the oil is warmed up? even it reaches 50 at 5K i wouldnt use it tho do you really have only a dummy gauge? i thought the C4s had oil press gauge. All oils are 5 to 10X more viscous at start up. shouldnt be driven at high revs (say over 3.5K in your car) before the oil is warmed up. that's your hot psi at idle usually around 19 or 20 psi i would think in your car, and coolant temp at normal operating temp

I think by "dummy" the gentleman was referring to a [censored] factory gauge that is notoriously inaccurate. You are correct in that it does have a "real" oil pressure gauge, but accuracy is not proven. Those pressure parameters were the first thing that I checked and they seemed to be well over the 10 psi/1000 rpm threshholds. Even at full operating temperature, at idle (700 RPM), the pressure was in the 10-12 psi range. As closely as I can estimate with the gauge. I decided that I will not be using the 0w20 in it again, so no worries there.