Engine Oil - '80-86 305 SBC

[Tynan918]

I spent $40 on 5 quarts of Lucas Hot Rod Motor Oil, specifically because it had zinc in it...

I can't keep paying that... Is zinc really a must have ?

I've had an '82 Impala, a '78 Impala, and an '86 Monte Carlo... Never had to use zinc specific oil in those engines...

I read and see so many other options...

Factory specs call for 5w-30, I've read others say 10w-30 in the winter and 10w-40 in the summer, some say use cheap oil and add a zinc additive, and I even read some using Rotella 15w-40 diesel oil...

I just don't and can't blow a bunch of money on zinc specific oil, and I'm sure there are cheaper options...

What exactly is zinc used for ?

How does 15w-40 diesel oil work in gasoline engines ?

Can someone explain and recommend something cheaper ?

 

[Tynan918]

That 15w30 is too thick and will increase wear which is the opposite of your goal. Engines wear most during cold starts which is why you want thin enough oil to start flowing immediately. The thicker the oil the slower it flows at cold start up. Once fully warmed up engines wear very little, the warmer the better to a point. I use 5w30 and add ZDDP to the jug and mix it around before pouring into the crankcase. Even 80's oil already had reduced ZDDP levels due to cat converters, but still higher than today's oils.

What ZDDP additive do you use ?

 

[Clone TIE Pilot]

ZDDPlus.

 

[olds307 and 403]

I used ZDDP plus with SL Quaker State Defy oil 1000/1100 ppm ZDDP, still had my 214/214 cam fail. Maybe the supposed BBC upgraded springs have a lot tension, not a dual spring though.

 

[g0thiac]

I use 4 quarts of 5W-30 Quaker State and a quart of STP oil additive. Works great on my 305 so far.

 

[vanrah]

Greetings Guys; My $.02 cents, influenced by one of the Ole' guys at Comp Cams. He gave me a oil lesson back in 2013. Comp did Not own Gibbs oil then. But had been testing it on their Dynos. So after (no exaggeration) 6 phone calls & 4 hours he had made it perfectly clear that ZDDP is a GOOD thing. And roller lifters vs Flat bottom that make little difference! Read that twice if needed. It's LOAD, Lbs. Per Sq. In., contract area! Once you add faster cam ramps & heaver springs the load goes UP! Now backing up previously to 2007 & again 1993 (?) ZDDP was removed from our oils. So you ask why don't we need the ZDDP in our modern engines & you have been led to believe its roller lifters. Yes they help carry the loads better than flat tappet. But the manufactures have went to variable duration cams that have modest cam ramps & Not very heave springs. Being many engines have over head cams that have lighter valves-retainers, hyd lifter pucks (lighter than the lifters we are concerned with) & No push rods. Less mass, less spring force needed, Less ZDDP Required. So if ya need the load carrying capacity of ZDDP & don't want the cost of oils that still (for how long?) have some just buy the 4 oz. $12 bottle of ZDDP & add 1/2 of all at oil change time. Please don't use diesel oil, it has VERY poor shearing package. In other words it hates RPM & aerates easily with upper RPM! Ole' Bob.

 

[olds307 and 403]

Spring pressure is no doubt a huge part. Chevy finally got their act together and cams almost never failed by the early 80's. Your call, stock weak springs and less than 200 duration numbers are much easier on parts.

 

[MrSony]

around me napa has cheap house brand conventional, i use t hat or normal valvoline and the lucas additive.

 

[bracketchev1221]

I ran Shell Rotella oil in my 7800 rpm race engines. No wear with 300 lbs on the seat springs and over 700 open. Dynoed the engine with 15W-40 standard and then changed to 5W-40 synthetic after break in. First engine was the 540, made 910 hp at 7100, the second was the 565, made 980 hp at 7200. Shifted both at 7500, and crossed at 77-7800. Steady oil pressure on the dyno with a good pan, and these were 4.25 stroke engines. Only difference I did ever see was dropping the level from 7 quarts to 6 quarts and found 4 hp due to windage. Not enough in itself to matter but I did find 22 hp overall on the 540 on the dyno. The 565 was run with the same accessories as the 540 did so only made a few pulls and I was done.

That 15w30 is too thick and will increase wear which is the opposite of your goal. Engines wear most during cold starts which is why you want thin enough oil to start flowing immediately. The thicker the oil the slower it flows at cold start up. Once fully warmed up engines wear very little, the warmer the better to a point. I use 5w30 and add ZDDP to the jug and mix it around before pouring into the crankcase. Even 80's oil already had reduced ZDDP levels due to cat converters, but still higher than today's oils.

The first number only applies at temperatures approaching 0 degrees F. Otherwise a 5W30 and 15W30 flow the same at 25 F and up. But yes, the ZDDP has an effect on catalytic converters. They tend to clog them up over time.

 

[olds307 and 403]

I actually burnt 5W40 Rotella when my lower rad hose blew on my 403. Like 20 miles on it, wasn't impressed. Glad that Rotella holds up in race engines with stiff spring pressure. Our brand of 15w40 diesel oil, 1400 ppm at the time, stuck rings in my Olds 350, there can be drawbacks. Our new synthetic diesel oil has like 900 ppm ZDDP, conventional just over 1000 ppm with a bunch of moly. He could mix half Lucas Hot Rod oil and half cheap oil as possible to save money if he is worried and trying to save a penny. Myself, I got some free SP rated 5W30 and 10W30 oil to break in my expensive motor. We get the occasional container that has a compromised seal, so we can't sell it. It will stay in the motor a very short time. I will discuss oil with Mark, among other things for this build. I have no problem paying $10 per liter for quality oil for this motor but this won't be a stock 305.

 

[bracketchev1221]

I actually burnt 5W40 Rotella when my lower rad hose blew on my 403. Like 20 miles on it, wasn't impressed. Glad that Rotella holds up in race engines with stiff spring pressure. Our brand of 15w40 diesel oil, 1400 ppm at the time, stuck rings in my Olds 350, there can be drawbacks. Our new synthetic diesel oil has like 900 ppm ZDDP, conventional just over 1000 ppm with a bunch of moly. He could mix half Lucas Hot Rod oil and half cheap oil as possible to save money if he is worried and trying to save a penny. Myself, I got some free SP rated 5W30 and 10W30 oil to break in my expensive motor. We get the occasional container that has a compromised seal, so we can't sell it. It will stay in the motor a very short time. I will discuss oil with Mark, among other things for this build. I have no problem paying $10 per liter for quality oil for this motor but this won't be a stock 305.

Not sure what caused stuck rings in your engine but I’ve also run rotella in my 76 Malibu with a stock 305, my 2006 suburban with the 8.1, the 70 ss nova with the 450 hp 355 and the Malibu with the 229 v6.