Recommendations for 500 HP Olds 455

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crashtech

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My brain is numb from looking at so many PDS's and forum threads. I need some expert advice on selection of motor oil.

1. Vehicle:
1966 Olds F-85, 455 V8, 538HP, 100HP nitrous plate

2. What your owner's manual says:
N/A

3. Where you live:
Southern Idaho

4. How you drive:
Cruising, punctuated by some very hard abuse.

5. What your daily drive is like:
Weekends and/or fair weather, and driven to a dragstrip about 50 miles away for 1/4 mile racing.

6. Whether your car has any known problems:
Oil clearances are wide, on the order of .0035-.004". This is a necessity on this engine at current horsepower levels.

Engine was broken in with Joe Gibbs BR 15W-50, oil pressure was good with this oil. it has not been run since the dyno. The BR is still in the crankcase.

This may belong in the racing oil selection, however I want to run a street oil if possible. There may be situations where a cold (sub-freezing) start is necessary.

I'd love suggestions!
 
Get a quality 15W-40 HDEO, like Rotella or Chevron Delo, and change it fairly often. Clean, fresh oil will be this engine's best friend.

Sounds like a beauty of a car - would LOVE to see some pics!
 
I worked with a guy that had a 70s Buick 400-something "built loose" and M1 red cap 15w50 worked for him with sub freezing starts.

I guess you still have a choke and that stuff for a dose of streetability. You could get a magnetic oil pan heater for those cold starts and not compromise your oil.

Diesels running 15w are cold-starting in the positive single digit temps, so it's something you can "get away with."
 
I appreciate all the quick responses! I planned on using a 15W-40 or 15W-50 synthetic oil, but my concern after extensive reading here on BITOG was the fact that these oils tend to be pretty thick at low temperatures. I wanted to be sure I should not be trying something like a 5W-40, not knowing what the impact on oil pressure would be on the high and hot end. I'm not expecting this engine to ever see extreme oil temps, would it be wise to install an oil temp gauge? RPMs are expected to be a bit high with highway driving, though eventually some sort of overdrive is desired.

I wish the car was picture worthy, it is in primer and I need to get it running as it is in the way. I may post some in progress pics, but it's in rather embarrassing shape right now.

P.S.
I built this engine!
 
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thanks for your post!!! now i cant get that country song 455 Rocket out of my head!! lol
 
Wow!!! wide bearing clearances . There are several things to consider. First, syn oil isn't really what you need in the engine . Why? I would imagine the forged pistons are set up on the loose side so between warm up a high performance jetting in the carb or FI setup there will be a bit of feul dilution add to that when the nitrous is used even more so. If this were a roadrace type of car then syn would do good as the oil temps will be high for a long period of time. As a hotrod and drag car you can't put you foot into it long enough to overheat the oil. Anyway you will be changing the oil because of blowby before you ever gain an ounce of advantage from the expensive syn oil {hint you should change out the oil often} . Too cold? Run a pan heater to warm up the oil before starting that beast. I am not an Olds expert but I built a bunch of big block chevy for my Flatbottom boat and basically they are drag race preped engines.
 
Yes, the clearances are wide. After running them closer (unsuccessfully) I have followed the advice of a reputable Olds builder who has experience at these horsepower levels. Really the problem was getting the machinists to comply with my directives. This time there was no glitter in the oil on the dyno (third time being the charm). Olds engines are not really meant to take this kind of power. Without adding a main girdle I would be asking for trouble if the car was ever raced at sea level (640HP or so).

So, dino oil and a pan heater, then? In a conventional oil I would gravitate toward a 15W-40, what would be recommended?
 
IF this engine will see any kind of cold starts, go with a 5W-40 - Rotella T6, M1 TDT, ...etc.....
 
Accurate oil temp and oil psi gauges are always wise. Upgraded oiling system?

I always recommend synthetic until all data proves it not needed. 0w50, 5w50, 10w60, 15w50, 10w50, 20w50, 0w40, 5w40, 10w40, and 15w40 "full synthetics".... are easy choices.
 
just curious, for you guys that say "change oil often", how often are we talking? X amount of 1/4 mile runs? X amount of miles? X amount of WOT pulls with the Nitrous?
 
FWIW, we tend to run 5w40/15w40-5w50/15w50/20w50 in 302's at that power level (Mustang guys).

I know two guys with stock-bottomed 302's at that power level that I know the oil type of; one makes 525RWHP, the other makes 534RWHP (610 and 625HP flywheel approximately).

IIRC, the one guy who daily drives his on the street during the summer uses Mobil 1 15w50 (used to run 5w50 when it was available). The other guys uses Castrol Syntec 5w50.

Both cars have been reliable and without any mechanical issues for years running like this. And both have made quite a number of drag strip passes.
 
Oil pump is a Melling HV, believe it or not that is the extent of the mods. But the engine makes max HP at a tame 5800 RPM, so at least it's got that going for it.

I'm not opposed to synthetic, though as previously mentioned I will not receive the benefit of long change intervals. The fact that synthetics have lower viscosity when cold is a real positive in my view.

So it's been narrowed down to 10 different viscosities, and we still need to make it to brand selection? This is going to be tougher than I thought.

I don't want to run any more viscosity than necessary. It takes horsepower to run thick oil. I think I want to avoid 60 grade oil.

I have heard that some of the oils with really wide spreads, 0W-50 for example, should be avoided since this is accomplished with additives and viscosity could break down unexpectedly.

So far the recommendations have been pretty diverse. I guess that is to be expected on an Internet forum, but still, I hope to start seeing some kind of consensus...
 
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I didn't see this before my last reply. I think this is useful information, thank you!
Originally Posted By: OVERK1LL
FWIW, we tend to run 5w40/15w40-5w50/15w50/20w50 in 302's at that power level (Mustang guys).

I know two guys with stock-bottomed 302's at that power level that I know the oil type of; one makes 525RWHP, the other makes 534RWHP (610 and 625HP flywheel approximately).

IIRC, the one guy who daily drives his on the street during the summer uses Mobil 1 15w50 (used to run 5w50 when it was available). The other guys uses Castrol Syntec 5w50.

Both cars have been reliable and without any mechanical issues for years running like this. And both have made quite a number of drag strip passes.

Any opinion on the Mobil 1 15W-50 vs the Syntec 5W-50?
 
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You are very welcome. The 2nd car ran on "Pinks All-out" a couple years ago. It is a blue '82 Capri RS with an '89 5.0L, H/C/I and a Vortec S-Trim. Engine is backed by a C4. Car went 10.3@12?Mph running out of gear (had 3.55's in it at the time, now has 3.27's).

Owner is a good friend of mine, and I've got a lot of parts for my car off him over the years.

Probably a toss-up between the two oils. I know the one run on M1 has a lot more miles on it if that helps? And at least as many, if not more drag-strip passes under its belt.
 
With those extra wide bearing clearances, you need a thick oil when hot.
BTW, high HP does not mean you need wide clearances.
.004" is as high and wide as I have heard for rebuild specs.
You need to overcome this deficiency in your build.
 
Originally Posted By: mechtech2
With those extra wide bearing clearances, you need a thick oil when hot.
BTW, high HP does not mean you need wide clearances.
.004" is as high and wide as I have heard for rebuild specs.
You need to overcome this deficiency in your build.


its very necessary for ahigh rpm engin4e to be loose otherwise it will take out the bearings unless your a millionaire and have billet everything. at high rpms things distort and thats why engine builders figured out race motors last longer loose.
there is no deficiency!!!!
 
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