Oil recommendation for a 1986 L98 Corvette, please

[A_Harman]

If it would help keep peace with your engine builder, the M1 0w40 would be OK. Now that you have gotten the flat tappets out of your engine, many Euro-spec oils would be fine. The German Castrol 0w30 I think would also be a reasonable choice for all-year use. The GF5 Valvoline Synpower 5w30 has some good specs.

Because motor oil base stocks have gotten better in the 25 years since your engine was originally built, 0w30's are now quite acceptable, 5w30's are the mainstream. I believe that 10w30's will soon be discontinued because they don't really offer much better protection than 5w30 (if you're just comparing synthetics).

What camshaft and intake manifold are you using?

 

[electrolover]

thats all fuel injected engines these days, its actually better because it burns off contaminates and keeps the oil clean.

you are going to want to change the first oil at 500 miles and maybe 1000 miles on the next then do 3k ocis for a while.
proper break in is extremely important, i would look for a GOOD break in oil or at LEAST add a zddp additve for the first couple ocis like comp cams break in add. cams are going flat all ovr the world, dont go cheap and loose your investment. you need at least 1200 ppm of zinc for regular operation and much higher for break in. also its a good idea to hold it at 3k rpms for 20 mins or so on the first start up to oil the cam really good and break it in right. trust me i have lost a few flat tappets in my time but i have had alot of success with these tips that came to me straight from comp cams

 

[A_Harman]

Originally Posted By: Finn

Last question on the subject:

Vettes run hot. Well, the thermostat is 195F so basically they run normal hot. Would you run short oil change intervals with mineral oil such as 5W-30 Pennzoil in it or would you still prefer semi or full synth?


The higher coolant temperature might actually help the oil come up to temperature more quickly and stay at a higher temperature more of the time. This would help oil life by boiling the water out of it, reducing the formation of acids. Short, slow trips where the oil doesn't get above 155F are what hurts oil life and causes sludge. Since I have used Castrol GTX in the Corvette for 18 of the 20 years that I have owned it, I can't really say anything bad about conventional oils. The GTX performed OK when I was doing up to 20 track days a year in the 1990's. Unfortunately, I can't remember what my change intervals were, between 3 and 5k miles. Basically I switched to Mobil 1 last year because I wanted to just keep one kind of oil around for my Camaro and Corvette.

 

[Finn]

Thanks, guys.

Crank is Scat forged 4340 std weight 435050L, rods Scat forged std weight 6600021SA H-beams with ARP 2000 7/16" bolts and pistons Wiseco Pro Tru PT017H3.

Cam is Crane 109671 ie. HR-216/339-25-12.90 IG

Basic Operating RPM Range 1,600-5,800
Duration at 050 inch Lift 216/224
Advertised Duration 284/292
Lift with 1.5 Ratio 0.509 int./0.528 exh.
Lobe Separation (degrees) 112

Intake is still a bit open matter but I'm leaning towards FIRST intake. http://www.firstfuelinjection.com/

It's like TPI but flows waaaay more.

 

[A_Harman]

With that cam and intake, I think you would have peak power at ~5400rpm, maybe a little less because of the large displacement. My engine is still a 350, and has a hydraulic roller with 222 effective duration, and an Accel Superram intake with headers. The heads are AFR 190cc's, and it has 10.8 compression ratio. It makes peak power at ~5800 rpm.

 

[Finn]

That must be a very, very nice engine to run. Must pull from very low rpm with that Superram. John Lingenfelter was genious of a man.

I was originally going to get a Superram along LPE 211/219 cam but then I realized that they didn't make the manifold any more. I was not keen in paying 1000 bucks for a used Superram so I looked elsewhere and found the FIRST. Everybody tells me to get instead Miniram but I don't want high rpms just low end grunt. And lots of it.

 

[SteveSRT8]

John L was the KING of torque.

 

[electrolover]

Originally Posted By: Finn
That must be a very, very nice engine to run. Must pull from very low rpm with that Superram. John Lingenfelter was genious of a man.

I was originally going to get a Superram along LPE 211/219 cam but then I realized that they didn't make the manifold any more. I was not keen in paying 1000 bucks for a used Superram so I looked elsewhere and found the FIRST. Everybody tells me to get instead Miniram but I don't want high rpms just low end grunt. And lots of it.

you should have PLENTY

 

[Finn]

Right. Had the engine broken in and run in dyno yesterday. The mild 383" made 507 lb-ft@3900 and 461 hp@5500 rpm. Which is nice.

The builder (30+ years of engine building expertise) uses Pennzoil oils but he said he has lately been testing this Quaker State, too. He said he suspects that it is the same product as Pennzoil GT Performance 20W-50. Any opinions on this matter? Engine was broken in with this Quaker State Performance Mineral Racing 20W-50.

 

[Merkava_4]

Most engine builders know what works in the engines they build. If he recommends a 20W-50, then in my opinion, that's what you should use. I can't understand why everybody is recommending a fuel economy 5W-30 for a built up 383. You gonna try to get 40 mpg out of that? I'd be more concerned with preventing metal to metal contact if it were my expensive engine.

 

[Clevy]

I would use a 5w-40 diesel oil with a can of liqui-moly. Diesel oils are detergent rich and tend to clean so well there isn't much film left on at start-up but with the rpms I am sure that motor sees a diesel oil has less tendency to shear with keeps it in grade. I use rotella t-6 5w-40 in everything I own. For the price it can't be beat. And the liqui-moly is key for protection at start up.

 

[45ACP]

Originally Posted By: Finn
Hello!

As it happens I have the old flat tappet L98 on the floor and a master builder is building me a mild 383" with forged Scat crank and rods, forged Wiseco pistons and AFR 180 heads. This is built on 87-> roller cam block so no more worrying about the lobes. The engine will be mild ie. 350...375 hp but with 475...500 lb-ft.

My question is as follows:

I have noticed that when the power levels rise from the original on built motors also viscosities people use tend to rise. Is there any need for this as the clearances are the same? Several of my buddies seen to run 5...10W-40 or even 15W-50 in this type of built "modernish" late 80s to mid 90s small block Vettes. Is there any need for this or would they do just fine with a quality 5W-30 viscosity oil?

I'm a bit puzzled as the builder said he'd run this new engine with 20W-50 Pennzoil GT.


Thats a nice car. The builder liked 20W-50 because he felt it would protect those cams. And it probably will. He isnt "wrong," just old school. Nothing wrong with that. Could even put 5W-50 in there. 0W-50 is.. too much cost. Again, thats why i recommend 0W-40, its virtually the same oil and maybe even a little better!

May i recommend a RL 0W-40 for this car. Sweet ride!

40-weight Group V RL (yeah i know but RL is good oil i should point out primarily why) should/may help woith consumption, and RL seems a good choice. Moly for months, too.

My biggest question is if you need ANY additional ZDDP in the oil, and if so, how much of that additive to put in.

I seek a car like yours.

Quote:
Most engine builders know what works in the engines they build. If he recommends a 20W-50, then in my opinion, that's what you should use. I can't understand why everybody is recommending a fuel economy 5W-30 for a built up 383. You gonna try to get 40 mpg out of that? I'd be more concerned with preventing metal to metal contact if it were my expensive engine.


Very well said. +1!

Some engines do well on 5W-020 or 0W-30, but this engine has needs that disqualify it from most lighter grades, including those except for MAYBE GC, MAYBE. Merkava is right, its not a Toyota Prius. You can have "thinner oil" but it still needs to be as thick as necessary.

GC or better, 0W-40 is my pick and some say 5W-40, thats a good grade too.

RL 0W-40 gets my vote, all things considered. It is a VERY good oil. M1 0W-40 if you dont feel like going the mail order route.

M1 makes a 5W-50 too.. could use that.. instead of 20W-50. The W number isnt hurting you..

 

[SteveSRT8]

Actually M1 makes a real nice 15w-50 that works well in motors with the enlarged clearances many builders like. M1 0w-40 is a little on the thinner side of most 40's.

I own a stroker small block with enough machine work to make anyone wince at the cost. I run Amsoil Dominator in it on track days.

 

[Finn]

Right.

Thanks for the suggestions and comments. Much appreciate your advises.

I was a bit tired this morning when I typed my question and left the important bit out: the clearances in this engine are not the modern tight clearances used with for example 0/5W-30 in an LT-1 or LS engines. Also the oil pressure was not at all too high with the QS 20W-50 when dynoed.

Considering builder's advise of mineral 20W-50 I have a couple of alternatives available. For me they all look alike as products. Do any stand out as better product?

All four first products cost about the same. Brad Penn here costs over twice as much. Price on the other hand is not deciding factor here.

 

[dailydriver]

Out of those, either the Brad Penn, or the VR1 would be my first choices, but you could not go too wrong with ANY of them.

 

[A_Harman]

Since your engine has a roller cam, you don't need a high zddp oil. (But OK if you use one; as long as you're not worried about the catalytic converter. The one on my Corvette came off and it was impossible to put back on.

)

I would pick M1 15w50 over Brad Penn 20w50 if they are close to the same price.

 

[Merkava_4]

The Valvoline Durablend 20W-50 that you have posted would be my choice.

 

[Finn]

If anyone's interested the dyno video of my 383 is here:

[URL]http://www.youtube.com/watch?v=GYcObg7AG2o[/URL]

 

[SteveSRT8]

Very nice.

Note that my Amsoil recommendation is also available in 15w-50.

As long as you're not at the road course tracking the car any of the above oils are just fine.

 

[aquariuscsm]

Originally Posted By: Finn
If anyone's interested the dyno video of my 383 is here:

[URL]http://www.youtube.com/watch?v=GYcObg7AG2o[/URL]


That video is AWESOME!!!!!!!!!!!!!!!!!!!!

My oil vote,Pennzoil GT,Quaker State,or Valvoline Durablend 20W50.