Had a 383 built for my 79 and the builder said i should use racing motor oil. Anyone have any suggestions on brands/weights?

Thanks!
Gary

 

Hard to say without knowing what components your engine uses.

There's a detailed oil discussion here: http://forums.corvetteforum.com/c3-t...highlight=zddp

 

You'd think any engine builder worth his weight in camshafts would go the extra mile and specify a specific brand and weight not just spew out the hackneyed, use racing motor oil. Unless he's named bubba.

 

Billa did a lengthy survey/discussion here recently worthy of a "search". It's way more complicated than I ever imagined & requires some study to get it right. Motor oils have changed a lot over the years thanks to gov't. regulations & the needs of newer engines. Flat tappet cam or roller cam makes a difference in your choices. Do the search. Many of these guys are extremely knowledgeable & they don't care much for repeating themselves & understandably so. I recently did a flat tappet build. I ordered the Brad Penn breakin oil- ran the motor for 20 min. at 2000-2500 RPM's- then changed the oil & filter using Brad Penn 20-50. There are guidelines to follow even for what oil is best. You are wise to consult with the gurus on this sight. The info on acceptable oils may be on a sticky at the beginning of this site. If not do a quick search & choose from the list Billa compiled. Why take the chance right? You just shelled out a lot of money & time- don't get in a hurry & blow it now. The better oils for breakin are often harder to find & often not on the shelf where you normally shop or -as you will find in the search- others feel the oil you need is right in front of you. Take your time & good luck. lonebull

 

The reason your builder recommends race oil, is they contain higher zinc levels for better flat tappet lubrication. Most modern motor oils have reduced zinc content, as most engines are now roller tappet, and possible zinc blow by into the cat converters, isn't a healthy thing. For what you're doing, don't think you can go wrong with anything offered in the Valvoline VR1 line.

 

He did make a specific recommendation, but I can't remember what he said....I can call him monday, but wanted to do it today and wasn't sure if there was a critical difference in brands. BTW, he is a true professional, but dealing with an amateur, me. :")

Thanks all for your info. I'll wait until I can talk with him.

Gary

 

Very good answer from a very knowledgeable individual

 

If your build used roller lifters, you probably would be best to use a good [full] synthetic oil. If you have flat tappets, follow the advice above.

[corrected as noted by following post]

 

7T1, I think you meant to say roller lifters? If the builder updated to a roller cam and lifters, the oiling issue is certainly not as critical. Just about any modern oil will work with rollers, but flat tappets still cause a lot of discussion.

Ralph.

 

If you are running a 15W-40 or a 20W-50 drop down to a 10W-40 or a 10W-30. Correct ZDDP if your running flat tappet. Synthetic oil has 5x higher film strength in the same viscocity as convetional so if your running a thick conventional oil for better protection your theory is flawed since you will bypass the filter more. Film strength protects the metal parts lubricated in the engine from making direct contact with each other, not oil pressure. More volume of flow will cool parts better. Thinner oil flows better thicker oil doesn't. 10 PSI per 1000 RPM when at operating temperature is the rule of thumb. Over that is not an advantage but a detriment. Adjust viscocity to reach the goal of 40 PSI @ 4000 RPM. The additive package in racing oils limits the miles between changes. If you run racing oil look at 500 miles between changes. It is not designed for a street car. I would use a good quality synthetic with the proper ZDDP level for my cam type. JMHO.

 

This article is an absolute must read.

http://ferrarichat.com/forum/faq.php...tor_oil_basics




I no longer run 10W-30 oil in any of my vehicles.

 

WoW after reading most of that I'm sort of wondering if a oil heater in the oil pan would help the 90% wear problem at start up.

 

MUST READ!!! Great article and pretty much spot on, especially the points made on the synthetics and the advantages in cold start and the viscocity modifiers not needed. There is a built in resistance in the corvette community to running thinner oils or synthetics. Don't know why. Even the great engine builders many times specify a 20W-50, Don't know why. The above artice is very informative. I do know the engine clearances will affect the oil pressure and modern high performance engines have tighter clearances than years past and many builds of chevy V8's. I think the main reason many recommend 20W-50 is the film strength. It is much higher than a 5W-30 but if you use a true synthetic this point is totally invalid. The disadvantages of this thinking far outweigh the advantages. One of the problems for many corvette owners would be to find a 0W-20, 0W-30 or 0W-40 oil with the proper ZDDP levels for a flat tappet engine. My recommendation is usually 10W-40 AMO Amsoil. It is a true synthetic with much better cold start viscocity protection than a 10W-40 conventional oil. The Amsoil Z-Rod 10W-30 is a new product and would be a better choice in most instances as long as your operating temperature higher rpm oil pressure don't drop below the 10 PSI per 1000 RPM you are looking for.

 

My new Honda Civic driver recommends 0-20. How's that grab ya?

Ralph.

 

This is the trend for new car manufacturers. The fuel mileage impovement is signifigant and the internal clearances and oil pumps are designed to run these viscocity oils at safe oil pressures. Many chevy V8's won't. The loading on the bearings are greatly reduced compared to a 400-500 hp V8. The article deals with viscocity only. Film strength also needs to be factored in and film strength does drop with a reduction in viscocity. The difference in cold start viscocity in the same weight oil when comparing conventional vs true synthetic oil is what should really be the biggest factor. I use true synthetics in all my vehicles. Many oils labeled "synthetic" are not true synthetics but ultra processed conventional oils that share some but not all characteristics with true synthetics. Amsoil and Royal Purple are the only 2 oils I know of that are true synthetics made with no group 3 base stocks, all group 4 and group 5. All others that can legally call themselves synthetic are primarely group 3 base stocks with group 4 and group 5 additives.

 

63mako, I have been using Mobil 1 ( 5W-40) twice a year with about 2K miles between changes. I am running a small cam .450 lift, on Vortec heads with standard springs.

Am I changing my oil too often?

Mobil 1 Turbo Diesel Truck 5W-40 1100 Phos, 1200 Zink
Fully synthetic Most diesel applications Applications requiring higher phosphorus (ZDDP), including engines with diesel particulate filters.
CJ-4, CI-4, CI-4 Plus, SM, SL

 

My 07 Grand Cherokee (4.7L V8) owner's manual specifies 5W-20 synthetic.

 

This is the only analysis I can find on it.
http://www.bobistheoilguy.com/forums...77#Post1939477
It has a diesel additive package which usually means much higher levels of detergents and dispersants which fight for the same space as the ZDDP reducing its ability to protect the cam lifter interface. This is basicly a SL oil with more detergent and dispersants for soot reduction. This particular diesel oil is actually not super high in detergents like some but as a rule I wouldn't use a diesel oil in my gasoline engine. Your cam is mild with low spring pressures so probably no harm done but I would use an oil designed specifically for gasoline engines and flat tappet cams. You do know Mobil was the company that filed a false advertising suit against castrol about using group 3 basestocks and labeling it synthetic in 1999. They lost the suit and now you have valvoline, pennsoil, castrol, and others using them and calling it "full synthetic". BTW Mobil 1 now does the same thing since the Group 4 and group 5 base stocks are more expensive and they can now get away with it. This is not allowed in europe. If you buy a fully synthetic oil there it is Group 4 or higher base stock (no petroleum products) and the formulations and additive packages for the european market are different even though the package and name may be exactly the same.
How would the yearly cost work out buying the Amsoil Z rod 10W-30 and changing it once every spring?
Here is an analysis on the Zrod 10W-30. Both are from the same lab.
http://www.bobistheoilguy.com/forums...45#Post2426045

 

"Race" oils usually don't have detergents, so they require very short change intervals (<500 miles)

I wouldn't bother with any oil with a weight greater than 30wt., unless you road race and your oil temps are 280F or higher.

 

Here is the ZROD 10w30 63Mako mentions above:

AMSOIL Z-ROD 10w30 Synthetic Motor Oil (Product Code ZRTQT)
(zinc – 1440 ppm, phosphorus 1320 ppm)

If any chose to go this route, I'd be more than happy to ensure you get it at my dealer wholesale, about 25% under retail, via the AMSOIL Preferred Customer Program. Drop me a PM if interested.