Oddball engine project; which oil to use?

[A_Harman]

Hello All,

I have been working on hotrodding a GMC 478 V6 that I got out of a 1968 dump truck. I'm planning on installing the engine in my '72 GMC shortbed pickup for saturday night cruising and the occasional hard run through the gears. I'm not planning to use the engine for towing or heavy hauling.

Here are some specs:
5.125 original bore, bored to 5.185
3.86 original stroke, stroked to 4.120
The new displacement is 522.
Compression ratio 9:1.
Forged Arias pistons.
Billet steel solid flat tappet cam
DLC coated lifters, .990" dia.
290 pounds valve spring open load
OE cam drive; helical spur gear
Duramax diesel rod bearings, 2.477" dia.
OE main bearings, 3.125" dia.
Rocker arms: needle roller bearing pivots, roller tips.
Engine will be converted to EFI of some sort.
5500 max rpm, aiming for 500hp @5000 rpm.

Because of the highly loaded flat tappet cam, I don't think I can use most SM-spec oils due to the low ZDDP content.

I have been considering a couple of possibilities for oil:
1. Valvoline VR1 racing oil owing to its high ZDDP and easy availability. I would mix the 10W-30 and 20W-50 grades to get something like a ??W-40.
2. Mobil 1 TDT. Good wear resistance, but expensive.

Would these be realistic choices? I'm open to suggestions and look forward to a thought-provoking discussion.

 

[Rouphis]

What about any good HDEO. Like DELO

-Rouphis

 

[d00df00d]

If you're using an xw-40, you don't have to worry as much about zinc content with API SM. The limits for xw-40 and up are higher than they are for xw-30.

Do you need something store-bought, or are you open to ordering it?

 

[rclint]

HDEO no doubt. I had a GMC V-6 of the era in a 1 ton dump truck. These engine just don't have any running power, they are built all on pulling torque. I have seen people hold the peddle to the floor with no load, and the engine just won't rev high enough to do any harm. They are a huge engine, and maybe you can hotrod one with some compression work, and a high performance cam if they make these things. Or you might even have the cam welded up, and ground down for a wilder profile, the pistons are huge for this engine.

I see you have done some work to alleviate some of the problems, but I still can' see it ever working from my experience with the engine. I'm not in any way downing your stuff, I'm talking about the one I had, but it drank gas, parts were hard to come by, and I did mention the power issue. I was amazed at this engine when looking at it, huge heads.valve covers etc... A oddball to say the least, I ended up parting much of it out, and used the radiator on my hotrod ( a real copper rad, with huge volume)

 

[willix]

I just like this out of the box plan. The gigantic V6 is no doubt a smoothy with a very unique sound tone. I wish success w/pictures.

 

[addyguy]

That is just awesome - I've always wondered how it would work to use one of these huge industrial V-6's as the basis for a monster hot-rod engine...must involve a lot of custom pieces, eh?

Where would you get oversize pistons for an engine like this?

 

[ARCOgraphite]

Man you should go for a 8-71 blower and run 7.5 dishes

With the cam its all in the break in. - should break it in using lighter valve springs - but 300 open isnt crazy. No shade tree does correct break in, as its a PITA. JD plus 50 is a good oil, OTW use a Marine 15-40, Joe Gibbs, M1 4T bike oil or your fav 4T dino bike oil - they are typ SH/SJ just for the ZDDP and no energy conserving.

 

[eljefino]

I'd use any favorite HDEO 15w40 with a quart of that valvoline racing oil.

 

[A_Harman]

I'm wanting to use oils that are available at my local Meijer or Advance Auto, etc.

 

[salesrep]

20-50 racing oil. 15-40 diesel would be ok as well.
Don't skimp on cost. I'd lean towards a semi-syn or straight Petro with a strong add pack.

 

[A_Harman]

Originally Posted By: addyguy
That is just awesome - I've always wondered how it would work to use one of these huge industrial V-6's as the basis for a monster hot-rod engine...must involve a lot of custom pieces, eh?

Where would you get oversize pistons for an engine like this?


Yes, I got into this project wanting to do something different. The only thing left in the engine that's original is the block.

Arias can make pistons to order up to about a 5.5" bore, so almost anything is possible. BRC and Ross also make pistons to order.

 

[A_Harman]

Originally Posted By: rclint
HDEO no doubt. I had a GMC V-6 of the era in a 1 ton dump truck. These engine just don't have any running power, they are built all on pulling torque. I have seen people hold the peddle to the floor with no load, and the engine just won't rev high enough to do any harm. They are a huge engine, and maybe you can hotrod one with some compression work, and a high performance cam if they make these things. Or you might even have the cam welded up, and ground down for a wilder profile, the pistons are huge for this engine.

I see you have done some work to alleviate some of the problems, but I still can' see it ever working from my experience with the engine. I'm not in any way downing your stuff, I'm talking about the one I had, but it drank gas, parts were hard to come by, and I did mention the power issue. I was amazed at this engine when looking at it, huge heads.valve covers etc... A oddball to say the least, I ended up parting much of it out, and used the radiator on my hotrod ( a real copper rad, with huge volume)


I had many of the same thoughts when I started studying this series of engines, but as I learned more about them, I saw some potential. These engines were seriously strangled from the factory with small carburetors to limit the power, and the ones built for heavy trucks had hydraulic governors that made it impossible to get the 478's over 3400 rpm. Needless to say, those features are being lost in the rebuild.

To get the engine to breathe at 5000rpm, I had Comp Cams grind a steel billet cam for me, with about .600 lift, and 240 effective duration. The original cam was .450 lift, 192 duration. Also, I have had the cylinder heads fitted with bigger valves: 2.35" intake, 2.00" exhaust. The original heads had 2.25 int, and 1.88 exhaust valves, so they weren't exactly small to start with. However, my valve sizing calculation indicated that the 2.25 valve would get restrictive at about 4700 rpm, while the 2.35 valve gets to 5000.

 

[A_Harman]

Originally Posted By: willix
I just like this out of the box plan. The gigantic V6 is no doubt a smoothy with a very unique sound tone. I wish success w/pictures.


Thank you, willix.

I have pictures posted on Webshots, just do a search for 522 V6.

 

[jazeo]

While I give you a thumbs up on the cool-o-meter and it will certainly be a great conversation piece, I'm not sure if it will meet all your expectations. I was curious so I google'd it and their listing it's dry weight @925# way fat!!!!

 

[A_Harman]

Originally Posted By: jazeo
While I give you a thumbs up on the cool-o-meter and it will certainly be a great conversation piece, I'm not sure if it will meet all your expectations. I was curious so I google'd it and their listing it's dry weight @925# way fat!!!!


I'm not sure it will, either, but I have thought about the various issues in building the engine, and think I have stayed within bounds of good engineering practice.

The 925-lb engine weight is for the heavy-duty truck version with big alternator, brake air compressor, and truck flywheel housing. Putting on the light truck equivalents will pare some weight, but it will still be a big hunk of iron. Probably 800-850 lbs. This engine was from an era when they wouldn't even make oil filter housings out of aluminum!

 

[jazeo]

Originally Posted By: A_Harman
Originally Posted By: jazeo
While I give you a thumbs up on the cool-o-meter and it will certainly be a great conversation piece, I'm not sure if it will meet all your expectations. I was curious so I google'd it and their listing it's dry weight @925# way fat!!!!


I'm not sure it will, either, but I have thought about the various issues in building the engine, and think I have stayed within bounds of good engineering practice.

The 925-lb engine weight is for the heavy-duty truck version with big alternator, brake air compressor, and truck flywheel housing. Putting on the light truck equivalents will pare some weight, but it will still be a big hunk of iron. Probably 800-850 lbs. This engine was from an era when they wouldn't even make oil filter housings out of aluminum!


Well like I said it's way cool and I wish you luck with it. In regards to the oil, like others have said a good HDEO or Valvoline racing oil should work pretty well! Both are easy to buy and always in stock at your local auto parts store...

 

[rclint]

I hope I didn't come off as snubbing your work, as you are doing something that many don't have a clue about, you are working out your own designs etc, breakthrough so to speak on what YOU want.

I have pet peeves that I have to voice at times. Many people think the word billet is a worthy component substrate, when in fact it's raw substrate that is not suited to anything near metal for a cam, pistons etc. I will let you look up the word, I myself was also stunned at what billet aluminum, steel, stainless whatever really is, and the market has spun the word billet to make it something special when in fact it's worthless in just about everything in any end process... It really takes away from all of the heat treating, the alloy, and machine work that goes into components like cams, pistons, gun parts etc..

On edit I assume the word billet became such a big word as it differentiates a cast piece from a well billet piece, and people seen the opportunity for a quality difference.

ok ok a lazy search, but do search out the term...help educate others please.

"Before steel products are sold on the market, the steel must first be processed into more functional pieces. Raw steel cannot be of use while in its pure form, thus it has to be cast into shape. The freshly made steel, which is still in the form of a metal bar or rectangle, is called steel billet.

Uses
1. Billets, or ingots (as they sometimes referred to), are not of practical use until they have been formed into more functional shapes and sizes. While they have already been put in the furnace, they still require a series of shaping and molding procedures such as hot and cold working, milling and cutting before they are sold in hardware stores, or used for different applications. The unformed billets, however, can be used in striking currency such as coins and as reserves, similar to gold bars. "

 

[Shannow]

I reckon the concept is worthy of legend personally.

Too many people take the common road.

And in this concept, billet is what is appropriate, as I doubt that there are spare castings/forgings that would take a decent grind, and finding the axe handle inside a stump is probably the only way out.

 

[A_Harman]

Billet is a term that is overused in the performance aftermarket, and has become synonymous with "high-strength", and that's not always the case.

Strictly speaking, billet comes from either a continuous casting furnace or an ingot breakdown mill at a steel factory. At this point, the alloy chemistry is already determined, but the final shape is not. Products made from billet include rectangular and round bar, wire, and seamless tube or pipe. These geometries are all produced by passing the billet through rolling mills at high temperature (hot rolling). Out of the rolling mill, the steel is in a soft, low-strength condition that makes it easy to machine. Subsequent heat treatments can be done to increase strength in the final product.

When you're in the business of making one-off or small quantities of prototype components, machining from billet is the quicker, more cost-effective way to go. It would not be economical to pay for patterns to make a cast-iron cam to get one final piece. So what do you do? Grit your teeth and shell out the bucks to have one whittled, chip-by-chip, from bar.

My cam was turned from 8620 bar stock, and carburized to get wear resistance. Jesel made the cam blank, then shipped it to Comp Cams, who did the lobe roughing, heat treat, and final grind.

 

[CATERHAM]

First welcome to BITOG.

With a 925lb dry weight that's one heavy engine and certainly would have no track use applications.

Being the engineer that you are, if you haven't planned on installing oil pressure and oil temp gauges that's what I'd do.
This will enable you to fine tune precisely the oil's viscosity. Since the application is street use, I'm sure max' oil temp's will be low so a light 30wt is likely all you'll need, in fact I wouldn't be surprised if a 5W-20 dino wouldn't more than satisfy OP requirements.
As far as ZDDP levels are concerned, I'd choose the oil first then adjust to whatever level you feel you need with a ZDDP oil suppliment from Crane or Red Line.