[quote]Not trying to steal the microphone from EB, but I have lots of experience with SYN lubes.....Overall, they are better.
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>>>*Heck, I invite comment, the whole point of starting the thread. GOOD tech piece, Keith!

*Synthetics are better simply because they will withstand more heat and loading. In most situations, regular Dino oil is more than adequate. In my Motor Home and Corvette, yep, synthetic. In my Camaro, good old valvoline 10W-30W. Same with the ranch rigs, *Yotas, good old Dino oil.

The BIG word in there is "balance", that is right on and it is the key. Too much pressure just robs power and heats the oil, not enough creates spectacular demonstrations of mechanical force.

Both can cause the same end result...Big cloud of smoke....

I do mildly disagree on one small point, once we had some really GOOD crankshafts to work with, we started to REDUCE crankpin diameter. We had plenty of strength, and reduction in size reduced bearing surface speeds, the difference between the surface of the shaft and the surface of the bearing was lower. This lowered friction, reduced heat buildup from hydraulics, and reduced the amount of pressure required. That meant more power left over to use to go fast.

Towards the end we had a Smallblock with a wet sump that we couldn't get the oil above 180 degrees on a hot day. Well, that one was a tiny Chevy V-8 (it had Toyota pistons, long story...) 3.1" stroke by 3.50" bore, yep..20R..In a 1980 267" V-8 case....The rod journals were only 1.970", mains spaced back to 2.970". (350 CFM 2BBL rules...)

Won the season with that one. You should have seen the tech official's faces when we got accused of cheating (again) and they pumped the engine for size, everybody else had a 355"....heehee...*EB

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One thing I will say is "oil volume" which is needed to cool the bearing faces... in order to get volume you need pressure, canÆt have one without the other and get the oil to where itÆs needs to go.... [/quote]

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>>>*I kinda think that the meaning of "volume" doesn't refer totally to the amount forced into the system, it also refers to the sump or storage capacity. The more volume we have not in use at any given time, the more chance for air bubbles to burst and heat to bleed off. Then we can press the larger and cooler volume into the system with effect.

Our enemy is always the hydraulic effect, the simple act of squeezing or forcing the oil to move excites the molecules, which is heat.

Our early attempts at racing engines were always to the loose or increased clearence side. Oil is easier to move through a larger space of course. Then along came synthetics, which will flow more readily in all situations.

Next was machining techniques, we could create dead true circles and surfaces of so close to perfection that almost no one could measure the flaws (which are always there, even today). Right behind was materials so strong we no longer needed 1000 gram connecting rods, I have installed rods that are under 500 grams and twice as strong as the best we had 20 years ago.

So crankpins now are smaller, reducing surface to surface speeds, clearences are closer with less restrictions, so pressures can be reduced. Even bearing width has been reduced, because the new materials can withstand the loading, this means less friction, too.

Weight is down, hydraulics is down, strength is up. Combine that with current knowledge of port shapes and combustion chamber shapes and we drag more power out of an engine than was possible just a decade ago.

Those gains are coming fast too. I would hazard a guess that even with my poor knowledge gains over the last decade or so, let me put it to use just 15 years ago and I could build an engine that would beat the best of the time, with ease!

And there are young folks out there way ahead of this old man.

*Wunnerful stuff...keeps me going. Things to learn...*EB

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A friend of mine works for a large race engine builder in L.A. Last time I saw him, he commented about the heat gun I was using to strip paint, laughed and said that the guys at work use the same kind to pre-heat the motors before start-up on the dyno because they run ZERO clearance on the main bearings. He said after the parts heat up that there's enough room for lubrication.


Really blew my mind <img src="/forums/images/graemlins/zombie.gif" alt="" />

>>*Yes, those are for qualifying engines, but not for endurance yet that I know of. they are even running 5-W oils in those. That is like WD-40 stuff...

New NASCAR rules make them run the engine they qualify though, so that may be out the window in the future.

*More stuff to learn, more tools to buy, more engines to build, more stuff to invent...

*Thinking this old man still has a few tricks to learn...maybe I will see 90 after all...*LOL**....*EB

Stickied or put in the archives?

I concur, off it goes! Good call.

Mike