[hojs69]

https://www.hotrodders.com/threads/p...-build.179825/

See 4 - 5 posts down.

I ran across an old post on another forum from the late WDCreech (2010) where he was mentioning he was running his engine up to 8,000 rpm. I thought that was quite impressive. Wrongly assumed it was a lower rpm endeavor.

[Steve C.]

Note his comment..... "Your biggest concern spinning a Pontiac for extended periods is going to be your oiling system."

Now this from the internet....

"Mean and maximum piston speeds are still valuable calculations for any engine builder making a change to a proven formula. Exceeding 5,000 fpm in mean piston speed should get your attention and prompt rethinking on parts selection. Excessive piston speed can lead to inconsistent lubrication of the cylinder wall, and in some situations the piston will actually accelerate faster than the flame front during combustion. While the former can cause parts failure, the latter is lost horsepower."

5-inch stroke at 8000 rpm = 6,667 ft/min

Here's an interesting tid bit from Car Craft.....

"Think about rpm for a minute. That's revolutions per minute, referring to an engine's crankshaft speed. At 6,000 rpm, that's 100 revolutions per second, or one revolution every hundreth of a second. If you've got a 4.250-inch stroke, each piston is traveling 70,8333 feet per second at 6,000 rpm, which is about 48 mph, and it has to change direction twice every hundreth of a second. And you wonder why stuff breaks."

With a 4.500-inch stroke a piston will be traveling 75 feet per second at 6000 rpm.

Now consider the 5-inch stroke at 8000 rpm !


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[Dragncar]

Langer runs a Melling pump on his 550+" ci, 8000+ + RPM Pontiac.
What is the point of a Titan oil pump for 99% of us if that guy does not need one ?

[Steve C.]

For the 1 % that feel the need.

High-flow oil delivery and prevents cavitation at higher RPM.


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[steve25]

Airated oil is maybe even more damaging to a motor then not enough oil.

[Dragncar]

Yes, and exactly why I enlarged the pickup dia in my Melling pump to around .900 inch.
A Luhn pump, based on the Melling pump will prevent cavitation. They are the folks who told me how to modify my pump and it works fantastic.

[Stan Weiss]

Originally Posted by Dragncar

Langer runs a Melling pump on his 550+" ci, 8000+ + RPM Pontiac.
What is the point of a Titan oil pump for 99% of us if that guy does not need one ?

I don't know about today. But 10 or so years ago. 565 ci, 4.6" stroke, 1290 hp @ 8300

Stan

[Steve C.]

Of interest. Not Pontiac specific but here they mention cavitation....

"While most applications – whether stock or performance – use a wet sump system, it should be noted that they have some rpm limitations. There is a physical limit related to rpm on a wet sump, where once that threshold has been crossed, the gears or rotor sets can no longer continue filling with oil, and cavitation will begin. This happens typically somewhere between 6,500 and 7,500 rpm, but may occur at lower or higher rpm levels."

https://www.enginebuildermag.com/202...umps-and-pans/


Mark at Luhn used a pick up tube simlar to this:

Oil Pump Pick up tube (15/16) for Ford Modular Engine 4.6 / 5.4
https://www.modularmotorsportsracing...roducts_id=381

The early Luhn design pick-up was based on the oil pump study by Ford and Aston Martin and had a proper oil inlet tube diameter for high performance use at high rpm.
It was similar to the Ford Mustang Cobra Pickup

As Dragcar did, we bought one similar in the Ford system for our own use and cut it to length.


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[Dragncar]

And you have to remember, atmospheric pressure is what pushes the oil into the pump. When you run a vacuum pump there is less of it in your crank case to get the oil in your pump.
The new engine got a V pump and that is why I was so worried about the inlet dia on the low pressure side.
Lot of work. I would just buy a Luhn now.

[Steve C.]

Within the link in the first post, keep in mind what the fellows goal is...

"My concept is an engine that'll win me the coveted "Red Hat" at Bonneville and get me into the 200 mph club with my dream car, a 1979 Pontiac Trans Am."

This is not a quarter mile race situation. With that in mind there could, or should, be a difference in a discussion regarding proper oil control.

As alluded to in the post made by WDCreech when he brings up the subject of "extended periods".....

"Your biggest concern spinning a Pontiac for extended periods is going to be your oiling system. The stock type gear to gear oil pump just doesn't have the volume to do the job satisfactorly. I have two Pontiac engines and after years of running stock type pumps and bearing failures, I have switched to a Titan pump on my 474 (4.25" stroke) and a Peterson dry sump on my 606, (5.00" stroke) which sees over 8000 rpm, but I have GMP aluminum rods and light weight JE pistons. With over 150 passes on the 474, the bearings were near perfect, but it only turn about 7600. Remember to pay close attention to detail when you build your engine."


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[Steve C.]

Related to the subject of a Vacuum pump.

Our engine in John's Fairmont in my signature made 920 Hp at 7000 RPM on the dyno. It is a race only application and it runs nitrous at the track and built for 1/8 mile heads up racing.

In short... We use a vacuum pump with a blueprinted Melling 80 lb pump (I don't recall the details on it). Also a standard Canton oil pan and pick up.
For oil control it uses a crank scraper and oil restrictors for the top end. If memory serves me right with the 'proper' converter it is typically shifted at 7200-7400 rpm.

However on one occasion we tried a different converter that turned out to be way too loose for the application with excessive rpm. So lose that on the first pass we found the oil catch can that holds one quart was completely full of oil !
With this in mind and not wanting to risk damage the car went back on the trailer.

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