Stock Eliminator secrets?

[The Iron Icon]

Thanks, looks like I have some weekend reading now.

[RDY4WAR]

Those “vent” holes in the LS mains you’re taking about were first used by GM 45 years ago on the 260 olds when they were chasing every last mpg they could get during the gas crunch era

It was to reduce pumping losses in the crankcase which helped free up power...and mpg

GM used that the following years in the 350 and 403 olds..the old wives tale that it was to reduce weight and casting costs is not true

There is a very detailed technical paper online that Chrysler paid some outside engineer to do on crankcase pumping loses and reductions down to cylinder to cylinder venting ...it even has the vent hole sizes being different for the Center 4 cylinders than the outer 4

I used a vented main webbed block in the 2008 and 2011 EMC for that exact reason...in 2008 I was torn down for a photo shoot and questioning...the holes where clearly visible,, but was never asked why they were there

Any idea where I could find a copy of that paper?

here it is. the conclusion for the vent passages between cylinders for cyl to cyl venting was to make the holes as large as possible and to promote ease of air exchange, smooth rounded edges and also not make the block weaker by doing so. the holes in the olds blocks are really quite large.

150+ pages which includes many other tests on reducing crankcase pumping losses

https://scholar.uwindsor.ca/cgi/viewcon ... ontext=etd

That is an extremely valuable resource. Thank you posting it.

[gmrocket]

Any idea where I could find a copy of that paper?

here it is. the conclusion for the vent passages between cylinders for cyl to cyl venting was to make the holes as large as possible and to promote ease of air exchange, smooth rounded edges and also not make the block weaker by doing so. the holes in the olds blocks are really quite large.

150+ pages which includes many other tests on reducing crankcase pumping losses

https://scholar.uwindsor.ca/cgi/viewcon ... ontext=etd

That is an extremely valuable resource. Thank you posting it.

you're welcome. there are some really interesting findings in that paper...like how on that small V6 the negative work(higher pumping losses) were on just one side of the engine, while there was positive pumping gains on the other,,,very slight. but on average it was negative pumping losses for the whole crankcase,,,one rear cylinder having the worst loss, front the least loss because its next to a larger open area due to the timing chain area etc.

then the three tests with vent holes of 25mm, 30mm and 35mm,,the bigger the better as it kept dropping the pumping losses as rpm increased

[Walter R. Malik]

here it is. the conclusion for the vent passages between cylinders for cyl to cyl venting was to make the holes as large as possible and to promote ease of air exchange, smooth rounded edges and also not make the block weaker by doing so. the holes in the olds blocks are really quite large.

150+ pages which includes many other tests on reducing crankcase pumping losses

https://scholar.uwindsor.ca/cgi/viewcon ... ontext=etd

That is an extremely valuable resource. Thank you posting it.

you're welcome. there are some really interesting findings in that paper...like how on that small V6 the negative work(higher pumping losses) were on just one side of the engine, while there was positive pumping gains on the other,,,very slight. but on average it was negative pumping losses for the whole crankcase,,,one rear cylinder having the worst loss, front the least loss because its next to a larger open area due to the timing chain area etc.

then the three tests with vent holes of 25mm, 30mm and 35mm,,the bigger the better as it kept dropping the pumping losses as rpm increased

Not allowable with a Stocker but, That is one of the reasons why the largest volume oil pan you can fit will help.

[RDY4WAR]

That is an extremely valuable resource. Thank you posting it.

you're welcome. there are some really interesting findings in that paper...like how on that small V6 the negative work(higher pumping losses) were on just one side of the engine, while there was positive pumping gains on the other,,,very slight. but on average it was negative pumping losses for the whole crankcase,,,one rear cylinder having the worst loss, front the least loss because its next to a larger open area due to the timing chain area etc.

then the three tests with vent holes of 25mm, 30mm and 35mm,,the bigger the better as it kept dropping the pumping losses as rpm increased

Not allowable with a Stocker but, That is one of the reasons why the largest volume oil pan you can fit will help.

I may be remembering it wrong, but I think Engine Masters compared a dragster pan to a rear sump car pan and found more power with the car pan.

[RDY4WAR]

I noticed the following line on page 57 from the paper linked above.

In any case, also a too low pressure inside the crankcase is not optimal for the engine
because below the crankcase, in normal wet sump engine, there is also the oil in the oil
pan; the oil property and motion will be affected by the too low pressure level, increasing
even more the splashing.

This seems odd to me as I figured the more you can scavenge the crankcase, the lower the crankcase pressure, the better with the only downside possibly being leaks with elastomer seals. I figured a lower crankcase pressure would make it that much easier for the oil to drop to the tank and out of the windage cloud. Maybe this will be explained further down as I keep reading. Any thoughts?

[gmrocket]

Stocker bottom end

What's the purpose of the holes in the bottom of the cyls? Something to do with crankcase venting?

equalize pressures that are developed
reed

Sort of

[gmrocket]

Stocker bottom end

Is this a pic of the bottom end of that chevelle stocker using the 305 bowtie GM block built by BES?

[EDC]

I may be remembering it wrong, but I think Engine Masters compared a dragster pan to a rear sump car pan and found more power with the car pan.

Weird...

I remember Lingenfelter saying he wanted to run a Corvette in Comp (or Super Stock) versus the typical Camaro because that chassis could run a full length oil pan and not just limited to a rear sump. The cross member issue.

Worth more power he said.

[tenxal]

In a traditional internal oil pump/wet sump application:

-Is it advantageous to pull a slight vacuum in the pan, if possible?
-Are there any detriments to doing this?
-Is some positive pressure in the crankcase ever a good thing?

[RDY4WAR]

I may be remembering it wrong, but I think Engine Masters compared a dragster pan to a rear sump car pan and found more power with the car pan.

Weird...

I remember Lingenfelter saying he wanted to run a Corvette in Comp (or Super Stock) versus the typical Camaro because that chassis could run a full length oil pan and not just limited to a rear sump. The cross member issue.

Worth more power he said.

That was episode 56. The Moroso car pan was worth +27 hp over the Milodon dragster pan. However, the Moroso pan had a kickout to it where as the Milodon pan did not. Moroso in blue, Milodon in red.

Engine Masters oil pan test.jpg

[dannobee]

The increased power came from the kickout and whatever they were running for a scraper and/or windage screen, not where the sump was. If legal in class, run the biggest kickout you can, and put a smaller starter on it and run an even bigger kickout.

[EDC]

Typical BS testing.

Let them try this dragster pan...

[steve cowan]

In a traditional internal oil pump/wet sump application:

-Is it advantageous to pull a slight vacuum in the pan, if possible?
-Are there any detriments to doing this?
-Is some positive pressure in the crankcase ever a good thing?

I thought for a while on these three questions,I doubt there is a simple answer...
I think vacuum in the crankcase would always be an advantage but not always achievable even with a vacuum pump as in more horsepower on the dyno.
The return for effort may be lost as in losing hp to turn a vac pump,depends on oil pan design as well.
Positive pressure i don't know but referring back to the picture of the 327 on dyno measuring blow by, shows where maybe equality ( if possible) of pressure in the engine might help by putting it upstairs in the valley area or valve covers and away from crankshaft.
I am wondering if the gauge measuring CFM or PSI for blow by ?? I can not tell by photo.
I kinda suspect there is a fair amount of oil restricted to the rockers even at the cost of valve spring life to stop oil from travelling back down to fall on rotating assembly but this is a uneducated guess on my part.
I think this is a excellent thread.

[1972ho]

A lot of some these things are not allowed on a stock eliminator engine no vacuum pumps,no big oil pans only a stock replacement no pan evacuation system.