Cummins 4BT & Diesel Conversions Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
179 Posts
Discussion Starter #1
Race cars run em . Some stock Dodge came with them and it was found to be the cheapest , fastest way to get more horsepower from your engine. That was before adding headers or going for a different carb . When I ran a 390 ford Fe block in my old 4x4 I tossed one in . police interceptor stuff.
Did Cummins ever use a windage tray ? Has any body considered running one or a scraper blade in their 4bt ?
What I am looking for is extra power that does not mess up the fuel milage . As an aside I sure wish someone would show us what happens on a dyno when exhaust pipe diameters are changed .

Bruce
 

·
Registered
Joined
·
3,391 Posts
It seems to me the functionality of a windage tray/crank scraper was directly related to rpm? That is, at 5k-6K rpm there's this huge wad of oil spinning around with the crank, causing major parasitic drag [you know, like a politician?]. At the lower diesel rpm's the usefulness is somewhat doubtful, but not to say it wouldn't help a wee bit, just not that much compared to a high reving gasser.
 

·
Registered
Joined
·
179 Posts
Discussion Starter #3
I considered that Jimmie

I used to have the RPM numbers and torque / horsepower gains for the Chrysler blocks . They are long gone. Ditto with the police interceptor stuff . But I do know that the FE block would come apart after 4500 RPM.
There may be some data out there someplace but until someone actually produces it or runs the new part on a dyno we have no idea as to the benefits or handycaps that a mod will provide to a 4BT.
In the long run I may build my own , but there may be better ways to improve power without messing the fuel milage.
 

·
Registered
Joined
·
3,391 Posts
Yeah, all my info is from Hi-Perf Dodges or Mopars. On engines that really spin up, like a 383 hi-po that can turn an easy 8,500 rpm it's a major improvement. Not a lot of help on a Slant Six 1bbl....

There's at least 2 different types, one a baffle that covers the whole top of pan and bottom of crank, with louvers in it for drain back, and another that's more similar to a blade scraper. The blade scraper has to be pretty stout steel because of the torque of spinning oil blob. I think the single wide one with louvers is the best bet.
 

·
Registered
Joined
·
137 Posts
I wouldn't bother. As stated, higher RPM applications will benefit a lot more... You're going to be seeing what, 3k on a 4bt???? I guess if you've got a rainy day or something. :D
 

·
Registered
Joined
·
3,391 Posts
Yeah, and a lot of guys have taken it even farther: knife edging the crank journals so they cut through the oil more easily. Actually that crank profile's not what causes the phenomenon. It's more like occlusion, where the spinning mass sucks up the oil, rather than it sticking to crank to form a progressively bigger glob.

Always important to consider what function splash oiling plays in a particular engine, regarding the lubrication of lower cylinder walls. A windage tray is going to effect that and on some engines that may not be a good thing. Don't know for sure regarding the Cummins, but I think it's a factor there?
 

·
Registered
Joined
·
1,462 Posts
But I do know that the FE block would come apart after 4500 RPM.
I ran a bunch of 'em. Never had a low end issue with an FE, actually, they're kinda notorius for having a pretty rock solid bottom end. The 427 SOHC ran piston speeds in NASCAR testing in the 60's that should have sent it back in time.

I had a windage tray on the FE in my truck. It didn't make a noticeable difference in mileage.
 

·
Registered
Joined
·
179 Posts
Discussion Starter #9
FE block

We would lose the bottom end around 4800 . it was an oiling issue . There was some tricks that helped cure that problem and 6500 and change seemed to be ok. The side oiler was pretty sweet. i tripped over one a year or so back for a grand . i did not want it but a buddy grabbed it pretty quick .

bruce
 

·
Registered
Joined
·
808 Posts
We would lose the bottom end around 4800 . it was an oiling issue . There was some tricks that helped cure that problem and 6500 and change seemed to be ok. The side oiler was pretty sweet. i tripped over one a year or so back for a grand . i did not want it but a buddy grabbed it pretty quick .

bruce
Ok, for , me living in the mountains under a rock, in the back of a cave, what the hell is a windage tray ? Now, I can tell you about squeezing maple trees ha ha

PAul
 

·
Registered
Joined
·
3,391 Posts
Well, Paul, it's like this: When the crank spins at hgh rpm on an engine the back side of the journals create a negative pressure area, much like taxes due to your income. Similarly that vacuum pulls up the oil out of the crankcase, like the IRS yanks up people's savings, and the oil forms a blob that travels along with the crank. It can be as much as 1/2 the pan's capacity in some circumstances. This adds the effect of additional weight to the crank and to a limited degrees causes a resistance to rotation, but very limited.

The other name for a windage tray is 'crank scraper' because that's what it does. It fits on the top of oil pan and is cut precisely to the contours of the crank throws. They scrape the blob of oil from the crank and thereby remove the parasitic drag. Usually they are a louvered tray to encourage drainback of what little oil still follows crank.

The knife-edged crank journals are supposed to help too, but they do little and then only on real hi-revving engines. Because this oil mass is a function of vacuum behind the throws the knife edging is bordering on silliness except in allowing the crank throw to enter the oil reservoir with less reistance.
 

·
Registered
Joined
·
179 Posts
Discussion Starter #13
paul there is also another theory

If you are in a pool and wip your arm in an arc all the water will travel off your fingers in a stream . Advertising has used this effect with womens hair for many years and most of us have seen this.. In an engine the same effect happens but the stream contacts the oil in the pan . You then get the crank dragging oil up from the pan . This is a form of "viscous friction " . I have seen the dyno tests on running a windage tray . They do work .I do not have the RPM numbers though .
Most windage trays are nothing more than a screen that bolts between the pan and block or use the main bolts. This breaks up the stream of oil from the crank.
 

·
Registered
Joined
·
808 Posts
If you are in a pool and wip your arm in an arc all the water will travel off your fingers in a stream . Advertising has used this effect with womens hair for many years and most of us have seen this.. In an engine the same effect happens but the stream contacts the oil in the pan . You then get the crank dragging oil up from the pan . This is a form of "viscous friction " . I have seen the dyno tests on running a windage tray . They do work .I do not have the RPM numbers though .
Most windage trays are nothing more than a screen that bolts between the pan and block or use the main bolts. This breaks up the stream of oil from the crank.
Thanks Bruce, very interesting. This effect in engines is all new to me, but it sure makes sense.

Paul
 

·
Registered
Joined
·
3,391 Posts
This effect is another reason to go dry sump in ultra-high performance apps.
 
1 - 15 of 15 Posts
Top