joonas

http://44cup.zeroforum.com/zerothrea...stid=2744#2744

Erics post

I am using a different method as suggestd by Greg Fordahl out on the West Coast. They support a lot of ITS 944's out there and though his local contacts with a NASCAR engine builder, was able to use their equipment to come up with a simple solution to the #2 problem.

According to their research, the #2 bearing gets almost no flow ad idle which is the cause of the premature wear. Cross-drilling the crank doesn't improve flow. They used the Nascar engine flow tools to look at a simple ratio of oil being pumped through the system. #1 and #4 bearings were getting 50% more oil than #2 and #3. To even out the flow, they simply installed restrictors in the #1 and #4 oil galleys that provide about 50% restriction. The result was near even flow through all 4 bearings and much-improved flow at idle for the #2. The machine shop that did the crank polish and hole on my engine was familiar with this technique and it cost almost nothing to have it done while the engine was in their shop.

Only time will tell, but Greg assures me that they have tried cross-drilling and other techniques and this one seems to make the engines last the longest.

I emailed Eric to get some details and I got following answer

What I can tell you is that I raced the car for 3 seasons and won a championship. I then sold the car to another guy. He ran it for two seasons before selling it. As far I know, the engine was still strong after 5 seasons.

The mod was described to me by Greg Fordahl of Fordahl motorsports on the West Coast (Chief Engineer for the Alex Jobs ALMS team and Brumos Porsche Daytona Prototype team). I mentioned to the guy at the local engine shop and he knew exactly what to do. You need to restrict the #1 and #4 galleys by threading in an allen plug then drilling it out to provide 50% restriction. (have to do some math on that one as I don’t remember the diameter of the galley).


Has somebody seen this setup?
Comments?

hacker-pschorr

Same theory as this, also from Greg Forhdal:

https://rennlist.com/forums/4776255-post19.html

944obscene

Cool. Sounds like something to look into if I ever do an engine build. So which is arguably better. Restricting 1 and 4, or opening 2 and 3?

Will Feather

That makes sense.

m73m95

This thread was dropped rather quickly.

Can anybody in the know (Somebody from LR, Vitesse, SFR, Chris White, etc....) give their thoughts on this?

It sounds like a good idea to me, but the danger of oil starving 1 & 4 when trying to help 2 & 3 seems high to me.

Thanks,

gt37vgt

well under the same theroy it would seem if one was cross drilling the crank one should ony drill 2 and 3 I'm a big bleaver in the ol fluting method were the leading edge of the mains hole is sort of ported and the trailing edge of the big end hole

Chris Prack

Having built a lot of these engines I am always interested in hearing about new ideas to improve the oiling system. Unfortunatley most of the time the theories are disproved but it is still interesting to hear more about them and the thought behind.

Thanks for posting this.

Drilling #2 and #3 only would not increase oil flow nor would fluting the holes. Think of it this way, if you turn on the water faucet on the side of your house and let the water run with a standard hose you will have water pressure that will spray water so far. Now if you don't touch the faucet but install a larger diameter hose, like a fire hose, you have the same pressure at the faucet but now the water only trickles out the end of the hose and you have the same amount of water but at a significantly reduced pressure. Now imagine you have four hoses connected to the same faucet. If you replace two standard hoses with two fire hoses you have also now lost pressure at the standard hoses. Alternatively, if you keep the four standard hoses but put a finger over two of the ends, pressure will go up on all four hoses due to the restriction.

It is an interesting theory for a fix. Not a new one but it's good to see someone trying it out.