j9fd3s

i think its an old school mod, but we just never knew about it. all of the motors that racing beat had out during sevenstock had that mod. even the 3 rotor (3 seperate lines)

Jeff20B

That's interesting. Maybe I should run two oil feed lines instead of one.

BDC

One more thing I was going to quote now that I'm taking a closer peek at it -- It looks like there's three 90 degree turns:



) from the oil filter stand to the dowel run

) from the banjo bolt to the vertical gallery head down (have you ever looked at the width of the hole in that banjo bolt? It's very scary small)

) from the drilled vertical gallery 90 degrees to the lateral gallery leading towards the gear



There's also a few points of turbulence through the dowel pins throughout the dowel run.



There's some local fellas here in the area I've talked with that claim that, besides all of the pressure drop point reductions made, it's efficacious from the standpoint of _reducing oil temperature_. They say that it helps greatly to run a line externally because the oil going through the 'dowel run' is being heated by ambient engine block heat. What do you think about this? If it's true, it seems to me that the quantity of oil present at the front gear bearing is lower as well as having a substantially higher temperature.



The upside in doing this mod would be to theoretically help balance out the lubrication of both gear bearings. The downside would be an additional set of possible failure points (tapped fittings, hose) being added to the picture.



Whaddya think, Lynn?



B

Silver Ninety Three

11.8 is quite lean. I wouldn't recomend getting into the 11's at all under boost. I like 10.8 to be safe.

kahren

yep

Lynn E. Hanover

Well, I think it is a great idea.



On those rare occasions when we loose a rotor bearing, it tends to be the rear rotor, and I think this is because the rear rotor housing gets a bit hotter coolant than the front. I have absolutly no data to support that statement, but that is what I think. You can get away with almost anything, if, you can keep the oil cool. The oil does most of the rotor cooling, and if the rotor temperature gets away from you everything goes down hill very fast.



First, detonation can start even though inlet air temps are in the green. Not bad enough? Try this: The lead indium overlay on the bearing starts moving around. It ends up in places like the oil pan, and oil filter element. Very bad.



Before I saw this mod, we seemed to loose front or rear bearings in equal numbers. The rear main bearing gets higher pressure oil, and has a channel around the outside of the center of the bearing shell, with the three windows to let oil in. Perhaps if the front bearing were done the same way, there would be no need for this mod at all. I might try that some day.



Once the engine is being used hard, the oil is as thin as cat **** and is going through the engine between 10 and 18 gallons per minute. So I suspect that oil going through the dowels is not in there long enough to pick up more than one or two degrees of temp from the rotor housing. Generally the oil would be hotter than the housing anyway, so it should be loosing temp to the dowels not picking it up.



There is an amount of heat that will be generated by the turbulance caused by the many 90 degree turns and the threads in the dowels, but again, not much.



We do drill out the run from the filter mount to the rear main bearing and from the brass plug in the drivers side of the front iron into the front main bearing. Since we are in there anyway.



If you have the stationary gears out to replace the bearings you may notice that the oil gallerys usually don't line up with the hole in the bearing exactly, and this can be repaired with the bearings out. On the front stationary gear, you should match up the hole after the new bearing is pressed into place.



If you have shaved the irons more than one time, cut a little chamfer around the inside end of the rear main bearing. It runs with very little clearance between the radius on the crank cheek and the front end of that bearing. I have assembled engines and felt a very stiff drag caused by that rear bearing running up on the radius. I was able to save a guys engine at the Runoffs several years back, by adding a paper gasket between the thrust bearing plate and the front iron. That moved the crank forward the thickness of the gasket, and the rear main was moved down off of the radius. It worked just fine.



Another (Don't try this at home) tech tip.



In this picture notice the smooth curve of the Aeroquip aluminum hose end with the super light "Push On" Aeroquip Kevlar hose. Good for 250 PSI, but it takes 3 people to push a fitting into the hose.



And todays "Think about this" That is a Chevy S-10 pickup truck bell housing. Sorry about the weld.



Lynn E. Hanover