Does anyone have any pix of their oil supply mods to the rear main bearing cap?

 

On p. 78, Bill Trovato says it is not needed. I have generally chamfered, lightly ported the inlet hole in the cap, and rolled over the edge at the end of the recess where the outlet from the pump overhangs. Don't take off a lot of material as doing so could weaken the cap.

 

I would think you are on the right track...

 

I left mine alone and haven't had any oiling problems for 12 years of racing and street miles. 80 psi cold 40 psi hot idle.

 

Here's a pic of mine. It had been done before I bought the motor.

 

Thanks... looks good!

 

This engine is for my dirt car and I have always subscribed to having the best oiling system I could afford or the rules allowed. Sometimes these little things don't do much by themselves but they can help contribute to better engine life.

It looks like I will spin this thing to 6500 rpms or better two nights per week... roughly 25 miles. I need all the help I can get!

 

I would go with Run to Rund, it does make a difference. Same with chamfering the oil holes in the crank and oblong the chamfer opposite of crank rotation. I also run a "scraper" bolted to the main cap to keep oil from "creeping" up the back of the pan sump, plus a windage tray. Also, in large, smooth, and contour the oil return holes in the heads helps oil return.

Olds engineering did al lot of testing in (BBO especially) oil flow, pressure drops etc. starting in 68'.

BTW: Olds engines (non-ultra HP engines) do not like high oil pressures. Smooth, high volume oil flow is were it is at.

just my 2 cents.

 

Thank you

 

I smell a 6 page thread on Bernoulli's Principle coming up..................

 

I have a 72 455 block that has the rear main cap blended,and the melling pump was done to match.This engine was done by Mondello's back in the 1990's.It had a very short life.About a week.It killed every bearing in there,and turned the crank blue.The block also had restrictors in the mains.

All you need is VOLUME.

 

Nope, you want both.

 

Slight hijack but relevant... anyone got the Ford or AMC part number for the neoprene rear main seal used as a rope seal replacement for an Olds motor?

And as far as volume goes, I always had the understanding that if you were looking for short bursts of high revs, a high volume pump was the way to go, and for a roundy round constant rev motor, normal volume high pressure was the way to go. Daily drivers could get either...dependant on the driving habits...

 

Yes 380/425 Racer,you do need both,but for someone being concerned about how to enhance their oiling,you don't need a crazy high pressure.Get plenty of oil around the bearing. I have between 5-10psi of oil pressure at idle,when hot,or sitting at a light.It's been like that since it was built in 1999,and we knew it was going to be like that before it even started.I also have to run 20/50. I tried 15/50 once,and my pressure is pretty much zero at hot idle.Cold start it is 55-60psi idle,then drops as it gets warm.It gets a lot more street use than it does strip use.This does not have a ported main cap,and has the HV pump,the way it came out of the box.No restrictors.Nothing special.I also enlarged the oiling hole for the distributor gear,which is bronze,and it has lasted much longer than my other bronze gears with the standard size hole.
I know the new engine will be completely different,but the way everything is on this one works great.I did do a bearing inspection after the 1st two seasons,and the bearings still looked like the day they went in,so that satisfied me enough to leave it alone. I guess I should have reworded my comment to "All I need is VOLUME". It was good advice I took from Travis Quillen before,to be more concerned with volume.I've taken the same approach to everything else that I have built or had built since,and all is fine.
That Mondello 455 had all the fancy oiling tricks & mods,and it failed.I never saw a crank that bad.They even glyptoled the valley so it could ski down quicker.It just couldn't get where it needed to be,on the bearings.Maybe one of the students built it.Who knows.

 

I would be willing to bet that oiling wasn't the issue more than the oil recovery. If you use a high volume pump, and then you run out of volume because its all sitting under the valve covers, or intake.... then cooked bearings will result.

John

 

cutlassefi: If you know Ohms Law and the Principles of Hydraulics. that will answer your ?????

You can have volume without high pressure, by enlarging the diameter of the passage/tube without changing the pressure will decrease pressure. Same as Ohms Law by decreasing the size of the wire proportional to the amount of pressure (amps) increases resistance (slows down the flow of electrons)! Also, anytime a liquid makes a turn (in a curve) of a passage/tube it slows down, because why, resistance. When you can limit the amount of resistance in a curve you increase flow (volume). Another point is "blue printing" the pump itself. Checking pump gear end clearance above the pump body, usually .006" to .009", will decrease "gear bleed off" at both ends of the gears. Make sure you have a min. of 1/4" thick end plate. Check pressure regulator piston to bore, to no more than .003". Use a light to check bore/piston for scuffing, lightly use fine crocus cloth to remove if any, recheck bore/piston clearance, if over .003", toss it all! In creasing the pick-up diameter is another over looked item. All my engines use a 5/8" tube. Plus how many check the pick-up tube clearance to bottom of oil pan?

Currently I use 15W40 Syn. Race Oil made by Brad Penn. Cold pressure at idle is 75 psi and at 180 degrees it is 60 psi, at 2,000 rpm it is 65/68 psi, thru the traps at 6,000 it is 45 psi. A little high to my liking, so next oil change I am going to try 10W30, which I would prefer anyways, as it should free up more HP.

Even using my 21 body part digits, I built more race engines than I can remember, and I never, ever, lost an engine/rod bearing in both my Stock and Super Stock engines. Now I did break some pistons, thru a few rods out the side of the block, had to install a few sleeves, but not ever destroyed or wiped out a bearing.

 

Brian,
The way I look at it is like what a fireman needs. Enough volume to put the fire out but the need of more than enough pressure to reach the fire. My engine sees no less than 30# at hot idle with 10-30 oil and 60-65# going down the track. Have inspected the bearings twice now with no loss of the coating what so ever. I use a HV pump with lifter restrictors. I have .001 clearances for every 1" diameter of the journal 2.5" main 2" rods.Next winter I will have Milan do a few of his tricks to make it even more effecient.

 

I really should edit that last part. The mains are .003 and rods are .0025.

Also I could never sit there with the engine idling and only see 5 psi on the gauge on my $18000 motor !!

 

The 351-C Fords we ran in our dirt stock cars needed a 100# pressure relief spring to get enough oil to the engine. We used a standard Melling pump.... hot oil pressure was about 65-70lbs. Those Cleveland's had poor oiling systems... we restricted the three center lifter oil galleries above the mains with a .020 drilled set screw. We had solid lifters... Never had an oil related failure...

 

1. To and from the oil filter adapter drill to 5/8

2. Connecting passage to the pass. oil galley drill 9/16 , which will include a Time -Cert
to replace the rear main bearing threads.

3. Drill to 1/2 the pass. side oil galley

4. Drill to 3/8 to the main saddle

5. About .375 shim in a HV pump {roughly 80psi cold)

6. That will make a fully stepped oiling system and eliminate surging and turbulence.

7. Normal driving my 480 is 70psi max and 30 @ idle , after a good pounding
60psi max , 20 @ idle

8. Its virtually impossible to have too much HOT oil pressure on a BBO.

 

ya, what Milan said X2. Must be for very high rpm engines?