Final days of the 401 on the dyno

[fuzz401]

jeep_man_401, cools stuff!!! Makes me want to pick up another one and 'try so stuff' - 'Course I'd probably become single and living in the shop, but hell ....

I will try it on the next motor but I will still be in the house due to it will be her gremlin

[jeepsr4ever]

Chris you are correct! The fastest way to the oil galley without creating a new feed from the top would be from the pressure port. Alot of racers including Hemmy Adtkins and John Garland use our 534 plate and use that port to feed their race motors.

[Blown7]

So this was my first problem





Anybody see whats wrong with the design?

Moving on, I did all the mods jeepman401 did in regards to the oiling system.
But one of the most interesting things that was discovered was the pressure drop of the left side galley rear. And the lack of drop at the right ( where the valley oil line is connected.)

The left rear read approximatly 10 PSI lower thru all the RPMs than the right galley input. (at the conventional gage port) Which sounds reasonable. What was interesting was the right rear had the same reading as the convential gage port. MEANING the valley oil line is doing what it was designed to do.
MOVING OIL AND PRESSURE.
HOW MUCH?
I don't know I didn't have a flowmeter handy but I think I'll install one later in the valley oil line with a one way check valve.

Now I know ol' 82 Waggy will disagree, but my evidence is given the pressure drop of all the 90 degree bends (which jeepman401 described so elegantly above and which BTW drop about .6 inches of Mercury per each bend or about .25 PSI per 90 degree bend ) I should have noted a pressure drop at the right rear galley even for the distance involved not including the actual pathways of the galleys off the main galley there should be a pressure drop, but I was reading the same pressure as the main feed galley from the pump output.

Now I calculated long ago I needed about 1/2 gallon per minute oil flow thru the main bearings ( I drilled the main feed to the bigger size drill and have a cross drilled crank) to keep the bearing heat radiating capacity temperture rise under 20 degrees F with 190 degree incoming oil with a SAE 50 weight oil. Given a friction HP loss of about 1/2 HP at each main not including the thrust bearing which takes more given it's length to diameter ratio. BTW I calculated the mains at .24 with a full oil groove. But maybe thats why it accelerates so well
Actually now that I look back I could have use solid bearings with just a oil hole on the last two mains to get the l/d ratio double thereby increasing the torque parameter vs Eccentricy ratio by double.

My main journal bearing lubrication analysis indicated a bearing load of 593 lbs/sq in at 6000 RPM with a surface speed in inches per minute of 47118 inches per minute or 3926.5 feet per minute. That little journal travels 3/4 of a mile in one minute at 6000 RPM (2.500 journal diameter x pi x 6000 RPM)
My clearnace modus was .0012
Main clearanace was set to .003 giving me a actual hydrodynamic flow of .1926

Bottom line for me
Valley line works period.
Oil filters suck (but what can you do? )
There is no such thing as a magic number of a certain engine RPM per what oiling mod to do. You have to look at each design parameter then decide what or if.
I think all the "big names" in the AMC engine building world knew all this 30 yrs ago but they still ain't tellin'
and damn Ol' Smokie Yunicks dead.

The rear main bearing problems alleduded to in so many posts and articles is real but it may not be from lack of oil or pressure but from bearing friction heat rise, crank whip, assymetrical torque loading, hydrodynamic flow or lack therof or even line bore/crank error.

BTW next segment discussing the oil filter adapters.

Jeff

[fuzz401]

could it be the passage between the 2 filters necks down tomuch

[Blown7]

On a entirely separate note many have asked me why I didn't use 4 bolt mains given the HP output.
1. I don't think they are needed given the size ans strength of the webbing.
2. I have seen aftermarket 4 bolt splayed caps break a block given how they "pull" the casting and create new fatique lines and stress risers.
3. It is my belief that the two bolt mains will never give me any heartburn given everything has been seasoned and relieved for 30 yrs.
4. If I did it again I'd prolly use dowel pins instead.


Jeff

[Blown7]

could it be the passage between the 2 filters necks down tomuch

Yep thats a series flow filter, the oil has to flow thru both filters till it gets to the output side. 10 psi loss thru each filter then add 10+10 lbs =20 PSI pressure drop right there.
I thought it was a parallel filter I didn't look close enough.

Jeff

[82Waggy]

Sorry Blown7, but until you run it without the valley line and measure the same drop on the right side I won't be convinced.

Sounds to me like you have a restriction on the left side to me.

[jeepsr4ever]

Sorry Blown7, but until you run it without the valley line and measure the same drop on the right side I won't be convinced.

Sounds to me like you have a restriction on the left side to me.

Yep its called cam bearings

[1980_Cj7]

So this was my first problem





Anybody see whats wrong with the design?

Jeff

YES! It's blocking the picture of the girl on the calendar. No wonder you can't get the juices flowing!

[82Waggy]

Sorry Blown7, but until you run it without the valley line and measure the same drop on the right side I won't be convinced.

Sounds to me like you have a restriction on the left side to me.

Yep its called cam bearings

How do cam bearings interfere with the flow down the left hand (drivers side) lifter gallery? For that matter, they cannot be interfering with flow down the right side gallery either.