RPM and stock 360 pan

-
gregcon said:
Ever, in any engine?
Click to expand...

Find a picture of any Ford Cleveland engine. 351C, 351M or 400. Look at the intake valley. They need all the oil drain back help they can get at sustained high RPM. Yes, I think with an HV pump and stock pan only running 5 quarts, they might pump the pan dry.

By stark contrast, look at any of the older pontiac V8s. They have so much drain back area, some of the lifter bores are hanging out in no man's land. In fact, it's a common failure on high RPM Pontiac V8s to actually break lifter bores off because some lack good support. But they don't have trouble with oil drain back. lol
 
gregcon said:
Ever, in any engine?
Click to expand...

And lest you think I'm kiddin, here's the Pontiac. Look at those lifter bores just hangin out. LOL

PONTIAC.jpg
 
And here's the Cleveland. Major drain back problem with sustained high RPM.

351C VALLEY.jpg
 
I'd rather use a Briggs & Stratton than a Pontiac lol.

I'm not sure 'failure to drain back' is entirely a lifter valley issue. Don't forget, much of what drains through those big passages falls right onto the crankshaft and (can) get whipped around so that it only eventually reaches the bottom of the sump. I think oil return is multi-faceted affair.

Either way, I've had big blocks lose their oil pressure from sucking the pan dry.....do nothing but let them sit a while and they start up with oil pressure again. These all had one thing in common - 100% stock oiling systems with HV pumps.

I also seem to recall reading/hearing about police cars with 440's that would starve for oil in high speed pursuits. These were considered properly maintained cars so I can't say they were low on oil, etc.

I'd be willing to bet if you took a bone stock 1970 Challenger 440-4 car and ran it on Bonneville, wide open, it'd run out of oil before it ran out of anything else.
 
I don't use a HV pump with a stock system, no need to.
Stock pump high pressure spring is all that's needed with a stock oiling system.
grooved mains create oiling problems with the stock system and no oil mods.
 
More than likely, on a Mopar if one loses oil pressure it's from the oil going to the back of the pan on hard acceleration, than pumping the pan dry. That's easily remedied using a baffled pan and or a windage tray.
 
There wouldn't be a ton of rearward G's at 4500RPM and 130MPH for 5 miles. Plus, the 440's had windage trays (stock).

It's not hard (for me) to imagine oil failing to return to the pan as fast as the pump can suck it out.....actually, it's surprising it doesn't happen more. 4 quarts is not a lot of oil.

I read an article way back by Smokey Yunick where he ran a SBC with lots of plastic windows to observe oil behavior. The two points he took away were:

1) Different oils stay apart way more than you'd think. He could add 2 quarts of Quaker State on top of 3 quarts of Pennzoil and he could see it in the running engine as two separate oils.

2) Oil goes all sorts of places besides the bottom of the pan, and likes to stay there. There is a lot of windage and sheer mechanical force acting on the oil. Imagine tossing a liquid into a blender - it flies all over and lots of it stays off the floor.
 
gregcon said:
I'd rather use a Briggs & Stratton than a Pontiac lol.

I'm not sure 'failure to drain back' is entirely a lifter valley issue. Don't forget, much of what drains through those big passages falls right onto the crankshaft and (can) get whipped around so that it only eventually reaches the bottom of the sump. I think oil return is multi-faceted affair.

Either way, I've had big blocks lose their oil pressure from sucking the pan dry.....do nothing but let them sit a while and they start up with oil pressure again. These all had one thing in common - 100% stock oiling systems with HV pumps.

I also seem to recall reading/hearing about police cars with 440's that would starve for oil in high speed pursuits. These were considered properly maintained cars so I can't say they were low on oil, etc.

I'd be willing to bet if you took a bone stock 1970 Challenger 440-4 car and ran it on Bonneville, wide open, it'd run out of oil before it ran out of anything else.
Click to expand...

The big blocks came with a pan at least one quart too small. It’s a wonder they didn’t kill more of them.

It’s not that the pan is getting sucked dry, the heads hold a quart, the filter has a quart and the rest of the system is close to a quart. And then what happens when Joe Blow and his buddy Joe **** the rag man don’t check the oil and it’s a quart low??? Rut roh raggy, we got truble...

That’s 2 plus 1 plus 1 for 4 quarts total. That doesn’t count any oil trapped by the worthless skirted block. Unless it’s cross bolted, it’s a power loser. And even if it IS cross bolted, it’s a power loser.

When David Nickens was developing the 99 hemi, one of the things he did was mill the skirt off the passenger side of the block. It took about 2 hours to pull the pan, and about 4 hours to put it back on. That’s right from his own mouth.

He didn’t say how much power they gained by getting rid of the skirt, but he said it was worth the labor without question.

The moral of the story is you can run a engine out of oil, but the pump doesn’t do it.
 
I think it becomes a game of words at some point. There is a marginal amount of oil in the first place, so the addition of a HV pump tips things over the edge. So the HV pump is to blame for sucking the pan dry as (presumably) it would not have been sucked dry with a standard pump.....just almost sucked dry. You can bet that when the standard pump is 'not sucking the pan dry' it is sucking a lot of air along with the oil.
 
Hello all, would just like put to rest where the "myth" but factory known reality of where the "sucking a pan dry" word derived from plus just a bit of personal experience on the OP subject since I just pulled my 7200rpm street/strip 408 out for a check over and HP gain detail. This probably is just for the 1%. Growing up all my dad's friends and himself had Hemi cars(they all tend to know each other) so it was just more common knowledge between them. That being said the 426 Hemi which has the worse oil drain back(two 3/8 holes per head going down in a passage through block) was all they had. In 66/67 the Hemi had just a 5 qt pan which is when Chrysler realised the issue so went to a 6qt pan for 68-71. With a 1/2 oil pump pickup,the steep angle of the heads and small about 3/8 oil returns the heads would fill with oil fighting against a large oil pump pickup and just gravity draining through a straw for almost 2 feet back to the pan could suck the pan dry. My dad actually was able to get his second Hemi car because of this problem. 67 car was all done and the owner at that time was racing on the highway with 3.91's against a Corvette when oil pressure dropped to zero. Luckily he noticed so shut it off before completely blowing it up. I'm sure many have seen 66 block over the years with a big window out the side. With how beefy the Hemi bottom end was we can assume many were from the rod seizing on the crank. After my dad pulled the engine out luckily it had just spun a rod bearing but everything else of the engine was in spec.
Now to my experience on the OP subject my car is fairly low and after taking out two Big block pans in the car (years previously) I decided to stay with a stock depth small block pan. I hadn't planned on it spinning 6700 through the lights or making peak hp at 6400rpm so just kept a eye on oil pressure. Anyways 4 years on the stock pan with the 7000rpm(limiter set at) 360 in it previously and another 4 on the 7200rpm(limiter set) 408 in it now and the bearings are all still like new and were also when the 360 came out. I am planning on doing baffles and a scraper now and maybe going to the Kevco 6qt pan to be safe since it will get some more HP. I will add a skid plate either way since I did have scrap marks on the pan.
Here are some picks of the Hemi oil drains in the head and the angle of the heads

IMG_20231030_084027868.jpg


IMG_20231030_084041197.jpg
 
Me <== checks dates on thread. Just over 3 years too late to put to rest this myth... lol. :p
 
You must log in or register to reply here.
-

Back
Top