help with switching to 0-30w oil

[Wolfplace]

I trust you do not squeeze the rods with your high dollar rod bolts installed do you? Again info described on this board not found elsewhere.

PFM

=
Yep,,
If you think pulling the rod in with a clamp a few thou is going to hurt the bolt what do you suppose happens when it is zippin around at 8000 RPM especially on overlap when you are trying to throw the piston out of the engine

[Darin Morgan]

I trust you do not squeeze the rods with your high dollar rod bolts installed do you? Again info described on this board not found elsewhere.

PFM

You torque it up with the high dollar rod bolts just like it will run in the engine. If you can damage the rod bolts with a pissy little c-clamp, they aren't worth using. Like Wolfplace said, Its really amazing how little pressure it takes to oval them. If it takes so little pressure with a c-clamp to oval the rods just think what's going on in the engine at full load!!

[BRENT FAY]

I had an old timer tell me that I had hired (God rest his sole) "Brent just make sure they are perfect from 9:30 to 2:30 and 3:30 to 8:30 and you will be all right.) I asked him why and he didnt know but never had any failures. I've thought about why bearings were thinner at the parting line,but why? This defintly shone the light. Thanks Darin and Larry for the info!............ What kind of bad breath would a shop get when another shop would check the rods and block if they didnt use this forward thinking?? Brent

[Ed Wright]

[


Royal Purple #9 is usually around 5 to as much as 12+ HP
more than Mobil 1 or Castrol Syntec
its been awhile since i last tested these Oils, formulations may change ??,
results may vary ?

Larry, have you seen any power gains using Royal Purple #9 in a wet sump engine, stock-type oil pump engine? I have a 383" LT1 that showed nothing at all with that oil vs 0-W-20 (or 30, forgot which) Mobil1. Many of my Super Stock & Comp friends swear by it. I was kinda dissapointed. All I have is a chassis dyno, but expected to see something. I run .003 & .003", with standard volume oil pump, at 35 psi max pressure (clipped the spring). Due to using the factory computer, it won't run past 7300 RPM. Maybe RPM needs to be higher to see a qain with that oil?

Thanks, Ed

[hotrod]

Smokey Yunick mentions the issue with the bearing parting line closing in on the journal in his book "Power Secrets" on page 20. He talks about how the pounding from detonation causes the bearing to curl in at the parting line and act as a scraper and peels the oil film off the journal -- boom instant engine kit. He said he first picked up on this in the 1950's and eventually after trying everything he could to clamp the bearing so it would not spin went to a bearing manufacture and talked them into building a bearing shell with a relief at the parting line. What we now call eccentricty.

I'd seen the results of this, a friend of mine has a rod with a pair of rod inserts that are curled so they appear they were intended for a rod journal about 0.250 smaller in diameter than the rod big end.

Some of the turbocharged imports have trouble keeping rod bearings from spinning, and I've seen the characteristic wear pattern going all the way to the parting line. Why I did not think of this simple solution is beyond me, I've been looking for a bearing that has more relief on the parting lines for quite a long time.

Thanks guys --- very useful information!!!

Larry

[maxracesoftware]

Larry, have you seen any power gains using Royal Purple #9 in a wet sump engine, stock-type oil pump engine? I have a 383" LT1 that showed nothing at all with that oil vs 0-W-20 (or 30, forgot which) Mobil1. Many of my Super Stock & Comp friends swear by it. I was kinda dissapointed. All I have is a chassis dyno, but expected to see something. I run .003 & .003", with standard volume oil pump, at 35 psi max pressure (clipped the spring). Due to using the factory computer, it won't run past 7300 RPM. Maybe RPM needs to be higher to see a qain with that oil?

i've had only 1 Engine on my Dyno so far that
didn't gain HP/TQ from switching over to Royal Purple #9
it was Bobby Cassard's 305 Chevy SuperStock engine.
we tried RP9 a few different times over Mobil 1 or other oils
in his 305, but made no differences.

all the other various type engines over the years,
always picked up at least 4+ HP or so, sometimes much higher.

i'll make a webpage up of some of the Oil Testing
later this Month

[machine shop tom]

A rod bearing having eccentricity is different from having a relief at the parting line. Eccentricity is a gradual change in thickness from the middle of the bearing arc to the ends. A relief at the parting line is akin to a gradual bevel to where will be no ledge above the intended bearing surface caused by cap-to-rod misalignment.

While I understand the need for larger clearances in all-out race engines, I am just waiting for Darrel Dirt and his brother Darrel to come in the shop and ask for "them tree and tree clearunces for our tree-fitty-five mouser wit' the 650 Hollleee and the Eldenbrock hi-riser wit' the tree-corter cam and the hi-domed flat-tops in our Pinto roundy-round racin' buggy".

tom

[Darin Morgan]

I had an old timer tell me that I had hired (God rest his sole) "Brent just make sure they are perfect from 9:30 to 2:30 and 3:30 to 8:30 and you will be all right.) I asked him why and he didnt know but never had any failures. I've thought about why bearings were thinner at the parting line,but why? This defintly shone the light. Thanks Darin and Larry for the info!............ What kind of bad breath would a shop get when another shop would check the rods and block if they didnt use this forward thinking?? Brent

Its funny you should bring that up. I have had a customer call me up and tell me that the rods we sold him where defective because his local speed shop told him that they where out of round! I then tried to educate him in the finer points of high performance machine work and let them in on the secret. He thought I was just trying to screw him over and he had obviously been taken to the cleaners way to many time because he would not believe me. I had to give the guy his money back and let him get his rods from his local "high performance machine shop". The engine was a 351 Cleveland and the stock rods are dicey as it is. I knew he was going to use the tachometer as a fan due to his inexperience so I gave him some very ovalized rods for a little insurance. Well, his brand new high performance perfectly round rods that he got from his local speed shop blew out the side of the block (I $hit you not) IN THE WATER BOX! Did I take the high road and not tell him I told you so. NO, I called him and asked him how well his rods worked. He promptly hung up the phone on me.

Oh well, you can lead them to water but you cant make them buy the right parts!

[SWB]

Darin,

Apparently you can lead them to the water box and then watch them blow!

Too bad... Sometimes it takes us all a lot to learn..

SWB

[Erland Cox]

Oil does more than just lubricate the bearings, it also has to cool them. If you run to little bearing clearance or side clearance you don't get enough volume flow for cooling. Every time a bearing looks shiney or melted on the surface I open up the clearance a little and the problem goes away. I found out about the merit of oval rods years ago when i rezised the rods in my 446 Mopar. This engine saw 8000+ rpm even though it didn't make power that high. The non rezised rods where oval and in these the rod bearings looked like new on dissasembly but not in the newly resized ones. That tought me a lesson. And yes, making long burnouts at 8000+ rpm:s with heavy pistons make the bearings spin. I also learnt that. The engines oil pressure only feeds the main bearings. You have to have enough oil pressure to overcome the centrifugal force from the oil in the crank. So smaller main journals need less oil pressure. The rods oil pressure comes from the centrifugal force acting on the oil that has entered the crank. If you let the oil enter the crank in the center you can have lower oil pressure and loose less power in the oil pump. And Darin, thank you for your posts. I'm printing them out for reference.

[Erland Cox]

The higher rpm your engine is turning the stronger the oil films hydrodynamic wedge gets. So a low reving high torque engine needs large bearing journals while a high reving engine can use smaller ones. A low reving big journal will have about the same periferal speed as a high reving small journal. Erland.

[DavidHarsay]

The higher rpm your engine is turning the stronger the oil films hydrodynamic wedge gets. So a low reving high torque engine needs large bearing journals while a high reving engine can use smaller ones. A low reving big journal will have about the same periferal speed as a high reving small journal. Erland.

I agree, but it's also important to note that as the load increases, the more of a wedge the oil forms. With little or no load, the wedge thins out, and you're in trouble with the high RPM's.... high RPM's and no load that is.

When I was in A&P school, one of the instructors had an old tape he showed with this principle... as the load increased on a bearing, the special cameras in the experiment showed the wedge growing. Weird stuff, goes against our intuition that's for sure.

Dave

[RW TECH]

This is a very interesting topic and I am glad that Darrin was so descriptive in his original response.

Without a doubt many engines can be run with clearances that are much tighter than .003" but component deflection must be minimal along with round/straight journals that have good surface finish quality.

The above statement doesn't agree with current industry trends where reduced journal diameters and light-weight components are commonplace.

Components that are rigid enough to allow lesser clearances in applications like high RPM drag racing would become so heavy nobody would consider using them.

Aside from ultra-high RPM situations with light rods/small cranks/big pistons, it is not unreasonable to expect good performance in an engine with bearing clearances set tighter than .003".

Also agree with the comments about certain oils not being adequate for racing..............

[Farsighted1]

What are the properties that are required in a racing oil? Specifics in the additive package? Viscosity? Synthetic or mineral. Or?

[bigjoe1]

The biggest differance in street car motor oil and racing oil is that the racing oil has been made with anti foaming a very high priority. This is what make it cost so much more than every day motor oil. I have seen the Royal Purple # 9 pick up 25 HP over Valvoline Racing 20-50. I have seen this twice. Thats alot.

JOE SHERMAN RACING ENGINES