Rod journal size re oil requirements

[Michael H.]

Re: Rod journal size re oil requirements

I just got back from the Portland historics. Things were great until a rod froze and came out the side of the pan.

Sounds like the bearing suffered the black death and spun before the connecting rod failed? Do the remains of the bearing show signs of high heat?

What was your oil temp, especially in an early AM practice??

Small journal/large journal in a small block Chev has nothing to do with it.

[Jerry G.]

Re: Rod journal size re oil requirements

Speaking of oil pans.... Canton makes darned effective road race pans for wet sump systems. We have Canton pans on both our cars and have had zip-point-zero oiling problems.

Jim

I was using a Canton road race pan with a Canton acusump setup. I don't think Canton has enough oil capacity. (5 quarts in pan) I plan to switch to Aviad ( 8 quarts). I can't really say what the final culprit is. Clearly the 1.8 Gs and hard braking was uncovering the pickup and traping oil in the upper end of the motor. I'm thinking the acusump also wanted to refill at the same time as the motor was starving for oil. I'll send pictures.

[Jerry G.]

Re: Rod journal size re oil requirements

Oil temps were good right up until the motor started to seize and then they shot up . I imediately shut down the motor but the rod broke almost simultaniously. I have oil presure and temp warnings. The problem was low pressure. It had been dipping down to 15#s all morning.

[Clem Z.]

Re: Rod journal size re oil requirements

I was using a Canton road race pan with a Canton acusump setup. I don't think Canton has enough oil capacity. (5 quarts in pan) I plan to switch to Aviad ( 8 quarts). I can't really say what the final culprit is. Clearly the 1.8 Gs and hard braking was uncovering the pickup and traping oil in the upper end of the motor. I'm thinking the acusump also wanted to refill at the same time as the motor was starving for oil. I'll send pictures.

5 qts is not a lot of oil for road racing. i always used moroso pans and they were 8+ qts. i used road race pans on my circle track engines because of a spin out and the oil could get away from the pickup on a left turn only pan. you see these drivers when they spin out just hammer the throttle to get themselves going again no matter which way the car is pointed.

[Jim L.]

Re: Rod journal size re oil requirements

I was using a Canton road race pan with a Canton acusump setup. I don't think Canton has enough oil capacity. (5 quarts in pan) I plan to switch to Aviad ( 8 quarts)

I've heard good things about Aviad pans, but Canton makes larger pans, too.

We use a Canton 15-260 pan on my car, 7 quarts + filter + oil cooler, ~9 total, no Accusump. Once in a while at Laguna, after braking hard for and entering turn 2, my oil warning light flickers briefly. It's set to go off if pressure drops below 50 PSI.

I can't really say what the final culprit is. Clearly the 1.8 Gs and hard braking was uncovering the pickup and traping oil in the upper end of the motor. I'm thinking the acusump also wanted to refill at the same time as the motor was starving for oil. I'll send pictures.

1.8 Gs! Wow. That's impressive and almost certainly a contributor to oil starvation.

When I ran an Accusump (prior to switching to the Canton pan), I also used a high volume pump. I did this specifically so there would be enough pumping capacity to supply the engine and refill the Accusump.

Do send or post pictures, when you have the time.

Jim

[Jerry G.]

Re: Rod journal size re oil requirements

I've heard good things about Aviad pans, but Canton makes larger pans, too.

We use a Canton 15-260 pan on my car, 7 quarts + filter + oil cooler, ~9 total, no Accusump. Once in a while at Laguna, after braking hard for and entering turn 2, my oil warning light flickers briefly. It's set to go off if pressure drops below 50 PSI.


1.8 Gs! Wow. That's impressive and almost certainly a contributor to oil starvation.

When I ran an Accusump (prior to switching to the Canton pan), I also used a high volume pump. I did this specifically so there would be enough pumping capacity to supply the engine and refill the Accusump.

Do send or post pictures, when you have the time.

Jim

I also run a melling high volume blueprinted pump.

[Chris W.]

Re: Rod journal size re oil requirements

Ouch! Premature ventilation of an engine is never good.


I think the local expert is right, but for the wrong reason.

Switching to a small rod journal, if accompanied by a corresponding reduction in the size of the big end of the rod, will yield less rotating mass and the engine will spin up quicker..... definitely a good thing.

As to the oiling issues.... I dunno. Not an oiling expert. However, I've run large rod journals in my racing engines for 9 years with no oiling issues.

Next engine, though, is going to have small rod journals (283, or maybe even Honda) just for the reduction in rotating mass.

Jim

I used small journal rod and big journal main cranks in vintage racing for years with great success. Big journal mains helps with stiffness and small journal rods keep the rotating mass down.

Chris

[Jerry G.]

Re: Rod journal size re oil requirements

It would help if you would post a photo of the rod when you get it out, but I will tell you that most broken rods I've looked at exhibit a bending mode failure, and the likely cause of such a failure is the rod bearing seizing due to oil starvation. When the bearing seizes the rod experiences a HUGE bending load and snaps like a tooth pick.

The oil starvation is most likely due to the pickup being uncovered or air entrainment in the oil, not some minor difference in journal size or oil viscosity. Brief periods of starvation due to an oil/air emulsion at the pickup may not be detectable on even the most responsive oil pressure gage (and you can't look at it continuously while your driving on the track, anyway). Such damage may be only minor per episode, but cumulative - ultimately resulting in sudden seizure.

That's why SCCA finally let production classes go to dry sump systems in the late sixties or early seventies - can't remember the exact year.

Once dynamic loads get up to about 1g, keeping the oil around the pickup is problematic, both due to "slosh" and that fact that there is two to four quarts of oil up in the engine that can't get back down to the pan due to crankcase windage and what does usually has a lot of entrained air.

Sorry to hear about your misfortune, but the fact remains that even current "vintage" classes that try to maintain some semblence of "vintage" performance via tire and engine configuration restrictions still results in more grip and higher revs than 40 plus years ago, so vintage racing organizations have the same dilemma as SCCA did back then - keep the cars "stock" and let them blow up regularly costing racers a huge amount of money and grief or allow dry sumps so the engines can live.


Duke

Well said. I ran for 15 years with a dry sump with no oil related problems. Oh well, I'll just have to figure it out, with lots of help. By the way does anyone use restrictors in the oil gallies going to the cam and lifters? I may have too much oil going up top.

[Clem Z.]

Re: Rod journal size re oil requirements

Well said. I ran for 15 years with a dry sump with no oil related problems. Oh well, I'll just have to figure it out, with lots of help. By the way does anyone use restrictors in the oil gallies going to the cam and lifters? I may have too much oil going up top.

not with stock type rocker arms. if you are using a production block where the oil to the mains goes in the grooves behind the cam bearings make sure the cam bearing oil holes are at 5:00 o clock position when faced from the front and the block right side up to prevent a BIG internal oil leak. also i would feed the accusump into the main oil gallery directly in the front above the timing gear cover. also do not install any trap door pan on the engine stand with the engine upside down as the doors can get trapped in a open position

[Jerry G.]

Re: Rod journal size re oil requirements

You have just triggered something in my mind. Thank you. I have 50mm roller cam bearings. I wonder if these type of bearings block off or cause a major leak in the system. Any ideas how to figure this out?? Jerry

[Clem Z.]

Re: Rod journal size re oil requirements

You have just triggered something in my mind. Thank you. I have 50mm roller cam bearings. I wonder if these type of bearings block off or cause a major leak in the system. Any ideas how to figure this out?? Jerry

you must have a bow tie block and these bearing would not cause a problem because they are oiled differently

[Jerry G.]

Re: Rod journal size re oil requirements

you must have a bow tie block and these bearing would not cause a problem because they are oiled differently

Your right. i do have a 'Bowtie" block. So does that change your opinion about restrictors to the cam and lifters. i wonder if a bowtie block caused an internal leak that the wet sump just could'nt keep up with?/

[Clem Z.]

Re: Rod journal size re oil requirements

Your right. i do have a 'Bowtie" block. So does that change your opinion about restrictors to the cam and lifters. i wonder if a bowtie block caused an internal leak that the wet sump just could'nt keep up with?/

a bow tie block race is designed for race application so i doubt there are any compromises in the oiling system. a bow tie sportmans block uses the same oiling system as a production block so which one do you have ?? i would try edge orifice lifters to cut down some on the oil upstairs but i would not restrict the lifter oil galleys

[Jerry G.]

Re: Rod journal size re oil requirements

do you know how to tell the different Bowtie blocks? What shoulsd i look for?

[Clem Z.]

Re: Rod journal size re oil requirements

do you know how to tell the different Bowtie blocks? What shoulsd i look for?

there is no oil filter boss on the driver side of the engine on the race block.