Rod bearings scored?

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67 gt said:
Time to think about that stroker build now...:lol:
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My dad just called and I asked him to run his finger nail over the journals. He said he could feel the ridges with his finger nail but nothing caught it.
 
Those look like it was dirty when it was fired. Yes, crap went through it after but that's a mess. BTW - lack of oil pressure is a critical deal. It's not "insignificant" at all.
 
doogievlg said:
This was after it showed up. I didn’t give it time to warm up when I started it
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Roger.... well, 5 psi cold is gonna be 2-3 psi hot. But it could have just been the main already being damaged. Have you taken the oil pump apart and measured internal clearances and inspected? When you do, look carefully at the bypass plunger and see if it moves freely. (It will be quite hard to push against the relief spring when fully assembled.)

FWIW.... I would expect to see rod bearing problems the same or worse than the mains if it was consistently just oil pressure failure. May I ask what was used to check the main bearing clearances originally?
 
This isn't the only problem obviously but what oil pan are you running? I can't stress it enough that a factory center sump oil pan ain't worth a hoot for racing because it has no acceleration baffles to keep the oil where it needs to be. I learned this the hard way yrs. ago after oil starvation from hard launches ruined the bearings in a 360 I was running in less than 3000 miles. You can weld in an acceleration baffle or buy a good aftermarket pan with them and more capacity. Oil is the lifeblood of the engine
 
nm9stheham said:
Roger.... well, 5 psi cold is gonna be 2-3 psi hot. But it could have just been the main already being damaged. Have you taken the oil pump apart and measured internal clearances and inspected? When you do, look carefully at the bypass plunger and see if it moves freely. (It will be quite hard to push against the relief spring when fully assembled.)

FWIW.... I would expect to see rod bearing problems the same or worse than the mains if it was consistently just oil pressure failure. May I ask what was used to check the main bearing clearances originally?
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nm9stheham said:
Roger.... well, 5 psi cold is gonna be 2-3 psi hot. But it could have just been the main already being damaged. Have you taken the oil pump apart and measured internal clearances and inspected? When you do, look carefully at the bypass plunger and see if it moves freely. (It will be quite hard to push against the relief spring when fully assembled.)

FWIW.... I would expect to see rod bearing problems the same or worse than the mains if it was consistently just oil pressure failure. May I ask what was used to check the main bearing clearances originally?
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Plastigauge was used to check clearances. Probably should have used a mic as well.
 
fishy68 said:
This isn't the only problem obviously but what oil pan are you running? I can't stress it enough that a factory center sump oil pan ain't worth a hoot for racing because it has no acceleration baffles to keep the oil where it needs to be. I learned this the hard way yrs. ago after oil starvation from hard launches ruined the bearings in a 360 I was running in less than 3000 miles. You can weld in an acceleration baffle or buy a good aftermarket pan with them and more capacity. Oil is the lifeblood of the engine
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Factory oil pan.
 
doogievlg said:
Plastigauge was used to check clearances. Probably should have used a mic as well.
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Been using plastigage for 40+ years and have never had any bearing issues due to clearances and about 40% of my builds have been for racing. (Rally) So IMHO the method used was OK. But I always run the clearances up in the .002"-.003" range for any engine that is gonna get hammered on.
 
So next time I’ll loosen up my tolerances and check the oil pump clearance. Lesson learned
 
Get yourself a micrometer set and dial bore gage if you're going to build another few. Also make sure you wash the block before any cam bearings or plugs are installed. You had some basic problems there that cleanliness and the right tools would have caught.
 
I
yellow rose said:
It's something to check. Most people think you need .250-.375 pan to pick up clearance. That's only on aftermarket stuff. On an OE style pickup it needs to touch the bottom of the pan.
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Thought the pickup was supposed to sit a 1/4" off the bottom of the pan? I was always under the impression that the pump would suck the bottom of the pan up against the pickup and block oil flow.
 
Not with the stock pickup. It has a 'shield' (for lack of a better word) on the bottom, spaced under the screen maybe 3/16", and an opening to the side where the oil actually enters. (Some aftermarket pickups do indeed pickup up through the bottom and they need the spacing.)

Adding more spacing under the spacing already provided by the stock pickup design just increases the chances of sucking in some air, which is YR's point.
 
Chained_360 said:
I

Thought the pickup was supposed to sit a 1/4" off the bottom of the pan? I was always under the impression that the pump would suck the bottom of the pan up against the pickup and block oil flow.
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nm9 has it correct. Many guys think they are sucking the pan dry but they are not. The pickup is too far from the bottom of the pan and it runs out of oil.

This is for OE style pickups.
 
it is unlikely a stock pickup in a stock pan will be so far from the pan that it runs out of oil. check it anyway, in case of some crazy mismatched parts. sucking the pan dry can more likely occur when we are running a hi volume pump in a 5 quart pan for an extended blast and are a quart low
 
Marcohotrod said:
it is unlikely a stock pickup in a stock pan will be so far from the pan that it runs out of oil. check it anyway, in case of some crazy mismatched parts. sucking the pan dry can more likely occur when we are running a hi volume pump in a 5 quart pan for an extended blast and are a quart low
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I've had them come in at 3/8 off the floor and they complained it was sucking the pan dry. It's not hard to figure out with 5 quarts in the system and the pick up that far off the floor it's leaving at least a quart and a half in the pan.


A high volume pump can't suck the pan dry. I wish that lie would die off.
 
I can see it going dry more readily at higher RPM's (more oil flung everywhere, more in the heads, etc.) but it's not due to a HV pump per se. With the same relief spring in both pumps types, both are limiting at the same pressure out of the pump, which will push the same oil into the system for both.

It certainly will pump more with higher pressure relief spring....
 
Some pictures to show the factory installed position of the pick-up tube/screen using this old dirty 340 as an example. Like YR said, it's supposed to touch the pan.
100_1365.JPG
100_1366.JPG
 
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