355 just went back together and in for the 2nd time and the oil pressure still seems so-so. Rod & main clearances are tightened up by .0005" to about .002 to .0025. Now running a Canton HV oil pump with standard pressure relief spring. OP is about 50 at 6500 RPM. If I recall my Eagle crank and Eagle H beams had a good bit of side clearance as received from Eagle. Could this be where my oil is going? What are reasonable limits for side clearance. Oh yea, 10W-30 Mobil 1


Thanks

Steve

 

Put some descent oil in it and see 20/50 maybe.
Side clearance won't effect pressure if ya have volume..It effect's how much oil is thrown on the cyls and splash but not to much at holding the oil in the brg. I have run as much as .020 and it didn't drop pressure.

 

.015 is a good number to shoot for?

Did you measure what you have?

Bret

 

Thanx for the replies guys

Steve

 

find out what the tolarance is on the rods and crank .0025 seems a lil on the losse side but liveable....

 

So what's the complaint? That's exactly what it should be.

If things are loosey-goosey the first place it'll show up is your oil pressure when idling hot. Idling at say, 800-900 fully warned up what kinda pressure are you seeing? 5? 15? 25? 500?

BTW- maximum side clearance for a SBC is .025" measured by pushing the rods apart and inserting a feeler gague between them. Really you want it more like .015. Loose clearances betwen the cam journals and cam bearings is another source of oil volume loss that is sometimes overlooked, often when replacement cam bearings are installed in place of factory original units.

 

Bret, the Eagle crank/rod setup typically (as mine is/was) runs in EXCESS of .020". I consider that side clearance excessive. The rod width is std. The problem is the crank journal. I used to be able to get grinder 'put on' wheels. They have long since stopped makin' those. I'd like to see .015" max myself. The more thrown off, the more of a burden that is put on the rings to control. The less thrown off, the less needed to satisfy the bearing.

 

Clearances were in excess of .020". Probably closer to .025". Why would Eagle do this? Is there a fix to close up these clearances?

I guess the only downside to running 15W-50 M1 would be a couple of HP loss - yes?

Steve.

 

Only good way is to go in there are re-grind the fillet radius larger on the cranks.... Or make wider rods. If the rods are .940" wide on the big end, then it's the crank.

The .025" is ok, it's a little loose but I wouldn't worry too much about it your not going to kill yourself there.

Bret

 

In regards to correcting anything, what's the point of that? As I noted above, a guy needs a 'put on' wheel. Tough grinding somethin' that ain't there.
No question, it's the crank, Bret.

 

If you grind the rod journal smaller you can enlarge the fillet radius....

Bret

 

Sure can, Bret. However, that has absolutely nothin' to do with narrowing the crank journal width in regards to rod side clearance, which I believe is the issue here.

I hope you are not telling me you can, or expect to 'ride' on the radius of the crank journal.

 

Arnie.... the larger the radius the more it narrows the width.... which will take down the side clearance. Think about this one a little more.

Eagles cast cranks have a .093 radius and the forged ones are .125, the larger the radius the narrower the rod journal

Bret

 

Hmmm, apparently you are not aware where the side of the rod makes contact with the crank journal.
See the edit above:
I hope you are not telling me you can, or expect to 'ride' on the radius of the crank journal.

You testing me? This is crank tech 101.

 

Not regarding Eagle cranks specifically, but cranks in general; this is where the novice gets himself in trouble. They use a crank with larger (stronger) journal radii, but attempt to use rod bearings that do no allow for (have the additional clearance for) that extra material of the larger radius. They end up riding on the radius and wonder why they have problems. Hmmm.

Sure, the novice makes the mistake once, and he then learns. However, for the experienced to fall victim to this, is well.... unforgivable.