Originally Posted by MER Performance (Post 3625988)

Have watched this thread long enough. Here are some facts not opinions. This is just pertaining to Main bearings. The rods are depending on the oil supply from the mains, which is totally dependent on oil lead in or tear drop shape if you call it that,,how much oil volume do you feel is lost by over sizing the lead in on main surface, if to wide it will simply dump oil at that point. The lead in groove provides a low pressure area to enhance the oil flow to rod journals. I have not seen any crankshafts with lead in groove on the rod journal surfaces.
If you would like to do a search on full grooved main bearings you will find this same information. I have spoken with my Clevite rep in reference to this Thread. These bearings are no longer mfg, they require more oil volume, which requires more hp from the circle track circuit. They have even shortened up the upper bearing groove also, before it reaches the parting line. Crankshafts have also gone to smaller oil galley holes being drilled into them. Nothing is wrong will a lead in slot as long as its been done properly, to wide will just dump oil volume, same goes for rod journal if any groove it should be a trailing groove complete opposite of main.

Various forms of main bearing grooving have been used over the years. We are frequently asked what difference grooving makes.
First, it’s essential to understand that bearings depend on a film of oil to keep them separated from the shaft surface. This oil film is developed by shaft rotation. as the shaft rotates it pulls oil into the loaded area of the bearing and rides up on this film much like a tire hydroplaning on wet pavement. Grooving in a bearing acts like tread in a tire to break up the oil film. While you want your tires to grip the road, you don’t want your bearings to grip the shaft.
The primary reason for having any grooving in a main bearing is to provide oil to the connecting rods. Without rod bearings to feed, a simple oil hole would be sufficient to lubricate a main bearing. Many early engines used full grooved bearings and some even used multiple grooves. As engine and bearing technology developed, bearing grooving was removed from modern lower main bearings. The result is in a thicker film of oil for the shaft to ride on. This provides a greater safety margin and improved bearing life.
In an effort to develop the best possible main bearing designs for performance engines, we’ve investigated the effects of main bearing grooving on bearing performance. A simple 180° groove in the upper main shell is still the best overall design.
While a slightly shorter groove of 140° provides a marginal gain, most of the benefit is to the upper shell, which doesn’t need improvement. On the other hand, extending the groove into the lower half, even as little as 20° at each parting line (220° in total), takes away from upper bearing performance without providing any benefit to the lower half. It’s also interesting to note that as groove length increases so do horsepower loss and Peak Oil Film Pressure which is transmitted directly to the bearing.
P-Series Bearings
These are not to be confused with the standard passenger car and light truck parts for the same retention applications which also have a “P” suffix letter. These high performance parts have unique core part numbers different from the standard parts for the same application. P-Series parts are the oldest series of Clevite high performance bearings. The rod bearings in this series typically have the greatest amount of eccentricity. Most rod bearings are available either with or without dowel holes for use in aluminum rods. Most P-Series main sets are full grooved to maximize oil flow to the rod bearings. Both rods and mains have high crush for maximum retention, and a reduced overlay thickness to prevent overlay fatigue, sometimes referred to as hen tracking.
Rod bearings use a hardened steel back for added strength and resistance to fretting. Extra clearance rod bearings are available for .001” additional clearance and select fitting. Use the P-Series rods where extremely high RPM’s cause severe rod bore close-in. This is typically indicated by nearly full parting line to parting line shaft contact with bearings having less eccentricity. Use P-Series mains where higher eccentricity is desired to narrow bearing contact patterns and to provide increased oiling to rod earings. Rod bearing oil starvation is typically indicated by polishing and smearing of the bearing surface, possibly accompanied by discoloration predominantly concentrated at the axial center of the bearings.
H-Series Bearings
These bearings are identified by a letter H in the part number suffix. Part numbering is based on the same core number as the standard passenger car parts for the same application. These bearings were developed primarily for use in NASCAR type racing, but are suitable for all types of competition engines.

Originally Posted by yschmidt (Post 3625930)

Funny...there is enough info here for you to claim they are good...recommend me using them...you offer to buy them...now they are suspect.

Back to the trash. Funny.

Originally Posted by Panther (Post 3626039)

Nice cut-paste...
http://thmotorsports.com/clevite_77/.../g-62379.aspx]

Originally Posted by MER Performance (Post 3626049)

Is there something wrong with that?

Originally Posted by Zone 5 (Post 3626074)

Yea, you should have stated where you got the info from, not posted it like it was your own!

Originally Posted by mike tkach (Post 3626037)

yschmidt,i wanted pictures to see if the journals are blue,you say they are not,but you cant send me pictures,i am not concerned about the radising of the oil holes,only concern is condition of the journals,now,for some reason i am the enemy,buddy,you can shove those crankshaft,s where the sun don,t shine for all i care.i can understand you being upset over this mess,but it seems to me thet you have ISSUES.i came on here trying to help you,at this point,im sure you are beyond help!:angry-smiley-038:

Originally Posted by Zone 5 (Post 3626074)

Yea, you should have stated where you got the info from, not posted it like it was your own!

Originally Posted by Panther (Post 3624227)

I asked the same question on another site and he didn't answer me. Some people prefer not using HX bearings. So long as the crank radius isn't extreme, you don't need an HX bearing.