What is the difference between Clevite regular bearings and race (H series) bearings?

I want longevity rather than a tad more HP if that helps.

 

My builder recomended the "h series" also, I think they are coated...correct me if I am wrong people. I know they use the "H Series" on NASCAR engines im pretty sure.

 

I have heard the story both ways???

 

Like I asked on LS1tech, whats the crank?

Bret

 

Cam berings are the big concern now, I will be using a refreshed LT1 stock crank.

 

You don't want H series then. You need to match the bearing width with the radius on the crank journals, that means a P series. You can use H series if you want but the P series is a better fit for a stock crank.

Bret

 

How about an Eagle forged 3.75" crank? What bearings?

 

Look at the crank. Pay attention to the area where the journals mate with the "cheeks". On a stock or low quality aftermarket crank, the two surfaces meet at a right angle. This causes a stress riser and is a common place for cracks to form leading to crank failure. Higher quality cranks are ground with an ~0.125" "fillet radius" in this area. This decreases the chance of breakage. When reconditioning a crank, this radius can be ground in when the pins are turned. It is commonly done when prepping a stock crank for race use.

A chamferred bearing is required to clear the radius, as it narrows the available space for the bearing surface. You can use a chamferred bearing like the Cleveite "H" with a stock crank, but you are giving up bearing area needlessly. There is no advantage and there is the possibility of decreasing bearing life.

Listen to Bret, he does this stuff every day.

Rich

 

As Rich said.... the forged Eagle crank will use a H series because of the radius fillet.

Bret

 

Bret: you make it too easy. I wanted him to look, so he would really SEE what was being talked about. The old Mk. I eyeball is the most useful tool we have.

Rich

 

Would using regular bearings on forgred Eagle crank cause any problem.

Rich,

Don't be so hard, old man..heh. I still have the engine running just might take it apart to swap to flat top pistons and would like to make sure I get the correct parts before I take it apart.

wrd1972, sorry to hijack your thread.

 

Yeah, your right..... should just waited.

BlueCamaro....if you had material where the radii of the crank fillet is on your bearing do you think it would be a problem?

Bret

 

It'll clearance itself...

 

It's clear now.

For the Mains, there are: MS909H, MS909HG, MS909HK, 1/ 2 Groove and Full Groove, Upper and lower Groove, coated and not coated. So, which one?

For the Rods, there are: CB663H, CB663HD, CB663HK & CB663HDK, all std size and will fit LT1 based engines. Difference is some has Dowel Pin Hole, some are not and are coated, some are not. Which one?

 

From Clevite's catalog.

INFLUENCE OF GROOVING ON MAIN BEARING PERFORMANCE
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 groovingwas 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. Upper main shells, which see lower loads than the lowers, have retained a groove to supply the connecting rods with oil.

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. The graphs on the next page illustrate that 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.

Rich