Full or 1/2 groove main bearings?

[toad490]

I've pretty much decided on Clevite-H bearings for my build, they're available in 1/2 or full oil grooves. Working on the more is better theory, the full groove should be better, or not? Oil pressure comes to mind.

[TK]

i use full grooves and never had any problems, thes ereally help with start up wear too.

[dwc43]

Always use full grove bearings for best oil control.

[383_Coronet 440]

Hmm. Increase oil flow and you decrease oil pressure, which lessens oil flow in other locations. That's why when I do things like that, I use a high volume oil pump which takes care of that problem.

[demonman]

i dont have a hi volume oil pump in my motor and the oil pressure is just fine

[sanborn]

There is a place for both full groove and half groove main bearings. Full groove aids oil dispersal around the full surface of the bearing---which is good.

But, the groove in the cap half also lessens surface area to absorb torque. And, depending on the torque generated by the engine can lead to crank grooving in high torque applications.

In past years we always used full groove mains. But as HP/torque increased in our engines, I began to see crank grooving. I thought it impossible(cranks are supposed to be harder than bearings) but it was occuring. And, I saw it with billet SB cranks and with stock type BB cranks. When we changed to half groove, the crank grooving stopped.

So I've gone counter to all the recommendations of the others. But I think it's due to application and HP level produced.

For street, moderate HP applications, full groove is probably the best. For high HP/torque applications, I would recommend half groove. What do I consider high HP to be? Starts around 600HP.

[TK]

makes since sanbrn

[MitchB]

Use Federal-Mogul's 270 degree grooved bearings. Gives full bearing surface area where max load occurs and promotes better oil flow.

Mitch

[Billydelrio]

MitchB, I have used the 3/4 grooved mains on Chevy engines, but have never seen them listed for small block Chryslers. I guess I need to update my old books. Thanks for the tip.

I agree with Sanborn on everything except his 600 HP. I like to consider 450 as a high horsepower number, this allows me to say I have a high horsepower 318!!

[cutting torch]

Whatever you tell yourself to feel better, I do it!

torch