Re: [FWDLK] 413 Rod Bearings

no std replacement bearings are grooved- race bearing [as far as i know- for rods] do not have that groove- stock repl's have a groove in 1 half of the main bearings- mains can be had with a full groove- this is for pressurized oil to be available to the rods at all times- as the gundrilled hole from main to rod journal is the only means of oil delivery to the rods- a groove on the rod bearing is a bad idea anyway- it reduces surface area of bearing>crank journal- and is essentially useless in aiding lubrication- the oil is delivered to the contact/loaded area of the rod bearing by the oil supply hole from the main journals- it is centered, so in the perfect world- oil is dispersed evenly across the contact surface during rotation.

as far as less surface area for contact- a good bearing uses a slightly narrower groove than stock- for a few thousandths of surface area without compromising oil supply.

i've used clevite tri-metal bearings in big block storkers down to stock rebuilds [496">58 350's] with great results and longevity, and that includes over 700 naturally aspirated hp, so your 413 will be fine with the bearings you have- provided the journals are true- not polished only- which can leave an inconsistancy if the rod bearings were grooved- the center area common to that groove can be up to .002 larger.

i do have to say- [though i'm not a production engine builder] i have built over 150 engines, all [and only] mopar and GM from engines produced 1956 through present.... not one chrysler original or rebuilt had grooved rod bearings.... of all only 2 were 413's though.... an F spec'd 60 engine and a 65 ny'er 413... have a 59 ny'er 413 i plan to open soon to use the crank in a 440 to run an iron t/f [for an odd reason of my own!] so that has yet to be seen- but doubt i'll find grooves.

the rod bearing part number services 58 350's right up to 78 400/440 the main bearing design changes with the advent of the cast crank- whose thrust bearing has an double surface, due to the lower surface hardness of the cast crank over the steel/forged cranks- '73 and older

jim

-----Original Message-----
From: ajl <alacaria@xxxxxxxxxxx>
To: L-FORWARDLOOK@xxxxxxxxxxxxx
Sent: Sun, Jan 24, 2010 3:59 am
Subject: [FWDLK] 413 Rod Bearings

Hello;

I am in the process of putting a 413 back together, polished crank etc.. taking my time. I purchased a rebuiliders kit has Clevite bearings. I have a question about the rod bearings. My originals top and bottom have a half moon when put together forms a circle, this circle is for oil flow around the rod bearings. The new Clevite rod bearings do not have this setup for oil flow. Does anyone know of a brand that does?

A picture of the two bearings, old and new, can be found at www.myimperials.com/bearings

Thanks;

Anthony

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