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#1
03-21-2012, 12:23 PM
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Race bearings for the street?
I need to replace the bearings in my 400 after a bad initial start up experience.
Are race bearings a good choice for a street engine not seeing the high side of 5500rpm? I have read some of the posts and it seams that 3/4 groove main bearings are preferred. What main and rod bearings would you suggest for a street engine?
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1967 Firebird project in the works 400, 670 heads, 2802 cam, Hooker comp, Crosswind intake, Quadrajet, 700r4, 3.42 Posi. |
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#2
03-22-2012, 12:43 PM
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"race bearings" is a wide term covering various materials, coatings and construction.
Specifically the 4040M 3/4 groove main inserts are excellent, as they improve oil supply to the rod bearings, while providing the hydrodynamic oil wedge required to support the bottom of the crank main journals. The clevite trimetal rod bearings are good for street/strip engines. Shoot for .002-.0025" on the mains and rods. The aftermarket forged rods will run wider side-clearances, which costs some oil pressure but provides better bearing cooling. The oil throw-off coming from the side-clearance carries heat away from the bearings. Blueprinting the M54DS oil pump is just as important.
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I could explain all this to the girl at the parts store, but she'd probably call the asylum. White '67 LeMans 407/TH350/Ford 3.89... RIP Red '67 LeMans. 407/TH400/Ford 3.25 |
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#3
03-22-2012, 01:05 PM
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The main difference between race and street in terms of bearings are the clearances. A race engine will usually have a bigger clearance.
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1969 GTO 4spd. Antique Gold/black, gold int. 1969 GTO RAIII 4spd. Verdoro Green/black, black int. 1969 GTO 4spd. Crystal Turquoise, black int. 1970 GTO 4spd VOE Pepper Green, green int. 1967 LeMans 428 Auto. Blue, black int. |
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#4
03-22-2012, 02:38 PM
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Thank you for the replies.
I was thinking the sealed power 4040M-10 main bearings and the Clevite CB758HN10 rod bearings. I have a new M54DS pump that I tack welded the pick onto and installed the 9/16 check ball with a .060 shim. What else should I do to the pump?
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1967 Firebird project in the works 400, 670 heads, 2802 cam, Hooker comp, Crosswind intake, Quadrajet, 700r4, 3.42 Posi. |
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#5
03-23-2012, 11:48 PM
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A write up on bearing coatings from clevite
http://www.mahle-aftermarket.com/C125790900540AC0/vwContentByUNID/856F9F7662D109D8C12579BC005E5D93/$FILE/TB2077.pdf
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1970 Bonneville Convertible |
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#6
03-24-2012, 11:28 PM
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race bearings are often of a harder material than street bearings.
softer bearings are used on street applications where there will often be more dirt or grit in the oil. the grit or dirt will imbed itself in the softer bearing material rather that score the crank. Most GM products used the softer bearings on origional applications because to get an engine absolutely clean during the assembly process is vertually impossible. an individual building a race motor can spend alot more time getting the parts spotlessly clean and changes his oil quite often . Veru rarely will dirt or grit get into a race engine. race bearings come in alot more sizes than street bearings |
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