kahren

i think lynn sands the breaings down to get the clearance down before he starts racing, if you break the motor in properly u wont need ot do this. correct me if i am wrong lynn.

Lynn E. Hanover

Ok, I missed the point.



I do not know if there is less overlay on the race bearings. It never occured to me to think about that. I suspect that the same thickness is on both bearings. The race bearings are only .0005" larger in diameter than stock. The overlay is a flash plating operation, to keep thickness uniform. So lets just say it is the same thickness.



The thicker oil film is an advantage only at very high output. I raced with stock bearings for years, and after each teardown I would see shiny spots and rings around the ends of the stationary gear bearings. I would sand these off gently and go again. Once the overlay was very thin in most places, and missing around the ends. There would be no further problems. So I am thinking that the overly was about .0005 thick to start. Now I can put in new stationary gear bearings and just sand around the very ends of the shell and a bit where they bend the tang out, and they work just fine. Usually they look the same at the end of the year as they did going in.



The bearing in the picture had two years on it and was going in for this rebuild just as you see it. I don't try to reduce the overlay on race bearings. Just at the ends where they will scuff a bit on a missed gear, and at the tang. It tends to deform a bit when they bend it. Note that the front bearing tang is left on the bearing. There is just one oil gallery hole in the front bearing, and it must be indexed to line up properly.



Just solvent in the cleaning tank and you fingers for a few seconds to but that bright shine back on the surface is all it takes.



If I say that race bearings are not required on the street, then tonight there will be a missed shift in Pomona and a nastygram about it Thursday. If I say that they should be used on the street there will be 100 nastygrams that complain about the oil idiot light coming on at stop lights.



Higher oil pressure does two important things at once. It increases the hydraulic pressure around the bearing and helps keep a high pressure wedge between the bearing and the crank. It also increases flow rate, so that superheated oil is being flushed from the bearing so it cannot overheat the bearing material. I have an external pump to do this, but the stock pump can do some of it also. I like 90-95 pounds. Racing beat says a top of 115 pounds. That seems a bit high to me, but too much oil pressure is like too much money. The people that have it seldom complain.





Also, keep in mind that even though the bearing sizes are the same, all that 13B stuff weighs a lot more than 12A stuff, so a missed shift by my driver may be just a driving error for me. It can be a disaster for you. A little money now for a rev limiter can save a huge amount of money later.



I kind of like the sound of the limiter going off. It means he is going through peak power before the shift.



Lynn E. Hanover

Apex13B

that funny that you mention that, building a f-atl Toyota 4AG (or whatever its called now) motor today i had the #3 rod give me totally non-linear clearancing, there was a little piece of **** burr on the bearings backside that would more around as i would clamp the rod up. drove me nuts for 15 minutes. I always use a little nail file that you buy at a drug store to de-burr all my bearings, piston or no piston motor.







-nick the racing idiot

Drago86

Thank you. I'm definatly replacing them.