.100 or .125 bore without sonic testing the block? How Safe?

I've built three .125 over 8BA's and only ran into one slight problem. On the last one, the boring exposed a small flaw in the casting that had been hidden previously. The machinist said it would be just fine the way it was, but I had him sleeve that cylinder just to make sure (and it was less than $100 extra). Never had a problem and there are probably 2 or three cleanup bores left in it. After those have been exhausted, I'll let the museum curator in 2120 worry about what to do next.
 
Glad to hear the overbore worked out. I had to use oversize cam bearings as well. I believe there was only one supplier, at least from what I could find. I purchased my 0.010" oversize bearings from Reds Headers. I just checked their site, and they have 0.020" and 0.030" but it says they are unavailable. You should still give them a call if they can save your cam, but it still might not be cheaper than purchasing a new cam.
 
My engine (a 59L block) is at 3 3/8th + .030". According to the builder (Ronnie Roadster), the bores still have plenty of meat left; even at this large bore size.

Maybe I got lucky, but sonic checking is a must and believing what you see vs. believing old tales of a few bad blocks that have now become the gospel regarding flathead bore thickness.
 
Given you 3 5/16 bore, you might consider putting a different cam in it to add a bit fun to the mix. Yes, the stock cam has plenty of low-end torque . . . but you just gotta have a good flathead sound! Think about a Potvin 3/8 grind - is one heck of a good running cam and sounds fantastic. Pete1 can regrind a stock cam core for you - given the weight, shipping should not be too bad.
 
This is simple---select the most cost effective option for your circumstance. The performance differences are unrealistic considerations.
 
Well, the most cost effective option is to use the stock 8BA cam and bearings I already have.
But, If the EAB cam could be used, the cost of the new bearings and machine work would be more than acceptable, due to the benefit of a better cam that I already have.
 
You must log in or register to reply here.
Back
Top