The flat head bearings was the idea of the machinist that was doing my
engines in those days. I have owned a few Ford flat heads over the years
and remember the unique chirping noise that loose rod bearings would
emit. That about sums up my expertise on that subject. The flat head rod
bearing is two rather heavy halve shells that are allowed to float
within the rod and around the crank pin. Oil on both sides of the
bearing helps to cool the bearing and, of course, negates the
possibility of a spun bearing. It seemed to work well for us. I
understand that the smaller journal size results in less friction. When
we went to the large journal three inch stroke Chevy crank that was on
the negative side in making that decision. We did it for strength.
We use bearings that are designed for racing motors. As for the bearing
composition, I don't know, I believe that it is a softer material,
though. Probably the proper clearances are the key factor.
Tom, Redding CA - #216 D/GCC
brian falkner wrote:
>
> < "Thomas E. Bryant" <saltracer@awwwsome.com>
> Wrote
> <Dick,
> <My engine was a stock '55 block, '54 crank (eventually cut and fitted
> <for the full floating Ford flat head rod bearings), stock rockers, 12:1
> <Jahns cast pistons, Isky flat tappet Cam, heads ported by me, adjustable
> 8888888888888888888888888888888888888
>
> Hey Tom, the bit about the Flathead full float brngs is interesting to me &
> no doubt some others!.
> I guess this was done for durability?..those full floaters made the early
> flatheads almost indestructible in that area.....as compared to the 1/4 shells
> that were used in the Canadian engines from 41-48 & all the 49-53 8BA blocks,
> ['54 in the Commonwealth].
> Crankshaft rod journals lasted at least twice as long and if your "Donk"
> developed a big end rattle, [low oil pressure a major factor] it would
> still get you home, and survive a lot more thrashing for many more miles
> especially if you chucked in a can of Bardahl Heavy Duty!.
> These brgs are a horrific price now and I'm wondering...
> Is this STILL a viable Hemi trick?.
> What is the ultimate bearing design & composition for high revving V8's
> these days?.
> What is the ideal journal size dictated by "bearing speed" and what other
> factors have a bearing..[sorry] on any decision on journal diameter.
> I understand some journal diameters are reduced to minimize bearing speed.
>
> Just a coupla questions to keep you all
> from dozing off!...from the
> Antipodean BDF
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