Another day, another plan of attack. Met
Walt at the shop this morning and as usual he was already on the
throttle! He was over at Tucks Machine shop behind my section and had
the intake I left there yesterday evening in his hand. Tuck had machined
the intake out in the middle removing the separated bores from the
plenum. (A Tom Culbertson suggestion). Tom had also supplied a medium
riser block made out of aluminum and had Tuck match and machine it for
the Holley carb we are using as well.
It seems that the mill had opened up the floor to much and had punched
thru to the heat riser passage in one spot. Walt was on his way to Denny
at Hammer Art to get it patched up. More on the intake mods in a
minute..
Our plan today is to change the oil (we think it was over full ) with
15-40 Shell Rotella
(if it’s good enough for a diesel its good enough for a flathead). Rbg
:>), install new plugs (when we quit yesterday we had a high rpm
misfire), remove the Mallory dual point and install our Mag tech magneto
from our other engine and install a 390 cfm carb just to see how that
works out.
Got the oil changed (it was over full), new plugs gapped at 35,the 390
carb mounted and the magneto installed. While installing the mag Walt
noticed that the drive gear had safety wire thru the roll pin and asked
me to show him the gear before I slipped it in the cover again. I
removed the magneto (without cap and wires) and had the output lead in
the palm of my hand. Walt couldn’t see the gear roll pin and reached
over and turned the mag gear 180 degrees. BANG the output hit me in the
palm and the spark came out my elbow!! Dude that hurt like hell!! If the
mag wasn’t so heavy it would have been thrown thru the dyno room roof.
Walt thought this was pretty funny stuff he didn’t care who ya was!!
After fighting a fuel leak on the 390 we couldn’t make it quit dribbling
fuel in the venturis we decided to pull it a couple pulls and take it
off. Pretty amazing as the little carb made more torque that the larger
600 had ever made but died really bad above 3000 rpm. The 390 needs some
work??
The 600 was reinstalled and another pull was made. IT’S BETTER! The
engine will now make power at a higher rpm and seems to like the magneto
and the present spark timing, without a misfire up the rpm scale.
We are now ready to install the new modified intake manifold. Once on
the engine we had remarked the timing marks and ran the engine with
added spark timing and the new intake. Oops we are losing power, and the
ignition is breaking up above 4000 rpm. The exhaust you can see thru the
window glass looks like the header is belching fire!! What the hell has
happened now?? Our average numbers that had shown promise have just
fallen off more than 20 horse power. WOW this really sucks! Let’s go to
lunch, grab some more fresh plugs and try this one more time after
lunch.
After lunch we installed a fresh set of Champions this time. (When you
are using lawn mower plugs, you take whatever brand you can find 8 of)
Rich walks into the dyno room and looks at the mag and says “the xxxx
mag is retarded”!!! I guess I got to be the guilty one as I had the job
of tightening the hold down bolt. I grabbed my tools and checked the mag
. It was tight! It appears our old flathead style hold down wasn’t
holding the mag in place!! Rich quickly fabbed up a bearing collar and
set screw to help secure the magneto in the front cover. We also
advanced the timing a couple degrees. We have been running 28 degrees
total advance and thought we could use more. After a couple more pulls
we decided the engine didn’t like more than 28 degrees (lost power) and
re set the timing to 28.
One more change was to remove the thermostats as we couldn’t really get
the engine flow water as the dyno tank was pretty cool and the hoses
weren’t very hot. We stopped, drained the cooling tower and removed both
thermostats. OK, timing set, no thermostats, 600 Holley at 65 front and
76 rear and our day is quickly coming to a close. Ok stand on it!!!
WOW from yesterday the little engine is more than responsive, and
carries the rpm right up to the 5000 dyno cut off. The torque curve is
now hanging in there at 4000 to 5000 rpm and this dude is really
smooth!! Maximum horse power peak was 180 horsepower last pull at 4600
rpm. The engine no load will hit 6000 pretty quick and all of us feel
much better after three grueling days of constant changes etc. One more
pull based on Walt’s desire to want to know how much hp the twin water
pumps. Pop off the drive belt and hit it one more time. The answer is 3
horsepower!!
And NO we can’t drive it 4 miles on the salt with no pumps!!!
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