my 195.6 OHV state-of-tune

i've been too conservative on my carb issues. for this engine, at least, the 38/38 is far too small. at 3200 it starts choking, enrichment beyond jetting. the guy at racetep.com pointed this out from the power and flow (CFM) and A/F numbers i'm getting.

i've pretty much ruled out EFI, even throttle body. i;'m fine tuning carbs and more than confident in the Webers so i'm going to make a manifold/cover for the IDF 44 or 48. that's externally jettable so changes on long trips is not unreasonable. and beyond the manifold fab, required for any path at all, a new IDF is $400. it's a dual carb with interchangable everything including venturis.

EDIS is far, far more reliable than any distributor could be. drop-deal solid track record for Ford, modules are common and plentiful. zero moving parts. the MJ box has been solid, but the connector has been tugged at over the years, before the power tour, i'm gonna order a new conenector and rewire with 18 guage. it's only 3, 4 wires. even if that were to die, it has limp-home 10 BTDC advance.

Since you're making a cover, a pair of 32/36s would be awesome! More for looks than anything though. I had thought about a pair of side drafts on a 196 OHV. Plate with 90 degree sweeping turns welded on. The port arrangement #1, #2/3, #4/5, #6) make spacing a bit tricky though. When I ran a pair of YF singles I placed the carb holes about 2/3 over the siamesed ports with the other third to the front/back of that anti-reversion ramp. With a pair of 2Vs, I'd run with one barrel over the siamesed ports and maybe 1/4 of the second one over the siamesed ports, 3/4 toward the lone end ports.

Twin YFs worked well, no issues until I had run them 2-3 months and maybe 2K miles. Then I burned a hole in #6 piston. Thought it was trash in a jet, but upon close inspection the rear carbs and a two number smaller main jet in it! That escaped me when I was rebuilding because the carbs were otherwise identical and had come off similar L-heads. IIRC I figured out one had been jetted for higher altitudes -- larger than normal. Both had the same tag number, I had made sure of that!

I switched back to a WCD -- found a much better carb than the worn out one I had replaced with the dual YFs.

Are you sure it's the carb and not the cam that's causing it to fall flat after 3200 rpm? I guess the power flow/ A/F readings are indicating the carb though. I guess you'll find out!


Edited by farna - Apr/19/2018 at 6:05am

I think a small turbo or supercharge would really breathe some life into a 196. The thick block and forged crank and rods should tolerate it well. Only five mains, but they are pretty wide and the crank is quite heavy... and forged also. They couldn't make cast cranks that would hold up well until the mid 60s -- that's why they are forged. Not sure about cast rods, but the 196 rods are forged.

farna wrote: Since you're making a cover, a pair of 32/36s would be awesome! More for looks than anything though.

it would actually work pretty well too, with the small primaries. it's a squat, funny looking little thing! i think the YF is nicer looking! lol i agree a poor way to choose a carb! YFs are nice rock solid carbs and cheap too.

bummer about the burned piston.

Are you sure it's the carb and not the cam that's causing it to fall flat after 3200 rpm? I guess the power flow/ A/F readings are indicating the carb though. I guess you'll find out!

yes, i'm quite sure at this point. i resisted the idea for most of a year, going by the "CFM" convention. "CFM" as a rating i dont think is very meaningful per se, but it's a fine comparator for american 4-bbls. displacement, RPM, VE mean that my little 200 ci engine simply can't pump 200 cf/m of air. the sports car crowd goes more by horsepower vs. throttle more diameter, which seems just as arbitrary. but i thinbk the point is as long as you compare apples with apples it works.

but by every thing i read that uses sporsrt car lingo going by throttle bore two 38mm's is way to small. and yeah, the A/F R meter says it's rich. and it's super consistent and repeatable every single time.

for comparison: the 38/38 is exactly HALF of a 390 holley, bore-wise.

farna wrote: I think a small turbo or supercharge would really breathe some life into a 196. The thick block and forged crank and rods should tolerate it well. Only five mains, but they are pretty wide and the crank is quite heavy... and forged also. They couldn't make cast cranks that would hold up well until the mid 60s -- that's why they are forged. Not sure about cast rods, but the 196 rods are forged.

head sealing. that's the biggest weakness of this engine. i havent had a flathead since the 70s, though i suppose i could look in a TSM, to see if the bolt pattern is any better. its really poor on the flathead.

i always "assume" (pointless fantasy) that AMC gave the head-design job to a junior engineer, and said "we need it next week" or something.

i've had a slightly more fun, but maybe less likely, fantasy of making a new cross-flow head. seriously -- three slices, each water cut and milled: combustion chamber from a 2" slab, a milled out hollow with the tops of the ports and water jacket, then a cover that would hold the rocker shaft. a crapton of quality small screws holding the sandwich together.

of course it's silly, but it's not crazy, and i could *almost* do it with what i've got. technology today makes it a lot easier. sealign the three slices is no big deal. aim for 300 hp. there's enough V8s in the world, the one-off stuff to me is a lot more fun to see.