Fast Fred's OMC Mod 50 secrets Thread #2

[Danny Pigott]

Anthony, I think the F-3 record 104 mph is a kilo not around the course. UIM is hard to understand an I could be wrong ,but this is how i see the record. Maybe i'am looking in the wrong place.

[David Mason]

Always heard the rumor about Mike Lopez and the sleeved down 56........ decided to test the theory. As stated before, much as it's intriguing, we'll never see F3 speeds because Mods run gas & oil. I'll be glad to see one of the twins get laps speeds of 90 for 1 mile 3-lap. Can't wait!

It works real well. A OMC Tech was flown to the Mod Nationals in Hinton WV one year to prove that the engine was indeed a 56 CI block. It was verified there. He also admitted to sleeving it down to 3" bore. he holds the records in the old FEH and now known as 850CCMH, ovals. I beat his 1 mile record one time by less than a 1/8th of a second for one heat. Next heat could not back it up and it was not beat by enough to call it a record. That was at Dayton in the summer. I can say one thing, you have to be able to turn wide open throttle and not touch your sponsons or rear chines much if at all to even come close at lets say close to 95MPH. In a kneeler it was exhausting to wrestle the torque through the corners, in a laydown it would be much easier.

At any rate, no, Lopez was not allowed to race his engine at the Hinton WV Nat's that year. Rules are pretty specific on building upon a recognizable service block of no more than 49.9 CI. Most of us now know what the "other" blocks look like now.

I guess this brings to perspective how expensive it can get to race this class. No wonder the number of participants is almost to the point of putting the class on probation. Given the state of the economy, it does not surprise me.

[OUTBOARDER]

Anthony, I think the F-3 record 104 mph is a kilo not around the course. UIM is hard to understand an I could be wrong ,but this is how i see the record. Maybe i'am looking in the wrong place.

UIM F3 is a "Circuit" on the course Record. Probably on a really large course.

Kilo and Top Speed records are called Kilo or Top Speed.

[Racer's Edge]

I guess this brings to perspective how expensive it can get to race this class. No wonder the number of participants is almost to the point of putting the class on probation. Given the state of the economy, it does not surprise me.

Dave, I believe you must be mistaken. According to APBA's web sight in 2009 850H was Modified Outboards third largest class with 40 entries. The only two with more were 500H and 750H.

[wolfgang]

And from what I gather, legal in APBA Modified Outboard 850CCMH and 850CCMR classes only. Looks like the rule book has been beat for some time now. I just hope someone can beat Lopez's 56CI records set in the class..

If the 56ci block commensurately has larger ports, sleeving it down to 50ci would be the same as casting a special (50ci) block with larger ports. On the other hand, it all depends upon what the rule book, the inspectors and MONEY allow.
I remember, that Renato Molinari`s motors were breathed upon by Autodelta (at the time the racing arm of Alfa Romeo). That produced astonishing results, like a three cylinder OE engine welded up from a disected TwisterII block. Similar treatment apparently was given to the iL6s and V6s, iro crankshafts, flywheels, con rods, also not quite in line with the UIM regulations for ON.

[Powerabout]

I would have thought that without access to the exhaust side of a 56 er' a 49 based engine would always make more power?

[Tim Kurcz]

Side exhaust was avoided due to cost/complexity. It's easy and inexpensive to sleeve the 56 - did it in the home oven while my wife was out! The real advantage is piston durability because of better piston skirt suppor. My FE's wear out pistons in only 15 hours because there is so little sleeve after finger porting. Am hoping to find out if the engine actually produces power. No body has ever confirmed the rumor that Mike ran this type engine for the lap records. We all know Cheney used a conventional FE for the Kilo........... Time will tell!

BTW: Research indicates F3 was run on alky for some time in Europe putting USA drivers at a disadvantage there.

[850cc racer]

Hey Tim, its an interesting one, pistons support,being no blister sytle ports? have bridge port or oval been used?
interesting you say 15hrs. my old motor i ran it for 5 years untouched, thats a 49.7 fingerported had FT (dome topped) pistons in it.. used to pull 6500 all day long until it slightly lifted the top edge off the piston and broke the top ring.. still pulled 5800 when i realised something was up, didnt hurt the bore at all

[Mark75H]

If I were an inspector in mod, I would DQ the 56 block because it is visibly different from the legal 49 ci block.

Don't the rules say you must start with and present for inspection what is visibly obviously a legal block?


I have been told this is how inspectors planned to check on the illegal 650x/700x blocks vs the legal 650xs block ... even though the rules allow you to port an XS to be identical to an X.

[Tim Kurcz]

For Rob and Sam - Getting away from the "blister" sleeve to the full support "Mod-50" style sleeve and making power is the test. There is no advantage in port size - the 56 won't support the width through existing exhaust ducts. Also the block & crankcase is 5# heavier, and has less the effective (though potentially quiet internal) exhaust feature (see picture again).

The fact is 56's are plentiful and offer better durability for overall lower cost. But will it make power in the 3" bore configuration? Example is my FE's turn 8200-8600, this is likely why they wear out pistons so quickly. One evil twin is a 56, the other a 49.9 with McDaniels pistons and fishing rods. Both are ported identically. Testing will prove which is better soon.

As for the rules; IF Mike Lopez actually ran a sleeved down 56 for the records (which I doubt), AND those records were accepted by the APBA (they stand today), THEN the powerhead would have been deemed legal by APBA inspectors (in 2000), and therefore should be today.