HPBCANADA.COM

I will make a suggestion that will encourage former T racers with MOD 56 fishing motors to return to racing. The reason they said for not racing is their current motor is illegal and they do not want to build a new motor. The problem that happened with the MOD 59 fishing motor was the altered porting caused the compression to reduce. That meant the motor can run a smaller CC head than an SST60 and still be below 160lb. compression on a gauge. Doing the math based on cylinder volume the running compression was well over 190lbs. That is the reason many MOD 56 fishing motors had to run race gas.
We know that a pure SST60 motor has to run a 30 to 30.5 CC head to be at 160 compression. That motor is the yardstick for all 56 omc motors.
HERE IS MY SUGGESTION
Make a head spec rule for the 56 omc....30.5 CC minimum. If that head produces less than 160 on your motor....so be it..... If it produces more than 160 you must run a larger volume head to be at 160.

your other suggestion was better...160lbs compression and limited to how big of jet you can run 72D or 73D jet or less don't care how or what you do, the jetting will handcuff the porting.

I got mixed feedback from T850 racers when I talked to them about a maximum size jet rule. I came up with the idea at Dunnville after seeing a T850 go from dead last to first in 3 laps. That motor had 79D jets. I said to Thom who was doing the inspecting that a simple way to slow the boat down would be to limit jet size to the SST60 jet which uses a 73D.
I spoke to the owner of that boat......my motor will blow up with a jet less than a 79D
Thom and Todd liked the idea and had no problem with the rule
Top Gun had no problem with the rule.
Others did not know you could get a jet larger than a 73D.
It was only some of the altered fishing motors that had a problem......some still run 76D jets
It's a simple rule and easy to enforce.

We will meet and review any concerns noted but please keep in mind... A: our purpose is to be as inclusive as possible and keep classes exciting, and B: we are trying to keep our rules as simple as possible. At this point, nobody's racing for major purses, entertainment value and participation are our goals. Please email us using the "contact" link on our website (opbra.ca) so we can address your concerns, as Paul has. That way the whole board sees your message, we have record of it, and it can be discussed. Personally I don't have a lot of knowledge of the T classes and have placed my trust in Craig's years of experience to put a cohesive ruling together, but I am totally open to discussing any input from anyone more versed than I am. Looking forward to a great 2019!

I have no problem with keeping the jet size in a certain ballpark. However, we have to be a little flexible either side of a given nominal jet size. Our rules allow any tuner, and any ignition timing. A SST-60 with stock timing should run 72 or 73D's. However, if timing is jacked up, then perhaps 74D's are required. So it should be ok to say 73D's +/- one or two jet sizes would be acceptable. We always ran 73 or 74D's in our T-850. In T-750 the standard OMC SST-45 jet is 56D, but the parts list shows 52-58D's . So again, perhaps a two jet size tolerance either side of nominal, should be considered legal.
I agree that a T-850 running 80D's is obviously illegal as hell, or a hopped up Oval Port.

Just sayin',

Thom

I assume the sst60 gearcase is still an illegal case to run in drags? Drags would interest me to run with our delta but have an sst60 lower

3 cylinder rules indicate "low water pickup, nose cone permitted" based on how written a sst60 would fit within rules "nose cone permitted", send them an email should be able to clarify

So this limit on jet size would accomplish what it intended: generally limit performance. So you therefore it will not allow you to run that kind of (higher performance) timing.. Correct?

What I meant is, since we are allowed to run any tuner or any timing, we should have some flexibility on jet size above or below nominal. At the least, be allowed to run the jet sizes recommended on the illustrated OMC parts list, or other manufacturers parts lists. However, running jets sizes 6-8 sizes larger than stock should be disallowed. That is why I suggested +/- two jets sizes from nominal. Hope that helps.

Mike and myself tried our SST60 gear case versus a borrowed nitro gearcase back to back with 4 different props on our critchfield. Each prop ran a different speed/rpm but the nitro case was 1 or 2 mph faster than the SST60 case with any of 4 props. Not sure of the results on other hulls but the SST60 case had no advantage on our critchfield.