Thoughts on the Stock Class rules

[Daniel's Racing]

Run the engine the way it came out of the box. If you replace anything it must be EXACTLY what you take out.

This is like the simplest set of rules. It doesn't have to be complicated.

The only way to know if all those parts are still as Zenoah had them out of the box is going to be time consuming unless you have xray eyes.

Raise your right hand and swear the engine is frigging stock before the race should be enough.

It is too bad that anyone would ruin the trust we have in everyone and not just run a bone stock out of the box engine.

Hard to understand what reward someone would feel in the accomplishment of winning a stock class race with a illegal engine.

 

[Hydro Junkie]

It is too bad that anyone would ruin the trust we have in everyone to just run a bone stock out of the box engine.

Unfortunately, there are some that want to win and rules be dammed if they get in the way

 

[user 21992]

Want to start by what Don Maher said in post #159, "This subject" just has gotten a little off track from the original post! And I have to agree with that, I'm not a politician by no means, and for many years, just loved building and racing RC Gas Boat in all classes.

Chris Herzog, I comment you for the effort, in attempting to set straight forward and simple rules for measuring and items to look for in the event a club need to inspecting motors at Major Gas National Events. Have read a few or some of the ways a motor can be manipulated to gain an advantage, along with those that have not been mention yet. I'm sure, you have made an account of all of them, already. It would be interesting to start a new thread with the title, "Un-for Seen Ways" on what to look for in "Inspecting Stock Class Zenoah Motors".
Hope the best for the Hobby, Stay Well !!

Let's Start: 1. Removing small diameter spring from the rear and front rubber case end seals. --------------------------
In turn reduces engine drag.
2. Using a wider Tiger King wrist pin bearing. No power grain but may add longevity to the motor.
3, 90* water fittings. May only help astatic for a clean routing of water lines.

Only #1 might have a small advantage in power grain, but lets face the fact that all three are not the way the motor came out of the box,

 

[Bradley Maglinger]

Bradley -

Yes, the boats were all teched before the race at Evansville, and I think that was great of the club to do that. I should have been more specific in what I meant to say. I did not see any post race tech of any of the top three boats. It’s a quick thing to do, and could be streamlined by doing just the 1st place boat. I get that at Evansville doing a pre race boat tech was sufficient, I think going forward, a post- race boat tech might be worth doing. Thanks for clarifying Bradley.

Mike

Mike, just wanted to clarify we did do a post race tech, that is how we found discrepancies in SS Mono and Crackerbox. When we found those discrepancies, we went to the next boat which in that case they didn't have any discrepancies so we didn't have to check anymore beyond that in that class.

 

[Daniel's Racing]

You can check bore/stroke, carb and some other things without really taking anything apart so those few things should be done to ALL boats racing in a points or national stock class race.

 

[DON MAHER]

Daniel,
i am anything but a motor guru, so is there a tool to check the bore without removing the cylinder?

 

[LohringMiller]

The cooling jacket diameter is different with the different bore sizes. The two examples I grabbed show 50 mm OD for a 32 mm bore and 53 mm OD for a 34 mm bore Zenoah.

Lohring Miller

 

[Wasted wages]

But the bore could have been changed internally and that would have nothing to do with the external water jacket size...

Like Don said above, I also have no knowledge of how anyone could check bore size externally..

Now,, one could argue that if the piston was pulled to a pre determined point (ports closed off ) and the cylinder was filled with a known amount of fluid,,, bore and stroke could be determined to be legal in this manner..

 

[Daniel's Racing]

Daniel,
i am anything but a motor guru, so is there a tool to check the bore without removing the cylinder?

It is a stock 260 class. The guy's teching the engines should be able to recognize a G260PUM cylinder from 10 feet away.

If the outside is correct you can be 99.99% sure it is what it is on the inside.

You can verify the bore by using stick end of caliper and going through exhaust port to the other side of the bore and measuring out to the face of the exhaust port. Knowing this measurement from a known stock cylinder would tell you if any monkey stuff happening. Lol.

The stroke is easily measured through the sparkplug hole.

The PUM case itself is all the same from the 23cc to the 29.5cc so any from 231, 260, 290 or 300PUM engine is legal.

 

[Wasted wages]

You can verify the bore by using stick end of caliper and going through exhaust port to the other side of the bore and measuring out to the face of the exhaust port. Knowing this measurement from a known stock cylinder would tell you if any monkey stuff happening. Lol.

I would agree that a go no go gauge could be made for the thru the exhaust port measurement, where a caliper could be subjective to the person measuring or hitting the cylinder dead center. Measuring out to the exhaust flange does leave room for monkeying
around with the final measurement by cutting or sanding the flange though...
Bore measurement with a bore gauge is the only "real" measure..

Of course, stroke can be measured easily with a depth mic or caliper.

 

[LohringMiller]

"But the bore could have been changed internally and that would have nothing to do with the external water jacket size... "

Don't be silly. The reason the water jackets are bigger is that the cylinder OD is bigger. Who do you know who is able to rebore and recoat a die cast cylinder? The wall thickness is going to be too low in any case.

The exhaust port measurement will require engine removal in a lot of classes. If you need to do that you might as well remove the cylinder and check for other modifications.

Lohring Miller

 

[SayMikey]

Nine pages of nothing,The stock class rules are working. Whats broken is racers not having the balls to protest at races. Put up or shut up I say

 

[DPeterson]

LOL Mike, I'd like to pre-protest all the top 3 place winners in all IMPBA races this year. Where do I send the money?

 

[SayMikey]

Great point Doug LOL

 

[Don Ferrette]

Nine pages of nothing,The stock class rules are working. Whats broken is racers not having the balls to protest at races. Put up or shut up I say

DING! DING! DING! We have a winner folks, give Mikey a cigar.

 

[Kevin Sheren]

What Mikey said!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Wasted wages]

"But the bore could have been changed internally and that would have nothing to do with the external water jacket size... "

Don't be silly. The reason the water jackets are bigger is that the cylinder OD is bigger. Who do you know who is able to rebore and recoat a die cast cylinder? The wall thickness is going to be too low in any case.

The exhaust port measurement will require engine removal in a lot of classes. If you need to do that you might as well remove the cylinder and check for other modifications.

Lohring Miller

Not to keep harping on this but it has been suggested that some people have heated cylinders and squashed them in a press....

Are you saying that after this has been done that the bore is still round and straight?
I doubt it.... So the bore would have to be resized in some fashion, honed oversize...

 

[LohringMiller]

Good luck with trying anything like this. In any case checking the water jacket diameter is just a quick screening method. A complete tear down of the top finisher's engines is probably the only way to satisfy everyone at a national event. In my local club we run all engine sizes together and somehow the best guys still win even with smaller stock engines against bigger mod engines.

Lohring Miller

 

[LohringMiller]

I just measured a 34 mm bore broken cylinder I had . It has 2 mm wall thickness. Increasing the bore to 36 mm would leave 1 mm wall thickness. I broke this cylinder with a 2 mm wall. Good luck with 1 mm.

Lohring Miller

 

[Wasted wages]

I doubt there is anything to be gained with squashing a cylinder either... especially if the case is that thin...I doubt there is much liner coating left once it has been rehoned straight anyway...