LA Meeting

[Cookie_13B]

Has anyone heard of any rule changes that took place at the LA Meeting ?

[DeanFHobart]

The SORC allowing the Yamato cooling hole to be drilled out to .310" diameter.

[KURPS]

.310 inch odd size, do you mean .3125 inch = 5/16 inch drill bit

[DeanFHobart]

Correct, that is an odd size, but it is .310" ...... not .3125" = 5/16. You will need to contact an SORC member to explain, I'm not sure. M drill size = .295", 19/64 drill size = .296875", N drill size = .302". I would get all the drill sizes between the starting diameter and the final diameter and do it step by step. Also, grind off the tip so not to damage the copper tube. And, find out how deep you can go. Also, reamers could be used instead of drill bits.

[csh-2z]

We went with .310 specifically to prevent somebody from using a 5/16" bit and inadvertently or accidently making the hole oversized. When you drill with a 19/64" (.296875) bit and wobble a little bit, you're not oversizing the hole out of spec.

[guedo499]

We went with .310 specifically to prevent somebody from using a 5/16" bit and inadvertently or accidently making the hole oversized. When you drill with a 19/64" (.296875) bit and wobble a little bit, you're not oversizing the hole out of spec.

I believe they had my skill in mind when they thought of .310....

Next question:

SO, how do we do this chumfering?

[csh-2z]

It will need to be done very carefully. I believe Tom Johnston would be able to provide the most accurate process. I also believe he is planning a set of instructions and possibly an angle template to make it easier. I'll get back with you all on that.

[DeanFHobart]

I have heard that TJ is going to make a guide drill plate available. And an instruction sheet. Give him a call.

[flatsmoke]

Actually the copper tube is 7.9 mm which is .3110". So, not much need to police that hole as it won't help to go bigger. However, be careful to center drill the tube so you don't drill through the wall of the copper tube.

[daveracerdsh]

I sure hope racers take care of this before they come to the first race if they so desire.....would hate to see people get thrown out at a race for drilling hole out wrong at a race....

[flatsmoke]

The sooner the better on getting the drilling rules published.

[daveracerdsh]

it will happen soon. I think this rule is a huge mistake and will result in many many many racers getting tossed out in inspection for illegal hole size. the cool tube was so easy...but no. we had to make it harder. just my 2 cents worth.

[stockc]

Let us drill till our individual cooling needs are met. No inspection, its just water.

[Harold8]

And how many will drill through the copper pick up tube? Is this tube replaceable if wrecked?

[Ram4x4]

I understand the 'cool tool' was voted down because of a fear of radical tuck angles and so forth. If the new hole size, plus chamfering works well, what is preventing radical tuck angles with that solution? What prevents radical tuck angles for other classes running engines that don't have these cooling issues?

We now have a 'solution' that requires drilling a potentially sensitive hole <snork> and currently no directive on how it should be done. I understand there are intentions of supplying some directions and possibly a template, but the possibility of buggering it up is still there. I guess as the saying goes, it's not the size, but how you use it....

Just so I'm clear, we've opted for a solution with a more difficult modification to implement that may, or may not allow for, or prevent that which sank the easier alternative. With the new hole and chamfering we'll potentially have a select few who will be able to radically tuck and cool as opposed to an easier to install option and easy to define and measure tuck limits. We've also created another thing to inspect and some sort of inspection tool/device will be needed by the inspectors.

On the good side, the 300SSH guys aren't excluded from the fun.

[Brian10s]

Ed,
You don't need to do anything to your stuff and I would recommend you don't. I am certainly not touching this. And the radical tuck has always been there - the vote wasn't to prevent it. All the vote did is for those few that had cooling issues, is provide additional cooling.

And there is no rule that says you go at it with a black & decker (from cooling to lowering the CC's). If you don't know what you are doing - DO NOT do it. There are plenty of guys who have the skill and equipment to do this correctly, without making it illegal.

[Matt Dagostino]

Ed............if you own a 321 you will need to do every bit of what was legislated to have a chance to cool your new engine in 20ssh/CSH. This issue has been all about getting the new model 321 to cool! Other out of production Yamato models do not have the serious issue the Model 321 has and hence the new rules will help if you are having issues.....stay cool my friend! Brian, i was at the meeting and made a presentation and heard every word! The hypothetical argument was made by several commissioners that the external cool tool would lead to radical tuck and boat designs and that drilling would not. Most are just happy something got done to help our Yamato products cool. That was the goal.

[dholt]

Don't overstate the issues here.
1. This is NOT MANDATORY. If you don't have issues pumping, then leave the hole alone. For anyone running CSH, CSR and 25SSR...that's probably the case at 3/4".
2. There was already a max diameter spec on the water hole. It's been there forever. People could have drilled it out to max...and in theory the hole should have been inspected just as any other measurement on the Yamato. Why do you think it will become an inspection nightmare now...if it wasn't before?
3. If you're gonna open the hole up, be smart and careful.

[Brian10s]

Exactly! There was a very limited need for additional cooling before, it has not changed. There are very few people who actually need to drill anything.

[Matt Dagostino]

Most believe drilling out to .297 is/was ILLEGAL. That was the reason for the rule clarification on page 73 Rule 1 under non permissible modifications. Drilling or TOUCHING the inlet hole was only allowed in the case of a 'repair' as stated on Page 72 Rule 16! Most believed just because the spec of .297 existed in the index did not mean you could hog out the stock hole from .260 up to .297 to gain a advantage!

[stockc]

Post #4 shown below:

"We went with .310 specifically to prevent somebody from using a 5/16" bit and inadvertently or accidently making the hole oversized. When you drill with a 19/64" (.296875) bit and wobble a little bit, you're not oversizing the hole out of spec."


Ok, max. legal hole size is .297 which already slightly exceeds the 19/64" bit we are being instructed to drill with? Say one wobbles just right and achieves a .309 hole, how much more water intake will that tiny increase yield and what temp reduction should drillers be expecting?