Marathon Rules

[Cookee]

Originally Posted by Tony Davis

Rob, read paragraph "B" of this.... http://www.britishpowerboatracingclu...ry/classes.pdf

Surely it's OK if you rebore to +30? It must be the original CC that is relevant?

[Jon Fuller]

The 250xs & 300xs were definitely intended for the lower classes. As Optis, I considered them production motors, even if they technically get supplied from Merc Racing.

A 2.5 EFI ROS (Race Offshore) is what I would have considered a race engine.

This wording is unfortunate, as it really refers to the inboard motors. I think Bob is right, this needs to go through the TWG to get clarified.
All the clean engines that clearly come from a mass production line should be allowed in the lower (E, D & C-stock) classes. We can't have this situation where interpretation can vary. As I wrote much of that wording, I'll happily take it on the chin, blame wise.

Conclusion: It needs fixing.

6.2/6.3 thing, well, I dunno, it's very grey, and when the rules were done, I/we didn't know about the remanufactured range from merc, not even sure they existed then. Even with the knowledge, I'm not sure how we'd deal with it. I suppose, as long as the exhausts meet the ruling, 6.3 might have to be allowed, otherwise we're gonna have shed loads of smartarses 'doing a Cutler'. But that wasn't how it was intended.

I would have been happy with a 12 litre limit in D, aiming at twin 5.7's (350ci) but with the 6.2 being the current main offering as a small block, it really had to be 12.5 litre. As I say, I/we weren't aware of the reman engines from Merc when this was done.

[Jon Fuller]

Originally Posted by Cookee

Surely it's OK if you rebore to +30? It must be the original CC that is relevant?

That's how I see it, but the smartarses will be lining up, I assure you. Which means the rules, or at least the wording, is flawed.

I think the advertised std bore /stroke are the relevant figures, but agree, it's all a little close for comfort.

[Cookee]

Originally Posted by Jon Fuller

The 250xs & 300xs were definitely intended for the lower classes. as Optis, I considered them production motors, even if they technically get supplied from Merc Racing.

A 2.5 EFI ROS (Race Offshore) is what I would have considered a race engine.

This wording is unfortunate, as it really refers to the inboard motors. I think Bob is right, this needs to go through the TWG to get clarified.
All the clean engines that clearly come from a mass production line should be allowed in the lower (E, D & C-stock) classes. We can't have this situation where interpretation can vary. As I wrote much of that wording, I'll happily take it on the chin, blame wise.

Conclusion: It needs fixing.

I thought the early version of the rules even mentioned the 2.5 ROS motor and that the CC differences were set to take account of them versus the EPA motors?

Here you go:

* = non epa OB’s, including EFI ROS motors with direct crankcase fuel injection allowed for 3 years
(grandfather) , beyond this time (start of 2012 season) these will NOT be permitted.
*** = Non epa OB’s excluding EFI ROS with direct crankcase fuel injection allowed for 3 years
(grandfather) , beyond this time (start of 2012 season) these will NOT be permitted.

You can have 2.5 ROS's until 2012!

[Mike Lloyd]

We are using the 6.2litre small blocks in the new Ring 34 as most people are aware but if you wanted to come out with a pair of OLD Merc small blocks bored out to 6.3litr I don’t think we for one would start jumping up and down Tony shouting foul.

At the end of the day it’s what happens out on the water over 180 miles and if you can beat us with your 6.3’s then good on yer. You wouldn’t hear any complaints from us, except in the bar as a bit of fun!

Anyway, You said you had packed up racing?
ML.
.

[Jon Fuller]

Yes, as I say, this wording really relates to inboards. and yes, the cc figures were supposed to level the field as best as possible tween the OB's

Originally Posted by Cookee

I thought the early version of the rules even mentioned the 2.5 ROS motor and that the CC differences were set to take account of them versus the EPA motors?

Here you go:

* = non epa OB’s, including EFI ROS motors with direct crankcase fuel injection allowed for 3 years
(grandfather) , beyond this time (start of 2012 season) these will NOT be permitted.
*** = Non epa OB’s excluding EFI ROS with direct crankcase fuel injection allowed for 3 years
(grandfather) , beyond this time (start of 2012 season) these will NOT be permitted.

You can have 2.5 ROS's until 2012!

[OCRDA]

Dont take this as gospel until you calculate it yourselves but !!

The Spec on the 6.2 that I have found shows:

Bore & Stroke 101mm x 95mm = 6090cc
+.030 Rebore 101.75mm x 95mm = 6181cc

Unless I have pressed the wrong buttons !!

Bob

[OCRDA]

Originally Posted by Cookee

Surely it's OK if you rebore to +30? It must be the original CC that is relevant?

The normal way for this rule would be to allow reboring to manufacturers max oversize which I am guessing would keep it within its catalogued spec.

Bob

[Jon Fuller]

the metric numbers you've found are 'rounded off'.

bore and stroke are actually 4.000 x 3.750 , or, 101.60mm x 95.25mm capacity, 377ci, or 6175cc

the remanufactured engines are 383ci which is 4.030 x 3.750 , or, 102.36mm x 95.25mm, or 6273cc

[OCRDA]

Originally Posted by Jon Fuller

the metric numbers you've found are 'rounded off'.

bore and stroke are 4.000 x 3.750 , or, 101.60mm x 95.25mm capacity, 377ci, or 6175cc

the remanufactured engines are actually 383ci which is 4.030 x 3.750 , or, 102.36mm x 95.25mm, or 6273cc

In that case they are too big !!

[wickedtopspeed]

Best is to get it clarified asap, so that everyone knows where they stand, and then there can be no argument. Arguments only lead to making the sport look silly from an external perspective.
IMHO

[Jon Fuller]

Originally Posted by OCRDA

In that case they are too big !!

I think the problem is, because the +0.030" happens to be the difference tween the motors AND a recognised std oversize of the 377 engine, policing it would be hard. It's a fkk up, and I know how it was supposed to be, but am starting to think that 4.030 x 3.750 should be the maximum allowed, end of. It would keep the smartarses happy, and clarify things. It would also mean dropping the allowable oversize rules for the 383, as it would have already been used up, more confusion. next, someone will break a 383 and complain they can't oversize it,...more smartarses.

Exhaust rules would need to be strictly adhered to, that way the 400hp 383ci engine doesn't fit, at least not without an exhaust change, which would hopefully bring it's power in line with the 360hp models..

[FLYING FISH]

I know this doesn`t answer the original question re working the rules to the maximum,but in the course of compiling the offshore statistics I always note the horsepower of the various craft,which when only the cc is stated becomes a pain trying to convert,in actual fact you can`t,but the attached list just shows what a muddle all this can become when you look at the conversion factor list.
Jon has already seen this list,and as I said to him at the time,despite one`s best efforts you will never write a set of rules that is completely watertight.
Note: the statistics are based on that given in the entry lists for better or worse.

[FLYING FISH]

Hopefully bit more readable.

[FLYING FISH]

Well,that didn`t work out,try again.

[Mike Ring]

Originally Posted by OCRDA

In that case they are too big !!

Thats why a lengthy discussion took place before we ordered our Motors.

Mike

[Mike Lloyd]

A few emails have arrived over the last two hours which have cleared the smoke.

I think it’s all quite clear. There are obviously individuals who are trying to get a steal on those who have already committed or have already purchased engines for racing in Class D and at this late stage that cannot be allowed to happen.

The rules quite clearly state that the maximum CC for Petrol in Class D is 12.5. That allows the Merc 377 to be used which is what most people have acknowledged, as we have (Ring 34 Team).

The rules do not allow the Merc rebuild 383 to be used in Class D as the bore and stroke exceed the 12.5 limit and it's a different engine. End of story.

If anyone thinks they can get round this by the so called “re-boring” then they are wrong. If you re-bore an old 377 then that’s fine but to try and slip the 383 in as a re-bore is just not playing the game and WOULD be protested!! It’s a different engine and is catalogued and sold as such.

The rules will NOT be changed just because someone wants to get an edge. It simply isn’t going to happen.

Marathon Rule change has already been discussed with some heat at the ORC and it was agreed that the Marathon rules cannot and should not be changed until a few years have elapsed. It's not fair on those who have already spent considerable money buying the correct engines and it's not fair on those boat builders who have also spent considerable amount of money manufacturing boats for those individuals who want to go Marathon racing. There has to be stability and continuity.

Marathon racing is now hugely popular and growing fast and has one of the biggest fleets in the U.K. 47 boats in the RB08 and there will probably be even more at Cowes this year. Mess about with the rules and you will destroy it as has happened in the past.
ML.
.

[Jon Fuller]

That's good.

I will be asking Barrie, Bob etc to consider and clarify the OB wording, as it is clearly flawed at present, and must be sorted. I think the OB's generally shouldn't fall under the wording about 'Race engines/production engines'. And even the pure race engines such as the 2.5efi ROS will be outlawed at the end of next year automatically, and I wonder how many people would realistically want to run such an engine anyway. Certainly all the clean Opti type motors, regardless of their labelling, should be allowed in all classes, as intended when the stuff was written.

Lets hope we can sort these details and move on.

[Matt]

So a 377 scorpion is ok?
But a +30 377 scorpion that's been rebuilt isn't?

[Jon Fuller]