It is currently November 24th, 2024, 10:23 am

OPBRA......ENGINE RULE CHANGES FOR 2019...OVAL T750 & T850

View active topics

All times are UTC - 5 hours [ DST ]


Post new topic Reply to topic  [ 53 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6  Next
Author Message
 PostPosted: January 29th, 2019, 1:25 pm   
Member
User avatar

Joined: June 5th, 2015, 8:56 am
Posts: 533
Don,
what I meant was:
-there are people who already have race rigs but are not coming out to races to compete..
-will a particular rule change help get them to participate and race?

I know there are some who just don't have the time. But my statement was specific to those who would come out if rules were different, or if there was an additional motor class (T950?) for stronger motors...?

So again, my comment/question is specific to getting current owners to come out and race..

Those of you who do fit the above description, if you can, please provide some feedback - here or in private message/email.

_________________
Critchfield T850 OMC 56ci
Delta T750 Yamaha 55
1989 Voodoo Yamaha 70
1980 Thundercraft v142 Restored


Top
 Profile Send private message  
 PostPosted: January 29th, 2019, 6:58 pm   
Team Member
User avatar

Joined: April 3rd, 2012, 7:53 pm
Posts: 406
Location: Lakeport, MI
- sponsors / entrance fees to cover show / prize money
- marathon event like TOPO (on the Grand River)
- solve nitro gearcase high repair cost issue (merc gear case / adaptor plate)
- loaner safety gear for new racers (something APBA does)
- more high spectator race events (like Gravenhurst)
- driver school (like in Dayton, OH with APBA race boats available to drive)

A few ideas....


Top
 Profile Send private message WWW  
 PostPosted: January 30th, 2019, 10:52 am   
Member
User avatar

Joined: June 5th, 2015, 8:56 am
Posts: 533
sheuninck wrote:
A few ideas....


Thanks Steve. Those all make sense.
Some of those ideas are in place in one form or another. I believe it would take more resources (sponsors money, volunteers' time) to make things ideal..

-TORC has a driver's school.
-both TORC and OPBRA Gravenhust, and OPBRA Peterborough had decent spectator attendance.
-other racers were great and helpful, lending me safety gear my first season of running.


I've been asking around to see what it would take to make gear sets... it is far from trivial or inexpensive.

Would anyone want a rule change that allows custom mids or adapters so you can use off-brand gearbox on the 3cyl OMC, for example..?
Adapt a Merc or Yamaha gearbox to the OMC 3cyl?

_________________
Critchfield T850 OMC 56ci
Delta T750 Yamaha 55
1989 Voodoo Yamaha 70
1980 Thundercraft v142 Restored


Top
 Profile Send private message  
 PostPosted: January 30th, 2019, 11:54 am   
Team Member
User avatar

Joined: April 3rd, 2012, 1:52 pm
Posts: 3168
Some additions to Matt's post.
Another BIG RACE
From OPBRA facebook
Some dates you may want to keep open this summer:
July 13-14. Nice time to visit North Bay
August 10-11. Great weekend for being in Gravenhurst
September 14-15. Perfect end of season in Peterborough..

NEW RACER:
YOU SHOW UP AND RACE YOUR T BOAT AT AN OPBRA RACE......I WILL REPAY YOU THE $75.00 ENTRY FEE AND SUPPLY THE SAFETY GEAR


Top
 Profile Send private message  
 PostPosted: January 30th, 2019, 3:03 pm   
Member

Joined: August 22nd, 2013, 4:13 pm
Posts: 273
Gear sets for the OMC Nitro case are available from SeaWay Marine


Top
 Profile Send private message  
 PostPosted: February 5th, 2019, 1:07 pm   
Team Member
User avatar

Joined: April 3rd, 2012, 1:52 pm
Posts: 3168
The 160 lb compression rule measurement when running an SST60 motor or a 56 fishing motor.
A fresh SST60 powerhead built to APBA spec will have 180 lb compression.
That is with a 28.5 cc head and .444 inch pocket depth.
A 30cc head is required to average 160 lb. and .550” pocket depth.
Here is the SST60 Spec Sheet:
https://www.apba.org/sites/all/files/do ... 022515.pdf

A bone factory stock 56 fishing motor
When I originally played with the compression on the 56 fishing motor I found that just putting an SST60 head on the fishing motor got 157 to 162 compression.....and the performance was equal to 49 OMC and Yamaha 70CES.
When I rebuilt a stock fishing motor and decked the block just to straighten it, I needed a larger volume head. I race tested many different volume heads. The best fishing motor powerheads ran at 147 to 155 compression. and on 91 octane Shell gasoline.

You can always take more off the head, but I would start with a 31 cc head.


Top
 Profile Send private message  
 PostPosted: February 5th, 2019, 5:22 pm   
Team Member
User avatar

Joined: April 1st, 2012, 12:29 am
Posts: 1445
Hounddog wrote:
The 160 lb compression rule measurement when running an SST60 motor or a 56 fishing motor.
A fresh SST60 powerhead built to APBA spec will have 180 lb compression.
That is with a 28.5 cc head and .444 inch pocket depth.
A 30cc head is required to average 160 lb. and .550” pocket depth.
Here is the SST60 Spec Sheet:
https://www.apba.org/sites/all/files/do ... 022515.pdf

A bone factory stock 56 fishing motor
When I originally played with the compression on the 56 fishing motor I found that just putting an SST60 head on the fishing motor got 157 to 162 compression.....and the performance was equal to 49 OMC and Yamaha 70CES.
When I rebuilt a stock fishing motor and decked the block just to straighten it, I needed a larger volume head. I race tested many different volume heads. The best fishing motor powerheads ran at 147 to 155 compression. and on 91 octane Shell gasoline.

You can always take more off the head, but I would start with a 31 cc head.


Current rules as they read don't allow head cutting :?

_________________
Bullet 20 cc Super Comp
Delta with a slow 56
Jcraft with a ProV 150


Top
 Profile Send private message  
 PostPosted: February 6th, 2019, 9:45 am   
Team Member
User avatar

Joined: April 3rd, 2012, 1:52 pm
Posts: 3168
LittleCharger wrote:
Current rules as they read don't allow head cutting :?


That was the reason for my post. An SST60 head is the shaved fishing head. To reduce the compression on a pure SST60 to 160 the head has to be a larger volume. You are making a SST60 head and just not shaving as much off.


Top
 Profile Send private message  
 PostPosted: February 6th, 2019, 10:19 am   
Team Member
User avatar

Joined: April 1st, 2012, 12:29 am
Posts: 1445
Hounddog wrote:
LittleCharger wrote:
Current rules as they read don't allow head cutting :?


That was the reason for my post. An SST60 head is the shaved fishing head. To reduce the compression on a pure SST60 to 160 the head has to be a larger volume. You are making a SST60 head and just not shaving as much off.


Current rules don't mention head shaving only mentions 160lbs as limit not how achieved. Only thing you can touch sst60 wise by current rules is "engine block and rotating assembly" and a permanent block at that 8-)

I don't believe this was intent so have asked for clarification.

_________________
Bullet 20 cc Super Comp
Delta with a slow 56
Jcraft with a ProV 150


Top
 Profile Send private message  
 PostPosted: February 6th, 2019, 11:13 am   
Team Member

Joined: April 4th, 2012, 10:08 am
Posts: 626
OPBRA Rules Committee is meeting again at the end of the month.
These comments will be discussed.
Stay tuned!

Remember, they are doing everything they can to get more racers out in T-boat.
The crowd loves them!!

_________________
Specializing in custom marine performance product fabrication


Top
 Profile Send private message  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 53 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: Hounddog and 7 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  


Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Style originally created by Volize © 2003 • Redesigned SkyLine by MartectX © 2008 - 2010