ORC Technical Bulletins

Technical Bulletins from APBA Offshore Racing Commission

Class: Stock

Bulletin Number: 95 - 2.0

Date: 8-24-95

Effective Date: 9-3-95

Subject: Electronic Control Unit

Please be advised that the APBA Offshore Technical Committee and the APBA Offshore Racing Commission have determined that the Electronic Control Unit (ECU) for the fuel injection systems on the outboards is to be considered as a tuning device rather than a spec. device, as long as it is an OEM unit for that make/model of outboard, it may be interchanged between year models. This will define the 200hp model analog and digital ECUs as interchangeable on the Mercury outboards.

Class: Stock

Bulletin Number: 95 - 3.0

Date: 8-24-95

Effective Date: 9-3-95

Subject: Electronic Control Unit

Due to a mid-year introduction, the 1994 200 hp Mercury outboards spec. sheet will not properly describe later 1994 200 hp Mercury outboards. In this case the 1995 spec. sheet should be used, as the later model will be the same for purposes of inspection and compliance to the stock specifications .

Class: General

Bulletin Number: 95 - 4.1

Date: 8-24-95

Effective Date: 1-1-96

Subject: INBOARD PRODUCTION Cylinder head criteria and modification limitations.

Cylinder heads used in this class must be CAST IRON in material. The cylinder head castings must be provided from the original manufacturer with the standard port options, and must have the guides installed in accordance to the tolerances set forth in the original engine manufacturer's specifications. The cylinder heads must be equipped from the original manufacturer with the accessory mounting holes provided. For big block Chevrolet engines, any cast iron head manufactured by General Motors for Chevrolet, and the cast iron heads provided by World Products, part number 3003 and 3004, meet the required specifications. Other cylinder head manufacturers may apply to the ORC Technical Committee for approval of their product. (See bulletin 95 - 4.2)

Class: General

Bulletin Number: 95 - 4.2

Date: 8-24-95

Effective Date: 1-1-96

Subject: Cylinder head modifications or features NOT ALLOWED for INBOARD PRODUCTION

The spark plug holes MAY NOT be relocated or altered.
The valve guides and valve stem angle MAY NOT be altered.
The rocker arm stud location or angle MAY NOT be altered.
The cylinder heads MAY NOT be angle milled. The engine block head surface MAY NOT be angled-milled to create a similar effect.
The 90 degree relationship between the deck surface and the intake manifold surface may not be altered.
Titanium valves MAY NOT be used.
Valves with stems that are less than 3/8 inch diameter (in the guide region) MAY NOT be used.
Titanium valve spring retainers MAY NOT be used.
Aftermarket shaft mounted rocker arm systems MAY NOT be used.
Rocker arms with ratios other than 1.7:1 MAY NOT be used.
Using offset head guides or altering the stock mounting location of the head on the cylinder block is prohibited. (See bulletin 95 - 04.3)

Class: General

Bulletin Number: 95 - 4.3

Date: 8-24-95

Effective Date:1-1-96

Subject: Allowed modification and required criteria. Inboard Production configuration.

Specific criteria and ALLOWED modifications.

Inlet exhaust ports and runners MAY BE modified and polished.
Combustion chambers MAY BE polished
Cylinder head castings MAY BE deburred and internally painted.
Heat riser ports on heads so-equipped MAY BE blocked.
Cylinder head deck surfaces MAY BE straight milled.
Any valve seat angle or width is ALLOWED.
Valve head diameter MAY BE altered as long as the original seat center locations are not altered to accommodate excessive valve head diameters.
Any length valve MAY BE used.
Any steel spring retainer and keeper MAY BE used.
Any make, stud mounted 1.7 ratio rocker arm MAY BE used.
Any rocker stud girdle or support MAY BE used.
Valve spring seats MAY BE lowered to provide for additional spring clearance or installed height.
Additional head bolt systems MAY BE used for attachment to the engine block.

Technical Bulletins courtesy APBA.