260-280 merc

[vi top shatta]

how can I tell the difference between the 260 and the 280. Are thir any visable difference. I've been told that one is nikcol plated and the other is a tan color, is this true and if it is who is who. I am thinking that the 150 175 200 are black. Thanks for all the help.

[Markus]

The 280 has an automotive style alternator. The 260 does not unless it is aftermarket. That's the easiest way to see the difference.

There are plenty of pictures in different threads here. If you look at airhorn, throttle/timing arm and coils, you will see clear differences.

[MODXR6]

260 has gasketed heads

280 has O-ring heads

[Jay Smith]

280 verses 260: they also have completely different , ignition systems , fuel system ( fuel processor ,ECU ) block chest relieving , charging system, flywheel , top bearing cap adapters,fuel rail is slightly shorter and port timing is also different

280 has a LOWER exhaust port height to replace torque lost by their gutted chest , 260's exhaust port timing under the shelf is 1.565" and 280 is 1 .610" ( drag is 1 .535" ) all measurements are taken from the flat of the existing stock deck to the highest point under the "shelf " of the port with a dial caliber (not the radius as all stock blocks vary.. ...)

hope that helps,
Jay

[TheRickster]

260's exhaust port timing under the shelf is 1.565" and 280 is 1 .610" ( drag is 1 .535" ) all measurements are taken from the flat of the existing stock deck to the highest point under the "shelf " of the port with a dial caliber (not the radius as all stock blocks vary.. ...)


Are all the 280's O'Ring style heads or are some Gasketed? If all are , Are the 280 hads recessed to allow for the decreased quench from using no gasket or is there a deck height increase like on the O ring fishing motors?If a deck height difference is .040" or so is the deck height difference already subtracted from the port height in the measurements you show for the 280?..

Rick

[Jay Smith]

Rick,
All 280s that come across my shop are O ringed headed . The piston comes at or near the block deck and the head has a machined "pocket" to produce a squisch band., unlike some of the newer 200 2.5 that utilize the block deck .040" higher and the piston recessed to create the squisch and use a flat O ringed head.

Good luck,
Jay

[TheRickster]

Thanks Jay, that answers the question of deck height.. I wondered if they tooled up a new deck height or just recessed the head..

Rick

[vi top shatta]

thanks for the help. You really help me with this