vertex pistons

[dalecarver]

hey guys what is the proper break in for these pistons 175 efi mercury. .030 steel sleeves.

[ChrisCarsonMarine]

Opinions vary,you can print our breakin skedual from our website,chris

[bigtis]

heat cycle the engine. keep it under a load so the engine will make heat. make sure to vary the rpms. The vertex are some good pistons!!!!! Make sure to break it in with blue quicksilver, not the premium plus or any other synthetic blend of oil.

[h2oskiier30]

Make sure to break it in with blue quicksilver, not the premium plus or any other synthetic blend of oil.

Red Quicksilver is the dinosaur oil to break in with....blue is the Quicksilver Premium Plus synthetic blend. Most suggest it's ok to break in with the synthetic blends, too. I usually start out with the red for the first 4-5 hours, then transition to the blue.

[dalecarver]

Does anyone know the correct clearance for the vertex pistons . I can find out what ever I want about mc bikes but not outboards . Block will be board ..030 over I assume about .004-.006 will do I want a reliable motor and don't want

[dalecarver]

Dang I pad . I do not want to risk meltdown with to tight of clearance. Any help would be great.

[ChrisCarsonMarine]

As with any motor,piston clearance is built into the piston,and in the case of a stock(or near stock)motor using cast pistons no additional clearance should be necessary.Do realize however,most folks aren't aware of the correct bore of some of these motors,and your machinist may be among them.The correct bore for a steel bore 2.5 is 3.501,not 3.500,as the specs read in most service manuals,so 015 over is 3.516 and 030 over is 3.531.If the motor is a steel bore 2.4 the clearance should be adjusted by boring 002 oversize because the pistons were designed to run in chromed aluminum cylinders that expanded more than steel sleeves.Whatever you have a minimum of 006-007 would be needed,004 is gonna stick,chris

[Jay Smith]

Well every bodies got an opinion here's mine.


I have had GREAT success ( zero failures so far ) with cast pistons on steel bores at the bore size of the piston application advertised over bore size ,I rely on the factory built in clearance as Chris said, BUT I always have bore them dead nut on and check with a dial bore gauge as well as the ring end gap on EVERY hole ..

In other words if a piston is a .030" over I have a finish bore at EXACTLY 3.530", then I will use a plateau brush to knock the higher plateaus down a bit to save the ring life.

One of the main issues with steel bores is when they are machined I find they are impregnated with the hone material, and left without a cleaning end up scratching the bores. I spend a mega amount of time with a 4000 PSI hot water & soap washer and a bore brush then a cleaning with transmission fluid ( 3 complete cleaning passes ) then one last pass with acetone before I coat with Quicksilver and shrink wrap complete block before I assemble .

Remember a clean motor is a happy motor !
Jay

[ChrisCarsonMarine]

Jay,as I said,most service manuels,mercurys included before updates and service bulletins state standard bore on a 2.5 ( steel bore ) as 3.500.This was updated to 3.501 some time back,and I believe the oversizes are 3.516 and 3.531,being 015 and 030 oversize,respectively...check it out,I think I'm correct.I'm with you 100 percent on the clearance being built into the piston,and the hot soapy water,Chris