260 Power Head

[lost2a6]

I'm new to the 2.5 v6 Mercs so please excuse the stupid questions. I'm looking at a boat that appears and I'm assuming it to have a pro max mid section because it has it on the cover. However it has supposedly has a 260 power head with wizard pistons and the good rods. I don't really know what to look for other than the center air horn to which this power head has. I'm thinking that I would rather have a pro max 225 PH because of being able to put many hours on it without a rebuild and not having to deal with the nicasil cylinders, and being cheap to rebuild. I'm not concerned with trying to get as much power as possible. Should I be able to just swap back over to a pro max PH? And do you think that it would be easy to trade my 260 for a 225 pro max? The owner of the 260 says that two cylinders had lost compression because of the previous owner building it with the wrong rings. He has since installed the right rings and all is good now. He stated that the compression is now 155, which seems to be on the border line for pump gas. He also said that it didn't hurt the nicasil coating. It sounds a little fishy to me. I just don't want to buy someone's nightmare.

[Tom Foley]

I'm new to the 2.5 v6 Mercs so please excuse the stupid questions. I'm looking at a boat that appears and I'm assuming it to have a pro max mid section because it has it on the cover. However it has supposedly has a 260 power head with wizard pistons and the good rods. I don't really know what to look for other than the center air horn to which this power head has. I'm thinking that I would rather have a pro max 225 PH because of being able to put many hours on it without a rebuild and not having to deal with the nicasil cylinders, and being cheap to rebuild. I'm not concerned with trying to get as much power as possible. Should I be able to just swap back over to a pro max PH? And do you think that it would be easy to trade my 260 for a 225 pro max? The owner of the 260 says that two cylinders had lost compression because of the previous owner building it with the wrong rings. He has since installed the right rings and all is good now. He stated that the compression is now 155, which seems to be on the border line for pump gas. He also said that it didn't hurt the nicasil coating. It sounds a little fishy to me. I just don't want to buy someone's nightmare.

I would ask to remove the heads and have someone who knows what they are looking at inspect the Nikasil coating on the cylinders . You may have to supply a new set of gaskets if you don't buy . They are nice engines but will require rings every 100- 150 hours of running . Replating is expensive at around $1000.00 just for the plating no labor .

[tripower]

I've owned both the 260 and the 225 PM, and they're very different motors. Sounds like you understand that. Most important thing is that for your usage, you don't need a 260, so I wouldn't plan on keeping that. High maintenance, high idle, no shifting while running, etc. The 225PM also uses a 2 piece adapter plate, and the 260 is one piece, so the mids aren't the same. Which do you have?

[patchesII]

The mid is the same and you can use a one piece plate for a 225 Promax

[tripower]

The mid is the same and you can use a one piece plate for a 225 Promax

Sure but now you're talking about a modified configuration that doesn't have the same cooling characteristics of an every day, easy going stock 225 PM. At that point I'd rather have the 260 :)

[lost2a6]

I've owned both the 260 and the 225 PM, and they're very different motors. Sounds like you understand that. Most important thing is that for your usage, you don't need a 260, so I wouldn't plan on keeping that. High maintenance, high idle, no shifting while running, etc. The 225PM also uses a 2 piece adapter plate, and the 260 is one piece, so the mids aren't the same. Which do you have?
It has a Bass mid with a 260 tuner. Owner said that the reason why the rings gave way is because when it was built, they used rings for a steel sleeve. I'm beginning to think that this engine is a frankinmerc and something is telling me to steer away from it. The rev limiter has been raised to I believe 10,800 rpms along with the fuel curve. So I can only assume that running this engine at the lower RPM's is going to suck.

[tlwjkw]

The owner of the 260 says that two cylinders had lost compression because of the previous owner building it with the wrong rings. He has since installed the right rings and all is good now. He stated that the compression is now 155, which seems to be on the border line for pump gas. He also said that it didn't hurt the nicasil coating. It sounds a little fishy to me. I just don't want to buy someone's nightmare.

this sounds like a load a BS ta me???...… jmo

off shore clamp/trim or production clamp/trim?

[lost2a6]

I think production. It has the single trim cylinder with the mercruiser pump in the boat.

[tlwjkw]

that would be hi perf (off shore).. all hi perf chrome and/or nic motors came with that trim (not necessarily that type pump) anda one piece plate but with either bass or offshore "cans".. jus from what you described think it might be wise to pass on that motor unless you can do little "check out" on it.. why would ya replace rings (no mention of pistons?) on jus two holes unless those two holes went down?.. jus a little suspect imo.

but tha pro max ona one piece plate will work with some tweakin' on tha water stuff.. lotsa threads on here ta make it pretty easy ta do..... jus with two piece adapter its a no brainer....

[lost2a6]

that would be hi perf (off shore).. all hi perf chrome and/or nic motors came with that trim (not necessarily that type pump) anda one piece plate but with either bass or offshore "cans".. jus from what you described think it might be wise to pass on that motor unless you can do little "check out" on it.. why would ya replace rings (no mention of pistons?) on jus two holes unless those two holes went down?.. jus a little suspect imo.

but tha pro max ona one piece plate will work with some tweakin' on tha water stuff.. lotsa threads on here ta make it pretty easy ta do..... jus with two piece adapter its a no brainer....
He supposedly did replace all of the rings. It also supposedly has the top pin Wizard pistons.

[Markus]

It has a Bass mid with a 260 tuner. Owner said that the reason why the rings gave way is because when it was built, they used rings for a steel sleeve.

Some people used the steel sleeve rings in Nikasil engines. I was recommended to do that as well. The rings did wear fast, but I did not have or have ever heard of any other problems.

[Markus]

Is it an unpainted 260 block, or a painted Promax block, btw?

[lost2a6]

Is it an unpainted 260 block, or a painted Promax block, btw?
Unpainted. From what I understand, promax blocks are also unpainted?

[tlwjkw]

Unpainted. From what I understand, promax blocks are also unpainted?

yep...

[tunnelmike]

Sounds risky. Mike

[Varmint]

that would be hi perf (off shore).. all hi perf chrome and/or nic motors came with that trim (not necessarily that type pump) anda one piece plate but with either bass or offshore "cans".. jus from what you described think it might be wise to pass on that motor unless you can do little "check out" on it.. why would ya replace rings (no mention of pistons?) on jus two holes unless those two holes went down?.. jus a little suspect imo.

but tha pro max ona one piece plate will work with some tweakin' on tha water stuff.. lotsa threads on here ta make it pretty easy ta do..... jus with two piece adapter its a no brainer....

All bass 260's i ever saw or had ,had the o/shore clamp and mercs own solid lower mounts.

[tlwjkw]

yep on tha clamp.. came on all high performance 2.4/2.5 except tha 2.5 Promax line.... had ta give tha bass boat guys more room for all tha batteries.... :reddevil: