needs advise on mercosil block

[lcp8410]

can i bore a 25hp mercosil block oversize?can it be done on any machine shop?

[lcp8410]

mercosil bore

not the nicasil chrome bore.i mean the one with aluiminium bore.

[laddies]

Mercosil is boreable as it is not a plating but a aluminum that is saturated with silicon which gives it a hard glass like surface, it is boreable with a 3 step system that requires a diamond hone so not many shops are capable of doing the job and the ones that can get about $125 a hole. Mercisil blocks have the Mercisil label cast in the outside of the block

[lcp8410]

mercosil bore

thanks for the explanation. any suggestion where can i send these block for rebore?

[lcp8410]

mercosil bore

any idea who has the equipment and experiece to bore these block?

[laddies]

Here's a good machinist http://forums.iboats.com/member.php?u=111828

[lcp8410]

mercosil block

link dont works.anyone else can bore these block for me?

[Dave M]

Try Lee

Might contact Lee Tietz, not sure if he has the right equipment, but worth a shot. He is a sponsor on this website, Machined Components.

[pops67g]

Is the bore damaged?

You haven't stated why you want to bore this block. If the bore is damaged and needs to be cleaned up that is one thing. If you just want to make it bigger thinking more power or something that would be a waste of time and money. It's true that straightening out the bores helps make more power but is the high cost of the machine work and corresponding new parts worth the relatively small gain you might get?

[hydrosports]

Might have luck with these guys http://www.cvtech-aab.com/contenu/index_ang.cfm

[lcp8410]

bore mercosil

thanks for the link.look like these guy good on nicasil bore.the one i got is not nicasil or sleeved.the bore got a deep scratch on it.i dont think honing will not help clean up the scratch.thats why im thinking of oversize.

[Steve77t]

Try these

thanks for the link.look like these guy good on nicasil bore.the one i got is not nicasil or sleeved.the bore got a deep scratch on it.i dont think honing will not help clean up the scratch.thats why im thinking of oversize.

US Chrome ( The company that does all of Mercs) Malienium sp they do this work as also others. They can bore and then plate to whatever your piston size or block can handle. Most composite bores do not offer oversize pistons but it can be done. steve

[25xs]

Mercosil... It's the entire block, not a coating or treatment.

Starting in 1981 Mercury made 18/20/25hp engines from an aluminum block with hard chrome plated bores (Nikasil). US Chrome did the plating for Mercury Marine and can still rechrome bores for the older engine blocks. It's not, however, a cost effective repair. I think Mercury started doing plating inhouse but eventually stopped chrome plating when the Mercosil metallurgy was ready for production. All these engines have serial no. 0G202749 and lower.

All the 2-stroke Mercury 20/25hp blocks 1994-1/2 thru 2006 are die cast aluminum block with high silicon content and have the word "Mercosil" is cast into the intake side of the top cylinder. The piston & rings wear directly on the high silicon bore surface. Mercosil is a boreable, machinable material. The previous post mentioning the bore & diamond hone is correct.
Mercosil blocks are serial no. 0G202350 an higher. Mercury sells 0.030" oversize pistons & rings for the Mercosil blocks.


Motorcycle shops are most likely to handle it correctly. Just talk to them first and verify they finish with a diamond hone. Some manufacturers recommend a chemical etch to relieve the aluminum from the bore surface so the piston & rings wear on the hard silicon and not direct aluminum contact.

Here is a great read from Sunnen regarding aluminum bores; http://www.sunnen.com/newsdetails.aspx?newsid=11


MarFab (Marine Fabrication) in Sparta, TN can handle this work.
http://mar-fab.com/

[lcp8410]

mercosil block

thats really some usefull information.

[laddies]

You have a PM