is nikasil and chrome the same thing?

[hugh j.]

is nikasil and chrome the same thing?



chrome is that shiney stuff on your car!.


nicasil is dat stuff in da hole in da sillynders of da moter on da botes

NiCom®- Nickel Silicon Carbide Composite




NiCom® plated cylinder bores on high performance marine engines
As an alternative to hard chrome plating, U.S. Chrome now offers a Nickel Silicon Carbide composite coating. NiCom® is an electroplated nickel matrix with hard particles, of SiC, uniformly dispersed throughout the coating. NiCom® has a plated hardness between 550 and 650 HV100; however the particles are much harder (SiC: 2400 HVN) which give this coating excellent sliding wear resistance. The mating surface "rides" on the surface of the hard particles, not on the nickel matrix, which is the principle behind NiCom®'s excellent sliding wear characteristics.

NiCom® can be applied in a range of thicknesses from 0.0005" to 0.030" on a wide variety of materials. NiCom® is functional as plated in thin deposits, but can be machined or honed in heavier deposits.

[FUJIMO]

I was not aware that the early "chrome" motors such as say a 2.4 litre 1979 200 had any sleeves. I knew they could be sleeved if someone needed just one cylinder repaired and was willing to go steel along with the appropriate ring. But if the Chrome motors originally had sleeves then why couldn't they be repaired with a new chrome coated aluminum sleeve? I guess I always thought the older chrome motors were just an aluminum block that had a chrome coating applied to the cylinder portion of the block.

Correct.

[gotboostedvr6]

I was told several years back from Mercury that all things being the same a coated motor will make 12 more HP ( 1 1/2 boat length in the quarter ) than the same motor with steel bores.....

I have never witnessed a steel sleeved motor run "with" a coated motor ALL THINGS BEING THE SAME ( C.I. to weight ratio being the same, and no power emhancements { NOS , alky } )

from my observations,

So guys with 260 and 280 Mercs make 12 more HP and have to rebuild every ~ 200 hours and are OK with this tradeoff?

[Da Bull]

I just found this thread in a search. Very interesting read from some knowlegable people. I am older than most here and started racing outboards in 1978 and when you race you must know your equipment and how to work on it. My experiance with 2.4 chrome Mercs tell me that although Nicom/Nikasil is harder and more durable chrome motors last way longer. I suppose this would be more of a ring issue than cylinder plating matieral so i have a question. In a lake boat situation that see`s lot`s of cruise time even with 260`s or 280`s why not use some other type ring instead of the gold coated one`s from Mercury?

DB

[eli]

have been using moly rings they are friendlier
on bores and are broken in as soon as you start the motor no need to pussy foot around .

[Da Bull]

Good to know. Where do you get molly rings for a 2.5? How about Pro-Marine?

[bobthebuilder]

Ductile iron sleeves are fine for a fishing motor.. I even turn my 245 which was a 260 before I went to carbs now turning 7500 rpms on iron sleeves and top pinned pistons..

[eli]

Good to know. Where do you get molly rings for a 2.5? How about Pro-Marine?

John Marles US1

[eli]

Ductile iron sleeves are fine for a fishing motor.. I even turn my 245 which was a 260 before I went to carbs now turning 7500 rpms on iron sleeves and top pinned pistons..

so you had all iron sleeves installed i was thinking that same thing buying sleeves porting them then install ,Wam O long life

[Da Bull]

I`ve done that twice with great results and a bud is doing it right now. I did it for nitrous.

DB

[H2OPERF]

Aluminum is too soft for a sleeve material since it will rapidly be worn out by the piston rings. Therefore an aluminum sleeve has to be coated with something that is harder. On high-performance engines, Mercury used Mahle's Nikasil coating up to the mid-nineties and then switched to US Chrome's Nicom. Similarly, Mercury coated the aluminum sleeves with chrome in 2.4 liter fishing engines. Since it is just a coating, it will be removed if the cylinder is bored.

[A steel sleeve, as used in most other outboards, is the same material throughout. Therefore, it can be bored.]

On the Verado, Mercury uses cast iron rather than steel. It, too, can be bored.

I thought all the sleeves these days were spun cast iron, not pure ductile cast but still cast iron not really steel. dave

[Markus]

I thought all the sleeves these days were spun cast iron, not pure ductile cast but still cast iron not really steel. dave

Correct. Just because everyone called them steel sleeves, I thought they were steel sleeves.

At least the replacement sleeves from LA Sleeve are cast iron. I will correct my earlier post.

(Not everyday you get a chance to correct a post from 2004 )

[H2OPERF]

funny,I didn't realize this post started in 04, amazing how long we have all been on here. honestly I have heard sleeves being refered to as steel and cast iron for along time and was not sure myself until i did some reading on it. When you bore one you know right away its not really steel it cuts out in tiny chips not like ribbons from steel or aluminum.Dave

[bobthebuilder]

James Perry can make sleeves and does a fantastic job if you can get him to do them for you. Any port timing you want. CNC Mill set up.. Also oversized to fit your hole..

[25XS]

Starting on page 2 of the first linked document below, you can read information about Mercury Marine's research with Mercosil aluminum block & bore and their production:

http://www.ncccoat.com/PDF/MercuryNC...icalpapers.pdf

Here is another great article. http://www.sunnen.com/NewsDetails.aspx?NewsID=11

Another great article... Especially good near the end! http://www.mmsonline.com/articles/ne...cylinder-bores