Plating Iron lined cyl's, ala CR500

[Masterphil]

Has anyone ever had a standard Iron lined cylinder, such as found on older dirtbikes and CR500's, plated? Would there be any negative effects such as heat transfer or different expansion rates between having the plating on an iorn cyl. vs aluminum like modern cyl's are constructed? What I was thinking was if I had a CR500, when it was time for the first overbore, just bore it out 2mm over and get the cyl plated and ported. Since the top end interval for a CR500 is ridiculously long anyway, this would effectively allow the cyl to last forever as long as there was no damage to the plating. BTW, a CR500 with 2mm overbore would be 513cc.

If this is possible, would the frictional advantage of using a plated cyl. free up any measurable ammount of power?

Another question that really dosen't belong in this thread, but, If you were to port/head mod two different engines for the same rider, except one for pump gas and one for race fuel, would there be changes to the cyl or only the head. I guess what I am asking is would the porting specs for the cyl be the same reguardless of fuel type used.

Eric, If you'd like to E-mail me with any specific pricing on this: [email protected]

 

[flattie]

cant go wrong with US chrome's plating, i had a iron sleeved cylinder done and loved it. there plating is the toughest you can buy. i had a ring break and snag a port, and trashed the piston. cylinder was unscared. wiped it off and replaced piston good to go! also never had any heat problems.

 

[highmileage]

This brings up an interesting point. When looking at some of the small motors and building for performance; i.e look at the CRF150F builds. Does plating the iron sleeve have a positive impact on performance and durability of the big bore application? Also heat is a major factor in these small air cooled motors, plating seems like it may be a good investment for heat control alone?

Looking at a build such as this...a 1/2 to 1 hp gain is a significant gain, whereas on a larger motor this is not so statistically significant.

Looking forward to the discussion...

 

[Rich Rohrich]

Wear is much better on a plated cylinder compared to an iron liner. Heat transfer on a plated iron liner will be worse than the iron liner alone. The plating will work as an insulator.

 

[Masterphil]

Wear is much better on a plated cylinder compared to an iron liner.

I am assuming that this is true because of the plating having less friction, but in this case, wouldnt the tightened piston to bore clearance be a major contributor to increasing the life of the piston? I have heard many CR500 owners way that they usually crack pistons before they wear past spec. Are we talking double the life of a piston? 1.5 times as much?

Heat transfer on a plated iron liner will be worse than the iron liner alone. The plating will work as an insulator.

Is this really going to be a problem? Wouldn't this be similar to thermal barrier coatings that can be applied to piston crowns and combustion chambers? Wouldn't this allow more of the energy to be used to push down the piston? Would this also create a stronger pressure wave exiting the cyl?


I may be blowing this way out of proportion, or I may be incorrect alltogether. :blah:


The Pro's:
Reduced frictional losses
Increased piston/ring life because of reduced friction and tighter clearances
No need to overbore again assuming that the cyl. dosen't get damaged

The Con's:
The plating will act like an insulator
If a piston/ring breaks, it could ruin the plating(but that is a threat with any modern plated cyl engine)



What about boring out all of the iron sleeve and replacing it with an aluminum sleeve to be plated?

I'm about all thunked out for the night...

 

[john stu]

i thought you needed to use different rings on a plated cylinder? does anybody make them for the cr500?

 

[Pete Payne]

Cr 500's break piston skirts due to the high MSV rating of the cylinder head.

 

[Masterphil]

Cr 500's break piston skirts due to the high MSV rating of the cylinder head.

Do you care to elaborate?

 

[highmileage]

I guess the other question here is that assuming that you are required to resleeve with an iron cylinder. I know that there are manufacturers out there that make aluminum sleeves for these bikes (Advanced Sleeve in Ohio?). If you are going to resleeve...Based upon Rich's response, why not do it with aluminum if you are going to NiCom coat it? Then you have all the benefits without the downside of the iron sleeve. Rich???

 

[2kCR500R]

Do you care to elaborate?

Explain?

IMHO, it is caused from wear and being left in past its service limit.

My original Honda piston had 4+ years on it before it cracked on the intake side. I measured it and it was worn past the service limit in the Honda repair manual. :nod:

 

[john stu]

i thought you needed to use different rings on a plated cylinder? does anybody make them for the cr500?

is this thing on lol

 

[john stu]

i wish rich or eric would add some more info to this subject.......i am very interested to hear there responces

 

[Hart89]

I remember reading (or dreaming) somewhere on this site that Eric was unable to port one type of plating because it would chip. Eric, Rich if i'm not just dreaming this what plating was this? Would it be a good idea then to get it ported before you plated just so you don't have this problem?

 

[Pete Payne]

If the MSV rate is too high . this could cause pre ignition , (knocking ) in the engine , this excesively loads the piston skirts and over time causes problems. one could be a broken piston skirt, among other problems .

 

[Masterphil]

If the MSV rate is too high . this could cause pre ignition , (knocking ) in the engine , this excesively loads the piston skirts and over time causes problems. one could be a broken piston skirt, among other problems .

Yea, we got that part.

Hart89:
I believe you may be thinking of Kawi's Electrofusion plating. It is some pretty thin and weak stuff, but I do believe that in most cases, Kawi cyl's can be ported without any problems.

Still in question:

Is/are the piston/rings as designed for an iron lined cyl. compatible with a plated cyl?
Does anyone make an aluminum sleeve that could be installed in place of the iron liner and plated to prevent the Iron liner's "insulating" effect or is the "insulating" effect even a big deal?
Are pistons produced for the CR500 made with close enough tolerances to use in a plated cyl?

If all of the above cannot be met using "off the shelf", than custom parts and an unrealistic ammount of $$$ would be needed for this project.

 

[Pete Payne]

Aluminum sleeve can be made by any of the poulat sleeve company's , LA Sleeve , advanced sleeve , etc, . They are not normaly off the shelf parts though . Yes the heat transfer should be better than a cast iron sleeve.
The standard issue wiseco rings work on most bores except chrome plating . Chrome plating was used many years ago I believe and is not to popular any more .Chrome platins is different than NiCaSil

 

[Pete Payne]

Sorry ,That should be Popular , not poulat.OOPS

 

[matt-itude]

why would you be able to run tighter tolerances with a plated cylinder? I would think the tolerance (piston to cylinder) would depend on the piston alloy and the piston temp.

 

[Masterphil]

Plated Cyl's can run a tighter tolerance because the aluminum cyl will expand at a more equal rate with the piston than an Iron liner will.