Torque Plate Explanation Please

[tinkerman]

Can someone run me through the requirement for torque plates when honing cylinders for my evo engine.

I have likely honed the cylinders from 30 - 40 engines over the years, including snow machines and all I have ever done was secure the cylinder where I could comfortably work on it and hone them free hand. Now, I would endeavour to come up with a stroke that would create the cross hatch pattern recommended and would do the same number of strokes per cylinder on a multi cylinder engine but it seems to me that the honing procedure was a fairly straight forward process. All I ever used was a old three stone hone and whatever light oil I had kicking around.

From what I am reading in the shop manual for my 88 Evo the honing of the evo cylinders is a little more complicated. I believe I have done cylinders with cast liners before as well which I suspect is the reason for the evo torque plate requirement. Perhaps reducing torque on the cast liner/cylinder casting fit?

Can someone shed some light on this?

Tinkerman

[choseneasy]

 The cylinders distort when they are in the engine with the heads on. Torque plates simulate the stresses on the cylinders and allow for straight boring or honing.
The three finger hones will not hone a true bore.  A sunnen hone is used on Harley cylinders. It will correct taper and get you the desired tolerances.

[wfolarry]

Take that 3 finger hone & some 600 paper & use it for final finishing.

[psyco369]

ya got me...I read the same thing and decided to take the top end in to the machine shop all the boys use and have the guru clean it up for me...it was a good move as I was going to go .005 over with new pistons...after checking and measuring he said all I needed was a clean up new stock rings reusing the stock pistons also a quick valve job and I was good to go and only around $230 including rings

[choseneasy]

 I should clarify- if your cylinders are good and you don't need to go oversize pistons , a sunnen hone is not needed. Torque plates are not necessary for glaze-breaking either. (cylinders should be checked for size, taper etc in torque plates tho.

[tinkerman]

OK Cool,

Cause the direction I was going was to send the heads and cylinders out to get them done but I have always done that level of work myself. By that I mean a simple honing to get some oil retention back on the cylinder walls and new valve guides if required and valve seals and lap the valves. I had a quick look at the cylinders using a ring and feeler gauges and the micrometer and they looked pretty good. Will have a little better look before I make a final decision but I don't expect any surprises.

I will need to use a ball hone for this right? That old bar stone I have is not the best option?

Thanks

Tinkerman

[choseneasy]

Are you using your same pistons or going oversize Tinkerman? I think you said 40 thousand miles on them? Not alot for an evo if everything looks good. A dingleberry hone (Flex-hone) works good for deglazing to brak in new rings. Pretty cheap to buy. If you hone oversize then finishing with the 600 like wfolarry said will work too.  (I've haven't done that to deglaze but if wfo says it is okay it is good enough for me)

[tinkerman]

Using the same pistons. A quick check with a ring squared in the bore top, middle and top shows minimal taper and out of round top and bottom is good.

Not clear if WFOLarry meant to run my three stone hone and then finish with the 600 grit paper or to cover the stones on my hone with the 600 grit paper and just deglaze. I have a pretty good idea from my other thread on ring type what cyl finish will be required for the moly rings that I have coming. Basically after one more close check of the cyl. bore I think just a deglazing will be good to go.

I checked out those ball hones and I can get one for around $65C. I have spoken to a shop that will check valve guides/reseat the valves in the heads and hone the cylinders to spec for less than $200 Canadian so if I can't pick up the tools to do the work my self for around that amount I will ship them my top end parts. These guys used to do some machine work for me when I was picking at the Brit bikes and they were very good to deal with. I hadn't spoken to them for a number of years but when speaking to them today they understood where I was coming from with regard to a finer finish for the moly rings. I would still like to do it myself however for the simple reason that I always have and I figured with the old tech in these Evo engines it shouldn't be a big deal.

Appreciate your help,

Tinkerman

[gaillarry]

I use a flex ball hone which works great, and simple to use:

http://www.youtube.com/watch?v=u9mZClv5Nfo

[Hillside Motorcycle]

When torque honing, you are loading the cylinder to replicate the stress involved when it is on the bike, torqued in place, insuring a round, straight, cylinder wall.
Those "berry brush" silicone-ball hones, are not what you want to use. They "scratch" the cylinder walls, and also load media into them.
A Sunnen hone, or even a Lisle 4-arm (2 stones, 2 wipers) with a constant-flood honing fluid, will do a great job in the hands of someone that knows what there doing, as long as the correct measuring equipment(dial bore guage, and the ability to set it correctly) is at hand.
Other than all that, it is a piece of cake.
Scott

[tinkerman]

Hey Hillside,

I am just looking at refinishing the cylinder walls rather than increasing bore size.

Gaillarry,

Thats about all I have ever done with a cylinder in my own shop except I always used the solid 3 stone hone. I may look at getting a ball hone. I have also sourced a shop that will refinish the cylinders and clean up the heads for me. I'll just compare their shop costs vs the costs of doing my heads and cylinders myself.

Thanks for the input,

Tinkerman

[Sonny S.]

Not clear if WFOLarry meant to run my three stone hone and then finish with the 600 grit paper or to cover the stones on my hone with the 600 grit paper and just deglaze. I have a pretty good idea from my other thread on ring type what cyl finish will be required for the moly rings that I have coming. Basically after one more close check of the cyl. bore I think just a deglazing will be good to go.

I believe that is what he meant. It's called plateau honing... I think. The stones will give the cylinder the texture needed to hold oil, and the 600 grit will knock all the sharp edges off.