Cylinder Honing Process

[KaminaSan]

So I'm looking at rehoning my cylinder walls due to them being too rough from another machine shop.

My block has been bored/honed(I bought it that way) for Mahle 8.5:1 86.5mm pistons.

My mechanics say that the walls look too rough from the machine shop, and the problem is, I don't have the Mahle honing instructions, since I purchased the block with them installed.

Does anyone have the usual forged piston honing instructions, or even the mahle ones?

What grit should the final hone be done with? The rings are 'steel nitrate'.

Any help/ideas would be greatly appreciated.

[JonGu]

86.5mm would be oversize pistons since the factory bore is 86.0mm

You would need to bore and hone the block if you wanted to use those pistons. You will need to send it off to a machine shop. Don't be cheap, do it once do it right.

[KaminaSan]

Maybe I should have explained better.

My block is already built. It has been bored and honed, with all new forged internals, bearings, and everything. That is how I purchased the short block.

However, my mechanic feels the cylinder hone is TOO rough, and suggested redoing it, so the piston rings don't wear out too quickly.

My question is more advanced. HOW should the machine shop hone the block?

What grit stones for the final hone?

[SpOOlin13]

Your question is very simple but very advanced for the illiterate and mentally challenged^^.That's not a good sign that your mechanic dosen't know of a competent machine shop.Goto C&E ([email protected]) machine on Main st. just south of the 60fwy.Good luck with your build.

[KaminaSan]

Your question is very simple but very advanced for the illiterate and mentally challenged^^.That's not a good sign that your mechanic dosen't know of a competent machine shop.Goto C&E ([email protected]) machine on Main st. just south of the 60fwy.Good luck with your build.

I appreciate your input. The shop i go to for all work is Pit Garage. They have been building engines for years, and that's the reason they knew enough to tell me that my hone sucked from the previous owners machine shop.

The machine work however was done by the previous block's owner, at some place called Coast Motor Supply.

So now I'm correcting all the mistakes they made.

But no ideas as far as the correct grit for steel-nitrate/moly rings?

I have been looking around and 280 seems to be a good finishing grit. Any thoughts?

[JonGu]

Your question is very simple but very advanced for the illiterate and mentally challenged^^.That's not a good sign that your mechanic dosen't know of a competent machine shop.Goto C&E machine on Main st. just south of the 60fwy.Good luck with your build.

You're right, it is easy to understand now that the post has been edited. :smash:

[Hashiriya415]

Contact the piston supplier/ or ring supplier. I know what you are talking about, some manufactures want a rough surface.

[ManoNegra]

pics of the cylinder walls?
the thatch marks after honing are prominent
they provide some material for the rings to settle into

[KaminaSan]

I guess I could take pics, and I will try looking into contacting the company again.

Pit Garage has been working with SRs forever, and and that's why I trust their opinion on the rings/hone.

I'll call Mahle and see what I can find.

To me, the hone job looked like what I see in most pictures.

http://www.theoldone.com/articles/badtothebone/Cylinder_Finish_1.jpg

Although my cylinder looks a little less shiny.

[daryl337]

The hone doesnt appear too bad, although it does appear they took alot of material off while honing vs. boring close to spec, and then honing the rest. A good rule of thumb is to run your fingernails across the hone un an upward motion, and see if the nails catch in any of the horizontal marks. If they do, then the hone may have bitten down too hard.


You want the hone to remain slighly rough to the touch, as it assists in the break in process.

[ManoNegra]

hone appears normal to me from that pics
did you check tolerances?

[WagDatto]

That isn't a picture of HIS block. He's saying his look "like that, but less shiny."

Either he's retarded or he's trolling.

If the former is true, then let me spell things out so people can help you:

1. Take pictures of YOUR cylinder walls
2. Post said pictures in this thread.
3. Wait for reply.
4. If reply is not sufficient to your needs, contact the company and get your information from the source.

[KaminaSan]

That isn't a picture of HIS block. He's saying his look "like that, but less shiny."

Either he's retarded or he's trolling.

If the former is true, then let me spell things out so people can help you:

1. Take pictures of YOUR cylinder walls
2. Post said pictures in this thread.
3. Wait for reply.
4. If reply is not sufficient to your needs, contact the company and get your information from the source.

I appreciate your how to, on how to get help, but sir, you seem to be the retarded one.

I was not asking whether or not my cylinder walls look ok.

I was giving an example of what the hone on my block looks like. Because it is at the shop I cannot currently take pictures of it.

Here is all the information I have gathered from speaking with Mahle:

Our rings are tolerant of a variety of bore finishes. In general, you want to rough the bores within 0.003-5" with about a 300 grit stone, then plateau hone to finish with a finer grit stone, about 400.
This will knock off the peaks of the crosshatching, simulating a broken-in bore. This will be easier for breaking in your rings.

My question is how do I translate this into 'non machine shop language?
Does that mean these rings are tolerant of a rougher hone, as compared to what my mechanics usually see for forged pistons?

Is the mahle recommended honing process finer, or rougher than most others?
What is the downfall of having a slightly rougher hone vs a finer hone?

[phobs]

Edit: wrong post

[nismoman]

If the hone is way off spec the rings may never seal properly or they may take much longer to break in. Worst case is you wil have excessive blow by, oil consumption and lower than ideal compression. You can achieve the needed hone by simply using a flex hone of the proper grit. That's what I would do. Only problem is you have to completely disassemble the engine and clean the block afterwards.

[ManoNegra]

I appreciate your how to, on how to get help, but sir, you seem to be the retarded one.


How so? Sean has built engines without second guessing himself
or asking kids on the internet whether his block 'looks' ok
without actually providing pictures of actual said block.
(Not that anyone can really give you good feedback by looking at pictures anyhow)
kinda retarded, no?


Here is all the information I have gathered from speaking with Mahle:


Originally Posted by Mahle
Our rings are tolerant of a variety of bore finishes. In general, you want to rough the bores within 0.003-5" with about a 300 grit stone, then plateau hone to finish with a finer grit stone, about 400.
This will knock off the peaks of the crosshatching, simulating a broken-in bore. This will be easier for breaking in your rings.


made perfect sense to me.

[onefst240]

A rough hone job just wears the rings down faster. It has nothing to do with the pistons itself. There are a couple different ring materials. Some call for a very rough cross hatch some dont. It all comes down to wat rings you have.

[KoukiMonsta]

This thread is so fucking stupid. OP is running in circles.

multiple guys have posted great info that you ignore.

Post a pic of your block if you want other opinions. Though apparently you feel that is unnecessary since your mechanic said so. Even though they/he/she is unable to tell you what needs to be done, just that it is "wrong"

Also what is there to not understand about the info you received from Mahle, that is as straight forward as it gets.

damn this is dumb

[KaminaSan]

If the hone is way off spec the rings may never seal properly or they may take much longer to break in. Worst case is you wil have excessive blow by, oil consumption and lower than ideal compression. You can achieve the needed hone by simply using a flex hone of the proper grit. That's what I would do. Only problem is you have to completely disassemble the engine and clean the block afterwards.

Thank you for your time/info.

Mods please close thread.

Thanks you everyone who posted, I appreciate your input, and engine building expertise.