240 or 320 Grit Flex Hone For Crosshatch? (steel/chrome rings iron bore)

Dan1950

Dan1950

1974 MK II Roadster
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Got my cylinders back from the machine shop and although the bore is bang on at 77.5mm, the crosshatch seem too fine. I'm going to get a flex ball hone and do the finish hone myself. Just a few passes to get a crosshatch that will work to seat the Steel/chrome rings.

Pistons are forged JS graphite coated. I'm leaning towards 240 grit as 320 might be a bit too fine. Wiseco recommended 240-400 grit for the rings. I'm wondering if the 320 might work best for the graphite coated shirts.

240 or 320 Grit Flex Hone For Crosshatch? (steel/chrome rings iron bore)
 
I will assume you're more mechanically inclined than I am - that's a pretty safe assumption, by the way - but I bought a flex hone when I was re-ringing, just recently binned it or I would offer to send it to you for postage (I know I researched intensely, as is my wont, when I bought it). I ended up chickening out and doing by hand with sandpaper (don't remember the grit there but if I was guessing I'd say 240).

I also did my usual OCD retorquing of the head bolts a half dozen times or so and really happy with results of the process. I know I needed the rings (my wife who usually follows my on her bike now enjoys breathing non-blue air....) and the increase in the "pop" of the exhaust pulses out the exhaust on first startup was as gratifying an experience as I've had with my clothes on.
 
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I wouldn't use a ball hone on what the machine shop did Dan. That fine grit those balls create is a PITA to get out of every crack and crevice it can and will find its way into. It can come back to bite without a lot of washing. Your call though and I agree that things will seat quickly doing it, but if any is left behind things may not end well.

The rings will seat, it just might take a while. In theory the top ring is supposed to seat nearly immediately even with that fine crosshatch. Anywho good luck with it all. You're getting there.
 
A few quick passes with the 240 Flex Hone gave me a nice consistent cross hatch without altering the bore.

240 or 320 Grit Flex Hone For Crosshatch? (steel/chrome rings iron bore)


240 or 320 Grit Flex Hone For Crosshatch? (steel/chrome rings iron bore)
 
Hi,
Am I silly to think that if a machine shop is capable of accurately boring your cylinders they should be capable of knowing exactly what hone to produce?
If you are concerned my first thought would be to ask them why they believe it is the most suitable hone finish.
As an amateur, to go back into a professionally prepared bore with a hone on the end of an electric drill (or similar) and believe you are doing a better job seems nonsensical.
just a thought
Alan
 
Alan L said:
Hi,
Am I silly to think that if a machine shop is capable of accurately boring your cylinders they should be capable of knowing exactly what hone to produce?
If you are concerned my first thought would be to ask them why they believe it is the most suitable hone finish.
As an amateur, to go back into a professionally prepared bore with a hone on the end of an electric drill (or similar) and believe you are doing a better job seems nonsensical.
just a thought
Alan
Click to expand...
In the US, most places no longer have the apprentice, journeyman, and master. We have Joe Bob who was shown a couple of times how to bore and may have no clue about honing. Professional today simply means paid in many cases and I don't think that's what you mean by professional.

When I was 18 I worked at a Triumph shop for free to learn about motorcycle repairs and maintenance and to beg a part from time to time. The shop had a boring machine made to suit 350, 500, 650 cylinders and it did nothing else. It was a free-standing machine that did both cylinders at once. I was shown once how to setup to bore to just under the desired oversize and then did them whenever I was there, and they had cylinders to be done. No micrometer needed. I was never allowed to do the final hone to size and then crosshatch - that was done by a paid employee that the owner taught.
 
There is usually some information on the packet of rings, at least on a decent aftermarket set, the older style of rings all used to get Sunnen AN200 stones .Flash moly filled types etc , would have a finer finish .
 
Onder said:
There are top shops that know what is what. Problem is knowing who they are and then getting in the queue...and waiting.
Click to expand...

R&L Engines

R&L Engines Specializing in High Performance Engine Rebuilding and Building, CNC Blueprinting with Latest Machinery. Vintage Muscle Car , Drag Racing and Street Performance Engines.
rlengines.com

I've been having my engine machine work done here for 38 years.
Leo will give whatever clearances & finishes you request.
Without any input for details, he'll draw on vast experience and good practice.
 
Alan L said:
Am I silly to think that if a machine shop is capable of accurately boring your cylinders they should be capable of knowing exactly what hone to produce?
Click to expand...
Even the best machine shop is limited by experience or more likely lack of when dealing with older technology. Honing grit size comes from 2 sources, the ring maker should include the info in his installing instructions and secondly people who have had the same rings installed, know what honing grit was used and how well the rings bedded in. Must admit I have never gone back to any machine shop to tell them how their honing performed, so they are non the wiser.
 
concours said:

R&L Engines

R&L Engines Specializing in High Performance Engine Rebuilding and Building, CNC Blueprinting with Latest Machinery. Vintage Muscle Car , Drag Racing and Street Performance Engines.
rlengines.com

I've been having my engine machine work done here for 38 years.
Leo will give whatever clearances & finishes you request.
Without any input for details, he'll draw on vast experience and good practice.
Click to expand...
R&L look like the real deal. Lucky man to be local to them.
 
Alan L said:
Hi,
Am I silly to think that if a machine shop is capable of accurately boring your cylinders they should be capable of knowing exactly what hone to produce?
If you are concerned my first thought would be to ask them why they believe it is the most suitable hone finish.
As an amateur, to go back into a professionally prepared bore with a hone on the end of an electric drill (or similar) and believe you are doing a better job seems nonsensical.
just a thought
Alan
Click to expand...
First of all you are making a judgment without having seen what the bores
of my cylinders looked like before I ran the flex hone through them.

Secondly I rebuilt my first motorcycle engine, an A65T when I was 22 some 50 years ago. Since then, I have rebuilt several motorcycle and automobile engines. I also worked for a time in my father-in-law's automotive machine shop and although I wasn't involved and boring and honing cylinders, I certainly saw my share and know what a properly honed cylinder looks like. You will note in the pictures I posted that the bores now have a nice consistent finish top to bottom. When I picked them up from the machine shop the cross hatching was not consistent.
 
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Cylinders look good to me after running the ball hone through them. Your rings will definitely seat quickly.

I probably would not have done what you did, but that means literally nothing, and is not a criticism. Crosshatching after plateau honing does not look like it is as consistent as one might expect. Plateau honing is a very common honing technique for performance engine builders these days. That is what was done on the 2 pairs of barrels I recently plopped down on my cases. Neither set looked like they would have in the 1970's. I get why you did it. Nice job.
 
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