bore out cylinders

[rudy]

hay guys,
I had axis to a internal grinder, made a fixture to grind cylinders, put the bolt pattern in and ground to the sleeve size, what a surprise to see the bore run out .014 when i wanted to take out .005? Also the flange was not flat, each bolt i tighen moved the bore? What the Heck??? How do you guys do it???

[Mike L]

When I'm taking out .010" or less I use a rigid cylinder hone. It centers the old hole. If I'm boring it I mount off the base with a torque plate. As long as someone before didn't bore it crooked before it usually cleans up.

[rudy]

bore cylinders

Thanks, they cleaned up at .020 over, I mounted a set of NOS cylinders and the base flange was flat and they ran withen .002. I heard of torque plats for newer motors, are they used on 45"? I left .002 for a hone and although they were to the tenth in the machine, they did go .0003 to .0004 out of round at the base when I took then out. Either way iam running them. But I still have to do my knuckle cylinders, is it better to make a top plate instead of using the cylinder base studs? Thanks again

[Mike L]

torque plate

The plates should be used at the base 'cause that's is where most of your distortion is when bolted to the case. I leave at least .003" to hone out after the boring. The cylinder usually tightens up below the base at the spigot and will pull out just above the base where each stud is. These will distort @ .003"- .006" at the base. I don't use a plate at the head surface on a S.V., there usually isn't any measurable distortion at the top to be concerned with. I found very few S.V.'s that the head surface was parallel with the base, and it is more important to keep the bore square with the base than the head surface. On an OHV at least do a plate at the base, again that's where most distortion is. I have a plate for top and bottom for Shovel's but find there is usually less than .001 distortion at the top. So I haven't made one for the knuckles or pans, since they'll be @ the same.

[T. Cotten]

I fully concur with Mike's findings, although distortions really only get significant at larger overbores. Plates work so well, that extreme overbores are possible: I have a 'godchild' '39 knuck in service at .155" over stock.

[rudy]

cylinders

Thanks,

[rudy]

cylinders

Ok, i got to ask, what is a torque plate? The fixtur I made has the Bolt pattern , then put it in the machine and ground the face, changed the spindle and ground fixtur bore to the base sleeve Dia. aim I on the right track? THANKS guys

[Mike L]

it's another boring subject

sounds like it. Just make sure you plate bore is larger than the spigot, you don't want a tight fit. just @ any good plate of steel, or a good hard plate of aluminum, a min. of 1" thick. I've been using 6061 1,1/4" alum. 'cause I got a couple 6' by12" piece's in a pile of scrap I aquired.

[rudy]

cylinders

ya, i have a 12' dia by 2" thick fixure, I was going to gring the cylinder head face, but Could not Ind. the head surface to see what was coming off. But with the same 2'' thick fixture I thought of blanchard grinding the head surface and depth mic. down to the fixture to make them the same. Is this a good idea or not?? That or I lap the head and cylinder head surfaces flat. (All this is free to me at work like hot water and a toilet). Thanks again, this is a first for me.

[Mike L]

?

Got me a little confused here. Either way, yes all surfaces should be flat and parallel of the honing plate, head surface, deck surface and base of jug.

[rudy]

cylinders

I guess what iam trying to say is I can take the same fixture and dust the head surface. on a machine, I should be able to mount the cylinders in the fixture and take them to a grant table and see how much the head surface is out of flat. The fixture is flat and parallel to . 0002 Will have to hand lap the heads.My motor man thinks iam going to extremes?? I think iam doing it right? need help?