Oxide on cylinder walls after build

[m_0ney_pit]

So its been about a month sincei turned my freshly built bottom end and it was spotless when I got it. Just checked it out to make sure everything is cool before I put the head on and I found some black oxide on the cylinder wall where the rings where on each bore. fawk

water must have dripped in there or its super humid in my garage. Do I have to have the block rehoned now or is there a way to remove it? Its not deep or pitted just discoloration.

 

[kchaazz]

Try putting some wd40 on a rag and wiping em down, and if it doesnt come off, you can put wd40 on a green dish pad and wipe it ever so gently. Personally, I always wipe the cylinders and headgasket surface with wd40 if the block will be sitting a bit, and I use acetone on a rag to clean the wd40 off head gasket surface when its time to put the head on.

 

[m_0ney_pit]

It doesn't come off. I'm just going to rehone and take the extra clearance, right now I'm at 0.004" PTW and 0.021" and 0.024" for the top and bottom ring so taking another quarter to half thousands for rehoning shouldnt be a problem but I'll be measuring before and after to be sure.

 

[kchaazz]

A little extra ring gap wont hurt, especially if youre going to be running lots of boost. Ive seen pistons where the ends of the rings actually collided and twisted and broke the lands off the pistons because some people use the specs for a "stock" motor. Im definitely not an expert, but everyone I know who builds motors to live through abuse will gap the rings a little on the large side.

 

[BogusSVO]

Keep in mind for every .001 in dia. you open the cylinder bore you will gain Pi (3.141) on your ring end gap.

Trying to hone out .00025 - .0005 will be about next to impossible, odds are you will end up with .001-.0015 removed, if a ridged block hone is used.

Now if you use a dingle berry hone, or the parts store 3 stone hone, since they do not use as much outward force, you may be able to keep it to the tolerance you want.

But be careful of the grit stones used, the wrong ones will be to rough and leave the wrong finish
and you will have ring seal issues, or worse, chewed up rings.

Get the cross hatch wrong and you will have oil consumption and smoke issues.

 

[m_0ney_pit]

I ended up buying a 3.5" 320 grit ball hone from brush research to cleanout the discoloration and finish the bores. I cant see ittaking more than a few microns to clean things up. As long as it stays below 10um of mtl removed myring gaps and ptw should be just fine.

 

[dsmcurse]

Keep in mind for every .001 in dia. you open the cylinder bore you will gain Pi (3.141) on your ring end gap.

Trying to hone out .00025 - .0005 will be about next to impossible, odds are you will end up with .001-.0015 removed, if a ridged block hone is used.

Now if you use a dingle berry hone, or the parts store 3 stone hone, since they do not use as much outward force, you may be able to keep it to the tolerance you want.

But be careful of the grit stones used, the wrong ones will be to rough and leave the wrong finish
and you will have ring seal issues, or worse, chewed up rings.

Get the cross hatch wrong and you will have oil consumption and smoke issues.

Listen to Bogus, he knows best

 

[Diamond Star Werks]

Keep in mind for every .001 in dia. you open the cylinder bore you will gain Pi (3.141) on your ring end gap.

Trying to hone out .00025 - .0005 will be about next to impossible, odds are you will end up with .001-.0015 removed, if a ridged block hone is used.

Now if you use a dingle berry hone, or the parts store 3 stone hone, since they do not use as much outward force, you may be able to keep it to the tolerance you want.

But be careful of the grit stones used, the wrong ones will be to rough and leave the wrong finish
and you will have ring seal issues, or worse, chewed up rings.

Get the cross hatch wrong and you will have oil consumption and smoke issues.

To add to this I usually never dry hone. I wipe the walls with engine slick. Helps keep material removal down but still give a good cross hatch.