[chrisjk383]

Hello,

I am rebuilding a 564ci BBC and am trying to decide if it is worth the time and money to get the bores re honed/new cross hatching... The engine was machined and honed last year (A very high-quality job I might add) and since then the engine only has about 20-30 1/4 mile passes on it. I am rebuilding for street usage and going from a high compression N/A setup to an 8.5:1 10psi turbo setup which means I will be going from a 44.9cc piston DOME to an 18cc piston DISH which is the reason I am debating new cross hatching to achieve a better piston ring seal. The hold up is that the current cross hatch is still in excellent shape, and I would hate to put it on a machine if it's not going to gain me anything. (See image below). What would you guys do if this was your build?

Part 2 to this question if I dare - JE told me if I gave them the weight of my existing pistons that they could add material to make the new pistons the same weight... With this said - would you guys re balance the rotating assembly? Note that the previous balance was done by the same shop whom I have great trust and does great work.

Thanks guys,
Chris

 

[BBF612]

Put a torque plate on it and do some measuring, then decide what to do.

 

[chrisjk383]

The block measures perfectly, this is not a question that will be answered with a torque plate. It is a matter of surface finish, not out of round

 

[Rcparker2]

The block measures perfectly, this is not a question that will be answered with a torque plate. It is a matter of surface finish, not out of round

Only a profimeter can tell you anything in regards to that. You need to look at the Vk to see it it has enough oil retention for your application

 

[heshtesh]

I would re-hone for what the new rings require.

 

[000Racer]

Awful lot of scuffing in the bore.
Re- hone it and chamfer the bottom of your bores smooth....
Let me guess, you got a full round design piston?
Put the extra weight you need in the wrist pin, minimum H13 pin with at least .220 Wall thickness.

 

[1963 corvette]

That does not look nice at all. I would not think twice about redoing that.

 

[1963 corvette]

Only a profimeter can tell you anything in regards to that. You need to look at the Vk to see it it has enough oil retention for your application

Don't need a meter to tell that needs redone.

 

[1963 corvette]

What's making all the marks ? You look at your piston skirts? Something needs addressed. I don't see our cyl walls looking that bad after entire season! It's all part of parts prep imo.

 

[Rcparker2]

Don't need a meter to tell that needs redone.

I agree, point it you can't really tell anything by looks. A lot of people think they have a great hone job by the looks and we are dealing with microns.

 

[000Racer]

I agree, point it you can't really tell anything by looks. A lot of people think they have a great hone job by the looks and we are dealing with microns.

Yeah, 100 micro inches is .0001
I've been running stuff with 110 RVK and make more power and pull more vacuum.

 

[BBF612]

crosshatch holds oil that seals the rings.

 

[SuperStock427]

I’d hit it with a clean hone, it doesn’t take much just to “clean” it up

 

[bigblockmark]

Consider what the rings are. Plasma moly coated rings take different hone than Steel rings. Plasma Moly rings are porous and hold oil better so don't need as deep of cavities in the bore, hone job. Steel is not as porous and needs deeper cavities to hold oil.

 

[1963 corvette]

I agree, point it you can't really tell anything by looks. A lot of people think they have a great hone job by the looks and we are dealing with microns.

I have been honing blocks for years, I don't need a meter to seal a engine. If you have a quality machine it takes care of the work for you.

 

[Rcparker2]

I have been honing blocks for years, I don't need a meter to seal a engine. If you have a quality machine it takes care of the work for you.

It takes good equipment but with the new coatings and ultra thin rings it gets very specific on the finish. I recently went from a diamond rough/ diamond finish to a diamond/cbn combo. The naked eye can't tell the difference bet the finish is much better when I measured it. Seems no to have as much rpk.

 

[fastfox420n/a]

The block measures perfectly, this is not a question that will be answered with a torque plate. It is a matter of surface finish, not out of round

Yes re-hone the block. You're getting new pistons, so hone to 100 percent clean up and then order them. That block is o ringed also, if it was honed with a torque plate it would not measure perfect as your stating. Surface finish is gonna depend on ring type, and usage.

 

[000Racer]

It takes good equipment but with the new coatings and ultra thin rings it gets very specific on the finish. I recently went from a diamond rough/ diamond finish to a diamond/cbn combo. The naked eye can't tell the difference bet the finish is much better when I measured it. Seems no to have as much rpk.

You'd be surprised what you can get away with, and I can achieve the same thing with my abrasive stones.... Recently did one with .9 .9 .2mm ring pack... Rvk was 100
Rpk was 15... Bitch made a lot of power, no smoke.... Shit ton of vacuum....
That profilometer is a pain in the ass. Never get the same reading twice even in the same spot not moved.

 

[Rcparker2]

You'd be surprised what you can get away with, and I can achieve the same thing with my abrasive stones.... Recently did one with .9 .9 .2mm ring pack... Rvk was 100
Rpk was 15... Bitch made a lot of power, no smoke.... Shit ton of vacuum....
That profilometer is a pain in the ass. Never get the same reading twice even in the same spot not moved.

Stones can do a great job, actually cut better than diamond. They just wear easier and require more work. Before cbn roughing with diamond and finishing with stone was the hot setup, may still for some.

 

[scott foxwell]

That hone job looks like ass.