So last fall I sent a block out to get sleeved, I won't say where but its been sitting on my shelf ever since. I just got my Fowler bore guage and my new starret 3-4" mic today so I though I'd take it down and measure it and see what I was dealing with.

I measured all the pistons and they were all within a tenth (.0001") of each other which I thought was very good. Here are the measurements I took on the block after setting the bore guage to the piston. I didn't even look at the piston spec sheet yet to see what the clearances should be, I'm just looking for consistency at the moment.

CYL # 1 .003 clearance up and down
CYL # 2 .003 at the top, .0028 at the bottom
CYL # 3 .0034 at the top, .0032 at the bottom
CYL # 4 .0018 at the top, .0032 at the bottom

Cylinder #3 could have been better but I'm obviously worried about #4 I'm a machinist/toolmaker myself and its been my expierience that a cylinder like this would most likely taper from top to bottom rather than be smaller at the top.

Surely theres no reason for this right? I plan on shooting them an email about it but I just want to verify I know what I'm talking about here. I find it hard to believe that it could be off so far (.0014" tapered) and not have been caught. I'd give them a few tenths, but this is like it was never measured.

Also what is the likelyhood that this can be set back up and "fixed" without taking more material out of the bottom and still keeping the bore straight? I was hoping to start building this motor soon, but now it looks like thats not going to happen.

 

It is more typical to have them tighter at the bottom.An experienced machinist can get the taper out of the #4 cylinder without removing much at the bottom.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NJIN BUILDR &raquo;</TD></TR><TR><TD CLASS="quote">An experienced machinist can get the taper out of the #4 cylinder without removing much at the bottom.</TD></TR></TABLE>

 

whats the bore?? and what kinda pistons do you have

 

88mm coated wisecos 11.5:1 w/h22 crank and rods (I'll be using h23 crank/rods though with thicker head gasket to keep the same comp ratio)

It sounds to me like a lil too much clearance in the first place, but like I said I haven't looked at the sheet.

 

its fine, have em bore em all out to 3.5 or 4 thou, you wont have any problems

 

I checked the paperwork and Wiseco reccomends .0025" before any coating (they ARE coated btw)

Also I remeasured again today, it looks like cylinder is just out of round at the top being .0018" in the Y direction and .0034 in the X direction. Measurements taken in the middle and the bottom were around .0032" both ways. Cyl's 1&2 are perfect at .003" and #3 is just a bit bigger at .0034"

Does anyone think that cylinder #4 might come into spec when a head is torqued down to it? I guess if it comes down to it I can bolt the head on and measure through the bottom of the block haha.

 

IMHO 0.0025 is too tight, typically the smallest p-w clearance we use is 0.004. you could try bolting the head to it to see if it straightens it out but idk why they all would be so inconsistent even if they used a torque plate.

 

I would be worried if the sleeved cylinder changed by .0016" just from torquing the head on.I'm assuming this is a closed deck B engine.Idk how you could hone only the top out of round.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">IMHO 0.0025 is too tight, typically the smallest p-w clearance we use is 0.004. you could try bolting the head to it to see if it straightens it out but idk why they all would be so inconsistent even if they used a torque plate.</TD></TR></TABLE>

yeah I don't get it either, but I'll prolly end up taking your advise. Just don't know if I want to risk sending it back to them or have someone else do the work. Thanks for the help.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NJIN BUILDR &raquo;</TD></TR><TR><TD CLASS="quote">I would be worried if the sleeved cylinder changed by .0016" just from torquing the head on.I'm assuming this is a closed deck B engine.Idk how you could hone only the top out of round.</TD></TR></TABLE>

Its an H actually, but its still closed deck. The sleeves are just straight sleeves, prolly .125" thick.

 

in my experience.. its easier to have a boring machine cut poorly than perfectly, and i dont mean on some POS old crap, ive had it happen with a rottler F80 using CBN as well.

i find the outer cylinders move around more than the center ones, probably due to being unsupported on the outsides. i also find that a honing machine removes material much straighter than a bore.. but its more time consuming, so half *** shops will bore a lot closer to final diameter than meticulous ones. i personally use coarse stones and hone all the way to the next size anytime i can avoid boring just to keep as much straightness as possible.. but thats just me, it isnt necessarily the "right way" to do it.

since your sleeves are straight wall and only supported at the bottom, im gonna say that when it was bored, the cylinder was walking with the cutter, then they honed it to size pretty quick. if it was measured, youd see exactly where the bore gage was slipped.. there will be faint drags in the honing teeth.

sunnen hones CK-10 and newer can definately dwell, some only at one point, some just about anywhere. find a shop who's got a newer one that can dwell on top.. they should be able to get the top straightened out without going too far on the bottom.

i bet the bottoms are nice and round though.. all that support from the block register doesnt let them move. aftermarket sleeves should all have built in "blockguards" for this reason IMO

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike_belben@yahoo.com &raquo;</TD></TR><TR><TD CLASS="quote"> if it was measured, youd see exactly where the bore gage was slipped.. there will be faint drags in the honing teeth.
</TD></TR></TABLE>

Many times shops will do a clean up pass with the hone to hide the bore gauge drag marks once everything is to size. Usually just to avoid the "OMG what the hell are those marks in my freshly honed engine?" questions.

You can take some clean steel wool and burnish away the skirts of your pistons down to the metal. The coating is still present so don't worry. But now you will be able to take a more accurate reading of your pistons sizes.

 

Thanks Mike, nice write up!