Piston/wall clearance & honing cylinders...

[Brandy]

This is very likely a dumb question for which the answer depends on a billion other things, but here goes.
I have gotten my 440 to the point where the heads are finished and the block is as clean as I need it to be, and I want to replace cam bearings and hone the cylinders to break the glazing.
There is a little at the bottom of the bores outside of the skirts and a bit at the top but not so much that you can catch a fingernail on it. I want to get a nice crosshatch going. The clearance as measured at the top of the bores is .008. Without the glaze I expect its more like .010-012. So, this is already .030 over and the pistons are flat top TRW 2266 L. So, if I get a flex hone and clean up the bores will I be in trouble with clearance and slapping pistons? And, the other info i'm sure everyone will need to know is the intake is an M1 MOPAR, the heads are 346 ported and polished, the cam is COMP 306-4 , crank forged stock journals, rods LY , carb 750CFM Holley dual feed, distributor Mallory UniLite.

 

[Don Frelier]

Honing the bores should not really change the inside diameter. You are just cutting some small grooves to hold oil.
In order words I would not expect any additional noise following a honing and new rings.
The big question is how good are the bores?
Size, taper and roundness?

 

[69Bee]

If you mean the "Three Fingers of Death" flex hone, I suggest you either throw it away, or sell it to some other sucker. That is the worst tool to use to deglaze a cylinder. A ball hone will NOT remove enough metal to change the shape or enlarge the hole. If you are already at 0.008" clearance, I suggest you have the block measured by a shop, and size willing, hone it to 0.040" os using new pistons. With all of the money you have spent so far, why shortchange your project now! Have a shop determine the oversize required, get new pistons, and hone (0.040") or bore/hone (0.060") to make the cylinder round and straight. New cam bearings, tower bushing, and freeze plugs should be replaced too.

 

[lewtot184]

.008" is quite a bit for those pistons, .010"-12" would be outrageous. they do have an offset in the pin and should help with noise but I don't think i'd do anymore than .003"-.004". I think minimum is around .0015"-.002".

 

[69Bee]

The newer Sealed Power L2266F pistons have a minimum clearance of 0.0015". Depending on engine usage and/or location (hot/cold), it couldn't hurt going 0.002".

 

[Don Frelier]

If you can't see any existing hone marks, then I would suggest you bore it.
This is the heart of the engine to get power it needs to be right.

 

[HEMI-ITIS]

You have to take off enough to make the walls straight,then find a ring pack that will fit.At that point you may need to take a little more for ring fit.The final bore is determined by what ring you use,then get the piston.

 

[HEMI-ITIS]

What do you think 69 BEE?? I have always cleaned the bore 'till it was good.Measured them up and the looked for a ring to fit.If the ring pack is slightly larger then hone to fit.

 

[69Bee]

You find the next bore size by what cleans up the cylinder, then get the pistons. Hone the cylinders to the pistons, and if you get a file fit ringset, THEN you fit the rings last. Rings never determine the bore size, the piston does.

Sorry, I type slow...

 

[HEMI-ITIS]

I'll agree to disagree.The next wing size has always chosen the pistons made to my spec.

Don't matter how fast you type,your opinion is what matters!!

 

[Challenger340]

Throw those dam 2266's in the trash can !

Get it Honed at a shop with a T/Plate to 4.3610".... yes, to .040" over and add .001".... go buy some .040" over L2355F's which will a composition Head Gasket and your 346's(86-88cc's assuming not excessively milled) and will put you mid 9's C.R., far better pressure availability for that Camshaft.

 

[Brandy]

Okay. I really appreciate the info and help. Here's my problem. This motor ran strong before I took it apart to fix the smoking cylinder with the stuck lifter and wiped cam lobe. I found the issue with that and fixed it. There were also 15 Teflon valve seals and one black rubber one. One bore has good crosshatch in it and the rest don't. The pistons are not the newer type. My guess is at least several years old. I had really intended to stay with the original parts if at all possible, excluding the cam and lifters of course. So I guess what I'm saying is I don't have the money for a bunch of new parts if the old ones will do. Which is why I wanted to just clean up the cylinder walls a bit and put it back together with new rings , seals, and main & cam bearings. I got to thinking about clearances and thought to ask. I will pick up some HP with the cylinder head work and a thinner headgaskets and the cam and the M1 single plane. Not going racing here just street.

 

[Brandy]

Honing the bores should not really change the inside diameter. You are just cutting some small grooves to hold oil.
In order words I would not expect any additional noise following a honing and new rings.
The big question is how good are the bores?
Size, taper and roundness?

I don't know the answer, but i'm going out to check right now. I will let you know in a minute.

 

[Brandy]

They all measure just short of 4 3/8ths both top and bottom. As far as round goes the piston has the same clearance right side up or upside down at the bottom of the bore. Sorry, I don't own a digital caliper. Just a regular one.

 

[Brandy]

If you mean the "Three Fingers of Death" flex hone, I suggest you either throw it away, or sell it to some other sucker. That is the worst tool to use to deglaze a cylinder. A ball hone will NOT remove enough metal to change the shape or enlarge the hole. If you are already at 0.008" clearance, I suggest you have the block measured by a shop, and size willing, hone it to 0.040" os using new pistons. With all of the money you have spent so far, why shortchange your project now! Have a shop determine the oversize required, get new pistons, and hone (0.040") or bore/hone (0.060") to make the cylinder round and straight. New cam bearings, tower bushing, and freeze plugs should be replaced too.

No, I know better than that. I mean a ball flex hone. Plus your talking about $1200 worth of machine work I cant afford.

 

[HEMI-ITIS]

If it just the one cylinder,clean it up,see what the old rings measure and go from there! Keep it within budget so you don't miss the whole season!!

 

[Brandy]

If it just the one cylinder,clean it up,see what the old rings measure and go from there! Keep it within budget so you don't miss the whole season!!

1/16, 3/16, and 4 3/8ths. Ring thickness, ring width and bore size.

 

[lewtot184]

1/16, 3/16, and 4 3/8ths. Ring thickness, ring width and bore size.

pretty sure those are 5/64" ring grooves for the compression rings; 3/16" oil ring. thinking about it, I think your measurements are off.
double check some things. a 4"-5" mic and a dial bore gauge will get you on the money. calipers won't work. another thing you can try is feeler gauges between the piston skirt and cylinder walls. not real accurate but I bet you can get closer than a caliper.

 

[Brandy]

pretty sure those are 5/64" ring grooves for the compression rings; 3/16" oil ring. thinking about it, I think your measurements are off.
double check some things. a 4"-5" mic and a dial bore gauge will get you on the money. calipers won't work. another thing you can try is feeler gauges between the piston skirt and cylinder walls. not real accurate but I bet you can get closer than a caliper.

.008 fits inbetween.

 

[Don Frelier]

So it sounds like the motor was already bored .060 over. Given that, it ran OK before you tore it apart and most importantly your budget.
Sounds like you are making the right move. Hopefully it runs real well when you get it all back together.