Cylinder boring - any idea on cost??

[92ShoOff]

Hey guys, upon tearing down the 3.2 that I plan on dropping in my '92 %-speed I noticed that the cylinder walls have surface rust on them. I'm sure that this should just simply clean up, but if it the even that the walls are actually pitted and slight boring of the walls would take care of it I was considering boring the walls .020" over. Does anyone have any idea how much I might expect to pay a machine shop to bore and prep the 6 cylinder walls for the new piston rings.

I plan on installing Total Seal gapless piston rings, so combined with boring the walls .020" over could I expect a worthy torque and horsepower increase? Or if the walls aren't pitted am I better of just having the walls prepped and installing standard sized rings without doing any boring?? Thanks in advance for your advice guys!

-Andrew

 

[Sh03d]

I'm not sure but you might have to get bigger pistons too.
Shouldn't cost to much for the machine shop to do that. Around 1-200 bucks at most. For boring, balance, cleaning I'm being charged little under 400.

http://www.shoforum.com/search.php?searchid=387348

 

[laxmax327]

yea, prob under 200bux. but yea i think youll need to new pistons, allthough im certainly no expert on this topic. but the machining isnt a big deal. not sure when youll need new pistons though.

 

[Sh03d]

I would get it honed or get the machinist opinion. He sees stuff like this all day long so he will have a good idea on what to do.

1. Ask Machinist
2. Get it honed
3. If you have to get it bored and new pistons (cheaper to find another 3.2 if you want to stay with stock compression ratio and cast pistons.)

 

[93superSHO]

The cost for machining is reasonable. You will need NEW .020 over pistons. I rebuilt engines professionally for 6 years and a GOOD shop will have you order the pistons and have them there when the machining is done so the cylinders can be bored for those pistons and honed for the correct Ra smoothness on the walls. Pistons have certain measurement requirements for each brand(wiseco, Je, Diamond, srp, etc.). You can't just have it punched out .020 get pistons and slap it together, NOT with these engines, I have personally built 3 of them two I own and they have VERY strict tollerances that do NOT allow slop that say a 350 chevy would. Just remember, you will or can spin these thing at 8000rpm+(You can't do that without strict tollerances). I hope this helps. :wave:

 

[Entropy]

The cost for machining is reasonable. You will need NEW .020 over pistons. I rebuilt engines professionally for 6 years and a GOOD shop will have you order the pistons and have them there when the machining is done so the cylinders can be bored for those pistons and honed for the correct Ra smoothness on the walls. Pistons have certain measurement requirements for each brand(wiseco, Je, Diamond, srp, etc.). You can't just have it punched out .020 get pistons and slap it together, NOT with these engines, I have personally built 3 of them two I own and they have VERY strict tollerances that do NOT allow slop that say a 350 chevy would. Just remember, you will or can spin these thing at 8000rpm+(You can't do that without strict tollerances). I hope this helps. :wave:

Listen to this guy!

 

[ManySHOs]

If it isn't practical to use your 3.2 block, I would find a 93+ 3.0 block and overbore that to match your 3.2 pistons. Hot tanking, boring, honing and re-hot tanking should cost between $120-$150. This is actually a really nice way to go as you'll have a fresh bore and proper ring/piston/cylinder clearances.

Now that you have everything apart, do yourself a favor and have the rotating assembly balanced (50% high speed overbalance). I have about 20 miles on my 3.2 (originally a 3.0, new rings, factory 3.2 pistons, balanced bottom end) and it is silky smooth and torquey. I love it. I can't wait to get out of work so I can drive it some more!

Ian

 

[drivinhard]

I would agree on the above comment about getting your pistons first, pick out what you want, and then bore the cylinders to match the piston size the recommended clearance.

Figure several hundred bucks for a quality clean/bore/balance assembly

 

[92ShoOff]

Okay so what I'm going to do is just use the factory 3.2 pistons with the 3.2 block and not getting it bored out. I don't have enough cash to get new pistons as well, I just thought that the factory pistons could handle .020" over with simply changing over to .020" over rings.

So what exactly is hot tanking? Will I need to have that performed on the block if I'm not having the cylinders bored? I'm taking it that hot-tanking is just simply a cleaning process, but I'm not sure. Also, what does the whole balancing process consist of?

I do have some sludge built up in the water pump inlet of the 3.2 block, so to get that taken care of and have the walls prepped for the new rings what all should this entail of??

Thanks for your help so far guys! It's definitely making understand this whole rebuild situation a bit better!

 

[93superSHO]

Hot tanking is a cleaning process which consist of VERY hot water/chemical solution that won't require you to remachine the block(bore, hone, line bore, re-deck, etc). Before you reassemble the short block- you NEED to deglaze the cylinders so the NEW rings seat properly and you get the most durability out of the engine. If I were you I would also mark and/or note which pistons come out of each cylinder and re-install them in that cylinder(If one cylinder has ovaled out on the bottom of the cylinder it is possible that you can get piston slap by putting any of the pistons in)-piston slap is where the skirt basically rattles back and fourth in the cylinder- common in GM 5.3 v8 first 18 months of production- sounds like marbles rattling in engine. You can get the cylinder de-glazer at any auto parts store(looks like cone with tiny balls all over it). You'll be fine

 

[93superSHO]

It wouldn't hurt to hot tank the block, I would. Balancing is where the rotating assembly(crank, rods, pistons, harmonic balancer, and flywheel) are put into a machine and spun and a computer balances the assembly. VERY good idea as it pretty much eliminates any vibration you will have at any rpm you'll run the engine at(a vibration will **** an engine fast, unless balanced/blueprinted all engines have an rpm point where there is minor vibration.

 

[Sh03d]

How important is getting the harmonic balancer and flywheels balanced? I had everything else balanced but not those.

 

[93superSHO]

All the shops here locally require the whole rotating assembly for balancing. I'm not sure why they did not have you include flywheel/flexplate or crank dampener( I called it h. balancer ). they are both part of the rotating assembly. If I were you I would question that with them :wave:

 

[Sh03d]

Well, I can bring down the harmonic balancer but I can't get to the flywheel now. I guess I will have to wait to get the flywheel done or find another.

 

[ManySHOs]

Well, I can bring down the harmonic balancer but I can't get to the flywheel now. I guess I will have to wait to get the flywheel done or find another.

The V6 SHO motor is internally balanced which means that it is not balanced with the harmonic balancer and flywheel. Your shop will need yours pistons, rods, wrist pins, circlips (just keep them together as one assembly), your crankshaft, rod bearings and piston rings.

If you do a google search for "crankshaft balancing" you'll learn a lot about how this is done. There's some great info out there that I was sifting through this morning at work.

If you install new rings (I would), the block should be honed. If it's honed, it will need to be hot tanked afterwards. We can give you advice based on (hopefully) experience but you'll probably get better answers to your questions if you talk to a machine shop about what you want to do. They do this day in and day out. Shop around until you find a place that you are comfortable to have do your work. You'll probably walk away with more questions than you had when you went there but it's all part of the fun and learning experience!

By the way, I would seriously consider having them reinstall the rotating assembly back into the engine for you. The oil rail rings on the SHO pistons are very thin and easy to bend when installing pistons into the block.

Ian

 

[93superSHO]

My bad, sorry I was speaking in general and talking to the woman at the same time and did not realize I didn't add that our engines are internally balanced, I'll slap her later

 

[ManySHOs]

My bad, sorry I was speaking in general and talking to the woman at the same time and did not realize I didn't add that our engines are internally balanced, I'll slap her later

 

[rangerj]

You got some great advice above and I'll give you some more. I'll repeat the advice that balance is critical for an engine that operates in the 7,000 RPM range. The cylinders also need to properly honed and crosshatched or the new rings will not seat. In general the 3.0 would not need this if the original crosshatching were still visible (per the Helm Manual), but you said your engine has corrosion on the cylinder walls and this needs to be cleaned up. Having the block tanked will clean both the inside of the block and the outside, including water passages and oil passages and is necessary in my opinion.

I too would have the shop assemble the short block, but first I would have the block magnafluxed for cracks. I would do this first before putting any money in the block. The block should be tanked before the magnafluxing.
Next the block should be checked for a straight (within tollerance) crank journal bore. Then the "deck" (top of the block where the heads are bolted) should be checked with a machinest straight edge for flatness, again within tollerance. If the block is OK for all the things I just mentioned it is now worth spending money on. If it is not within tollarances you have to decide if you want to find another block or pay for machine work to correct your block, e.g. line bore and deck the block.

Next comes the crank, rods, and pistons. Are the rods straight? Are the rod connections "round" within tollerance? Are the wrist pins loose in the pistons? In other words are the engine parts in good shape (within tollerance). If the answer is yes you can spend money on these parts and their assembly.

In my opinion it is foolhardy to assemble an engine with old nuts and bolts. Consider all new fasteners (nuts and bolts). Obviously new gaskets are in order and consider all new freeze plugs and any other passage plugs.

Lastly, remember that when assembling an engine EVERYTHING should be PERFECTLY CLEAN. Make sure all passages of the block are clean and clear of obstruction, especially the oil passages. The tanking process should do this, BUT CHECK.

 

[92ShoOff]

As always, some more great advice from RangerJ! Thanks!!! And thanks for your input as well, Ian!

So out of curiousity, why change out the freeze plugs and whatnot? It sounds like I'm also going to be spending a LOT of $$$ just checking to make sure that this engine is within its tolerances. Ouch!

I called up a local machine/performance shop this morning, and to hone the walls per specs required for the TotalSeal rings, to hot tank the block, and to balance it he said it would cost roughly $350. Doesn't that sound a little too high? He said that they don't do any assembly either.

I agree that I should leave the installation of the rotating assembly up to a professional though, mainly because of the installation of the piston rings. I do have experience with that part though, as I put all new bearings and rings in my 383 stroker motor some years back.... although I did of course break one of the compression rings while trying to put it on. I don't know anything about these "gapless" rings, but I'm sure they're no easier to install than a regular set of rings. If I can't find anyone to assemble the block, or assemble it for a reasonable price then I guess my best bet is to invest in TotalSeal's "Deluxe Piston Ring Expander" and cross my fingers, right? Here's what it looks like: http://www.totalseal.com/html/tools/index.htm

As foolish as it sounds to not do this I'm not going to be able to afford all new hardware for the assembly of this motor. I'm not even sure where to find hardware such as the connecting rod bolts and all of that, and I'm sure they're not the least bit cheap. Just in new gaskets, a reman. flywheel, two tie rod ends, new head bolts, and all new gaskets I'm already over $1k in just parts. I spent $700 on the motor just to use the frickin block and rotating assembly lol. So I'm about broke. Anyone need an extra complete 3.0 block or any 3.2 accessories???

 

[ManySHOs]

I would skip the magnaflux and the new bolts and hardware. Get new freeze plugs, oil galley plugs etc after the block is hot tanked and cleaned up. Your shop should do this for you as part of the cleaning process.

For $40, the only bolts I'd replace are the headbolts (Fel-Pro) but that's technically top end stuff.

Just keep your exsisting rod bolts, caps, etc all together. Your machinist should mic the rods and make sure the journals are not out of round. If you are using a block that didn't spin a bearing, chances are pretty good that your rotating assembly/hardware and block are useable. I've heard many say that when the rod bolts are replaced, the rod should be reconditioned as well. To me, that's an extra hassle that's not worth it on an NA SHO motor. On an American V8, I would probably do it. I personally think that magnafluxing is a waste of money on an SHO motor but you'll probably hate me if you assemble it and find that the block was cracked later on. Chances are pretty slim that the block is bad unless you pulled it from a boosted SHO that sheared its crank and spun bearings all over the place.

If you decide to install the pistons yourself, you may want to skip the parts store variety adjustable piston installers and get a sleeved ARP piston installer that's spec'ed for the correct 92mm bore of the 3.2. They are supposed to make installing pistons much easier. I think they are around $70 from Summit? The only downside is that you can only use them on that size piston. Then again, how many pistons do you plan on installing in your lifetime?

Ian