[383SBC]

Ok guys I need some help here regarding what my machinist is saying. A couple months ago I brought my 350 4 bolt block to a local machine shop to get a bunch of machining done to it for my 383 build. I told them to zero deck it, bore and torque plate hone to my pistons (forged wiesco's), install cam bearings, and do whatever else they thought would be necessary for this 500hp build. I finally gathered all my parts and went to a different machine shop the other day (this shop specializes and only does high performance work) to get my rotating assembly balanced and he told me to bring in all my stuff including the block so they could check it out to ensure everything looked good before they go ahead and balance it for me. So I brought my block down (its a stock GM 1970's 4 bolt 350) and he started measuring everything to verify the work that was done by the other shop. The first problem he said with the machine work that was done is that a couple cylinders have a .001" taper from top to bottom. He said for a stock rebuild this wouldn't matter but for performance use I can't have ANY taper and that he would have to torque plate hone them further to straighten them out ($350). The next thing he checked was the squareness of the deck surface to the crankshaft centerline to verify it was actually 0 decked. To do this he installed the crank and a rod and piston in all 4 corners and measured the differences in piston to deck heights. Well it turns out that one corner was 0.022 in the hole while the other three were 0.020" in the hole. I found this unbelievable because I told the other shop to zero deck it and they didn't even have my crank or rods. Anyway he said that I would have to get them decked again by him at $150 a side ($300). I can't see how that would matter so much because I could run a 0.020" head gasket and still have 0.040" quench. The next thing he came across was my stock main caps. He's telling me my caps go on too loosely and you should have to seat them via the bolts. It is only the front main cap that goes on a little easy but he is saying the cap will move from side to side with it like that. At this point I think he is feeding me complete bs and just wants my money because now he says I need to buy new main caps from him and then have the block align bored/honed (about $700). After that he says that if I didn't have "performance" cam bearings installed they are going to have to remove them and install performance ones because my 580 lift hydraulic roller cam will destroy them? The last thing I got done was have my scat cast 383 crank quickly polished (this crank has less than 1000km on it). He went ahead and gave it a quick polish then measured the journals and apparently two of my connecting rod journals are out of round by 0.0006". That's right 6 ten thousandths of an inch. So he said that is too much out of round and he would have to turn the journals to 0.010" under and charge me $150 for it. So anyways I am beginning to think he is in this for my money which is tight these days and by the time I got him to RE-DO all the work I already have done at the other shop this block would cost me over $2000 in machine work! Could somebody please tell me if the specs I have supplied and described to you ok for a performance build? I have looked around and see that 0.010" taper in a cylinder is max. allowable and I have 0.001" max. If there are any machinists here I would love to hear your honoust opinion because I think he may be exageratting the numbers and making this look a lot worst than it actually is.

Thanks for all the help and info here guys,
Keith

[406 bug]

I say run as fast as you can. Although some of what he said could be true (when he got to the part about cam bearings he is F O S). Just to note: a good shop can deck and measure without the rotating asmbly. installed.

[77'Omega]

if you can read a mic take it home and you can check deck height yourself as far as a .001 taper that should come out in the wash. this is only barely working your piston rings. and cam bearings, he is full of it. as long as they are installed right then they should be fine. play in the main cap is a bad thing.
but how many engines have you had fail. and have they all been machined at the same place. im not done a complete car build and im working on my first.
but as far as a engine build, i love building engines. but i mic everything my self and go tell the machine shop what i know i need and they do have digital maping machines that can tell them exactly what your block needs but most shops dont have this luxury and there trying to get you to pay for one if you get what i mean.

[dgcantrellsr]

What he said run fast he's shoveling chit at you, you can buy an after market block with all he's wanting to do for less.

Originally Posted by 406 bug

I say run as fast as you can. Although some of what he said could be true (when he got to the part about cam bearings he is F O S). Just to note: a good shop can deck and measure without the rotating asmbly. installed.

[weedy64]

I recently had a block zero decked and the crank/rods/pistons were not required. I asked for 9.000 deck height and that's what I got. An arbor was installed in the mains and the block measured .022 -.024 from end to end(at least on one side, I don't recall the other), the block was adjusted and ground so that the deck is 9.000 on all corners. When I installed my pistons with resized rods they are all within .001 of zero....good enough for me.

Did you get what you asked for? Did the shop #1 just deck your block or did you give them a target deck height to shoot for? Depending on the answer a refund may be in order.

Shop #2 at least knew enough to measure the stack height of the piston/rod combos and even took the crank out of the equation by using it as well.

Other issues. Bore taper is not desirable, did you just rehone and hope you were lucky or was this bored to suit? In terms of bearings there are good,better,best not sure what happens in the cam bearing world, it's probably a question of longevity. 6/10 out of round...I don't know.

Not sure if a 500hp 383 requires the level of machining being suggested, I will leave it to others.

[Duntov]

A Pro Performance shop uses a deck gauge, and does not install piston rod combos generally to Guess gauge a deck. How does he know your rods are right from center to center or if they're all the same temp? I mean I do that, but I have my own rod measuring and balancing fixtures. I get an otherwise perfect rod that is .001" long, not uncommon, I put it in the deep hole and get them all the same depth. I also balance my own rods within .1 gram, not necessary to be that close, but rarely get that quality by hiring it done.
I check everything a machinist does for me, before and as, I assemble.. And let me qualify that statement by saying that I live within the 100 mile circle of Charlotte. Dozens of Legendary shops.

Even if.... sounds like you're within .002. not bad.. Do you have factory rods? If so then your deck is probably closer than it measures given the technique he used.
I've had multiple dozens of 010 blocks decked in the last few years by a guy that charges $50 for the job if we tank first. He is not a performance guy and uses a spindle jig which goes fully through the cam and main bores..

Cuts one side, elevates, rotates 90deg, cuts the other side according to his elevation gauge. comes out +or- 001". Typical variation between four corners -001", .000" +.001", -.0015". .

When I'm really going all out, I go to the (local hero machinist) (guy behind half the front pack) at the local asphalt and dirt tracks and get it deck gauged.. comes up a little tighter than that but not all that much. He gets $75 to deck and $35 more to gauge deck... total $105 Also he won't read a block till it's been in the shop over night for uniform temp.

As to the taper you're not going to run the 600 at Lowes,.. besides I don't trust the guys readings.. Our best guy gets $100 to bore, and 45 extra to torque plate.. That's not per side either... Where in the world do you live that it cost like that? NO.. My first instinct is to get my stuff the H E double hockey sticks out of that shop. Should say I'm not all that happy with the taper but I'd get someone else to do it if I did it at all.. Hey buy a cylinder bore mic on Ebay and check it yourself.
I could be wrong about the shop Duntov

[ericnova72]

Lots of different issues here so I'll try to fill in the gaps. The .001" bore taper isn't great, I would have it plate honed again to remove it, but would give the 1st shop a chance to fix it as they did the work, unless thet can't hit that dimension target. Maybe all they do is production work and think itis good enough as is?? Don't let them tell you "close enough",... this isn't horseshoes. By the way, most will say .003 taper is too much even for a quicky re-ring on a wore out motor, maybe .010" is flathead specs from back in the day?? Certainly no performance at .010" taper. I find the second shop's charge to correct this as very excessive(in my area anyway, by about 2x).

The zero deck issue, .002" difference side to side isn't a deal breaker, but the fact it isn't zero decked to your parts is,... but if you didn't give them parts or part dimensions to determine where zero deck is it would be your fault that it isn't "zero'd". If they had a dimension to cut down to then go back to them to make it right. Shop 2 decking charge is high compared to my area also by 2x. You are correct that you can get to where you want to be with the head gasket if you want to go that way, no problem with that.

The loose cap is a stickier issue, Shop 2 is technically right, but it would be your call as to whether just peening the register beside the cap to make it tight, or replacement of the cap and line bore/hone. Shop 2 cost seems excessive here too, last one I had done was $550, including the splayed 4-bolt caps.

Cam bearing issue is Bull***** for the cam you have, but almost everyone has a preferred bearing that they use, could be he is just covering his ***(and name/reputation).

Crank sizing issue is valid for an all out performance engine, might be fine in your case, it would have to be your call.

I have to say where you see Shop 2 as being greedy, he is just trying to ensure that an engine with his name attached does cause a problem. Doing performance work he knows how good things have to be to be perfect, not just "good enough", and he may not want to deal with "good enough's".

Why did you go away from Shop #1??

[sickolds]

wow thats some bull ******* i only spent 6and some change in upland cal with a free tour of his chop people these days

[RattVette]

run asfast as you can to the door and spread the word to all your friends, guys a ripoff artist.

tell him to stick his .0006 where the sun don't shine, I work as a Machinist in a shop that builds engine and transmission components 6 tenths aint crap, maybe ifyou were building a 1600hp full race motor but for what your doing run run run away

Once some of these shops get a good name they get lazy or greedy, I am going thru the nightmare of having a motor reworked because the guy at our local racers shop got lazy and didnt properly clean out my block, less the 200 miles on the shortblock he assembled and my brand new eagle forged crank needs turned, my cam needs replaced as does every bearing, luckily it just ate the bearings and the cam could have been much worse considering that it was a block built for nitrous can only imagine what would have happened if I had hit that 250 or 300 shot. but atleast he's paying for all the labor and machine work, I'm just buying the cam ,lifters gaskets and bearings

Best advice is call ,visit and talk to several shops and go with who you feel most comfortable with, the little voice in your head is usually a good judge of character

[Fast 4 Door]

Originally Posted by sickolds

wow thats some bull ******* i only spent 6and some change in upland cal with a free tour of his chop people these days

I spent 900 I didn't even get it decked. ( only reputable guy around ) I think it is supply and demand depending on where you live. I think the further north you go, the harder it is to get good honest reasonable machinists. I'm in Ma. where everything is expensive. I want to move to the NC. A lot of the good guys are gone around here. Even the guy I use told me back in the day, he would have a dozen heads to work over on any given day. Then told me he's lucky to do one set a week. Chalk that one up to the internet and that little sticker that says " made in china".

Oh yeah, machinist #2 sounds like a real scoundrel Happy building

[DoubleVision]

The very second he said "I need to see your block" I would have hit the door with my parts in hand because I brought my stuff there to be balanced, not to have the block checked. He seen you as a walking profit.
I had a similiar experience when I was trying to find a shop to balance my 4.3 V6 rotating assembly. The minute they start talking BS I hit the door, I got no time to listen to it. If it came down to I had to use him out of no choice, I would have gotten aggressive and said "I asked you to balance the rotating assembly, you don`t need the block to do that"

[383SBC]

Wow thanks for all the opinions here guys, I was under the impression this was a money grab. At this point I think I am just going to assemble it and see what happens..... I already have $500 in machine work atleast in this block and I am not going to get it all done again at twice the price. The reason he charges so much is because (I'm assuming) it's a "performance only" type shop so you're paying for the quality of work as well. The reason I didn't go back to shop #1 for the balacing is because it is an hours drive from where I currently live and work, shop #2 is a 5 minute drive. I will make sure all my clearances are correct and measure everything three times before assembly but I can't see any of these issues being of catastrophic failure of this engine. Couple more questions now that we are here, when you say I should peen the main cap locating flange on the block, should I just notch it in 4 or 5 places with a chisel on either side? Also what is a recommended and safe main/connecting rod journal bearing clearance I should stick to for this 500hp application. I am under the impression that performance engines should use a slightly LARGER bearing clearance, is this correct? The last question I have is about my piston to cylinder wall clearance. I am running forged pistons in this 383 and I was planning on giving it a 100 shot of nitrous in the future. The piston to wall clearance after taking it to the machine shop SHOULD be 0.0025" according to the instructions that came with the pistons (I will verify they didn't mess that up too). Would I need a larger piston to wall clearance than that if I did give it some nitrous and if so what is the recommended? Anyways this is about all the questions I have for now and again I really appreciate all your help, its good to see that you can trust some people in this world we live in.

Keith

[ericnova72]

Peening is done with a blunt nose chisel, you want to push the metal of the block next to the cap back tight to the cap, might take 10 medium blows per side, work deliberately and careful, no hurry, you are lightly cold forming the block's cap register back to tight. Takes time to remove and check the cap to block fit, do it every couple of blows. Don't have the cap bolted down while doing this or the cap could be moved too.

Clearances .0022-.003" on rods, .0025-.0032" on mains, .003-.004" on rear main.

.0025" seems awful tight piston to wall, but I don't know who's piston you are using. I wouldn't go tighter than .0035" myself with the nitrous hit. Most forged street and sportsman pistons are .0035" minimum clearance, and are fine with the same clearance on a smaller than 200hp nitrous hit, but your .0025" scares me. Who's pistons??

[cobalt327]

While you're checking things, the ring end gap is critical- w/nitrous it needs to be opened up from what a NA engine runs.

Not doing this can allow the ends to butt together, and will put an instant end to your fun.

I could cite you what the various manufacturers say on this, better that you use the recommendations of the manufacturer of YOUR rings/pistons.

[oldbogie]

Originally Posted by 383SBC

Ok guys I need some help here regarding what my machinist is saying. A couple months ago I brought my 350 4 bolt block to a local machine shop to get a bunch of machining done to it for my 383 build. I told them to zero deck it, bore and torque plate hone to my pistons (forged wiesco's), install cam bearings, and do whatever else they thought would be necessary for this 500hp build. I finally gathered all my parts and went to a different machine shop the other day (this shop specializes and only does high performance work) to get my rotating assembly balanced and he told me to bring in all my stuff including the block so they could check it out to ensure everything looked good before they go ahead and balance it for me. So I brought my block down (its a stock GM 1970's 4 bolt 350) and he started measuring everything to verify the work that was done by the other shop. The first problem he said with the machine work that was done is that a couple cylinders have a .001" taper from top to bottom. He said for a stock rebuild this wouldn't matter but for performance use I can't have ANY taper and that he would have to torque plate hone them further to straighten them out ($350). The next thing he checked was the squareness of the deck surface to the crankshaft centerline to verify it was actually 0 decked. To do this he installed the crank and a rod and piston in all 4 corners and measured the differences in piston to deck heights. Well it turns out that one corner was 0.022 in the hole while the other three were 0.020" in the hole. I found this unbelievable because I told the other shop to zero deck it and they didn't even have my crank or rods. Anyway he said that I would have to get them decked again by him at $150 a side ($300). I can't see how that would matter so much because I could run a 0.020" head gasket and still have 0.040" quench. The next thing he came across was my stock main caps. He's telling me my caps go on too loosely and you should have to seat them via the bolts. It is only the front main cap that goes on a little easy but he is saying the cap will move from side to side with it like that. At this point I think he is feeding me complete bs and just wants my money because now he says I need to buy new main caps from him and then have the block align bored/honed (about $700). After that he says that if I didn't have "performance" cam bearings installed they are going to have to remove them and install performance ones because my 580 lift hydraulic roller cam will destroy them? The last thing I got done was have my scat cast 383 crank quickly polished (this crank has less than 1000km on it). He went ahead and gave it a quick polish then measured the journals and apparently two of my connecting rod journals are out of round by 0.0006". That's right 6 ten thousandths of an inch. So he said that is too much out of round and he would have to turn the journals to 0.010" under and charge me $150 for it. So anyways I am beginning to think he is in this for my money which is tight these days and by the time I got him to RE-DO all the work I already have done at the other shop this block would cost me over $2000 in machine work! Could somebody please tell me if the specs I have supplied and described to you ok for a performance build? I have looked around and see that 0.010" taper in a cylinder is max. allowable and I have 0.001" max. If there are any machinists here I would love to hear your honoust opinion because I think he may be exageratting the numbers and making this look a lot worst than it actually is.

Thanks for all the help and info here guys,
Keith

Pick up your toys and take them home this guy is a cheat. Even if what he says is true, you can only take so much material off a block, every cut weakens it. Constantly trying to fix things that are out of plane a bit finally results in a block that can't hold dimensional tolerances and dimensions when loads are introduced to it, so whether it measures up when sitting on the work bench becomes a moot point when it starts bending as bolts are torqued and operating loads are put into it.

One never just machines parts on whim such as your saying "zero deck it". Milling the deck like boring the cylinders is an operation intended to correct dimensional deficiencies, you don't do it if it isn't needed. By the way zero decking and or parallel milling isn't done to the crankshaft, it's done to a mandrel run thru the main bearing saddles and caps. The crank has its own foibles and certainly isn't anything you'd want to index other operations from.

For the most part GM does an excellent job of machining at the factory, the engine will usually remain quite dimensionally stable thru its life time except for the wearing surfaces that need to be renewed like the cylinder bores. Warpage of the decks and thru the mains and cam bearings are usually the result of the engine being repeatedly overheated. Most of these shops selling align boring and honing and surface decking can't come close to the factory specifications, they're just screwing around with expensive "feel good" operations.

Increasing engine size such as the 383 on a 350 causes problems with increased compression. Zero decking does two nasty things to you; one as I've already pounded to death is it structurally weakens the block at a place and in a time when the increased compression will require more strength from the top of the block. Second, is a stroker kit makes getting the compression back to something pump gas will tolerate becomes a problem and the loss of .025 inch above the piston just exacerbates the situation. But you've done it and now have to live with it. Best solution is D dish piston of proper volume to correct the compression. This puts the dish under the valve pocket and allows a close closing of the opposite sides squish/quench decks that optimizes these functions which results in high mechanical octane taking some of that critical load off the fuel octane rating.

Taking the out of round from the cylinders will require a torque plate hone, removing more material. This will increase the piston clearance unless you opt for a rebore and new pistons to start with a fresh dimension and proper clearances. Just rehoning your current situation will just increase the piston to wall clearance which is essentially aging out the engine without driving it. This is no improvement in the situation you're currently at if indeed the walls are out of round. I'd just leave it where your at. As with the decking, continued screwing around will probably only serve to make things worse in the long run. Obviously a rebore will require new pistons and rings.

Rehoning the main bearing bores is more of my yada, yada, yada. Leave it alone unless you can verify it being off so much that an improvement can be made.

A balance emporium should only need the crankshaft and the stuff that attaches on it, they don't need the block, nor the heads, or the alternator.

Times are tough in the hot rod business and shops are hunting for suckers. If your nervous about this engine I'd recommend getting some second opinions before embarking on any "corrective" actions.

Bogie