Bad machinist? (Proper piston-to-wall clearance)

laserspeeddemon · May 19, 2011

Well the first indication that my machinist may be bad at his job is he doesn't listen. I told him before he does ANYTHING to call me first. I call him a week later to find that he already bored the engine 0.040" over and he said it was done, problem is I was still waiting on the pistons from Manley. I just got them yesterday and he said the engine has been done for over a week.

My question is how do you know what to cut the bore to without measuring the pistons? My concern is that he cut the pistons larger than the pistons are, that be the case it would mean that I now have to go to 0.060" over and now I have to sonic test the block and get new pistons and.... blah. I'm hoping that when I measure my pistons tonight with a micro-meter it comes out to 86.003mm or something like that, so that he has to hone out the cylinders some and not 85.910mm or less.

What the machinist told me is that "it should be alright". When dealing in tolerances of 0.0035" (or 0.0889mm) on a car that I am dropping another $6000 into, I don't like the words "it should be alright." He told me to bring the pistons by and he'll measure them. I'm going to measure them for myself and see if he adjusts the number to not stupid for screwing up my block.

DSMReviver · May 19, 2011

Do not use that machine shop again. unless he know the diameter of your piston of the back of his head then i would maybe let him work on my block. Machine shop like him give dsm's bad name with their poor work.

He probably only know how to work on BIG blocks. and refuse to work on anything smaller. That makes me angry.

91stocker · May 19, 2011

Were you able to measure anything before taking it to the shop? Far as i know 0.040" over bore is the max on these blocks. Which leaves you no room for future builds. Plus get it to tight, piston will seize. Set the clearance to loose, and you will have piston slap.

Hope not but you might have yourself a nice 40 over table

Fejery4491 · May 19, 2011

Thats no good. You really can't get a correct piston-to-wall clearances without having the pistons to correct bore the block. .40" pistons are hardly ever ACTUALLY .40". Pistons that I've dealt with are usually smaller than advertised. So I would think your clearances will end up being excessively large.

turboglenn · May 19, 2011

Hey bud, your machinist owes you a new block, any engine machinist worth his weight in turds, knows you don't bore untill you have the pistons. He must have talked his way into a job he';s never really done before or something. What shop was it? Rememebr i tgrew up in the burg, and i can get you the right places to take it to with a phone cal or two. Because my friends ouyt there still have cars and bikes built and use one or 2 guys there they like and are good at their jobs. Hollar at me whenever, shoot me a text and i'll call or text ya back with good info

PM you my number now

Glenn

nitrouskris · May 19, 2011

turboglenn said:
Hey bud, your machinist owes you a new block, any engine machinist worth his weight in turds, knows you don't bore untill you have the pistons.

what he said. i had a machine do the same thing to me

jimbob_843 · May 19, 2011

Half a$$ shop! Steer clear

laserspeeddemon · May 19, 2011

Yea, he messed it up. The pistons I got were 85.5mm (instead of the 86mm I ordered), but even those measured 85.14mm with a micrometer. So if the 85.5mm are about .35mm to small than the 86mm are probably 85.54mm which means his bore is 0.5mm too big.

The block is now trash. I'm going to talk to him tomorrow about how he is going to take care of this problem.

DSMReviver · May 19, 2011

laserspeeddemon said:
Yea, he messed it up. The pistons I got were 85.5mm (instead of the 86mm I ordered), but even those measured 85.14mm with a micrometer. So if the 85.5mm are about .35mm to small than the 86mm are probably 85.54mm which means his bore is 0.5mm too big.

The block is now trash. I'm going to talk to him tomorrow about how he is going to take care of this problem.

I am angry for you! POS, and monkey rancher need to go out of business. I hate the fact that you are fixing to spend your hard earn money and they are going to f*** it up like that.

phunny · May 19, 2011

What's crazy is 98% of the guys on here would never even know anything was wrong. We need a write-up on what to do when doing a rebuild. Hey TurboGlenn, get on it will ya

laserspeeddemon · May 19, 2011

Ok so quick question: The piston to wall clearance is 0.0035" for Manley pistons. Is that all around the piston So that my piston diameter minus my cylinder bore should equal 0.007" total. OR is the 0.0035" total and I should have 0.00175" clearance around the piston? I'm thinking former is correct (0.007").

If this is the case I might be lucky, I just re-measured the piston and made sure I zero'ed it this time.
This pistons ranged from 85.24mm-85.38mm. So reason would dictate that the 86mm pistons are actually 85.74mm-85.88mm minus the bore and I got 0.26mm-0.12mm. or 0.0102"-0.0047." Which means some of the cylinders would be too small and need to be bored out, while the others would need to sent back.

**edit**
SEE THIS IS WHY I HAVE 3 SPARE 6-BOLTS!!!!!!

DSMReviver · May 19, 2011

phunny said:
What's crazy is 98% of the guys on here would never even know anything was wrong. We need a write-up on what to do when doing a rebuild. Hey TurboGlenn, get on it will ya

Until it blows up and blame it on the 20+ year old dsm. thats how normally goes.

turboglenn · May 20, 2011

phunny said:
What's crazy is 98% of the guys on here would never even know anything was wrong. We need a write-up on what to do when doing a rebuild. Hey TurboGlenn, get on it will ya

Hey, i'd be honored to write something up to help others out, but out of fear of leaving something out i'd like to work on in in collaboration with some one before its' posted. I'm running like mad trying to stay bussy and pay bills, but if i can share something that will save others a headache otr hassle i'm glad to do it.

What was the guy on here that did the machining? i wanna say bogusSVO, or some one that their screen name had a ford 2.3 turbo related gesture to it. becaus ei could list what i know but i'm sure there's well more than that, not to mention some things that i believe from my machinist that others might try and flame or fiught about (like not turning these cranks because of having to re-nitride them and the fact that you can't remove the plug that fills the holes from where the oil galleys' were put in the crank it's self due to metal getting in there and having no way to ensure it's ALL cleaned out)

My machinist went through 2 blocks (bought 2nd one on his own with out my knowledge and at no charge) after i brought in 2 extra cranks and 2 sets of ACL race bearings so that he could ensure everything was perfect (and he didn't even assemble it, just said it was safe for me to assemble with out plastigauging since i don't have the e3xpensive tools he does)

lets stay on this though, i would think it could be a great benefit as i remember spending 3k dollars on my first bolt build and although it didnt' blow up, the machinist ruined it to where it ate main bearings out every 500 miles untill i pulled it 2500 miles later

Glenn

BoostedBeaver · May 20, 2011

I do not know if manley's are the same but when I put together my block with weisco 1400 the clearance was built in, meaning mine had to be bored to exactly .020 over. You could always give manley a call and ask what they cut their pistions at and they will tell you what they are suppose to be. Also ask for the tolerance as there is one. They will also tell you what the finish bore should be cut to, this is all you will need to know if you have a trashed block. Hope this helps.

delta448 · May 20, 2011

laserspeeddemon said:
Ok so quick question: The piston to wall clearance is 0.0035" for Manley pistons. Is that all around the piston So that my piston diameter minus my cylinder bore should equal 0.007" total. OR is the 0.0035" total and I should have 0.00175" clearance around the piston? I'm thinking former is correct (0.007").

PTW is expressed as a total for both sides. They're recommendng 0.0035" total.

With 2618 alloy pistons, you want to aim for a clearance somewhere between 0.0045-0.006". The more power you expect to make, the more you should aim towards the looser side. IMO, 0.0035 is too tight and 0.007 is too loose.

laserspeeddemon · May 20, 2011

I went in and talked to him in person. He said he bored it out to 86mm. I said "86mm EXACTLY?" He said yes. I then called Manley and the vendor (who has been a GREAT help in dealing with my mess) and Manley me that the motor needed to be bored out, when I explained them the situation, they then said "No that's not right, you can't use those pistons." I called the vendor who builds 8 second 4G63 powered cars and they too told me that it was not right. I called the machinist back, chewed him out a little and then told him he owes me a new block. So he changed his story to "I was just telling you 86mm, so you would order 86mm pistons." Which is COMPLETELY contrary to him stating that the "engine was done" and ready to be picked up.

His new story is that he didn't think I knew what I was doing and he kept telling me 0.040" so I would order the correct piston size and then he could measure them and hone it to the proper clearance. He is now telling me that he actually bored it out to 0.038" and is read to hone it to each cylinder. Obviously, I will be taking it another machine shop to have all the pistons and cylinder measured to ensure this was done properly.

AK Maniak · May 20, 2011

laserspeeddemon said:
I went in and talked to him in person. He said he bored it out to 86mm. I said "86mm EXACTLY?" He said yes. I then called Manley and the vendor (who has been a GREAT help in dealing with my mess) and Manley me that the motor needed to be bored out, when I explained them the situation, they then said "No that's not right, you can't use those pistons." I called the vendor who builds 8 second 4G63 powered cars and they too told me that it was not right. I called the machinist back, chewed him out a little and then told him he owes me a new block. So he changed his story to "I was just telling you 86mm, so you would order 86mm pistons." Which is COMPLETELY contrary to him stating that the "engine was done" and ready to be picked up.

His new story is that he didn't think I knew what I was doing and he kept telling me 0.040" so I would order the correct piston size and then he could measure them and hone it to the proper clearance. He is now telling me that he actually bored it out to 0.038" and is read to hone it to each cylinder. Obviously, I will be taking it another machine shop to have all the pistons and cylinder measured to ensure this was done properly.

Thats really shitty man. But like someone mentioned in a previous post I would not have known anything was wrong. So turboglenn if you ever decide to do that write up i'll definitely check that out and i'm sure i'm not the only one.

Achelea · May 21, 2011

Question; In Aviation, pistons are actually ovals, not circular. Reason being is the thinner sides will expand differently than where the pin is. When you guys do your measurements, are you doing across the pin or with the pin?

laserspeeddemon · May 22, 2011

The measurements are done mathematically. So take the TRUE size of the cylinders and subtract the size of the piston. There's your clearance.

JacksonAuto · May 24, 2011

Piston measurements should be taken across the pin, about an inch above the bottom of the skirt. Reference the paperwork that came with the pistons and it will show you exactly where to measure the pistons. Every manufacturer is slightly different.

The block is not trash at .040" over. These blocks are pretty thick. We've done plenty at .060" over with no problems. If you are in doubt, have it sonic tested to determine the wall thickness. In fairness to the machinist he may have tried to go .020" but it wouldn't clean up. Sometimes these blocks have a tremendous amount of wear and going .020" wont make them round again. This would necessitate going to .040". If this is the case he still should have told you before he went farther so you could have gotten different pistons.

keltalon · May 24, 2011

91stocker said:
Were you able to measure anything before taking it to the shop? Far as i know 0.040" over bore is the max on these blocks. Which leaves you no room for future builds. Plus get it to tight, piston will seize. Set the clearance to loose, and you will have piston slap.

Hope not but you might have yourself a nice 40 over table

I am running a 60 over block taching 8300rpm and pushing 30+ psi with zero issues. put down 519whp last dyno and plan to redyno in couple i think car will do 570. 60 over is fine. If the machine shop bored for 40 over you might be able to get away with honing again to bring you within clearance specs. I am running .0040 piston to wall clearance on my cp slugs

phunny · May 24, 2011

keltalon said:
I am running a 60 over block taching 8300rpm and pushing 30+ psi with zero issues. put down 519whp last dyno and plan to redyno in couple i think car will do 570. 60 over is fine. If the machine shop bored for 40 over you might be able to get away with honing again to bring you within clearance specs. I am running .0040 piston to wall clearance on my cp slugs

Shut up and fix your motor mounts.

LOL

Any update demon?

arrowhead · May 24, 2011

0.0035 should be right although you never take a block to a machinist w/o your pistons.
Every manufacturer will give a proper clearance depending on the type of piston, forged,cast and hypert.
piston all have diff. expansion rate.

Sometimes for high perf. use a little looser clearances are used and for the old qualifying motors you had to get the engine warmed up real good and they sounded like they were about to come apart because of piston slap.

Rule of thumb .001 per inch of bore

laserspeeddemon · Jun 6, 2011

Sorry guys just been dealing with a lot, lately. I may have gotten lucky as far as boring it over, but the machinist was incompetent, if not lazy and fraudulent.

He told me that he left room for the final hone, I took his word for it and decided to proceed a head.

Since the I am still waiting for the pistons, the next thing that I could do was pick up the head and send it to Strictly Import Performance to get the stage 2 port/polish. Since I was at work I told my wife to go pay the machinist $500 and get all the head components. When I got home I was a livid. The head looked like crap, it didn't even look like he washed it at all. There was grease stuck in and on the outside of the head. Oil was still in some places. I confirmed the head was not cleaned when I found that the marks I used to make sure the cam caps go in the correct order were still on the head. It is important to mention that the marks was made using a dry erase marker. None of the valve lapping looked right and the deck looked like it was resurfaced using sand paper.

At this point, I knew I was screwed. I told the machinist that "plans have changed" and paid him the rest of the money. Since he still had my flywheel, clutch, Manley rods, block, etc. If I refused to pay him then he legally could hold at LEAST the block and rods. My wife is starting a business in 6-8 weeks. I need my car back on the road by that time.

I took the block to CNC Engine Dynamics. They looked at it and said it doesn't look like machinist did anything BUT bore it. It was NOT washed/hot tanked. The deck was not resurfaced, etc.

The head is even worse. Strictly Import Performance said that the Valve Guides appeared to be half-cut/grind-ed down on only about half of them. They confirmed the deck was not sufficient. They said the valves will probably have selling issues. To sum up how bad it was. They said "Hey! At least, the head is salvageable." But everything is going to have to be re-done. Both shops are willing to take pictures / make notes as appropriate to describe the condition of the engine.

There is NO DOUBT in my mind that I will be taking this guy to court within the next few months to recoup, at least, the fees he charged me and possibly the extra costs I have and will incur to fix his sloppy work.

Some pictures:

Grease on the head/ Exhaust ports absolutely fiflthy.