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I used to go to Dick Miller Racing for the specialty coated bearings, but he says getting standard sized coated bearings seems to be near impossible these days, with everything available being for .010 / .020 / .030 under size.
I have also considered just getting a good set of bearings and shipping them out to Calico Coatings to have them done.
So if you just spent a ton of money on a Rocket Racing block, and a CNC machined billet Scat crank, what would you reach for? I need standard size 3" Olds mains, and standard big block Chevy 2.200" rod journals.
Back 25 years ago, I really liked using King bearings, but I hear they just aren't the same as they used to be. Clevite and Vandervell have always done well for me too, but this engine has me really wanting to do the super wizz bang coated bearings.
So you should say ten thousands not tenths. Some times big boy machinist will say tens when talking to the right of the pimple point, never tenths.
I figured out two options for your new job.
1. Funny car driver, you really like to back pedal.
2. Join uncle Joe's cabinet.
I'm off to make dinner, later.
I’ll work on that Richard Cranium, thanks.
Last edited by cutlassefi; Mar 25, 2022 at 06:24 PM.
So you should say ten thousands not tenths. Some times big boy machinist will say tens when talking to the right of the pimple point, never tenths.
You may want to dial back the snark here bub. You're talking as a layman - not a machinist. There are quite few machinists who will say "tenths" when referring to 'ten thousandths". In fact, pretty much all machinists I've come across do (aerospace machine shops, engineering machine shops, or automotive machine shops). Do a search, or better yet, talk to an actual machinist. Simple google search will show that you aren't alone in being confused as a layman, but machinists are pretty united that a tenth is 0.0001".
You may want to dial back the snark here bub. You're talking as a layman - not a machinist. There are quite few machinists who will say "tenths" when referring to 'ten thousandths". In fact, pretty much all machinists I've come across do (aerospace machine shops, engineering machine shops, or automotive machine shops). Do a search, or better yet, talk to an actual machinist. Simple google search will show that you aren't alone in being confused as a layman, but machinists are pretty united that a tenth is 0.0001".
Duh is actually correct. I am a aircraft person 36 years . My bother is a aircraft machinist and a set up man. My dad was a CNC technician repair man.
I'm an engineer at an aerospace company. I've dealt with a ton of machinists over the years. I provided one link, I can fill this page with more. Your brother is an outlier, though I will say, as an engineer, he's appreciated for using standard terminology. The whole 'tenths' thing was confusing, particularly when I had a shop asking me if a part was acceptable being "a few tenths out of tolerance".
Last edited by Bubba68CS; Mar 26, 2022 at 07:34 AM.
I'm an engineer at an aerospace company. I've dealt with a ton of machinists over the years. I provided one link, I can fill this page with more. Your brother is an outlier, though I will say, as an engineer, he's appreciated for using standard terminology. The whole 'tenths' thing was confusing, particularly when I had a shop asking me if a part was acceptable being "a few tenths out of tolerance".
the last part is correct.
your own post earlier said the same ….the “tenths’” thing is “lingo”
saying the measurement in tenths, then leaving out the thou, or thousands , or ten thousands part, is asking for trouble…which is what lingo does
Tenths is not the correct technical term according to your own link earlier, they show both the correct technical term and the “lingo” term in a chart.
an example 3/10 in decimal form is .300
the only lingo I use and have heard used correctly would be 3 ten thousands …that’s actually technically correct because 3 divided by 10,000 is .0003”
to avoid confusion…you write it down for whoever is doing the actual machining
your own post earlier said the same ….the “tenths’” thing is “lingo”
saying the measurement in tenths, then leaving out the thou, or thousands , or ten thousands part, is asking for trouble…which is what lingo does
Tenths is not the correct technical term according to your own link earlier, they show both the correct technical term and the “lingo” term in a chart.
an example 3/10 in decimal form is .300
the only lingo I use and have heard used correctly would be 3 ten thousands …that’s actually technically correct because 3 divided by 10,000 is .0003”
to avoid confusion…you write it down for whoever is doing the actual machining
...I feel like you're just repeating what I said. Pretty much every machinist I've talked to has said "tenths", the link I provided says the same thing (a simple google search will show that is not remotely close to the only source on this, there are thousands) - talk to a machinist or go on a machinists forum and they're likely to use the "tenths" nomenclature. Of course it isn't technically correct and I never claimed it was. It can definitely cause confusion to the lay person (as I said in my first post), but when you deal with these guys enough, you use the context of who you're talking to to understand the lingo.
Having dealt with these guys for a couple decades now, YOU can go scold them for their industry nomenclature. I'll just roll with it and get what I need done.
Every tool & die maker or machinist I've ever worked with talked in increments of .001" meaning that if we say "take ten off of it" that means .010 or 10x .001 and if we say "take a tenth off of it" that means .0001 or one tenth of .001
Most importantly as mentioned above your clearances will shrink and if your crank is finished for non coated bearings as it may be too tight (sorry non technical term) The coated bearings may require you to re-machine your crank to allow for the coated bearings extra thickness.
Sound like its not your first time, I'm sure you will make out fine. You may try BTR he may have some stock.
As far as the measurement slang I'll go with Canadian Olds - if you right them down you can't go wrong.....well as long as you can read
Good Luck I'm jealous already, a RR block is a great foundation
...I feel like you're just repeating what I said. Pretty much every machinist I've talked to has said "tenths", the link I provided says the same thing (a simple google search will show that is not remotely close to the only source on this, there are thousands) - talk to a machinist or go on a machinists forum and they're likely to use the "tenths" nomenclature. Of course it isn't technically correct and I never claimed it was. It can definitely cause confusion to the lay person (as I said in my first post), but when you deal with these guys enough, you use the context of who you're talking to to understand the lingo.
Having dealt with these guys for a couple decades now, YOU can go scold them for their industry nomenclature. I'll just roll with it and get what I need done.
you are talking to a machinist. Since the early 80’s
My son is a CNC machinist in a top notch ISO certified shop. They would lose their ISO certification if they were found to be using machinist lingo. Times have changed.
I don’t know where you are an engineer at but that’s low brow stuff these days
Last edited by CANADIANOLDS; Mar 27, 2022 at 03:22 PM.
there should be no problem at all finding pre coated bbc rod bearings. If you can’t, then get yourself some X .001 bearings and have them coated if you are that concerned about the coating messing up your clearance.
If you are stuck for finding coated mains. I have a set of std Clevite’s in stock that are Polydyne coated I can sell you
Last edited by CANADIANOLDS; Mar 27, 2022 at 03:30 PM.
you are talking to a machinist. Since the early 80’s
My son is a CNC machinist in a top notch ISO certified shop. They would lose their ISO certification if they were found to be using machinist lingo. Times have changed.
I don’t know where you are an engineer at but that’s low brow stuff these days
My company is AS9100 and ISO certified. You wouldn't lose your ISO certification - that is complete and total BS (as someone who was directly involved with the certification process at a previous company). I'm not arguing the use of lingo is best practice (go back, re-read everything I've written). Only that it is in common usage. That is a fact that even you cannot dispute. So sh***** on someone for using said lingo just makes you look like an ***.
My company is AS9100 and ISO certified. You wouldn't lose your ISO certification - that is complete and total BS (as someone who was directly involved with the certification process at a previous company). I'm not arguing the use of lingo is best practice (go back, re-read everything I've written). Only that it is in common usage. That is a fact that even you cannot dispute. So sh***** on someone for using said lingo just makes you look like an ***.
nope. Hahahha. Because you of all people should not be using shop floor lingo
Phone calls or face to face conversations to clarify a misunderstanding on a measurement is not part of ISO
there is no such thing as “hey bud, I made a mistake on that drawing,, knock off another tenth and were good ok?”
it’s in writing or messaging and a specific procedure for corrections is followed. That’s how ISO standards work. I’m not shi t ting on you.. you are shi t ting on the whole profession.
you also assuming everyone on here is a dumb layperson is kinda ignorant
Last edited by CANADIANOLDS; Mar 28, 2022 at 09:39 AM.
Every tool & die maker or machinist I've ever worked with talked in increments of .001" meaning that if we say "take ten off of it" that means .010 or 10x .001 and if we say "take a tenth off of it" that means .0001 or one tenth of .001
Same as my company. As a tool designer we say:
.125 = one hundred and twenty five thousands
.0625 = sixty two and a half thousands
.001 = a thousandth or a mill
.0005 = half a thousand, five tenths, or half a mill
And to make things harder on me with converting of to metric, our Engineers are now saying Microns
Last edited by Noel Anderson; Mar 29, 2022 at 11:33 AM.
Same as my company. As a tool designer we say:
.125 = one hundred and twenty five thousands
.0625 = sixty two and a half thousands
.001 = a thousandth or a mill
.0005 = half a thousand, five tenths, or half a mill
And to make things harder on me with converting of to metric, our Engineers are now saying Microns
Well I will say this. For anyone saying lingo is acceptable when dealing with critical tolerance is just plain wrong. To brag about being a aircraft engineer is even more wrong to lord it above anyone. Fact engineers screw up plenty in aircraft and get corrected all the time by shop floor. Is this thread about being correct? I stand with Duh being correct. The rest of you saying different need to start getting rid of lingo. Oh and tool designers screw up plenty too.
Good grief. Every engine shop / machinist I've talked with uses "tenths" in terms of 0.000x, particularly when discussing engine bearing clearances.
To get back to the point - since you are buying a crank that is already cut to size, you're going to be stuck with whatever bearings work to establish the clearances you need, and the different brands never measure the same. You might be buying a few sets to make it work. If you want coated bearings, I'd get some that measure on the large size then send to Calico. I've had good luck with King bearings in my latest Mopar 440 build. If you can find a bearing that is available with +/- 0.001" sizes, even better - likely available for the 2.2 rod, but not for the Olds mains. Some bearings have lead times >6 months right now.
Good grief. Every engine shop / machinist I've talked with uses "tenths" in terms of 0.000x, particularly when discussing engine bearing clearances.
To get back to the point - since you are buying a crank that is already cut to size, you're going to be stuck with whatever bearings work to establish the clearances you need, and the different brands never measure the same. You might be buying a few sets to make it work. If you want coated bearings, I'd get some that measure on the large size then send to Calico. I've had good luck with King bearings in my latest Mopar 440 build. If you can find a bearing that is available with +/- 0.001" sizes, even better - likely available for the 2.2 rod, but not for the Olds mains. Some bearings have lead times >6 months right now.
You can't fix what machine shop guys do. But you can admit they are wrong with the lingo.
Being a VERY detail oriented person, I fully understand splitting hairs and making damn sure where the decimal point is!
Now beyond that, CanadianOlds says he has Standard Clevite’s in stock that are Polydyne coated. I have also ordered in a set of King Engine Bearings CR808XPNC from Atech (which I can return if I do not like once in my hands or sell off on Ebay):
Again, this is going into a brand new Rocket Racing block along with a Scat CNC machined billet crank, with the stock Olds sized mains and the Big Block Chevy, 2.200" full width rod journals (very unusual to have full width not requiring narrowed bearings). Scat explained that their thinking behind running a full width BBC journal was in a direct effort to maintain a full bearing surface load area, also allowing for good oil pressure control by keeping the rod end clearances on the tighter side so that a machinist could machine the big end widths down as desired to obtain the end clearances desired (which I agree with all the way). The rod bearings and rods will be here next week (crank is already here). I will test fit the rods and bearings on the crank while on the bench to see where we end up on that. The rods I ordered are .990 width on the big end (7.100" length for the 4.500" stroke) as the measurements I have show 1.982 journal width without a large fillet radius. I expect it to be tight in all directions, which to me is good because we can machine the clearances into perfection.
I spoke with Calico Coatings today, and they only want $45 to do a set of main bearings and a lead time of only 12 +/- days (which surprised me as I expected it to be way more expensive and have a much longer lead time). The rep I spoke with stated that their coatings typically add a 1/4 to 1/2 thousandth (no decimal points here lol). He recommended I see if I could find a set of .001 undersized mains to send in to them. Yeah right - this isn't a Chevy, where in the world am I supposed to find .001 undersized Olds big block main bearings. He recommended I contact Federal Mogul to see if they may have a set in this undersize. Well, it turns out they do not produce an "extra oil clearance" .001 undersized main bearing according to the rep I managed to get on the phone, and also through endless catalog searches.
Sooo... If I can fanagle the coated main bearings out of CanadianOlds, then receive the coated King bearings (which should be right on BBC spec but tight), I can have my incredibly fantastic mega machinist (Reed Grant at Grant Racing in Murfreesboro, TN) install the bearings into the block and rods, crank them down to spec, read them, then cut / polish the crank, align hone, and massage the rod big ends as needed to loosen the clearances up, as I am fully expecting things to be initially a hair too tight. Hey, much easier to remove material than to have to add material (!). This brings back memories of applying Loctite 262 to the back side of bearings to tighten them up just a hair when an ol' buddy of mine got into a pinch, but shhhh - don't tell anyone (worked like a dream on a low budget small block Chevy build I was helping him out with over a few beers on a Saturday night). We revved that poor '70 Nova SS 350 Muncie close ratio 4.10 car to 7500 RPM all damn day long for so many years I still can't believe it never popped, ah, but I digress... I wish Olds engines were that tolerant of sloppy clearances and ridiculous abuse!
With all of the machinists here discussing decimal points, does this all sound about right? It works in my mind. I tried to rethink it a thousand times, and no matter what, I'm willing to bet everything is going to be too tight. And like I said, too tight (initially) is great, as we can loosen the crank and rods up a helluva lot easier than having to go in the other direction. Andy from Olds Performance Products in NY cancelled my online order for the coated mains today. I got him on the phone and asked why he did that, and he said because nobody ever knows what their talking about and are always ordering in the wrong stuff (rather abrasive guy). He belittlingly laughed at me for ordering in the main bearing set without having the engine block in my possession yet - excuse me! sorry to have bothered you! I asked why he has them listed on his website for purchase, if the order is just going to get cancelled. He said he really needs to get measurements in the ten thousandths before he can supply bearings. Hey, that's great, but Ok, why not say "call to order" on the web listings instead of just cancelling off an order. He said don't call me back until you have the block in your hands... wow, ok dad.
Soooo... what do you think? I would really like your opinions, even if they may not be what I may want to hear.
Thank you kindly!
Paul
Last edited by Clark455; Mar 30, 2022 at 05:21 PM.
I’ll reserve comment regarding Andy Miller, or as he goes by today, Andy Mark.
Try grabbing a set of Clevite MS804HX bearings. They may still be backordered though.
Being a VERY detail oriented person, I fully understand splitting hairs and making damn sure where the decimal point is!
Now beyond that, CanadianOlds says he has Standard Clevite’s in stock that are Polydyne coated. I have also ordered in a set of King Engine Bearings CR808XPNC from Atech (which I can return if I do not like once in my hands or sell off on Ebay):
Again, this is going into a brand new Rocket Racing block along with a Scat CNC machined billet crank, with the stock Olds sized mains and the Big Block Chevy, 2.200" full width rod journals (very unusual to have full width not requiring narrowed bearings). Scat explained that their thinking behind running a full width BBC journal was in a direct effort to maintain a full bearing surface load area, also allowing for good oil pressure control by keeping the rod end clearances on the tighter side so that a machinist could machine the big end widths down as desired to obtain the end clearances desired (which I agree with all the way). The rod bearings and rods will be here next week (crank is already here). I will test fit the rods and bearings on the crank while on the bench to see where we end up on that. The rods I ordered are .990 width on the big end (7.100" length for the 4.500" stroke) as the measurements I have show 1.982 journal width without a large fillet radius. I expect it to be tight in all directions, which to me is good because we can machine the clearances into perfection.
I spoke with Calico Coatings today, and they only want $45 to do a set of main bearings and a lead time of only 12 +/- days (which surprised me as I expected it to be way more expensive and have a much longer lead time). The rep I spoke with stated that their coatings typically add a 1/4 to 1/2 thousandth (no decimal points here lol). He recommended I see if I could find a set of .001 undersized mains to send in to them. Yeah right - this isn't a Chevy, where in the world am I supposed to find .001 undersized Olds big block main bearings. He recommended I contact Federal Mogul to see if they may have a set in this undersize. Well, it turns out they do not produce an "extra oil clearance" .001 undersized main bearing according to the rep I managed to get on the phone, and also through endless catalog searches.
Sooo... If I can fanagle the coated main bearings out of CanadianOlds, then receive the coated King bearings (which should be right on BBC spec but tight), I can have my incredibly fantastic mega machinist (Reed Grant at Grant Racing in Murfreesboro, TN) install the bearings into the block and rods, crank them down to spec, read them, then cut / polish the crank, align hone, and massage the rod big ends as needed to loosen the clearances up, as I am fully expecting things to be initially a hair too tight. Hey, much easier to remove material than to have to add material (!). This brings back memories of applying Loctite 262 to the back side of bearings to tighten them up just a hair when an ol' buddy of mine got into a pinch, but shhhh - don't tell anyone (worked like a dream on a low budget small block Chevy build I was helping him out with over a few beers on a Saturday night). We revved that poor '70 Nova SS 350 Muncie close ratio 4.10 car to 7500 RPM all damn day long for so many years I still can't believe it never popped, ah, but I digress... I wish Olds engines were that tolerant of sloppy clearances and ridiculous abuse!
With all of the machinists here discussing decimal points, does this all sound about right? It works in my mind. I tried to rethink it a thousand times, and no matter what, I'm willing to bet everything is going to be too tight. And like I said, too tight (initially) is great, as we can loosen the crank and rods up a helluva lot easier than having to go in the other direction. Andy from Olds Performance Products in NY cancelled my online order for the coated mains today. I got him on the phone and asked why he did that, and he said because nobody ever knows what their talking about and are always ordering in the wrong stuff (rather abrasive guy). He belittlingly laughed at me for ordering in the main bearing set without having the engine block in my possession yet - excuse me! sorry to have bothered you! I asked why he has them listed on his website for purchase, if the order is just going to get cancelled. He said he really needs to get measurements in the ten thousandths before he can supply bearings. Hey, that's great, but Ok, why not say "call to order" on the web listings instead of just cancelling off an order. He said don't call me back until you have the block in your hands... wow, ok dad.
Soooo... what do you think? I would really like your opinions, even if they may not be what I may want to hear.
Thank you kindly!
Paul
have you measured the actual main housings in the block or does RR supply the dimensions on the block spec info?
I do not have the the Rocket Racing block in my possession yet (was told about 30 more days yet as they are also custom building my flat top pistons for use with 7.100" rods, with the two eyebrow valve reliefs coming in at +5cc dish value, custom honing their very hard block material, and setting up my plasma moly rings). When I asked John over there about the mains, he said they will measure in dead stock. Using the highly accurate $$$ Grobbet Vigor digital calipers that I have, the main journals are showing 2.999" - factory stock Olds big block, correct?
I am prepared to get everything together and then have Reed Grant of Grant Racing (awesome veteran machinist I am lucky to have in the area), go though it all and massage everything into perfection. Here is what my usual target is for clearances:
#1 Main 0.0029
#2 Main 0.0029
#3 Main 0.0030
#4 Main 0.0031
#5 Main 0.0045 <-- always been told that the rear bearing runs best a tad looser, have run 0.0040 ok before.
Sound about right? That’s what has always worked for my builds.
I typically shoot for .0025 - .00275 on the rods – sound right ?
You can go tight if you want. A stronger block, plus a stronger crank means things won't move around as much, so don't need as much slop. The rod journal is much smaller than the BBO, so can go tight there too. IOW, I wouldn't stress if mains are around 2.5 thou and rods are around 2.0 thou. Or, if you want, have a machinist lean into the crank with a new polishing belt. They can quickly pull 2 to 4 tenths off.
OR, if you want to be ultra-paranoid, measure everything, then send the crank to be ground with very specific instructions, and switch everything out to -10 bearings. And buy two or three sets of -10 bearings so you can measure the shells and swap them around as needed. e.g., my Clevite CB633 rod shells are pretty consistent, but my Federal 108M mains vary by 2 tenths. And if someone thinks I'm talking about tenths of an inch then they don't know engine clearances real well.
I'd expect the RR mains to be honed to the middle of the book spec. There's always variance in bearing shells, and cranks sizing can vary, so it's worth double checking a final assembly.
I don't worry about #5. It is what it is based on the bearing manufacturer. It's worth checking to make sure the bearing and/or bore aren't goobered, and make sure the crank journal is (roughly) the same size as the others.
Well, at least I'm looking good on my BBC rods with the coated King bearings on the Scat CNC billet crank:
The H beam rods and coated King spec BBC bearings came in today, so I wrestled the crank up onto the work bench for a quick test fit - perfection! Hey, something has got to go right once in a while. A quick mockup resulted in .020" rod to rod big end side clearance, and a caliper and Plastigauge check come in right at .002" So I was right, Scat did indeed set up the rod journals for full size BBC standard interface. I was concerned with the .990" BBC big end width specs, thinking we were possibly going to have to machine them in just right, but I got lucky (actually happens some times). I took my measurements, did my homework, ordered in the right parts and it all fit perfectly. Andy from Olds Performance Products was arguing with me about this on the phone, just about calling me dumb *** that didn't know what I was talking about when we were talking about the crank. "No way full size standard BBC is going to work - Scat wouldn't do that" Well, here you go Andy - you can eat your hat now.
Andy has contended that for years, even though he’s been proven wrong a bunch of times. The old ROP site had numerous posts about it.
Just consider the source.
Coated bearings
I understand splitting hairs
BBC 7.100" Rods on the Billet Scat Crank
