TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: d-rock on March 03, 2015, 07:14:09 PM
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well, had a bad day. pulled my engine apart last week to send cases for power coating. got them back yesterday, they look beautiful, but are now f*@$#&. all of the bearing now fall into the case. they pressed apart last week. they were 85 atc cases that had never been used. I'm sick to my stomach now. anyone else ever have this problem?
Thanks, Derek.
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wHaTTT! Something happened
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The cases expanded and the bearings are now too small?
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Even if the cases were heated they should have contracted back to normal. Sum thing is not right
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I think the bearings are falling out as if bores are to large? Ive read before that powdering the cases has to be less temp or differnet process than most parts. Did the ppl you send to have experience with powdering cases? And are you sure they are the same cases? Lol. What if they sent you the wrong ones? Just a crazy thought. Are they shady business?
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they are a very experienced company, used by a lot of people. I have seen Harley parts done there and lots of sled engine cases done. I had a set done 10 years ago and they were ok. but now these are garbage.
and yes the bores are too large now. the bearing all fall out. mains, and all trans bearings. (bearings are all new )
they are my cases, I had to clearance the top of the crankcase for my new +4 crank. and the serial number is the same.
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They were brand new and you had them powder coated? Sorry man, that sucks.
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I've been powder coating for about five years now and I have never heard of this before. Although I've never done a set of cases before I still find it strange. I've pc'd piles of cast aluminum hubs without any problems as well as a clutch side cover of my own and the new water pump besring went in snug as it did when i took it out. So did the mechsnical seal and the two dowel pins. If i were to pc my own cases i would have never given it a second thought, i would just have sprsyed them. I've also been going to school for metallurgy for the last two years and have never heard of anything like this. It has me really curious!
Is there any powder on the inside of the cases? ie was the inside portion taped off or was there over spray?
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I agree it doesnt make sense. But you can have the cases sent out and have the bores resized with steel inserts. Shouldnt cost to much.
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OK so I'm not the only one that thinks this isn't right. I did a quick search and i can't find anything. Something else that dawned on me......how many times have you (or anyone) heated up a part to get a besring in or out!? I think most of us have atleast once. I'd say its pretty safe to say that any part that houses a bearing is most likely a cast part. You say you know for sure these are your cases right? You mentioned clearancing your cases. My guess is they got powder in the bearing seat and they used a dremmel or something to clean it out.....like I said.....just a guess.
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Your looking at the cases, but you said they were new bearings, where did you get those, what if its the bearing tolerances that are bad?
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I'm with burns363r. I'd send em out to get fixed. Or sell em to me :)
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I just re-read the first post. It says you pulled your engine apart to PC the cases but then you said the cases were never used. I guess I'm a little confused
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I had the engine assembled last 2 weeks ago. But the paint looked shity , so I pulled it apart again and sent the cases out. All of the new bearings were tight in the cases, now they are loose. There is no power on the inside at all. It was taped off. The power coating is called sparkle silver. Then cleared. I don't know if it was actually powder coated twice, maybe that was the problem. Too much heat maybe.
The cases are from a 85 atc engine that has never ran but was assembled.
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im not familiar with powder coating. do you bake the parts at 400f for a hour or something like that ?
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I had the engine assembled last 2 weeks ago. But the paint looked shity , so I pulled it apart again and sent the cases out. All of the new bearings were tight in the cases, now they are loose. There is no power on the inside at all. It was taped off. The power coating is called sparkle silver. Then cleared. I don't know if it was actually powder coated twice, maybe that was the problem. Too much heat maybe.
The cases are from a 85 atc engine that has never ran but was assembled.
Yea it would be baked twice with the clear coat. If it was taped off then I'm baffeled as to the cause of your problem. Have you called them to talk about it?
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im not familiar with powder coating. do you bake the parts at 400f for a hour or something like that ?
Yes 400 deg. It would be in the oven for around 2 hrs, possibly more. Which (as far as I know) is below the temp that would cause any metallurgy change in the metal.
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Does anybody have a crap case that can be tossed in the oven for a couple hrs and measure the bearing race before and after?
On and I've powdered a engine cylinder and head before as well without any problems.
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400 degrees will not affect aluminum like that. Something else has happened.
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what do the surfaces look like? pics pls
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Have you called the powder coater? See what they say. Regardless of what happened, they're kn the hook
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Are you saying that you left the bearings in the cases and sent it to powdercoat and now they fall out?
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Did you have the bearings in the garage (cold) and the cases room temp? Just a thought..
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Seems like Jerry Hall has said they have had problems with powder coating cases before just can't remember if it was on here or the Quadracer site. But they did exactly what you described you may pm him and see what he says.
Sent from my iPhone using Tapatalk
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Seems like Jerry Hall has said they have had problems with powder coating cases before just can't remember if it was on here or the Quadracer site. But they did exactly what you described you may pm him and see what he says.
Sent from my iPhone using Tapatalk
I remember this too from there.... I think Q said something about it also....
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Metallurgical fact: The temper of most aluminum alloys are changed anytime the temperature exceeds 300 deg. The temper clock starts clicking when the temperature crosses through around 300 deg. and clicks faster the higher the temperature is raised. Most paint powders require the temperature to be above 400 deg F. for at least an hour.
It is unfortunate that your Powder Coater did not have the integrity and or the experience to tell you this fact before he took your money. I have seen this happen hundreds of times over the years and have made posts on this forum warning of the consequences of the powder coating. Most of the powder coaters in the Phoenix area also do not believe and will deny that they are ruining parts with their process. Again, NEVER POWER COAT ANY PRECISION ALUMINUM PART!! There is nothing you can do once the part has been cooked and the dimensions are altered by heat treating.
A powder coater down the street from me ruined a bikers Harley heads. The biker confronted the owner of the powder coat shop and wanted him to buy him new heads. The powder coat shop owner told him to get lost. The bikers came back, wrecked his shop and put the guy in the hospital. This shop never reopened.
Another power coat shop ruined a batch of aluminum parts that one of my customers manufactures. The customer took the powder coat shop to court. The court awarded my customer over $10,000.00. This shop closed its doors.
Also, the baking process that many automotive engine rebuilders are using to clean engine parts also changes the temper and alters the dimensions of the heads, engine blocks that they clean. This process raises the temperature of the components that they clean to around 600 deg. F. Most of the guys that are using these cleaning processes and the companies manufacturing the cleaning equipment are uninformed and not aware that they are changing the metallurgical properties of parts they are cleaning!
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Metallurgical fact: The temper of most aluminum alloys are changed anytime the temperature exceeds 300 deg. The temper clock starts clicking when the temperature crosses through around 300 deg. and clicks faster the higher the temperature is raised. Most paint powders require the temperature to be above 400 deg F. for at least an hour.
It is unfortunate that your Powder Coater did not have the integrity and or the experience to tell you this fact before he took your money. I have seen this happen hundreds of times over the years and have made posts on this forum warning of the consequences of the powder coating. Most of the powder coaters in the Phoenix area also do not believe and will deny that they are ruining parts with their process. Again, NEVER POWER COAT ANY PRECISION ALUMINUM PART!! There is nothing you can do once the part has been cooked and the dimensions are altered by heat treating.
A powder coater down the street from me ruined a bikers Harley heads. The biker confronted the owner of the powder coat shop and wanted him to buy him new heads. The powder coat shop owner told him to get lost. The bikers came back, wrecked his shop and put the guy in the hospital. This shop never reopened.
Another power coat shop ruined a batch of aluminum parts that one of my customers manufactures. The customer took the powder coat shop to court. The court awarded my customer over $10,000.00. This shop closed its doors.
Also, the baking process that many automotive engine rebuilders are using to clean engine parts also changes the temper and alters the dimensions of the heads, engine blocks that they clean. This process raises the temperature of the components that they clean to around 600 deg. F. Most of the guys that are using these cleaning processes and the companies manufacturing the cleaning equipment are uninformed and not aware that they are changing the metallurgical properties of parts they are cleaning!
Wow! Crazy! I'm glad I know this now. Thanks for posting it!
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i believe there are low cure temp powders just for these purposes.
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i believe there are low cure temp powders just for these purposes.
......... then..............Why are powder coat shops still using the high temp. powders and ruining parts? Surely they can recognise an aluminum part that needs to maintain its original strength and dimension and tell the customer that they need to use a different product or process.
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http://www.crosslinkpowder.com/low-temp-curing-powdercoating.html
uninformed powder coaters apparently.
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I'm sorry to hear about your cases, Rock. Jerry is right on about aluminum and those temps. I do know the powder coating industry, is working with UV curable powders. No heat!
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Well there's a lot of them out there. With a quick search I found a few that are listing prices specifically for ATV motorcycle engine cases. If there's people out there listing prices then there is a lot of people that have in fact coated cases without problems. Like I said I have coated clutch side cover and didn't have Amy problems with my water pump bearing and I bet that cover sat in the oven for 3 hrs. As soon as I can get my hands on some crap cases I will experiment.
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The bearings were all out.
I haven't contacted them yet but I'm not going to push the fact. They do a lot of work for the company I work for. Just going to cut my losses. I don't think it is worth fixing, all of the bearings fit loose now. Trans and crank. Maybe a set from ESR.
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So I just talked to a guy that has a set of r cases that are indeed powder coated and his engine is and has been together and running fine. The bearings were a tight press fit as they should be
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u can probably just get steel bearing seats cut and pressed in for cheaper than a new set of cases.
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I wonder? if a guy had them anodized would it build it up enough to make the bearings tight?
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For 500 bucks kind of hard to beat the price for new.
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Yes 400 deg. It would be in the oven for around 2 hrs, possibly more. Which (as far as I know) is below the temp that would cause any metallurgy change in the metal.
not sure what temp the changes occur. probly alittle above 300 like jerry said but i also think it has alot to do with how long it stays at that temp. if you were welding a small area i dont think its going to affect it the same way and welding is far hotter than 400f. in some service manuals like ktm is says dont heat the cases much over 300f when replacing the bearings. im guessing its because something bad happens when they bake at extended periods over 300f
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My cases were powder coated by the previous owner's engine builder. It has ran for the past 10 years with those cases. Maybe he/I got lucky?
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I had my cases powder coated locally and sent everything to CT in bags for a full rebuild. I didnt have any problems and thinking of powdering or chroming a second set to have as a spare.
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The bearings were all out.
I haven't contacted them yet but I'm not going to push the fact. They do a lot of work for the company I work for. Just going to cut my losses. I don't think it is worth fixing, all of the bearings fit loose now. Trans and crank. Maybe a set from ESR.
Considering it's work related in a sense, I wouldn't push it either, smart!. Talk to your Co. owner / Manager before calling them if your relationship is solid. Either way let the PC Company know what happen so it doesn't happen again.
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anyone know what series of aluminum the cases might be and if its tempered at all ? for aluminum to anneal i think it would need to be more like 600f-1000f depending what kind it is but thats not to say it wouldnt start warping or change shape at a lower temp. then factor in that it was in a oven for several hours
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annealing of aluminum is is in the 350deg-400deg range depending on the type of aluminum. i really dont see a structure built like an engine case warp at all due to all the inernal gusseting that the part naturally has. ive done a lot of searching on this matter and have come up with nothing but a whole ton of people that have powder coated cases and have not have any problems. as soon as i can get a hold of some junk cases i will experiment on them.
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I was told you need to use only low temp powder coat, or you will have problems!
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Seems to me if the cases have a looser fit on the bearings the rest of it would be sloppy also. I am glad I never heat my cases past 200. Paint case friendly.
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Where are all the powders made at, here in the USA or overseas ?.
Neil
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annealing of aluminum is is in the 350deg-400deg range depending on the type of aluminum.
where did you get that info ? It doesnt match the info I have
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where did you get that info ? It doesnt match the info I have
Some google searches and a little of what I remember from my metallurgy classes. I'm not claiming I'm 100% right either lol
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I powder coated a few set of cases and haven't had any problems yet, Maybe they put you case in a burn off oven. I measure a set of cases with our CMM before and after a typical heat cycle.
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anyone know what series of aluminum the cases might be and if its tempered at all ? for aluminum to anneal i think it would need to be more like 600f-1000f depending what kind it is but thats not to say it wouldnt start warping or change shape at a lower temp. then factor in that it was in a oven for several hours
Cylinders and heads that are sand cast are usually made from A356 or an alloy that has similar chemical mixture .
OEM cases, clutch covers etc are usually made using a process called die casting which uses metal moulds. The alloys used for die casting typically has a high silicon content but varies depending upon the complexity of the mould, strength needed, time it takes to fill the mould and pressure of the molten aluminum.
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Some google searches and a little of what I remember from my metallurgy classes. I'm not claiming I'm 100% right either lol
i guess it could be 350f but then again it could be much higher. without knowing the material its almost impossible to say for sure. there seems to be a very large annealing temp range. even if it doesnt reach the anneal temp maybe it could still distort the item ? ive got some old cases (not honda) and im thinking they might be forged. ill have to take a closer look one of these days.
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If I remember right, OEM Honda TRX250R cases are injection die cast & it could just be a run went through, with a different type of aluminum than normally used ( some of our jets shot down in war time & scraped ) & this is the results showing it.
All those area where bearings are to be installed, need to be carefully measured to see how much they have expanded. I might could be, they could be PCed on the inside & then the bearing areas cleaned up & bearings pressed in. How thick does the PC coat build up ?.
Theres got to be some way to repair them that wont break the bank.
Neil
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I'd have to spray something and then cross section it to measure but I'd guess .010 give or take .005. Just my off the wall guess. I'm spraying this weekend so I'll spray a scrap piece and measure
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The interference fit should be .0015" to .0020" on the main bearings. Fitting the bearings any tighter than .0020 will usually cause the outer race to shrink enough to cause the bearing to bind and cause it to overheat and fail. Out of round bearing pockets will also cause the bearings to overheat. I have not found any hand calipers that will accurately measure bearing pockets. It is best to use a bore gage that has .0001" resolution when measuring bearing pockets.
I have tried a lot of products over the years to try to fix loose bearing pockets. Some work a little longer than others but not of them have been a permanent fix other than resleeving the bearing pocket
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general rule of thumb is .001" PF per each inch of bearing diameter.
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general rule of thumb is .001" PF per each inch of bearing diameter.
Is that for C3 or C4 bearings?
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c3.
c4 would be .0015". general apps like PF on inner or outer only, not both. of course depends on the application thats why i said generally.
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I had the engine assembled last 2 weeks ago. But the paint looked shity , so I pulled it apart again and sent the cases out. All of the new bearings were tight in the cases, now they are loose. There is no power on the inside at all. It was taped off. The power coating is called sparkle silver. Then cleared. I don't know if it was actually powder coated twice, maybe that was the problem. Too much heat maybe.
The cases are from a 85 atc engine that has never ran but was assembled.
how was the paint removed....were the cases chemically dipped to remove the paint prior to powdercoat?
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cases were bead blasted, but not on the inside, still has factory overspray inside.