TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: rablack21 on January 08, 2015, 09:33:46 AM
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Disclaimer: This thread is for information to possible consumers out there about a potential problem. This is not a "how to fix the problem" thread. This thread is NOT meant for bashing Hot Rods, though does show my initial frustration. I would never bash a company without giving them the chance to rectify the mistake. If you look at the end of this thread, you will see they did just that. Just know that there might be other cranks in this batch that got out the door as well.
Quick catch up for those that don't know: I am working on assembling my new 363 stroker motor. See the link for additional info.
http://trx250r.org/threads/4726-Little-Engine-That-Could-changed-to-BEAST-MODE (http://trx250r.org/threads/4726-Little-Engine-That-Could-changed-to-BEAST-MODE)
I finished putting my engine together last night. I installed the piston and cylinder and just finished torquing down the cylinder base stud nuts. The piston was at TDC. I started turning the crank to make sure everyone was moving smoothly. The piston moves about 5/8" down from TDC and comes to a hard stop. I look through the intake port and see the stroker crank rod is hitting the cases. I back the piston off and try to go in the reverse direction on the crank. The crank rod hits the cases on the back of the crank rod also. WTF?!!
I call Eddie Sanders for some help where I bought this Hot Rods stroker crank from. Turns out, he had just run into the same issue. He said they just recently changed the color of the rods and were milling the bottom of the crank rod a little differently from before. He didn't think anything about it til he had one hit like mine is doing. Apparently, they are not tapering enough material off of the rod for clearance like they were before. FAIR WARNING TO ANYONE BUYING A 4MM STROKER CRANK SOON, if you get one that has a copper/bronze colored rod, these are the ones that are affected. I'm not sure if there is an issue with any other size stroked rods or not. Eddie is called Hot Rods to discuss this issue this morning and see what can be done. I am so pissed right now! I basically have my engine almost completely back together, already spent lots of time and money having the cases split, installing this new crank, all new seals, bearings, gasket, etc, and now I'm gonna have to tear it all back down again. I told Eddie that the recourse from Hot Rods should be to reimburse me for all of it, but I doubt it. This is a chance for them to do the right thing and fix this. If they do nothing, I will make sure everyone knows about this. This is a genuine design "F" up on their part. I don't have any pics yet to show you guys the crank rod, but I will take some pics when I start disassembling again.
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Ryan did he notch the cases for the +4 crank? Ive got both new and old style +4 and both required the cases notched.
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Doug. I will have to check closer to see. Honestly, I don't think I saw a notch on the cases. My understanding was the +4mm Hot Rods crank was a drop in part, not requiring any additional machining of the cases? Is this not the case? (pun intended)
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When Bubba Ramsey did mine couple years ago he had to notch both sides to clear the longer rod. When I got my new cases and new crank this time I had to do the same before I put the motor together. I can send you pics of my old cases when I get home.
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I thought notching for the +4 was common.
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Notching the cases is required on the majority of the stroker cranks I have used over the years.
When using a stroker crank or a aftermarket connecting rod, experienced builders install the piston in the cylinder on one case half with the crank installed and check for this common problem. I have been where you are now. Gaining experience is always painful and expensive.
Hot rods will probably tell you should have checked for clearance before final assembly. Good luck trying to get Hot Rods to compensate you for your time. They will probably try to send you a hat or T-shirt to try to smooth things over
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My cases aren't notched and I have a 4mil crank. I have a older one so maybe that's why. I do have a spacer plate. Eddie built my motor like 2 years ago and still going strong with 205psi on snap on compression tester.
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Here is the info right from Hot Rods website:
Heavy Duty Drop-in Stroker Crankshafts
In addition to Hot Rods heavy duty OEM replacement crankshafts, Hot Rods also offers a full line of drop-in stroker crankshafts. Not only do these stroker cranks bring about a heightened level of performance and increased displacement, but do so without costly case machining, custom cam chains or spacer plates. Better yet, many Hot Rods stroker cranks even utilize the engine's stock piston.
Additional Hot Rods stroker crankshaft features:
All stroker crankshafts are sold complete and ready for installation with the original proven Hot Rods connecting rods, top end bearings and crankshaft webs
Factory assembled and trued
For additional information such as stroke gain and displacement increase, see the individual products listings. Also be sure to check out our installation videos on YouTube.
It says it right there in black and white. Drop in stroker crank. No case machining. And it lists MY CRANK part number right there on the first page.
http://www.hotrodsproducts.com/productinfo.aspx?cat_id=11 (http://www.hotrodsproducts.com/productinfo.aspx?cat_id=11)
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Here is the info right from Hot Rods website:
Heavy Duty Drop-in Stroker Crankshafts
In addition to Hot Rods heavy duty OEM replacement crankshafts, Hot Rods also offers a full line of drop-in stroker crankshafts. Not only do these stroker cranks bring about a heightened level of performance and increased displacement, but do so without costly case machining, custom cam chains or spacer plates. Better yet, many Hot Rods stroker cranks even utilize the engine's stock piston.
Additional Hot Rods stroker crankshaft features:
All stroker crankshafts are sold complete and ready for installation with the original proven Hot Rods connecting rods, top end bearings and crankshaft webs
Factory assembled and trued
For additional information such as stroke gain and displacement increase, see the individual products listings. Also be sure to check out our installation videos on YouTube.
It says it right there in black and white. Drop in stroker crank. No case machining. And it lists MY CRANK part number right there on the first page.
http://www.hotrodsproducts.com/productinfo.aspx?cat_id=11
Before you talk to them try installing an OEM cylinder and piston on the cases an see if the rod hits the cases.
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Before you talk to them try installing an OEM cylinder and piston on the cases an see if the rod hits the cases.
What is the purpose for this?
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Im not sure Ryan but I have the same crank "newer style with copper rod" and had to notch mine just like my old set up.
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What is the purpose for this?
Hot Rods will probably say that it is "drop in" for OEM cylinders and pistons and cannot possibly check to see if their cranks will fit every possible combination that the end user can put together. My experience dealing with them on issues over the years has not been good. I do not think that it will make any difference what cylinder or piston you use but it seems they will try to dodge the blame.
The wrist pin is not centered in most pistons. (from front to back) If the pin offset is different on the ESR pistons than the OEM piston it could cause the rod to hit on one side of the case but probably not hit on the other case when rotated in the opposite direction.
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I've had to make clearance for my +4's as well.
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Just got off the phone with Eddie. He said that he talked to Hot Rods. They were looking into the matter and going to call him back. They were going to look at the older style and the newer style and compare the 2. Eddie told me he has been using these same stroker cranks for years without having to make additional clearance, and that he never had an issue with any of them until they switched to this new style. If it is their intention for builders to still have to clearance the cases, then it is straight up false advertising. Eddie said he would call me back this afternoon after hearing back from them.
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My friend and I both had to do a small notch on our 370's with +4 hot rods. The notch is toward the top front of the crank case. The rod hits halfway between the piston and main rod bearing. It can be notched without separating the cases if you want to risk it. Use a vacuum to suck shavings as you grind.
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My friend and I both had to do a small notch on our 370's with +4 hot rods. The notch is toward the top front of the crank case. The rod hits halfway between the piston and main rod bearing. It can be notched without separating the cases if you want to risk it. Use a vacuum to suck shavings as you grind.
I get what you are saving. However, what I am getting at is Hot Rods is advertising this crank to not need any case machining or clearancing. And according to Eddie, previous style ones have not needed it. If I purchased the stroker crank and their directions said to machine the cases, then I would be ok with that. But that is not the case here. People need to be aware of this issue.
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the crank +4 hotrods crank i used when i put my cousins motor together a couple of years ago didnt need any machining and when he switched to a prox cylinder the following year he never said anything about having any problems then either.
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mine also needed notched to clear cases.
John
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I had to massage rod and cases on mine just did this 2 weeks ago
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When using a stroker crank or a aftermarket connecting rod, experienced builders install the piston in the cylinder on one case half with the crank installed and check for this common problem.
yep its always a good idea when using nonstandard parts (longer rods, heavier duty rods, longer strokes) to chuck the crankshaft assembly in one case half and install the cylinder and piston to see if theres any clearance issues
I have been where you are now.
been there myself. although i feel the better option is to take the material out of the case (if theres sufficient material) rather than cut down the rod big end
Hot rods will probably tell you should have checked for clearance before final assembly.
if they use the same rod on a standard stroke and +4 it doesnt suprise me of this clearance problem. they simply had a brain fart and probly forgot the +4 needed the rod machined in order to be considered a drop in component.
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Hot rod does machine the bigend down to save you from machining the whole case bottom, but you have to remember the pin is now 2mm farther away from the crank center line and it is not a smart move for them to machine even more of the rod for the needed clearance.
They should have been more informative of what is needed when installing there crank for sure but IMO you are building a stronger setup than one with the rod ground down even farther for the upper case clearance. I have built probably 6 stroker 250r's and every one had the cases clearanced.
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According to Eddie, none of the previous hot rods cranks #4107 have needed additional clearance. He said that he noticed that they just recently changed how they were machining the crank rod end and it looked different. So clearly they were producing a drop in stroker crank that does not require clearancing of the cases.
The simple fact is , this is false advertisement and a design failure on their part. Just trying to pass this information on to other potential future buyers. I will get my engine taken care one way or another, just making people aware of this issue. Hopefully, they will recognize their mistake, fix this, and go back to their original process or alteast stop advertising these as drop in cranks with no machining required.
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...............you are building a stronger setup than one with the rod ground down even farther for the upper case clearance.
Yes, Yes Yes,
Leave the big end of the con rod alone and clearance the cases. Machining the big end of the con rod reduces the RPM where the big end distorts enough to stop the rollers from rolling.
The new rods (copper coated) are a better rod than the old (non copper coated) rods.
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Sounds like they updated the product without updating the documentation
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Here are some pics of the culprit crank rod and machining. If you look closely, you can see the high point of material they left on the crank rod that is causing it not to clear correctly. If they would have smoothed out the transition on the rod just a little more, the crank would have cleared like it was designed to. It is possible that this is just a machining error. Perhaps the cnc program was not set to transition enough of the material off. I still haven't heard anything back from Hot Rods yet.
(http://forums.trx250r.org/vbulletin_imports/100_4305_2017-04-18_1378.jpg)(http://forums.trx250r.org/vbulletin_imports/100_4306_2017-04-18_3300.jpg)(http://forums.trx250r.org/vbulletin_imports/100_4307_2017-04-18_6035.jpg)(http://forums.trx250r.org/vbulletin_imports/100_4308_2017-04-18_2967.jpg)(http://forums.trx250r.org/vbulletin_imports/100_4309_2017-04-18_9696.jpg)
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FYI i have never notched my cases for my +4 hot rods cranks. they are roughly 1-2 year old cranks. But still.
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Some guys have their cases machined for the big bore cylinders and some guys hand grind their cases. This fact may help explain some of the inconsistency why some guys have to notch their cases on the old rods and some do not.
..........and all shops do not machine the cases so there is the same clearance between the sleeve and cases.
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Some guys have their cases machined for the big bore cylinders and some guys hand grind their cases. This fact may help explain some of the inconsistency why some guys have to notch their cases on the old rods and some do not.
..........and all shops do not machine the cases so there is the same clearance between the sleeve and cases.
The way the cases are machined for big bore cylinders is not the variable here, the way the crank rod is machined is. If a person was using an OEM cylinder, no machining of any sort would be required to the cases for the Hot Rods stroker crank, according to Hot Rods.
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That's definitely a quality controlled issue. Hot Rods needs Process Engineers, to eliminate any issues when changing a process. You have my luck, Ryan. These things always happen to me. Good luck. I hope you get some compensation.
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That's definitely a quality controlled issue. Hot Rods needs Process Engineers, to eliminate any issues when changing a process. You have my luck, Ryan. These things always happen to me. Good luck. I hope you get some compensation.
Thanks Fred. My middle name might as well be "Murphy". LOL
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i dont see anything wrong with the rod. it just isnt machined down for a stroker crank. the only thing hotrods is guilty of is false advertisement i guess, for claiming the crankshaft is a drop in deal. you did say it swings through the bottom just fine but rubs at the top ? personally i would pull the crank out and just grind the top front/back alittle with a dremel. while your taking it apart you might look at how much clearance you have through the full stroke with the cylinder and piston installed on one half of the case just to be sure you have enough. i wouldnt feel comfortable with anything less than .020", alittle more would even be better. probly have to do something like this
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i dont see anything wrong with the rod. it just isnt machined down for a stroker crank. the only thing hotrods is guilty of is false advertisement i guess, for claiming the crankshaft is a drop in deal. you did say it swings through the bottom just fine but rubs at the top ? personally i would pull the crank out and just grind the top front/back alittle with a dremel. while your taking it apart you might look at how much clearance you have through the full stroke with the cylinder and piston installed on one half of the case just to be sure you have enough. i wouldnt feel comfortable with anything less than .020", alittle more would even be better. probly have to do something like this
Is that a case-reed cr250 case halve?
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Not sure what kind of case it is. JuSt for illistration to show where to grind
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Update: 1-14-15
Just got off the phone with Hot Rods. They concluded from their engineering department that they did in fact have a small batch of stroker cranks go out that didn't have the crank rod fully machined out on the sides of the lower part of the crank rod like they should have been. This can be seen in the pictures I attached and described earlier in this thread. They thought they had caught them all before they weren't out , but apparently some of them got out. So, if anyone else happens to run across this issue, hopefully they will take notice of this thread.
Now for the more interesting part, Hot Rods stepped up in a redeemed themselves. They were shipping me out a new crank with the correct machining and are sending me a return label to get this old incorrect one back on their dime. But that doesn't cover the money it cost me for the gaskets to put this engine together or paying my builder to install the crank and assemble the bottom end. So to help compensate for that, they are also sending me a full gasket set with the new crank, and sending my a bunch of Pivot works bearing kits to help offset my costs for the builder. They said they weren't able to send out actual money to compensate but could sent out some merchandise. I was surprised that they were willing to help make this right. But they did. In my eyes, they have righted this mistake and I am happy with their response.
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Update: 1-14-15
I was surprised that they were willing to help make this right. But they did. In my eyes, they have righted this mistake and I am happy with their response.
So they stepped up, your turn. All those Whiney false advertisement claims were pretty neat. I'm sure you've never made a mistake Ryan.
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So they stepped up, your turn. All those Whiney false advertisement claims were pretty neat. I'm sure you've never made a mistake Ryan.
I'm not really sure what you are getting at, pinned. I did not bad mouth nor disgrace hot rods what so ever. And was willing to work with them. I did not accuse them of false advertisement. Go back and read again. There was a very large "if" at the beginning of my information. I would never bad mouth a company without getting them a chance to reconcile.
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I'm glad they stepped up and helped you out . its good to here a company step up. taking care of a customer is not what all businesses do . This thread will not hurt them lol. Hopefully they keep up this kind of customer service.
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The simple fact is , this is false advertisement and a design failure on their part. Just trying to pass this information on to other potential future buyers. I will get my engine taken care one way or another, just making people aware of this issue. Hopefully, they will recognize their mistake, fix this, and go back to their original process or alteast stop advertising these as drop in cranks with no machining required.
Reading things.....
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Ryan I'm not out to make you look bad, just tryin to help a class act of a member out. Your opinion and facts are mostly valued on here. Going on a rant is not in your best interest of being a leader
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Ryan I'm not out to make you look bad, just tryin to help a class act of a member out. Your opinion and facts are mostly valued on here. Going on a rant is not in your best interest of being a leader
I value your opinion as well. I must be missing something. I really don't feel that I ranted about them, only gave observations and updates to a situation. I meant for this thread to be helpful to anyone that may run into this problem as well. Maybe I am mistaken. If so, I certainly meant no bad feelings toward hot rods.
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Disclaimer: This thread is for information to possible consumers out there about a potential problem. This is not a "how to fix the problem" thread. This thread is NOT meant for bashing Hot Rods, though does show my initial frustration. I would never bash a company without giving them the chance to rectify the mistake. If you look at post #34 of this thread, you will see they did just that. I commend them on their customer service. They also mentioned that their intention for these cranks, #4107, are in fact to be a drop in crank without any case clearancing. Just know that there might be other cranks from this batch that got out the door as well. So if you order a new one anytime soon, take notice of the previous pictures.
Update:1-15-15
I will take some pics to post of the new crank and rod once I receive it so everyone will know what they are supposed to look like.
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Hey right on. Its reassuring to hear that hot rods took care of this issue. I must applaud them. did you take note of who you spoke with? you should ask if they would possibly be a sponsor for our website. I'm glad they took care of your matter.
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Hey right on. Its reassuring to hear that hot rods took care of this issue. I must applaud them. did you take note of who you spoke with? you should ask if they would possibly be a sponsor for our website. I'm glad they took care of your matter.
I spoke with a customer service guy named Brad. Yep, they were willing to try to make the customer happy, and that goes a long way with me.
I didn't speak with them about becoming a sponsor. lol. Probably not the right conversation to discuss that, but it certainly would be a possibility.
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That's good to hear Ryan. :eagerness: In my opinion, you handled the situation, very applicable! :respekt: It's the adversities, that keep you strong minded! :victorious:
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I'm not really sure what you are getting at, pinned. I did not bad mouth nor disgrace hot rods what so ever. And was willing to work with them. I did not accuse them of false advertisement. Go back and read again. There was a very large "if" at the beginning of my information. I would never bad mouth a company without getting them a chance to reconcile.
You didn't bad mouth them and at least to me, you never seemed pissed or demeaning towards them in any way.
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Sorry but IMO you have created a disservice to yourself and the 250r community by wanting a crank rod with less material around the bigend bearing so it is a true drop in.
Someone with a engineering background at HotRod probably made the rod changes for increased strength and durability but did not make it known to the sales division.
I hope like hell they do not make the changes so they are drop in, Engine builders (not assemblers) should be assembling a motor with a stroked crank because of the porting and head changes that come along with it.
If you have ever looked at a typical snowmobile rod you would realize how small ATV/MC rods are, this is because of durability needs of a snowmobile engine, they run at higher rpms for extended periods of time.
But if you already take a rod designed to be lightweight and remove even more material what do you think happens to its durability? stroker cranks have always been notorious of high failure rates maybe its because of poor workmanship or maybe like JerryHall said its because the bigend of the rod is thinned out and the rod actually deforms and now the rollers bunchup together and can not freely turn.
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Sorry but IMO you have created a disservice to yourself and the 250r community by wanting a crank rod with less material around the bigend bearing so it is a true drop in.
Someone with a engineering background at HotRod probably made the rod changes for increased strength and durability but did not make it known to the sales division.
I hope like hell they do not make the changes so they are drop in, Engine builders (not assemblers) should be assembling a motor with a stroked crank because of the porting and head changes that come along with it.
If you have ever looked at a typical snowmobile rod you would realize how small ATV/MC rods are, this is because of durability needs of a snowmobile engine, they run at higher rpms for extended periods of time.
But if you already take a rod designed to be lightweight and remove even more material what do you think happens to its durability? stroker cranks have always been notorious of high failure rates maybe its because of poor workmanship or maybe like JerryHall said its because the bigend of the rod is thinned out and the rod actually deforms and now the rollers bunchup together and can not freely turn.
First of all, I agree with you that machining down the rod can weaken the design. Yes, it is a better design to have lots of material around the bearing. Being an engineer myself, this is not difficult to understand. Again, this thread was NOT to discuss design theory and maximizing durability. It was to discuss a defective batch of cranks that got out. And how they dealt with it. It's as simple as that. It was a product that got out the door with a defect, just like any other part you would buy from a parts store or retail store. I inquired about the issue, recorded it, and made a thread about it in case someone else might have ended up with one as well.
Also, I never said that I wanted a crank rod with less material over one with more material. You did. I went with this particular crank because of the budget I had to work with. And there are alot of people running them, not just in 250r's but many other 2 strokes and 4 strokes for that matter.
I spoke with the engineering department. This was NOT an engineering change for them. It was a mistake in the cnc programming. Their crank rod was DESIGNED to have smooth transitions on both sides. My crank did not work because it was not machined to THEIR DESIGN INTENTION. And yes, like you said, I hope someone put in the time and did the FEA on this design to make sure it wasn't detrimental.
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you have created a disservice to yourself and the 250r community by wanting a crank rod with less material around the bigend bearing so it is a true drop in.
sorry but you must have misread somewhere. how does having a smoother transition from the machining to the forging in this spot to clear the top area of the cases have to do with having less material around the big end bearing?
(http://i1251.photobucket.com/albums/hh548/JesseA421/rodissue.jpg)
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Might be, Hot Rods just needs to change the wording for their stroker cranks, to no say drop in replacement.
Things are strange how they work, just like that 6 mil ESR stroker Wayne Walker has, I wouldnt have trusted that crank to run across the road & stay together, but it has proved me wrong with as long as hes been running it.
Maybe he'll chime in & let us know the hours on it.
Neil
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I have one of these cranks. New in the box, but I will clearance my cases. (ESR offered to modify the rod but that was not Mr. Sanders recommendation.) Since my engine is not together then I will machine my cases. Once the Pics are posted of what Hot Rods is doing to fix the problem then I will decide if I want the exchange.
Just a question here also, are cranks balanced and if so are they balanced with the rod or without??
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im with rsss. i dont like the idea of reducing the the strength of the rod at all and i simply refuse to alter rods if it might compromise its integrity. heres a story from some years ago when i was much less knowledgable. my problem was similar to you guys. i installed a heavier duty rod which snagged right at the top and pretty much rubbed through the full circumference of the stroke. i had this brilliant idea to machine down the the rod completly around the big end circumference so it could make a full swing unobstructed. hell i even had to make a stepped crank pin so i could fit this new heavier duty rod.
well i almost got the engine assembled when somehow i came to my senses and realized i had a train wreck waiting to happen. so i pulled the crank back apart, installed a new unmolested rod, trenched and grinded the cases where needed, bored the hole of the crank wheels for the larger pin. i sleep much better knowing theres almost zero chance this crank assembly will fail. still got the machined down rod and step pin on the garage shelf as a reminded what a bad idea it was
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This post was moved to:
http://trx250r.org/threads/5107-Stroker-Cranks-and-Con-Rods-vs-OEM-Cranks-and-Con-rods
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Guys, neither of the last 2 posts are relevant to this thread. Please stay on topic. Again, this thread is NOT to talk about crank and rod design. If you want to talk about that topic, start another thread.
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Thanks rablack21 for bringing up this topic. I would also like to add this.
I am a novice at all this, but I am learning. This site has helped me tremendously. That being said, of almost 60 years of lifes experiences I have learned that for me to accomplish my goals, I must listen, gather information, and trust others in their experiences. We all started this "R' journey somewhere. Some have more experience at it than others. Some have more passion. Sometimes it is best to "AGREE to DIS-AGREE". At the end of the day I alone am accountable for my decisions and their consequences. Respect and consideration are some of the things that make this site a "GREAT" R forum. I thank you all for your contribution to my world!
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I would also like to add this.
The drop in crank vs the make it work attitude is easy to work out. But the motor builders tend to lean against taking too much off the big end of the rod. There is good reason for this and think it matters to everyone concerned. Thanks to those that add to our understanding why taking too much off the rod will lead to failure later on. Its too bad they cannot pour the rod without having to machine the much needed material here. I guess its just cost effective.
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First of all, I agree with you that machining down the rod can weaken the design. Yes, it is a better design to have lots of material around the bearing. Being an engineer myself, this is not difficult to understand. Again, this thread was NOT to discuss design theory and maximizing durability. It was to discuss a defective batch of cranks that got out. And how they dealt with it. It's as simple as that. It was a product that got out the door with a defect, just like any other part you would buy from a parts store or retail store. I inquired about the issue, recorded it, and made a thread about it in case someone else might have ended up with one as well.
Also, I never said that I wanted a crank rod with less material over one with more material. You did. I went with this particular crank because of the budget I had to work with. And there are alot of people running them, not just in 250r's but many other 2 strokes and 4 strokes for that matter.
I spoke with the engineering department. This was NOT an engineering change for them. It was a mistake in the cnc programming. Their crank rod was DESIGNED to have smooth transitions on both sides. My crank did not work because it was not machined to THEIR DESIGN INTENTION. And yes, like you said, I hope someone put in the time and did the FEA on this design to make sure it wasn't detrimental.
im sure you know now, or maybe you dont, theres nothing defective about that crank assembly. it simply has a standard unmolested rod on it, like what you would see on any standard stroke crankshaft.
alot of rods dont have a smooth transition at the sides, contrary to what you might think. got several rods from several engines sitting around and they dont have the smooth transition. some rods may very well be a smooth transition, depends on the design, manufacturer, etc. but to say its defective simply because its not a smooth transition is nonsense. you might be misinterpreting whats going on here. the rod you have is typicall of what you would see on a standard stroke crank. hotrods had failed to machine it down even further, in order for it to be considered a 'drop in' deal, but by no meens is it defective in design
if you dont mind me asking, what engineering field are you in ?
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im sure you know now, or maybe you dont, theres nothing defective about that crank assembly. it simply has a standard unmolested rod on it, like what you would see on any standard stroke crankshaft.
alot of rods dont have a smooth transition at the sides, contrary to what you might think. got several rods from several engines sitting around and they dont have the smooth transition. some rods may very well be a smooth transition, depends on the design, manufacturer, etc. but to say its defective simply because its not a smooth transition is nonsense. you might be misinterpreting whats going on here. the rod you have is typicall of what you would see on a standard stroke crank. hotrods had failed to machine it down even further, in order for it to be considered a 'drop in' deal, but by no meens is it defective in design
if you dont mind me asking, what engineering field are you in ?
you call it what you want to, but if a part in any manufacturing plant gets out the door without meeting its design intention and without all the proper machining to meet that design, then it is defective. And hot rods indicates this as well. Call it a manufacturing errors if it makes you feel better about the terminology. The bottom of this rod is purposely machined down to be a stroker crank. Otherwise it would be as cast. As would be expected with normal design. And just fyi, if something doesn't meet it's design intention, then yes it is defective. That is obvious. No, I don't mind you asking at all. I am a design engineer with emphasis on structural analysis.
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I am a design engineer with emphasis on structural analysis.
So when your rod fails you will understand why!
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So when your rod fails you will understand why!
Lol!
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since your not a engine builder or in a engineering field that deals with engines im just trying to help you understand whats going on here. many rods are machined on the bottom, whether their final destination is on a standard oem stroke crank or some after market longer stroke.
does the 250r hotrods 72 stroke crank not use the same rod as the +4 crank, 130.3mm ? hotrods only shows one rod available which suggests both cranks use the same rod. this is where i was trying to tell you the rod you have is what would be used on the 72 stroke crank, they simply take that rod and machine it further to be used on the +4, in order for it to be classified as "drop in". theres nothing defective about its design.
with some weird combination of 250r parts it seems like the piston skirt can contact the crank wheels at bdc. is the piston defective ? of course not.
but you insist on calling the crank defective. defective is a crack, or egg shape bearing hole, atleast in my book.
this is a rod intended for a oem stroke, as i recieved it from the manufacturer. its not a smooth transition and has been machined, no different than your defective rod :lol:
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You said that I wasn't in an engineering field that dealt with engine design. Not me. I am fully aware of engine design, crank rod design, material design, and stress analysis in general. I'm trying to get you to understand that some crank rods are not machined, but are as cast. Just like the standard hot rods crank that I took out of my engine that is as cast and not machined down. You seemed to be hung up on the word defective. Ok, let's call it a manufacturing error that not allows the part to be used correctly, just like an egg shaped hole or a crack. Both of those are also manufacturing errors. This rod is missing some machining that hot rods said that it is missing. So obviously they feel that the smooth transition needs to be there. Thus a crank rod and crank manufacturer has designed it to be that way. So maybe you should call and tell them they are wrong as well.they don't seem to understand either.
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You can't always believe what you read!
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You can't always believe what you read!
Unfortunately you right.
Our industry is plagued with manufactures and service shops that do not deliver what is advertised or promised. Some of it is due to not keeping their information up to date, some of it is intentional fraud and some of it is due to inexperience in their field.
As most Judges in courts of law say " buyer beware".
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i remember not long ago hearing about the wiseco cr250 crankshafts that were so horribly made that when the crank gear was installed it didnt line up correct with the clutch basket gear. hek i dont even think the gear would tighten down correct because the bolt threads in the crank snout werent tapped deep enough. read about this several times on another site. needless to say i wouldnt use a wiseco crank if it was the very last option. not to mention countless wiseco cranks that have broke in half or the flywheel snout snapped off