rod bearing and crank question

[jasonlee]

Hello,

Could anybody let me know if a rod bearing goes, and the crank gets a bit scratched up. but not too deep.... could it just be smoothed out and replace the bearings, or will machining be necessary? some of the bearing was still there but not alot.


thanks...

j

 

[Colossus]

Get someone to machine your crank a tenth over, then get tenth over bearings. You can go further, and get even bigger over bearings. But, go with a tenth and see if it removes the scratch. It should. They dont make a thousandth over, so the next step is a tenth.

 

[GTM]

Hello,

Could anybody let me know if a rod bearing goes, and the crank gets a bit scratched up. but not too deep.... could it just be smoothed out and replace the bearings, or will machining be necessary? some of the bearing was still there but not alot.
thanks...
j

You must measure the crank, buy a vernier caliper from Harbor Freight, $16
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47257
Take several measurments, then check another journal. You can buy some "PLASTIGAUGE" and check all the bearings. Take the best bearing set and move to the bad bearing journal, check again.

http://www.plastigauge.co.uk/

Some bearing makers make a .002" undersize bearings, these are their standard for "first overhaul" where the crank is in good condition but just worn through normal wear when doing a rubuild. Until you have measured you don't want to pull the crank when you don't need to. Is the engine out of the car?

A trick I've used when things get .001"-003" out of spec, is to tape a sheet of 1500 grit wet or dry sandpaper to a piece of plate glass, _not_ window glass, "plate glass". You then put the rod cap on the paper and then sand to take the machining marks out of the mating face. Don't go in circles but back and forth and a little side to side. If you take .001" off this will calculate to about .0025" which should bring you back into spec and not have to grind the crank.

Plate Glass is very accurate in 3/8"-1/2" thickness and can be used as a surface plate within reason, you don't need a very big piece for this application. If you want to check a head for warpage then you should go with the 1/2".

Keep us posted, ask questions.

Cheers,
GTM

 

[greycar]

Get someone to machine your crank a tenth over, then get tenth over bearings. You can go further, and get even bigger over bearings. But, go with a tenth and see if it removes the scratch. It should. They dont make a thousandth over, so the next step is a tenth.

Don't do this, your oil clearances will be screwed and you'll crap out another motor, if your crank is out of spec after a slight polishing, scrap it and find another. The other reason you don't want to do this is the crank will be weakened due to the fact that the nitrate coating will be eliminated, and if you wasted any bearings bad on the crank get the block line honed.

P.S. you can never take too many measurements while building a motor, double and triple check you oil clearances and make sure everything is within spec. I take 80-100 measurements when doing a build, this ensures maximum efficientcy and longevity.

 

[greycar]

You must measure the crank, buy a vernier caliper from Harbor Freight, $16
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47257
Take several measurments, then check another journal. You can buy some "PLASTIGAUGE" and check all the bearings. Take the best bearing set and move to the bad bearing journal, check again.

http://www.plastigauge.co.uk/

Some bearing makers make a .002" undersize bearings, these are their standard for "first overhaul" where the crank is in good condition but just worn through normal wear when doing a rubuild. Until you have measured you don't want to pull the crank when you don't need to. Is the engine out of the car?

A trick I've used when things get .001"-003" out of spec, is to tape a sheet of 1500 grit wet or dry sandpaper to a piece of plate glass, _not_ window glass, "plate glass". You then put the rod cap on the paper and then sand to take the machining marks out of the mating face. Don't go in circles but back and forth and a little side to side. If you take .001" off this will calculate to about .0025" which should bring you back into spec and not have to grind the crank.

Plate Glass is very accurate in 3/8"-1/2" thickness and can be used as a surface plate within reason, you don't need a very big piece for this application. If you want to check a head for warpage then you should go with the 1/2".

Keep us posted, ask questions.

Cheers,
GTM

I am speechless, I just feel sorry for you, man whoever tought you backwoods engine building should be banned from working on cars, I wouldn't recommend any of these techniques, because no of them can assure any sort of accuracy, no wonder evry DSM is a p.o.s with using techniques like those.

You shouldn't even be posting in this section cause that isn't extreme tech at all, its pure HACK

 

[jasonlee]

wow, big variance in ideas..

the enginge just a spare i got from a buddy, when he got his 2.4 magnus longblock. its sitting on the floor in my garage, i just wanted to make it usable incase i need a spare sometime.

i think i am just gonna drop it off at a local shop and have them replace teh bearhings and the rings just so i can save some time. too much going on right now, and with all the different answers i dont even know wich to try.

thanks!

j

 

[greycar]

If you are going to outsource it just make sure you get references about the machine shop you will be using.

 

[GTM]

I am speechless, I just feel sorry for you, man whoever tought you backwoods engine building should be banned from working on cars, I wouldn't recommend any of these techniques, because no of them can assure any sort of accuracy, no wonder evry DSM is a p.o.s with using techniques like those.

You shouldn't even be posting in this section cause that isn't extreme tech at all, its pure HACK

It's a good thing you are speechless for we wouldn't be looking at this nonsense. I note that you offer nothing except bad manners and a flip mouth. You are one of these people who never had an original idea and ready to condemn if it's not in _your_ book of how to fix things. Not everyone has deep pockets, not all cars have new parts available. Accuracy, criminies, I can hold .0001" with what I suggested. I suggested the plastigauge for it is suitable for the posters seeming skill levels, I've not used it in 30 years. This is board is for DIY or exploring those options, it's not for you to malign someone with obviously vast differences in skill level to trash because you have an ego to sell us.

Granted the post should not have been in this forum but I don't have the authority to move it, I do have means to deal with attitudes. It would be best to confine yourself to what you do know and not what you do not. It would also be prudent before you decide to trash someon on this board to look at their profile. Yours on the otherhand demonstrates loads of money but says nothing of your credentials other than some 1 word quip.

GTM

 

[gsx951]

It's a good thing you are speechless for we wouldn't be looking at this nonsense. I note that you offer nothing except bad manners and a flip mouth. You are one of these people who never had an original idea and ready to condemn if it's not in _your_ book of how to fix things. Not everyone has deep pockets, not all cars have new parts available. Accuracy, criminies, I can hold .0001" with what I suggested. I suggested the plastigauge for it is suitable for the posters seeming skill levels, I've not used it in 30 years. This is board is for DIY or exploring those options, it's not for you to malign someone with obviously vast differences in skill level to trash because you have an ego to sell us.

Granted the post should not have been in this forum but I don't have the authority to move it, I do have means to deal with attitudes. It would be best to confine yourself to what you do know and not what you do not. It would also be prudent before you decide to trash someon on this board to look at their profile. Yours on the otherhand demonstrates loads of money but says nothing of your credentials other than some 1 word quip.

GTM

Sorry man but you shouldn't be measuring journals with a caliper. There is no way a caliper can resolve 1/10000"

 

[GTM]

Sorry man but you shouldn't be measuring journals with a caliper. There is no way a caliper can resolve 1/10000"

Of course not, but few people are ready to plunk down $100-$300 for a set of mikes for something that may be a one shot deal. The $16 vernier will give him what he needs to know or enough information that needs more investigation. It has other features that would require additional tools such as the depth gauge for blind stud or bolt holes, measuring for drill sizes when you don't know a tap size plus inside diameters. As a first precision tool it's hard to beat for the price. As it turns out we later learn it's a spare engine and not he's stuck in some driveway thinking he's going to slam dunk a rod bearing so he can get home. This may be more than he ever wanted to be involved with, and for certain he at least understands he has options and can with nominal expense glean enough to know if a machine shop is trying to put the screws to him.

Cheers,
GTM

 

[gsx951]

Of course not, but few people are ready to plunk down $100-$300 for a set of mikes for something that may be a one shot deal. The $16 vernier will give him what he needs to know or enough information that needs more investigation. It has other features that would require additional tools such as the depth gauge for blind stud or bolt holes, measuring for drill sizes when you don't know a tap size plus inside diameters. As a first precision tool it's hard to beat for the price. As it turns out we later learn it's a spare engine and not he's stuck in some driveway thinking he's going to slam dunk a rod bearing so he can get home. This may be more than he ever wanted to be involved with, and for certain he at least understands he has options and can with nominal expense glean enough to know if a machine shop is trying to put the screws to him.

Cheers,
GTM

I bought my 1"~2" Starret outside micrometer used on eBay for $20.00. I have bought all of my inspection tools on eBay and then checked them to the Starret gauge block set we have and found them to be dead nuts on. Most of the Mics in this range go for no more than $30 get one with a standard and you are set.
I certainly will not argue the usefulness or versitility of a digital caliper, I just wouldn't measure a crank with one.

 

[greycar]

Look there is only one way to do it when we are talking about performance and that is to do it the right way, if you can't afford to do the correct work then maybe you should ease back on your hobby, because just maintenance on a DSM is a full time job and can break your hobby budget, so lets get real here, ARE WE NOT IN THE EXTREME TECH FORUM???, if you want hack tech then switch to a different section.

GTM thanks for the 2cents, maybe I'll spend it someday

 

[greycar]

Sorry man but you shouldn't be measuring journals with a caliper. There is no way a caliper can resolve 1/10000"

Right on Bro

engine building isn't cheap and neither is racing

 

[GTM]

Look there is only one way to do it when we are talking about performance and that is to do it the right way, if you can't afford to do the correct work then maybe you should ease back on your hobby, because just maintenance on a DSM is a full time job and can break your hobby budget, so lets get real here, ARE WE NOT IN THE EXTREME TECH FORUM???, if you want hack tech then switch to a different section.

GTM thanks for the 2cents, maybe I'll spend it someday

I have yet to remotely see anything that impresses me that you wish to contribute except provocation. This seems to prevail not only in this thread but in other areas of this board where you have been flip and insulting with other members. In this thread your offer was for the poster to buy a new crank without batting an eyelash. The only other mention was nitriding yet never mentioned this can be done if he elects to grind the crank. It was a freebie spare engine and you would have everyone that reads this thread believe that his _only_ choices are to spend great sums of money for something that may collect dust for the next x years. There are several methods of repairing the crank and heat treating it including carborizing. Can you even recommend how long and at what temp those jobs should be performed... have you ever done it? Hell no because you are a parts changer.

Pure hogwash, you have something to sell AND an ax to grind which doesn't make you especially objective. Before you were born I was building engines, my engines have been to Daytona USRRC twice and came in 2nd both times, they have been to Laguna Seca, Las Vegas, Ontario, if those names mean anything.

Here is another 2¢, either respect the opinions of others around here, couch your arguments in a civil manner or become a persona non grata and keep the snot nose ego which nobody likes. I known my share of bull sh*t artists who blow smoke when they don't know squat, don't tell me I can't post in any forum on this board including those you don't even know exist. I've not seen it said of you that you know more than any 5 members on this board. If I want to use an optical comparitor to measure a crank who the hell are you to tell me I can't.

You have a beef with me take it to the list owner, you think I've not paid my dues or not earned the title of Wiseman read my other posts but don't pee on my pants and tell me it's raining.

GTM

 

[greycar]

In this thread your offer was for the poster to buy a new crank without batting an eyelash. The only other mention was nitriding yet never mentioned this can be done if he elects to grind the crank. It was a freebie spare engine and you would have everyone that reads this thread believe that his _only_ choices are to spend great sums of money for something that may collect dust for the next x years. There are several methods of repairing the crank and heat treating it including carborizing.

You can get a good used crank for 100-200 dollars, trying to repair a DSM crank will cost well over that, the process of grinding, heattreating and recaoting.

Can you even recommend how long and at what temp those jobs should be performed... have you ever done it?

nope, and I not claiming that I know how too. What race team has a one man operation?? none, because there are certain people for each field(specialist), not 5 jack offs of all trades,

Hell no because you are a parts changer.

Hey now, I'm pretty good at parts changing.

Pure hogwash, you have something to sell AND an ax to grind which doesn't make you especially objective.

What am I trying to sell??? I just say it how I see it, in no way is everybody going like me, hell even I piss myself off sometimes.

Before you were born I was building engines, my engines have been to Daytona USRRC twice and came in 2nd both times, they have been to Laguna Seca, Las Vegas, Ontario, if those names mean anything.

Congradulations on your racing history. Did you do all of this with a DSM, just kidding

Here is another 2¢, either respect the opinions of others around here, couch your arguments in a civil manner or become a persona non grata and keep the snot nose ego which nobody likes. I known my share of bull sh*t artists who blow smoke when they don't know squat, don't tell me I can't post in any forum on this board including those you don't even know exist.

Chill Bro, I'm not out to hurt anyones feelings, or disrespect you. I get judged too, but I don't take it all to heart.

I've not seen it said of you that you know more than any 5 members on this board.

I have no friends.

If I want to use an optical comparitor to measure a crank who the hell are you to tell me I can't.

I didn't say you couldn't. I just made a statement that I would use a mic made by a good source, not Harbor Freight, and not a dial caliper, lets be real here you are measuring thousndths of a inch, not tenths.

You have a beef with me take it to the list owner, you think I've not paid my dues or not earned the title of Wiseman read my other posts but don't pee on my pants and tell me it's raining.

Just because we are arguing about something doesn't mean I have beef, just that we have differences. Just because of that doesn't mean we have to fight. I've earned the title of wiseass , watch out for the five day forecast

Sorry that I get taken so literal, I'll just shut up from now on out.

 

[GTM]

...
nope, and I not claiming that I know how too. What race team has a one man operation?? none, because there are certain people for each field(specialist), not 5 jack offs of all trades,

Pure hogwash, you have something to sell AND an ax to grind which doesn't make you especially objective.

What am I trying to sell??? I just say it how I see it, in no way is everybody going like me, hell even I piss myself off sometimes.

Congradulations on your racing history. Did you do all of this with a DSM, just kidding

Here is another 2¢, either respect the opinions of others around here, couch your arguments in a civil manner or become a persona non grata and keep the snot nose ego which nobody likes. I known my share of bull sh*t artists who blow smoke when they don't know squat, don't tell me I can't post in any forum on this board including those you don't even know exist.

Chill Bro, I'm not out to hurt anyones feelings, or disrespect you. I get judged too, but I don't take it all to heart.

I have no friends.

You have a beef with me take it to the list owner, you think I've not paid my dues or not earned the title of Wiseman read my other posts but don't pee on my pants and tell me it's raining.

Just because we are arguing about something doesn't mean I have beef, just that we have differences. Just because of that doesn't mean we have to fight. I've earned the title of wiseass , watch out for the five day forecast

Sorry that I get taken so literal, I'll just shut up from now on out.

Yeah, sure, what you said. Do you want to be at the top of the food chain or try to bully your way there...

All my life I've had to deal with incompetence and those who would have you believe they were the greatest thing since sliced bread.

As I said previously stick with what your KNOW and don't screw with people. You have managed to piss off the poor guy who wrote the original post... for what end, YOUR ego. Loose the ego, you have some thing to contribute, have a different opinion then support your arguments (legal/scientific context) without trying to as you did in this case insult.

I have no threat thus buy Harbor Freight tools and give them to my customers. If they get to use them, wonderful, they needed them. I've never had a problem with people fixing their transportation. On the otherhand...

Loose the ego, you have something to offer do so but don't go 1 step beyond what you know is factual. You will gain respect and friends, AIN"T nutting wrong with reading and first hand experiences. You get to have an OPINION but not insult anyone... read the rules.

This is going to sting. Every time one of your types gets on this board the original poster gets fed up and abandons the original issue. Hope you got your jollies at the expense of trying to show off. LOOK before you jump someone's bones on this list.

"jasonlee wow, big variance in ideas.."
Contact me off list if you need.
Cheers,
GTM

 

[Defiant]

And then it all gets locked.