CRANKSHAFT runout, out of round, taper. How to measure it all.

Step by step tutorial on how to measure run-out, out of round and taper on a crank shaft.

[@richardsterling691]

Your teaching method is clear, precise, and easy to understand this technical vital information. Thank You

[@planesimple8514]

Thank you very much Richard. I really appreciate the positive feedback and thank you for taking the time to write it.

[@nicholasmusevenzo979]

Perfectly clear and precise. Take me through cylinder bores measurement again

[@linmarsbacosa8747]

It gave me direct answer for clarifying the explanation I read from A&P handbook. It helps a lot! Thank you!

[@planesimple8514]

Thank you.

[@user-te3cg2eh5d]

Very well explained and easy to understand. Thank you sir!

[@planesimple8514]

Thank you very much Mark Douglas Parel. I'm glad you liked it and thank you for taking the time to write in a nice comment.

[@VusumuziBarnabasNdhlovu-cm5yo]

Thank you. I now understand

[@planesimple8514]

Thank you. I'm glad it helped.

[@lokeshhassan]

its a very useful information about measuring crankshaft taper and ovality

[@planesimple8514]

Thank you very much.

[@arrazolavenancio2751]

Thank you very much for this information it was very useful

[@planesimple8514]

Thank you for taking the time to leave me some positive feedback and I'm glad my video was useful.

[@vitalisziwake7340]

Fantastic easy to understand

[@planesimple8514]

Thanks Vitalis Ziwake.

[@torque5231]

Very well explained. Thank you.

[@planesimple8514]

Thanks @torque5231.

[@crazypilot4017]

Nice 👍

[@planesimple8514]

Thank you.

[@gerry.mcginty]

good video, though if I hand grinded a main journal with wet and dry sand paper to get minor groves out, how would then measure or know what size bearings to buy when finished

[@planesimple8514]

Measure the difference in diameter from the before and after. In theory you should add half of that difference to the bearings' thickness. A better method would be to use "Plastigauge" during assembly to measure the actual gap.

[@Alex-ns8zn]

tremendous.

[@planesimple8514]

Thank you Alex.

[@bobjaeger8425]

Very informative video, thank you for posting. One question, what keeps the crankshaft from moving back and forth while reading the flange run out while rotating the shaft? Thank you.

[@planesimple8514]

Set one of the V blocks up against the thrust face of one of the cranks, that will limit the axial movement

[@bobjaeger8425]

@@planesimple8514 Thank you, I'll try that.

[@Dpfdoctor]

Greatvideos i learned a lot hopefully i can apply it to my engine that i keep trashing and stop trashing it :) thanks!

[@planesimple8514]

Are you modifying the engine? racing it? What engine is it?

[@planesimple8514]

By the way, I'm glad you liked my video and thanks for 5aling the time to leave me a comment.

[@Dpfdoctor]

​@@planesimple8514 ​ It is a VG30DETT, v6 3 Litre twin turbo from a 1990 Nissan 300ZX Z32. highly modified pushing around 500 horsepower. I have been trying to run it in on special joe gibbs BR driven running in oil, had my bottom end built by a marine engineer specialist with 40 years in the industry and ive been through 3 crankshafts. for some reason the bearings keep going over and over. I am fairly competent but im currently acquiring the right set of micronmeters and dial bore gauges so I can measure everything myself and hopefully get an engine that lasts!

[@planesimple8514]

WOW...!!! That's one of my favorite cars from the 90's, of all times really. But they are known for being a pain the asz to work on because there's no space under the hood. Anyway, it's a helluva project. It sounds like you are doing all the right things and a professional is building the engine. Which bearings are spinning, the main bearings or the conn rod bearing? If it's the main bearings, the engine block may not be square. By square I mean all aligned, all main bearing seats and bearing caps perfectly in line. If this is the case, you'd be forcing the crankshaft to flex and wiggle like a worm with every revolution until the weakest link fails, the bearings. Otherwise, bearings being spun is usually the result of lack of lubrication or overheating. Lack of lubrication could be from bearing clearances being too large and the oil can just fling out versus being forced to create a film. Idk, I'm just a keyboard warrior from the internet so don't pay too much attention. I tend to trust the experts that do that for a living, but its weird to have three consecutive crankshafts fail with spun bearings. Like I said earlier, double check the block itself. Good luck.

[@josephsalazar8854]

thank you

[@planesimple8514]

You're welcome. Sorry I took so long to reply to your comment.

[@stealhty1]

Thx for share , I like to ask : where are the thrust bearing located ?

[@planesimple8514]

Hello stealthy1, the thrust bearings are usually all the first and last main bearing supports and the look very similar to the rest of the journal bearings that are plain bearings, except that the thrust bearings have a flange on either end of it to distribute load in the axial direction (thrust). Google pictures of crankshaft thrust bearings and it will make a bit more sense. I hope this answers your question.

[@stealhty1]

@@planesimple8514 Thanks Man, I close exam the Lycoming pics but couldn't see it , I know what you mean with those Flanges ( My subaru engine has"em) att: Nelson

[@manvirs7871]

Why did u have you have to subtract them? Wouldn’t the run out be 0.009

[@maheralazzawi7814]

Excuse me sir what we do if we have failure engine to start

[@planesimple8514]

Hello, sorry it took me so long to see your question. I don't have an answer for that. Or perhaps I should say I have too many answers to be able to help. It could be as simple as a dead battery to something as bad as a catastrophic engine failure, and anything in between. I couldn't possibly guess why an engine won't start without any more information than it just simply won't start. I hope by now you have already solved that problem. Good luck.

[@FlyingFrankie]

Cool. On flange is runout maximum limit 0,0050 in., so this crankshaft is just on it's maximum limit. Am I right? (trying to figure it out if I got it right, because I need to do this to my crankshaft too.

[@planesimple8514]

Hello Flying Frankie and sorry it took me so long to reply. I have no idea what the limits for this crankshaft are. It is only a teaching tool from the school that has seen many generations of students, so I can only imagine the abuse it has seen. Having said that, limits are defined by each manufacturer and you'd have to find what yours are.

[@khizerhusain5237]

Sir i have confusion kindly tell me how many axis in crankshaft

[@planesimple8514]

Hello Husain, I'm not sure what you mean by "how many axis". The crankshaft is really concerned about the longitudinal axis. That's the one that it rotates about. This axis is the imaginary line that runs along the center of all the journals. Please explain your question or expand on your question so that I can better understand it and try to answer it if I can. Thank you.

[@vladimirmacko1481]

What is the crankshaft sitting on?

[@planesimple8514]

Hello Vladimir Mako, the crankshaft is sitting on two "V" blocks and the "V" blocks are sitting on top of a surface plate. The surface plate is a precision ground piece of heavy stone or metal (in this case is steel) that is certified to be flat to a high degree of accuracy. The "V" blocks, are also precision ground for both to be the same dimensions. All this precision is to start your measurements from a stable, known condition and not introduce any external deviations to your measurements. This ensures that any deviation is from the piece you are measuring and not from whatever your piece is sitting on. I hope this helps.

[@vladimirmacko1481]

@@planesimple8514 Thank you very much for explanation. Appreciate that..I'm about to do the same and I was wondering how to perform the measurements in my garage. Those V blocks are crankshaft specific I believe. I'll look around if I can buy them. Or, do you think I can substitute these V blocks with a crank sitting in the block on the main bearings?

[@planesimple8514]

You are welcome. Those V blocks are not crankshaft specific, the V just has to be big enough to support the journals on the crankshaft. Also they need to be high enough to allow the crank pins or throws to rotate clear of the table, without hitting the table. I'm sure there many other setups that would allow the measurements to be made, they just need to be secure, precise, repeatable, solid, etc. again, to guarantee that your measurements are correct. As far as doing the measurements with the crank in the block...yes, you can do that, but you'd have to have the bearings in place. Otherwise the size of the half moon on the block would be bigger than the crank shaft and would allow side to side movement, ruining any hopes for any significant measurement. On top of that, you are assuming that the block itself is straight, which surprisingly enough is not always true. The block may be straight enough for operation, bit it relies on clearance between the crankshaft, bearings, block, etc. This clearance is taken up by the oil during operation. This means that the block may be straight enough and within tolerance to run the engine, but too crooked to serve as a reference surface to measure from. I hope this makes sense. Anyway, if the deviations you are reading are within spec, it should be ok, even if measured on the block. Good luck.

[@vladimirmacko1481]

@@planesimple8514 Thank you again for such detailed information. Means a lot! Thank you a million!

[@planesimple8514]

Glad I could help.

[@johnchibuike3270]

How do I get that gauge to my country

[@planesimple8514]

Hello John Chibuike, I don't know which is your country but I'm assuming you could buy it online and they'll mail it to you.