Komatsu D21P-5 serial 45515 Engine 4D94-2 casting or serial on block 15352 No problem right? Block tunnel bore is 75.75mm - I believe this is .75 mm beyond spec. It is round and had a non Komatsu PN# bearing installed which would work great if the crankshaft had not been turned down to 69.5mm I belive it's been line bored oversize for whatever reason. Not the standard way of doing things but this is what i have. I desperately need a set of main bearings . Komatsu .5mm bearings are 2mm+- too small due to the increased O.D. I can't find any supporting information on a standard block bore size of 75.75mm maybe someone can help me there. I really need bearings and i find nothing in the catalogs available to me. Any help is beyond appreciated as i have called, surfed, until I'm out of ideas . As a lurker around the site I thought if someone can find them or point me to them it will be here. Thanks for your help and good day! Thank You Broke! :Banghead
isn't it possible to get them through a engine rebuilder? maybe they can order them according to the dimensions and not by enginenr. etc. cheers Meindert
Do not know about Komatsu but some Cat engines at least used to have bearings available that were oversize on the O.D. to allow you to salvage a block where the bearings had spun. Some even had oversized O.D. and undersized I.D. bearings available.
CAT used to sell over/under bearings, don't know if Komatsu has a super secret parts book that shows those as an option or not. Was there a part number and/or manufacturers mark on the odd bearing you took out?
Apparently an engine they don't support anymore. It seems to be happening more all the time. I second the idea of working with an engine rebuilder. We have B&G Machine in the Seattle area who have been the gold standard for me for years. Good Luck!
I've got three komatsu wa270-2 in my clientel and even on those its already getting harder to get parts. And those are from 1999-2000..
Thanks to all, I will try to cover everything in my response. Komatsu does have different variations available for main and rod bearings our issue being they don't have the .75mm over on the O.D. I have searched everywhere i know of and there seems to be a pattern on all the bearings in the 75mm range. They are from 75-75.3mm before jumping to 76-76.3 and so on, there are exceptions to that just not in my favor. The machine shop says they had trouble finding bearings and are not any help beyond that. They also say i gave them the wrong specs because it says the 4d94-2 has a main bore of 75mm (can anyone verify) and they measure the block at 75.75mm. Part numbers to the bearings that were in it before the crank was turned .5mm 79,00 7405 1004058 p2 seems like one bearing was 7400 1004058 p2 The (7) in 7400 is not visible on all the bearings and only partially on the rest making for only a guess as to it's role in the number. The 79,00 above the main number is peculiar . I would think that would be a nominal size, if so was it machined. Also, the uppers and lowers are different and I find no part number for or on the smooth shell side. Part numbers given are for the oil grooved/drilled side or half shell. I have tried calling some manufacturers and major distributors but as soon as the pleasantries are over I'm dismissed for lack of an account. I've seen some discussion as to this engine being a Yanmar which I see no evidence of but maybe there is a similar engine or engine number . The 4d95 seems to be the earliest engine with information and parts somewhat available, why is the 4d94-2 considered grey market ? Was this the early years of importing or grey due to lack of parts etc? Thank You and Good Day! Broke
Thanks to all, I will try to cover everything in my response. Komatsu does have different variations available for main and rod bearings our issue being they don't have the .75mm over on the O.D. I have searched everywhere i know of and there seems to be a pattern on all the bearings in the 75mm range. They are from 75-75.3mm before jumping to 76-76.3 and so on, there are exceptions to that just not in my favor. The machine shop says they had trouble finding bearings and are not any help beyond that. They also say i gave them the wrong specs because it says the 4d94-2 has a main bore of 75mm (can anyone verify) and they measure the block at 75.75mm. Part numbers to the bearings that were in it before the crank was turned .5mm 79,00 7405 1004058 p2 seems like one bearing was 7400 1004058 p2 The (7) in 7400 is not visible on all the bearings and only partially on the rest making for only a guess as to it's role in the number. The 79,00 above the main number is peculiar . I would think that would be a nominal size, if so was it machined. Also, the uppers and lowers are different and I find no part number for or on the smooth shell side. Part numbers given are for the oil grooved/drilled side or half shell. I have tried calling some manufacturers and major distributors but as soon as the pleasantries are over I'm dismissed for lack of an account. I've seen some discussion as to this engine being a Yanmar which I see no evidence of but maybe there is a similar engine or engine number . The 4d95 seems to be the earliest engine with information and parts somewhat available, why is the 4d94-2 considered grey market ? Was this the early years of importing or grey due to lack of parts etc? Thank You and Good Day! Broke
Best guess: Russian. KAMAZ 7405 engine rod bearing. Yeah, we got those laying around on the shelf. Geeze. KAMAZ 5320 model truck. Guessing the P2 is an under/over thing. Seems to run from P0 to P13, also shown as -1, etc. The P2 is for an undersize crank pin of 79mm diameter as your marking suggests. How did they make a 79mm ID bearing work in a 75mm main bore?
The P2 is for an undersize crank pin of 79mm diameter as your marking suggests. How did they make a 79mm ID bearing work in a 75mm main bore?......... good question. My best guess is they machined them to size as the tang appears to be a bit small as if it has been ground on. However they did quite a good job and I could argue either way the marks or slightly rolled edge on the back side of the bearing are from being reworked or rough handling after disassembly. Mating faces look good , I think I will have a closer look. I just used a stronger magnifying glass and I believe the microscope may be in order for a sure enough closeup . I am now convinced they reworked these bearings to fit their need. As far as i know this machine has been running for years like this, not daily but regularly from what I'm told. So it looks like just find the bearing with the correct wall and make it fit! it all started like this.......... " hey I'm SWAMPED! do you have time to put this engine together? all the parts are finally in after sending us the wrong ones the first time." SURE ! I said , Heck , no problem when do you need it? couple days , Ha, no problem .............meanwhile.... Tick Tock they don't count weeks on clocks! They might be in the market for a block . I think if I was smart this is where I , WASH MY HANDS! Am I the only one who has a problem saying N n NN nnno NO! Thanks and Good Day! Broke! I may post a pic or two if anyone is interested, better yet who has done this sort of thing ? Any answers on that one may lead me to the last re builder who is welcome to it again. Have a good evening! and, As always any and all help is greatly appreciated.
Yeah, frankenmotor... fun. Some of us have a masochistic streak, we HATE to let something go unfixed, rubs us wrong.
Exactly! it's not like the thing is actually broke, destroyed or impossible to repair. How can 0.75mm become an impossible hill to climb or one that wears you out before you reach the top. I'ts not as if a bearing of that size would be considered bad work ethic if installed. Without going in to all the engineering data I believe it to be within normal specs if i could locate a set. Not engine spec but engineering specs. I think i would rather not rework larger bearings due to a number of reasons but, it was working in this engine . Working does not indicate correct in my opinion . Would it be considered acceptable? Thanks again! Broke!
I see no reason whatsoever it wouldn't be just fine, as long as the reworking was done with care and it didn't cause any issues with the bearing material. Bearing shells are always made to a larger radius than the bore they live in anyway to a degree, you always have to apply force to get them inserted. In this case just a bit more force and a trim at the plain end leaving a couple thou for crush? Hell they used to shim mains and those old engines lived a long time.
Thanks to all and the only thing i could find the correct length and width was a bearing in the 100mm range and I believe that would be a little much bending . Probably work just fine but they found a different block and i get it tomorrow. If it has the same bore ......... gone fishin! GOOD DAY, Broke
Heres the specs I have for this blocks main bore, which are close to what you are saying. Komatsu 4D94 2.9525-2.9535" (74.994-75.019mm) I have no experience with this engine but am curious if you have made progress with the bearings...?