b7100 engine upgrade, a new project to undertake.

hi guys,
I am about to embarke on another orange project , i may be completely bonkers but here goes.
I have made the mad descision of replacing my old B7100 engine(D750) with something that has a lot less hours and wear, I am not saying my old D750 is worn out , it starts well and doesnt smoke to much and does run pretty well but its done 4900+ hours and is starting to need a bit of attention as its breating quite a bit through breather pipe and sometimes seems to be lacking power at higher rpm's.
Anyway, i have aquired a good low hour D850 lump inc ancillary parts which which is prettywell straight swap over, i need to fit the injectors and swap over the bellhousing plate but cant see much else to deal with.
It will be intersting to see if it all works out, might even gain an extra horse or two.
i'll update in the next few days etc with progress and pics, just in case other like (bonkers) minder user are interested on doing the same.
rgds
rob

Thanks for the replies guys, i certainly hope this thread is of some help to others in the future.
I think by tackling these projects it gives other owners a few more options as regards to overcoming engine issues etc that may otherwise be something they would not normally consider.
Anyway, here we go then.
I have aquired a d850 engine,(awaiting its collection/delivery at this time) its 90% complete and i am led to believe is a good runner( time will tell though) It has all its own ancillary parts etc from its original installation , a welding unit, but the previous owner removed the injectors & pipes to use on another machine otherwise a good engine, so the overall basic engine layout makes for a good donor engine.
There are a few areas that will need to be addressed though and i'll outline them now.
I have attached a few pics which if you look at , the following notes will become clear.

firstly, on the plus side , because its from a welding unit the sump is pretty well normal, unlike the units from regriferation trailers and marine installation that have totally different sump arrangments. That said i still cant use the sump pan fitted because the current oil dipstick is on the opposite side to my D750 and goes diectly into the sump pan from the side.
Solution, the sump pan from my D750 will retro fit without any problem, problem 1 sorted.

next issue, the intake mainfold is has a vertical intake, solution since the both 750 and 850 use the same stud layout and port configuration, retrofit my D750 intake manifold, problem 2 solved.

problem 3, due to the way the D850 was mounted in it last installation, the oil filler point was changed, instead of the oil being added from the top filler cap on the rocker cover, instead there is a filling point on the side of the engine just below the injector pump, basically replacing the cover plate.
Solution will be to remove the filler plate/neck and retro fit my D750 cover, and refit my 750 dipstick to the correct place on the engine block which has a rubber plug in it at present.
that would seem to deal with problem 3.


Problem 4 is a very similar issue to above, there is no factory fuel pump fitted, but the port is their and has a removable cover fitted, so same format as above, remove the cover and retro fit with my D750 pump as they would have both been the same , if the 850 would have been fitted with one, i think that deals with problem 4.

Problem 5, the speed control/govenor linkage etc on the 850 unit is wrong for my use,they are connected to solanoid fittings, but simply a case of swapping over the control arm/linkage etc setup on top of the speed/governor so i can control the speed from the foot and hand throttle.
I think that will deal with issue that but need to check the intrrnal govenor assembly to make sure .

Problem 6, not really a big issue, the bell housing is wrong , so another swap over of parts here, i think the starter motor by not fit correctly with my bellhousing backplate so i may be swappping starters also, i may be wrong but i'll update you accordingly on this issue.

Another issue , is this, the alternator is mounted on the top left on the 850, whereas it is on the top right on my 750, the only way this can be overcome is by using the top mounting fittings bolted to the top of the cyl head at the front right hand side, which are currently on my 750 unit, so to ensure everything fit corectly, i will just transfer across all the required parts from my 750 and this should allow for a problem free refit of the engine into the B7100 engine bay, that should be that sorted.

Everything else is pretty well sorted and doesnt require any mods or retrofitting, but you never know, if i fine something out , i post it up here also.

the oil filter is in the correct place and the cranckshaft pulley wheel/shaft is correct also

One thing i must say is this, it appears from my goundwork so far that because the basic engine format of the D650-750-850-950 are all 70mm series engines, and as such share a common set of features, but, due to the the very large range of machinery etc that they are fitted in, the final build configurations of them can vary wildy.

they are used in so many applications etc that the amount of work required and changes required to make a given model retrofit into a B7100 for example can vary for a few mods or swap over of parts, to much more major changes that may not even work out in the end.

The unit i have chosen is a happy compramise, the changes are relativley straight forward on the scale of things as the basic lump is standard and the offending parts can be interchanged etc, other units may be easier with less to change if any, but refrig and marine units may be more work than is really viable.

Just a note to anyone who has any of the " for example D750-A" series engines , these "A "(agriculture) series engines do not have the waterpump setup as found on the "B" versions which is what is fitted to my B7100 and also on the 850 engine i have aquired.

Allthough the same method of swapping engines and retro fitting could be used for owners with D650-750-A etc, there will be an issue with the radiator, this is due to the "A" series using a larger diameter size radiator hoses, and what compounds the problem is that the radiator inlet/outlets will be a larger diameter also becuase of the thermo method of circulation , whereas, on the "B" series engines with the pressured/ pumped setup the hoses are a smaller diameter along with similar size radiator fittings.



So then, I hope by now after this long reply you are not all bored to tears and i certainly hope that i have not put anyone off doing the same.
I think it will be well worth the time , work and effot put in.
I'll update you all as i progress on with it.
pics attached

hi guys
1st update for you now, well the D850 lump arrived today and i must say, i am very happy with its overall condition so far, it certainly does not look to have been used & abused, but time will tell after a better exanination of the key parts.
Anyway, 1st posssible issue has appeared, i noticed this morning that the rocker cover does not have any decompression mechanism externally, but the cover may well have the fittings inside, its not really a problem as i can swap over the parts from the D750 unit inc the rocker cover if needbe, but i was hoping to have kept the old 750 lump as complete as possible, but i'' see how things work out.
i'll put up some pics shortly as i start to get the lump ready.
rob

Hi steve, i think it may well be case of a " no longer required" fitment, having just looked again ,all the harware is missing for decompression , as you say, its not really an issue , i never had any cause to use it on the 750 anyway ,so same would be safe to asume for the 850.

have found a few other very small differences, but i suspect they may be more of an improvement in the 70mm series engines, they wont effect my plans, may acctually enhance the overall installation and running of the 7100.

thanks
rob

As much as i would love to get the 850 fitted in and running, i think the best plan would be to give the 850 some intial checks, compression etc, get the roker cover off and see the state of the rockers etc before going too far into the fitting etc.
I've checked the internal condition of the water pump and thermostat housing and other water cooling areas, all appear to be excellent with no signs of calcium buildup or corrision, hoses are are the same, nice and flexy with no nasty stuff inside, all seems to tally up with the guys description so far of a lightly used engine.

If after the above is good, i'll give the engine a good flush through to clear away any old oil etc, fit a new filter , check and adjust the valve clearances, and progress onwards from there.

Hopefully that should be all that is required before i start the final retro fittment of items and final fitting to the 7100.

cheers
rob

Hi guys, a bit further into the project and i have encountered a few small probs.

First off, on tuesday i decided to make a start on the 850 lump just to see what the running state might be.

Rocker cover off completely, all looked good, then i noticed one of the pushrods was not fitted properly, no prob just slide it back into place carefully, errrrrrrrrrrrr no , things went a bit down hill from that point.
I noticed the rocker shaft mounting posts nuts were loose, then one of the cylinder heads bolts was loose also, then checked all the bolts only to find they were all loose, safe to say the head been removed allready at some point.

This wasnt looking good as the guy said it was running fine but they had just removed the injectors and pipes for use on another lump, and you wouldnt really need to remove the head etc to take out the injectors.
Amyway off came the head , no obvious signs of water damage etc or leaks but the piston head on No1 cylinder was very gunged up with thick crud, cleaned up ok and with no visible sign of damage to the cylinder bores on all 3.

Anyway , the head had a problem also, no's 2 & 3 had been running fine with very little deposits in the exhaust ports, but no:1 was really choked up with carbon and crud, inlet port was fine.

I couldnt see any obvious reason until i gave the cyl head surface a darn good clean, there must have been an issue with the injector on No1 as the round plug that sits beneath the injector with its small appperture, now had a very large hole burn through the plug.
I can only assume that this is the cause of the exhaust port fouling etc, all the valves are good albeit the exhaust valve on No1 needing a good clean.

The engine oil was really clean for a deisel engine, and all other parts do seem to be ok at this stage of the job, no oily sludge etc in the sump either.

All i can think is that the guy saw the problem and decided not to fix it, instead just to take some parts from it.

I managed to get some new plugs for a few pounds so that should be sorted now.

I have stripped away all of the parts that do not apply to my installation and getting ready to degrease all parts etc prior to next stage.

I was a bit concerned that the injectors and pipes from my 750 would not swap onto the 850, no probs they are the same part on the 750/850/950 lumps.

One area that may be of concern now is the flywheel, and as i dont have access to a spare loose 750 item i can't compare things.
I have been led to believe that the 750 flywheel will not fit the 850, but the crankshafts are the same item, so not sure what goes on there, maybe its the hole centreing on the flywheel, i expect it will become clearer shortly.

I do now think, that, because i have a basic 850 lump with the normal flywheel there shouldnt be any issues as the cluch mounting holes etc look to be right, but as before until i get to a fitting point i cant be sure.

thats about it as far, i'm going to reseat the valves as fit new valve guide seals this evening while i wait for the round injector port plugs to arrive.

taking some pics this eve also.

thanks rob

hi guys, just a short update on this project.
It is still a work in proggress situation with regards to the d850 engine, having stripped it down and ordered a few parts the rebuild is coming along nicely, which is more than can be said for the flywheel/clutch and drive shaft situation.
The problem i have is this, i am still using the B7100 daily , but, i dont have any spare items to use with assisting compatability issues between the two engines, and i cant rip the 7100 down yet as i am using it.

there does appear to be a good chance that the two engines do in fact use the same parts, but also that they are slightly different , in which i am stuck.

From my investigation this week it seems that the early D750 flywheels and clutch ass will fit the earlier D850 units, but , its all down to manfacture date.

The 850 flywheel wheel i have can be used but the clutch ass may not fit it, and also the drive shaft and spigot bearings are different, so, another issue has appeared.
I think the best option now (not ideal) would be to get the 750 lump out and see what from it fitsd the 850 and hope there is nothing to major adrift between the parts.
As the D850 is fitted in the B6200 you could asume parts would be similar , but it seems not that way.

If anyone has any thoughts on the issue i be greatfull for the input prior to me stripping out my 750 engine shortly.

thanks
rob

Update :
A day later and i have decided to bite the bullet and strip out the 750 lump and see what the format is.
Well, some good news and some less than good news, bad news first.
It would appear that i was just in time with this project as several issues have come to light which would hav eneeded attention asap anyway.
First off, the water pump bearing/seal had gone, leaving a large water leak down the front of the engine cover, there is a leak around the head somewhere with oil welling up from somewhereand then running all over the top of the head (not the rocker gasket leaking).
Seems to be an oil leak out the rear crankshaft seal also.
See Pics for above problems.

Now, on the plus side, after removing all the ancillary parts from the 750 that i need for refitting to the 850 evrything seems in order, no nasty surprises.
Now then, onto the flywheel issue, i was having concerns in this dept, after removing the 750 flywheel/clutch ass and comparing it with the 850 flywheel a few things become noticible.
1, they are both the same weight and diameter and thickness.
2, the clutch ass fits both units, but, there are some differences that may effect the clutch ass and its fitting /operartion, have a look at the pics and see what you think.
3, best news yet, becuase i have an midway manafactured 750 lump and a simlar 850 lump, the flywheel does fit perfectly, so i can that solves the possible major issue with that part.
It does appear to be an issue with the flywheel mounting bolts, both on mine use the older bolt/bend over tab fixing whearas they were changed to a newer bolt fixing without the bend over tab.
Anway, this is probably an area that is best looked into before anyone decides to do a similar retro fit to ensure you can get it all to fit on properly.

Off down to my local kubota parts guy tommorow to get a few parts, i have found that getting my parts from a kubota engine repair specialist is far cheaper than going to the groundcare kubota store, same parts, same part numbers except a lower price.
my groundcare dealer wanted £37.00 for a d850 head gasket, the engine dealer had the same item excatly for £21.00, same with all other parts also.

pics attached as promised.

few more pics of the 750 probs, i think there is an oil leak here.

pics of the 750 parts for refitting to 850 and the 850 lump itself waiting for parts.

pics of the 750 and 850 flywheels, can you see the differences, they do make a differnce.
also the fixing method.

When doing these sort of projects , or any other kubota etc work i like to have all the relavant info and data ready to hand.
solution, i put my old pc from indoors in the workshop, its loaded with enough kubota service and parts data etc to sink a battle ship, anyway, it saves having lots of paper material and quicker also to find specs and info.

rob.

Yep, a few more little mods that have appeared.
Due to my 850's sump pan being unsuitable for the retro fit because of the position of the dipstick on the side of the pan , i will have to use my 750 pan, no big deal you might think, just swap over, nope no quite that straight forward.
the 850 pan is deeper also, so when i tried fitting the 750 on it , the oil suction pipe assembly stopped the pan short of the mating surface, so i needed to swap over that part also, another porblem sorted.

a few other small things like bolts being shorter on the 850 due to the use of blanking plates, same thing though, making sure i swap over the bolts also on those items.

To anyone else thinking about doing this mod or maybe the d950, make sure you get as closest possible spec unit as possible to you exsisiting engine, it saves so much time and messing around swapping parts, i was ok as i can take the parts of my 750 and they do retro fit onto the 850, but the 950 is a bit harder and if you dont have any engine to start with, you may struggle trying to get the bigger lump to fit.

just my observations so far guys from my own hands on experence so far.

rob