Latest sounds like metallurgy/heat treatment and they are really made by DooWan, not Bosch.
Guess I owe Bosch an apology. An earlier report said an original (bad) IP was labeled Bosch and the replacement said Bosch on the box. However, the latest victim reports her IP had a tag that said it was made by Doowon (Korea) and another guy (who is a dealer) reports he gets these IPs repaired and Bosch parts fit. He also claims that some of the gears were over-hardened, making them brittle so they fail. So these IPs are copies of a Bosch design (called mini K, I think) probably made under license. In these small (20-50 hp) tractor engines, the IP cam shaft is insude the block, like a short valve camshaft. The IP flange bolts to the block and the IP's tappets ride on the camshaft in the block (kinda like just the top half of our Mercedes IPs). IP timing is adjusted by shims between the IP flange and the block. -----Original Message----- From: mercedes-boun...@okiebenz.com [mailto:mercedes-boun...@okiebenz.com] On Behalf Of Dieselhead Sent: Wednesday, July 18, 2012 10:57 PM To: Mercedes Discussion List Subject: Re: [MBZ] Bosch IP Durability Wrong metal? Poor metalurgy? >I wondered about that too, but you'd think that ULSD-caused wear would be on >the plungers and the cylinders, which are fit to precise tolerances and >lubricated solely by fuel. On these tractors IPs, the gear teeth and rack >teeth are actually breaking off (the plungers and cylinders are fine). Take >a look at these post-mortem teardown pictures: >http://tinyurl.com/c8llr53 > >The IP cam and tappets are lubricated with engine oil and I assume the gears >and rack are too. On the later models, the oil fill hole is on the access >cover to the rack pin; so there's got to be plenty of oil in there. Also, >forces on the rack and gears are normally pretty small, you can move easily >it with your finger. The only abrupt load I can imagine is the action of >the shutoff solenoid. > >My guess is that this is a bad batch of parts, probably from a supplier. As >I mentioned, the cylinder and plunger are critical, precision parts but the >rack and gears aren't. So maybe a vendor made them from sintered metal >instead of a casting or forging. Possibly these were spec'ed wrong by not >accounting for the jerk loading on shutoff. If you are still awake, there >were two shutoff solenoid designs: the original design used an electrical >solenoid to push the rack to the off position, and that could be abrupt; the >second design used a spring to push the rack to the off position and an >electrical solenoid to override the spring when the key was on. > >-----Original Message----- >From: mercedes-boun...@okiebenz.com [mailto:mercedes-boun...@okiebenz.com] >On Behalf Of Allan Streib >Sent: Tuesday, July 17, 2012 12:42 AM >To: Mercedes Discussion List >Subject: Re: [MBZ] Bosch IP Durability > >Designed for high-sulfur off-road diesel, and not liking ULSD? > >Just a guess. > >Allan > >"Scott Ritchey" <ritche...@nc.rr.com> writes: > >> Ladies and Gents: >> >> >> >> I'm looking for your experiences and opinions WRT Bosch Diesel injection >> pumps. My recollection is that they were near bullet-proof but maybe my >> memory deceives me. >> >> >> >> Among other things, I own a Kioti (Daedong of Korea) tractor and subscribe >> to tractor list (tractorbynet.com) with a Kioti section. The Kioti IP is >> made by Bosch and it is similar to our Mercedes Diesel pumps except the IP >> camshaft is inside the engine block and gear driven, like a mini valve >> camshaft. The Kioti IP bolts in place over this camshaft so it is much >like >> the top half of our pumps. Another difference is the Kioti fuel shutoff, >> which uses an electrical solenoid vs vacuum like MBZ. >> >> >> >> Now, lately, several Kioti owners have reported IP failures. Here's a >post >> showing damage to the gear and rack teeth after one of these failures: >> >> >http://www.tractorbynet.com/forums/kioti-owning-operating/225273-injector-p u >mp-failure.html. >> >> A new IP costs over $1K and rebuilds aren't available to this is a high >> interest item for many Kioti owners. >> >> >> >> These failures seem to occur with pretty low hours on the motor, like less >> than 1000 hours on tractors ma. >> >> >> >> So here's what I'd like to know: >> >> 1. Were our old Bosch IPs really as robust as I recall (I can't recall >any >> reports of similar failures). >> >> 2. What's going on here? Has the quality of Bosch products really gone >> south? Is this just a bad batch of parts? >> >> >> >> Thanks >> >> Scott >> >> _______________________________________ >> http://www.okiebenz.comFor new and used parts go to www.okiebenz.com >> To search list archives http://www.okiebenz.com/archive/ >> >> To Unsubscribe or change delivery options go to: >> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com >> > >-- >1983 300D >1979 300SD > >_______________________________________ >http://www.okiebenz.com >For new and used parts go to www.okiebenz.com >To search list archives http://www.okiebenz.com/archive/ > >To Unsubscribe or change delivery options go to: >http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > >_______________________________________ >http://www.okiebenz.com >For new and used parts go to www.okiebenz.com >To search list archives http://www.okiebenz.com/archive/ > >To Unsubscribe or change delivery options go to: >http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
