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Sbjd cams, pumps, ECT.
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WItitan2
Posted 1/16/2018 19:20 (#6510377)
Subject: Sbjd cams, pumps, ECT.


Pierce county WI
So coastal bends engine destruction earlier this morning got lots of people with theories, and saying Deere had a poor design. Here's what I found with putting this engine under serious strain. The cam itself changed a lot from a 4010 to an 8000 series. Obviously, the oil pump going from cam driven to crank driven was a big improvement! Next, the cam itself got strengthened a lot. The nose on the earlier 404s, 466s, early 7.6s were small, with a hub holding the cam gear and injection pump drive gear. I believe the cam gear itself isn't press fit, but it is held with one key. When we degreed a cam, we actually had an offset key machined for it. Then we would weld the pump drive gear to the hub. I think part of the reason it slipped on coastal bends was the fact it was a 4955 engine. The 4840/50/4955/60 ran a p series Bosch injection pump, the smaller turbocharged tractors ran an a series, or nippondenso pump equivalent. The p pump is way bigger, and takes way more power to run. Thats putting more strain on the cam. The 49s were kinda the end of that design. When the late 7.6 came out, like in the 8000 series, they changed all that. The pump drive gear is keyed along with the cam gear, all on 2 keys. The nose of the cam is twice as big 2. They didn't stop there, the gears went to a straight cut as opposed to the helical cut on the early 7.6 down. With wear, at high rpms, especially in tractor pulling applications can jump out of time. In pulling you are pushing way more fuel through a pump than a stock pump will deliver. So it would be great to put the late cam and gear set in the earlier engines. It can be done, but not the easiest project. I put a set of gears on the engine, but you have to switch the front cover. The cam on the early engines is held in with a retainer ring with screws. The late one has a thrust washer in the front cover. The problem you have is the crank on early engine won't let the cover go over the gear on the crank. So I cut out the front cover where the seal is with a hole saw and had a friend Tig weld it out further so it had a seal that would work and covered the crank gear. This worked awesome for a pulling application, I don't think it would be practical for an AG application. The late 7.6 and 8.1 are a really well designed engine. The 4955/60 are a really unique engine, cause it's a 7.6, and a p series pump. They also have a specific piston for those 2 tractors only. So hopefully you get it going coastal bend. Oh, and as far as welding the pump gear to the hub, I just grabbed the stick welder, and layed a couple beads. If the press fit worked, any weld should work.
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