View Full Version : D4 Precombustion Chambers
03-27-2012, 04:14 PM
My dad is working on his D4 and noticed that the precombustion chamber retainers look pretty tough. He was able to find new chambers from Regal but not the retains. I did not reading and found several posts discussing a new 1 piece chamber that replaces the 2 piece does this conversion apply to his unit. The retainer he is looking for is 4f-5678 By the way Cat wants a fortune for the retainers and he is having a hard time locating an aftermarket source.
serial number 7u11988
03-27-2012, 04:46 PM
The 4F5678 retainer is replaced by 7M7842
I show the one piece chamber for this application as a 2S1273 but check it out. I have never bought any of these and there seems to be lots of confusion over numbers and applications. The one piece also uses a different injection valve retainer nut #5H7225
03-27-2012, 07:09 PM
Thanks for the information. I just talked to my dad and the machine shop called and said they found box of old cat parts. Their are 6 precombustion chambers and retainers that look good.
03-27-2012, 07:13 PM
Attached is a link to my picture trail. The precoms I purchased from Dana at Florin. I cannot recall the part number. They were a one piece part. It has been a while, if I find the part number I will post. I posted more data after I did the work, I'll look for the post.
My tractor is a D42T series, fyi. Also, don't forget to drain the coolant from the block....
03-27-2012, 09:08 PM
Draining the coolant will not be a problem. I think the only thing left assembled right now are the tracks, roller frames, and the final drives. The transmission and everything in front of it is scattered across the shop floor.
Thanks for the information though.
The shop said they had a 3000 ft*lb impact wrench on the precomp chambers to get them out. They fought all the way.
03-28-2012, 08:16 AM
Good find.....but with my luck they would be for the later head.
03-28-2012, 11:42 AM
He was a little nervous about compatibility but he said they look exactly the same just in much better condition. Any differences to look for?
03-28-2012, 01:29 PM
They'll look the same but part numbers will be different and diameter will be larger.
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