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Cummins 8.3 Mechanical engine holset air compressor replacement

October 11, 2016, 09:44:09 am

Has anyone replaced their air compressor? I'm looking to tackle this job myself if I can get enough info about how hard it is.

1st question:
I am wondering after reading online that the compressor has to be inserted with the compressor gear mark at 12 o'clock and the engine set at "TDC". If this is true, will some one please confirm this.

2nd question is: what's the easiest way to find "TDC". I cannot find any mark on the balancer or on the timing cover, I really do not want to pull the valve cover. Any help appreciated, and if I am missing some other important information regarding this removal and installation please let me know.

Thanks

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Re: Cummins 8.3 Mechanical engine holset air compressor replacement

Reply #1 – October 11, 2016, 09:50:59 am

There is a timing pin that sits next to the injection pump.  You slowly bar the engine over while pushing the pin. When it engages you are at TDC.


http://www.youtube.com/watch?v=gwepAWiP_m0

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Re: Cummins 8.3 Mechanical engine holset air compressor replacement

Reply #2 – October 11, 2016, 10:05:29 am

Do you mean the air compressor or the injection pump,the air comp probably just bolts on,do you have a new one yet?I would
buy that manual on Ebay.

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Re: Cummins 8.3 Mechanical engine holset air compressor replacement

Reply #3 – October 11, 2016, 10:35:29 am

Yes I 'm talking about the air compressor which is mounted below the injector pump. I like that idea to purchase a manual, I will look into that. I also appreciate the you tube link I will have to study further, I tried to look for that plastic plunger but it was hard to see. I will look again. Thanks

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Re: Cummins 8.3 Mechanical engine holset air compressor replacement

Reply #4 – October 11, 2016, 11:38:33 am

Get yourself a free login on cummins quick serve. It has service and parts information you can load in more than one engine of you happen to have a couple. I think you pay after you register a fourth engine.

I am not sure why it wound matter on your compressor if you installed it on top dead center as it runs completely independent of engine timing it just happens to run off a gear in the timing cover.

I didn't remove my compressor on my 8.3 but I did slide it back to replace the mounting gasket between it and the timing cover. No real hidden issues but with the hyd pump still bolted on it was heavy. You might have enough hose going to the hyd pump that you will be able to swing it out the way if not you will have to drain that system. Disconnect your air hoses and drain your coolant and remove the two hard pipes that feed coolant to the compressor. (Mine were actually rotted and I replaced with hose). Two bolts hold the compressor on and lookout below it does have some weight to it. When you reinstall it having some one around to bar the engine over as you feed the compressor in would be a life saver to get the gear to line up and mesh with the gears. 

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Re: Cummins 8.3 Mechanical engine holset air compressor replacement

Reply #5 – October 12, 2016, 07:32:21 am

Thanks Toby,
I found my answer on Cummins quick serve, there they show the compressor being timed upon installation. Thanks to all for their input.

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Re: Cummins 8.3 Mechanical engine holset air compressor replacement

Reply #6 – October 12, 2016, 10:56:34 am

John,let us know the end of the story when it happens,if you buy a new one let us know how much and where,if there is no
core charge I would be interested in having a core to rebuild,thanks.

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Re: Cummins 8.3 Mechanical engine holset air compressor replacement

Reply #7 – October 17, 2016, 12:27:19 pm

Update:
I bought my remanufactured air compressor from NAPA at a cost of $288, core deposit is $410. Cummins dealer wanted $1200 for a remanufactured Holset compressor.

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