Good Sam Club Open Roads Forum: 1992 HMC with 12V Cummins
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 > 1992 HMC with 12V Cummins

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waynehuff64

Ogden, UT

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Posted: 06/22/21 05:07pm Link  |  Quote  |  Print  |  Notify Moderator

My Cummins 5.9 12v is missing the data plate and a prior owner replaced the injectors with 300 hp. I have excessive smoke and high exhaust temps. The engine data plate is missing. Does anyone know the stock hp of this engine or even have a photo of the data plate. I need to replace the injectors with original type and retime the fuel pump. Engine is in Hawkins Motor Coach Aerosport II 1992 year model 30 foot.

MountainAir05

New Mexico

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Posted: 06/22/21 05:47pm Link  |  Quote  |  Print  |  Notify Moderator

google is your friend. Maybe Wolfe will stop by later to add or modify this.

https://www.engine-specs.net/cummins/6bt.html

grldst

Dallas, GA

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Posted: 06/22/21 07:23pm Link  |  Quote  |  Print  |  Notify Moderator

I had a 1995 Safari with the 12 valve 5.9 rated at 230hp. Some of the earlier ones were rated at 210hp. Good engines, pulled very well for their rating.

Sorry, can't help with more info.

ScottG

Bothell Wa.

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Posted: 06/22/21 08:55pm Link  |  Quote  |  Print  |  Notify Moderator

The 92 would have been 160 HP and it's a wonderful eng.
300 HP sticks are going to have lots of smoke and heat. A turbo upgrade would help but those injectors are problematic in a heavy vehicle.

If it were mine, I would replace them again with 40~50 HP sticks. They aren't all that expensive and the job is easy. I have replaced a set in that eng in about 45 minutes.
Then if you want to upgrade further, replace the turbo's housing with a waste gated 16 CM unit and it will act like a totally different animal (quicker spool) and have less smoke.

* This post was edited 06/22/21 09:05pm by ScottG *

1320Fastback

Vista, Ca

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Posted: 06/22/21 10:07pm Link  |  Quote  |  Print  |  Notify Moderator

I daily drive a '92 Dodge 12 Valve. Don't get greedy with the sticks or you'll start breaking other things. Sound like the PO went beyond reasonable with 300s. I have some DAP 40 Horse in mine and with a HE351CW off a new Cummins it is fun to drive. Pulling our 8k loaded Toy Hauler up most hills in direct drive see around 1,100F on the pyro and 55-60 on the spedo.

Try calling The Hungry Diesel and talk to Eric. He lives and breaths 12 Valves.


1992 D250 Cummins 5psd
2005 Forest River T26 Toy Hauler


waynehuff64

Ogden, UT

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Posted: 06/24/21 08:18am Link  |  Quote  |  Print  |  Notify Moderator

Thank you all for the information and advice. If there is anyone with a Hawkins Motor Coach similar to mine I would like to know what the factory settings are for injectors and fuel pump settings. As of now I'm leaning toward replacing the turbo since I have low boost and run an oil analysis to check for fuel dilution which should tell me whether or not to change injectors. If I replace the injectors the injector pump will need to be retimed thus the reason for looking for factory specs.

ScottG

Bothell Wa.

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Posted: 06/24/21 09:47am Link  |  Quote  |  Print  |  Notify Moderator

Changing injectors does not disturb the injector pump but it's probably a good idea to check the timing since we don't know what a previous owner may have done. Wish I could help you with the data plate but any highly experienced shop should be able to do it. There is no adjustment for the injectors themselves.

OTOH, low boost doesn't mean bad turbo (it's easy to inspect a turbo BTW). There are a dozen places where you can have a boost leak (hoses, clamps, intake, intercooler, etc.) I just replaced a boost hose on my own rig that leaked like a piece of Swiss cheese. It looked fine outwardly.
You will not get enough healthy boost out of your stock turbo to support those injectors. The air would be too hot and you'd have to over drive that turbo real bad.
If you do get a new turbo, get one with a wastegate (See Fastbacks post) but with those sticks, it will only help slightly. It would be a big improvement with 40 HP sticks.

Your worst enemy is those injectors!

With the right combination of parts, that eng is an amazing performer!

waynehuff64

Ogden, UT

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Posted: 06/25/21 01:53pm Link  |  Quote  |  Print  |  Notify Moderator

Thanks again, Scott, you've given me a wealth of information.

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