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Discussion in 'Diesel Engines/Drives/Transmissions/Props' started by Hampton, Nov 16, 2011.
Thanks will be doing all above recommendations.
In my pre-purchase of my boat the Cummins tech left this note/comment. Can someone interpret for me the parts and P/N's that are being referred to?
Air Lines: Air sep hoses are badly cracked. Boost hoses are original.
Here is a picture of the air sep, the straight hose is Cummins pn#3971170 and the "s" shaped molded hose is #3971065. I'm not sure about the boost hose, check out Cummins Quick Serve online. Go to: parts- -air handling- -turbocharger plumbing for pics with part #'s
I own CAT's, but similar parts on both.
AirSep recaptures oily blow by air off the crankcase, and recycles the air/oil back into the air intake and oil sump. On my CAT's the hoses are about 2' long and I just replaced them at about $16/foot. Easy DIY job. They dont wear out very often, but can crack due to age, or in my case, become oil logged.
The boost hose is likely a piece of hose that carries the heated and pressurized air from your turbo outlet to the after cooler. If they rupture, you don't get your turbo boost and lose power. Those also can and should be replaced. I'd have to defer to a Cummins owner to see if thats a DIY job or not.
Here's the Walker Air Sep Page https://www.walkerairsep.com/product_detail.asp?id=613
Have any of you 44DB owners created a fuel consumption chart? I have QSC 500's and I'm in the process, logging RPM at 100 RPM intervals, with knots and GPH at each interval. Trying to get multiple readings at each RPM level and then take an average. Slow going, and just wondered if anyone else had similar info you could share.
I have not, I just know the couple of standard cruise RPM's we usually run based on conditions.
Before you go too crazy have you verified you are propped correctly, so all you fuel burns are at or under the Cummins specifications? If not do that first, speeds may come down based on that.
Here are some numbers I collected last spring:
I plan to redo this when I am back on the water this spring, and add more RPM points. I did some maintenance to the fuel system mid-last summer and I believe the performance improved....
I have some numbers I did when I was wondering how I was propped a couple of years ago. They are hand written at the moment and begin at 1500 rpm to WOT 2680. Might help?
Does anyone have a good source for o-rings? I'd like to change the o-rings when I do my impellers, and looked at pumpvendor.com and they're charging $16 for the big o-ring where the pump mates with the engine. That seems high. I'd like to stock up on all the common o-rings.
Are they not just standard O-rings?
Why can't you measure them and pick them up at NAPA or order them from Grainger?
There is viton, buna-n, silicone, natural rubber, PTFE, EPDM, neoprene, and about ten other materials and differing hardness'. Each has a specific service so unless the exact material is known it would be a crap shoot on a failure. With that said viton and silicone are the most common. O-rings from the typical big box auto parts store are minimal grade neoprene.
The Sherwood Impellers come with O rings in the package. What impellers are you using?
Yes indeed they do come in the package. Shouldn't need to buy them if you bought a Sherwood impeller new and in the box.
I’m using Sherwood impellers. I am looking for the o-ring between pump body and motor and to the seawater pipes.
Have you tried Seaboard Marine? They have o ring kits available.
Thank you. Yes, I've looked at their kits. They have a kit (#1730) with a football gasket, which is not what is originally used on my QSC-500, so I'm not sure it is correct for the pump I have, maybe someone can confirm if it will work as a replacement. I have the original pump which has an o-ring where the pump meets the engine and not a football gasket.
I would call or email sbmar, I cannot say enough how great a resource they are.
Thank you to bajturner and Carpediem44DB...those numbers were exactly what I was looking for and match up pretty well to what I'm finding. Nice to have confirmation.
Looking for some real-world experience here...I've pulled the aftercoolers, and one came apart OK, the other not so much. New aftercooler on the way from Seaboard. Ouch. Pondering what to do with the heat exchangers and oil/fuel coolers. I'm considering running Barnacle Buster through the system (once the aftercoolers are reinstalled obviously) but would like to hear from anyone who has done so, and from anyone else who can explain why doing so instead of taking the components off the engine would be a foolish move.
Have either fuel/gear cooler or heat exchanger ever been done? The fuel cooler is already more than half off to get at the after cooler, and if its been more than 5 years your due for a coolant flush anyway so its not that much more work to pull them off.
That said, I am 99% sure I was the first to do mine after 9 years and they weren't all that bad so barnacle buster may be fine for the fuel cooler and heat exchanger.
As you discovered pulling apart the aftercooler is very important!