Replacing air compressor on 53/54 MY

[Bill Root]

The air compressor that is mounted on the engine has gone bad. It's leaking air pressure into the cooling system, pushing the coolant into the overflow bottles and bubbling out the hole in the top of the bottle. Local advice from my diesel guy and others is to not repair it because there are at least three different ways that engine-mounted compressor can go bad and mess uopthe engine. Their suggestion is to remove it, cap the hole on the engine and replace it with an electric compressor from Home Depot or the like.

I have an air tank mounted on the aft bulkhead of the engine compartment that looks to be about 7 - 10 gallons, so the electric compressor would feed that air tank. Has anyone out there performed this modification? If so, what compressor did you buy, where did you mount it and how has it worked for you? If I only have to run it to pressurize the tank on the wall it would seem that I wouldn't need anything very big.

Thanks for your help.

 

[rsmith]

The air compressor that is mounted on the engine has gone bad. It's leaking air pressure into the cooling system, pushing the coolant into the overflow bottles and bubbling out the hole in the top of the bottle. Local advice from my diesel guy and others is to not repair it because there are at least three different ways that engine-mounted compressor can go bad and mess uopthe engine. Their suggestion is to remove it, cap the hole on the engine and replace it with an electric compressor from Home Depot or the like.

I have an air tank mounted on the aft bulkhead of the engine compartment that looks to be about 7 - 10 gallons, so the electric compressor would feed that air tank. Has anyone out there performed this modification? If so, what compressor did you buy, where did you mount it and how has it worked for you? If I only have to run it to pressurize the tank on the wall it would seem that I wouldn't need anything very big.

Thanks for your help.

I have a good one I took off my 12/71 a couple years ago don't know what its worth. I was going to get a small compressor but never got around to it. I miss the big air horns but when I had them rechromed they cracked and never sounded the same. I just have a small freon horn on the bridge. I always call bridges on the radio anyhow.

 

[GJH]

Strange sounding problem. I am trying to figure out how the air compressor is interacting with the cooling system. Where is the connection? Mine just runs from a little power take off off the back of the port engine, pretty much as the stabilizer hydro pump runs off the back of the starboard engine. Am I missing something here?

I have a small leak in mine up on the tank on the water separator I need to get around to; it just affects how long there is pressure with the engine off.

 

[Bill Root]

George:

Mine is cooled by the engine cooling system (8V92's). There are two hoses, one running in and another running out.

 

[Bill Root]

Robert:

Thanks for the offer, but I'm not sure your compressor would fit my 8V92's. The other problem is that the advice I'm getting so far indicates that the engine-mounted compressors take quite a bit of power from the engine and tend to be problematic anyway. Seems like best solution for me would be a free-standing electric compressor feeding the air tank I already have.

 

[rsmith]

That why I took mine off I need every bit of Hp I can get out of my N's

 

[StratPlan61]

I added a small oil-less compressor to the ER bulkhead and plumbed it to share the resevoir tank with the standard engine-mounted compressor. So when I want to use aux air for some project, I just turn it on, flip a valve to direct air to the tank and use it throughout the boat. I keep 100' of airhose in the 'tool closet', works great. I think I bought it at Sears for around $80. Plenty of psi for any jobs I need onboard, including blowing out water lines.

 

[SKYCHENEY]

Hey Bear,
I came over to your boat a couple of times last weekend, but you weren't there. Maybe we'll see you in the building this winter. I think Dale said that you are hauling out on Tues and we come out on Wed.

 

[Bill Root]

Thanks for the feedback. I'll post what I decide and how it works out.

 

[Fanfare]

I have 6-92TA engines now, and there was no room on my new engines for the blower drive power take-off my 8-71Ns had for their air compressor. The old compressor ran faithfully for 27 years, pumping 125 psi air to my airhorns and my 3 air-operated windshield wipers. This is the same pump that trucks use for their air brakes, so it must be pretty reliable. At some point I removed the wipers as they were always suffering from internal corrosion. Since it was just the horns now I installed a Pacific Scientific 12v compressor and 2 smaller air tanks, replacing the Hatteras original, which was just a portable air tank with gauge such as can be found at gas stations. Although I had regularly drained this it turned out to have not been mounted level and the lower back end inside had a lot of rust which I did not want to try to clean out.

This system worked fine in Florida and the Bahamas. But when we decided to take Fanfare to Nova Scotia it was inadequate for fog signals. The "prolonged blast" of 4-6 seconds every two minutes was more than my small compressor could handle. I added a Sears 110v compressor to the engine room overhead. Makes a lot of vibration and noise, but keeps the foghorn going. We use it a lot in fog. Also installed an electric foghorn timer in the air circuit, which really simplifies running all day in the soup.

I also added about 50 ft of airhose with its own shutoff valve. Using quick connects I have a tire valve head and a trigger operated nozzle for cleaning stuff out or pumping up the steering system. Do this by letting most of the air pressure out of the tanks and only add when the gauge reads about 20 psi.


For most things the 12v system is fine.

 

[sandspur1966]

For no particular reason other than I thought the OEM engine driven system was overly complicated and nominally impacted engine performance, I updated mione as well.

I looked at numerous 12 volt truck systems and ended up going with a 110 volt pancake compressor permanently installed under my fly bridge on a circuit poweered by my inverter.

I removed the PTO compressor and the engine room air tank but have a T in the line to the horn solenoid that feeds a nipple in the port engine room of my 58MY. I simply used the existing copper tube that fed the horns from the engine room and have a 50 foot reel that gets me pretty much anywhere I need to be below decks.

Bought the compressor from Northern Tool for about $150 bucks. It was nice to grab some extra wall space in the engine room as well now that that tank is in the basura.

 

[ThirdHatt]

I replaced the OEM engine mounted compressor with little effort and little cost. For anyone interested, here is what I posted here when I did it:

There have been several threads on this subject here that I studied before deciding how to diagnose, repair or replace the air compressor on the port 8V71Ti. I gave serious consideration to the widely suggested solution of removing it and simply plumbing in a small compressor that would run off the boat's AC power. On my boat it only supplies the air horn as the wipers have been upgraded to 12v units. I rarely if ever use air tools for mechanical work and with 2 gens and 2 mains, it's only a 25% chance that I'd need to use them on the port engine which makes the air so I decided the OE system works for me. I can always carry a pancake compressor on board and use as needed.

I ended up simply replacing the old compressor with a reman unit and I thought that what I have learned may help others who want to keep their systems original as well. I thought it was a Detroit part and called the dealer with my serial number. They told me that my engine did not leave the factory with a compressor and therefore it was not a Detroit part. Other posts here suggested it was a Bendix, and after calling them and looking at diagrams via internet and fax, it sure is. The problem is that the style is a Tu Flo 500, part number 280962 which is old and no longer in production so finding a new one is nearly impossible and finding a reman is not easy. I didn't have time to have mine rebuilt, so at Bendix' suggestion I got a Tu Flo 501, which is the newer version of the old one. Slightly different port locations, but mostly the same and it went on easily with no trouble. There are two Tu Flo 501's that will fit our application, part numbers 286540 (the one I got locally yesterday) and 286615. They produce 12cfm and there are other part numbers that will fit and produce more air if needed. I opted to replace mine with what was there and now my horn is nice and loud again!

Hopefully this will save someone some headache some day and know that these compressors are readily availabe at any heavy duty truck parts place for around $250.

 

[MikeP]

A very common "mod" in the off-road crowd is to use an old York ac compressor as an air compressor. They work great for that purpose though, of course you would have to fabricate a bracket and belt assy to use it.

I installed a 12v compressor and it works fine. The boat originally had a 32v elec compressor but when it went south (burned up - literally) I couldn't find a 32v replacement.

 

[Bill Root]

I just returned from the boat and saw the most recent posts. Thanks to all for sharing your experiences.

This morning I opted to go with the mechanic's recommendation to remove the old compressor and mount a 6 gallon 115v pancake compressor on the floor of the engine room, tied into the existing air plumbing. That should give me 6 gallons in the pancake and 10 gallons in the tank mounted on the wall, which should be enough to operate the air horns in most situations. My wipers are electric. The compressor recovery rate is only 3 cfm, so I can see where that could be a problem in fog horn mode. I do have fog horn capability in the hailer, though.

Today we got the old compressor off and the pancake compressor mounted. Tomorrow we hook it all up. I'll post how that goes when it's finished.