Has anyone made a difference in the noise of their Power Tech MH-10 Gen?
How to quiet down a Power Tech MH-10 Gen? September 13, 2011, 10:32:06 am Has anyone made a difference in the noise of their Power Tech MH-10 Gen? Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #1 – September 13, 2011, 11:44:30 am Good luck, Thinking about tradeing mine for enclosed Onan, or Power Tech. Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #2 – September 13, 2011, 01:11:19 pm My problem isn't as much exterior noise but interior noise from vibration through the chassis. I reduced the vibration somewhat by tightening down the mounting bolts for the slide. As soon as I can I plan to remount the exhaust on a flexible mount and install new pillow block isolaters from Power Tech. I have also thought about building a quiet box since it is liquid cooled. If anyone has done this, please let us know. Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #3 – September 13, 2011, 02:23:28 pm Quote from: Kent Speers – September 13, 2011, 01:11:19 pmMy problem isn't as much exterior noise but interior noise from vibration through the chassis. I reduced the vibration somewhat by tightening down the mounting bolts for the slide. As soon as I can I plan to remount the exhaust on a flexible mount and install new pillow block isolaters from Power Tech. I have also thought about building a quiet box since it is liquid cooled. If anyone has done this, please let us know. Going to try as Kent said, tighten down the mounts and then reroute my exhaust with a different muffler. Agree, vibration is the issue here. Exhaust has an offending hissing noise so going to put a larger, reverse flow muffler on. On some 10K units, the fuel shut off valve leaks diesel directly down on the rubber mount directly below (close to injection pump). Was also thinking of the sound studio style foam to cut noise also.Mine has a pronounced vibration while cranking and during shutdown so something is not doing it's job. Has been hard to pin down so far but feels like generator to body interference. Just a matter of finding where. Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #4 – September 13, 2011, 02:28:37 pm Art, My PT10 Kubota also has a hissing noise that goes away when I open the bay door, I have never been able to pin it down., Obviously it is an air flow noise but from what ? The hissing is not apparent from inside the coach. Mine also shakes on start up/shut down but runs smoothly from then on.Gary B Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #5 – September 13, 2011, 03:27:11 pm Quote from: Pierce & Gaylie Stewart – September 13, 2011, 02:23:28 pmGoing to try as Kent said, tighten down the mounts and then reroute my exhaust with a different muffler. Agree, vibration is the issue here. Exhaust has an offending hissing noise so going to put a larger, reverse flow muffler on. On some 10K units, the fuel shut off valve leaks diesel directly down on the rubber mount directly below (close to injection pump). Was also thinking of the sound studio style foam to cut noise also.Mine has a pronounced vibration while cranking and during shutdown so something is not doing it's job. Has been hard to pin down so far but feels like generator to body interference. Just a matter of finding where.Ours (8kw Isuzu) has a strong hissing noise from the exhaust also, and I've been thinking about replacing the muffler with a small auto aftermarket one and moving it up in front of the front wheel, since it's now the lowest thing on the coach. Haven't scraped it on anything yet, but it wouldn't take much. Is there anything special about the OEM mufflers, or can it just be replaced with anything large enough to handle the flow? Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #6 – September 13, 2011, 06:32:48 pm Gary and Dave,Mine does run smoothly after it starts but I feel the shaking at startup has to do with the vibration I feel during normal operation. The big Detroit can run from idle to max rpm without any kind of vibration. The generator should be able to do that. In fact I know it CAN be made to do that.Hissing noise comes from too small pipe exiting the muffler (my opinion). I am just going to use an automotive muffler that has the in and out connection where I want it to be. Pipe diameter will be much larger than the stock muffler. Will post with photos when I figure out which muffler and how I want to mount it. Stock exhaust system is not a really clean installation. Looks pretty haphazzard. (bought a bicycle from Hap Hazzard's bike shop in Santa Barbara before he died. Nice guy.) Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #7 – September 13, 2011, 06:54:42 pm OK, got off my rear and pulled the generator out. Think I have found the reason for the vibration and hissing.1. From the photo from below, you can see the mount has started (started?) to come apart. So, four new mounts are needed. Not really happy with the design as I think they should be thicker even if the generator had to go up an inch.2. Exhaust pipe has been rubbing on the foam insulation. You can't see in the photo that it has worn a polished area in the metal behind the foam. The asbestos has worn through until the steel pipe is burning the foam. Foam is in bad shape also everywhere.3. As per the caliper reading, the exhaust pipe is only approx. 1 inch in diameter. The engine is 1237 CCs. Have you ever seen a car with that size engine with a 1 inch tail pipe? Increasing the pipe to 2 inches would mean you could push 4 times the amount of exhaust gas through at the same pressure or looking the other way, you would only have to push 25% as hard to get the same amount of gas through the pipe. Translates to "no hiss".Solution: I am going to put a flat oval shaped muffler on the back side with a piece of "hardy backerboard" to keep radiant heat off the engine. I will bolt everything to the engine. Still have to design an outlet pipe that won't have to use flex tubing to get out. The 90 degree turn under the bottom will be eliminated so will have better ground clearance as this is the lowest point on the bottom. Will try and find better isolation mounts.Waiting for sarcastic remarks about my lack of P.M. from you know who. (Voldemort got his in the end) Any feedback/ideas will be appreciated. Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #8 – September 14, 2011, 12:14:07 am At the rear of my generator slide there are two V brackets of angle iron that were tack welded to the chassis. when the generator slide is pushed rearward into place and bolted these holds the generator firmly in place. The welds had broken loose and the brackets were just sitting there. I bolted these into placed and covered them with thick gasket material with adhesive. This markedly reduced the vibration on starting and stopping. Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #9 – September 14, 2011, 07:18:30 am Quote from: Pierce & Gaylie Stewart – September 13, 2011, 06:54:42 pmWill try and find better isolation mounts.Pierce, For the isolators see this postPowertech Vibration Isolater Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #10 – September 14, 2011, 05:10:41 pm Pierce, I can't get to my generator bay right now but I don't think my vibration isolaters look anything like those in your photo. Mine are gray rubber or urethane and showed no signs of fatigue as I recall. I am wondering if mine have already been changed by the previous owner. When I shake the generator, I can feel no metal to metal or anything hard which is why I think my problems may be more related to the exhaust. Also, Power Tech told me they now have a Pillow Block vibration isolater now available for my model so I presume for yours also. I think they are around $37 each but they should be much better than the originals. Quote Selected
Re: How to quiet down a Power Tech MH-10 Gen? Reply #11 – September 14, 2011, 06:22:44 pm Kent, your last owner must have changed them. The photo is of the bottom on the back side toward the rear of the coach. The others look OK, in fact they all look OK from the top. I can grab the plastic intake pipe and rock the generator quite a bit. Thought my generator was making a funny smell but when I slide it out and back in, the flex exhaust goes against the foam insulation in a different spot and melts it. As I said, the rubbing went through the insulation and also the heat wrap on the flex pipe so must be a source of vibration. The easy part will be installing the new muffler on the back side (once the generator is out) but the hard part is engineering the exhaust so nothing moves or bends when sliding the tray in or out and routing the piping so the gases are directed away from the rig. The small exhaust pipe did mean high velocity for the gas and maybe away from the area.Thanks for the tip about the new mounts from PTRick, thanks for the link! Quote Selected
Topic: How to quiet down a Power Tech MH-10 Gen?