I've got a masterfflow MV-50/ mv- 1050 in 2007 or so.
The quality control was quite poor.
Mine had NO wire strain relief on the 14awg coming out of the tail cap, and inside, the wire crimp nuts, were absolute jokes of electrical connections.
All 4 of the head bolts were various stages of too loose.
The finned heatsink head is too big to touch the walls of the cylinder at more than one spot.
The air inlet holes of the plastic air filter, were occluded with plastic flashing and obstructing airflow to a significant degree..
I retapped the head for 1/4 NPT fittings
I relubed piston skirt with Syl-glide
I used a higher quality airhose and locking tire chuck, drilling a hole in it to make it passive.
I used much better electrical connections and a better Bosch style relay inside the tail cap, and added strain relief to the 14awg.
I added a 80mm high rpm computer fan to blow over the head's finned heatsink, switched by the relay.
I added thermal grease to fill the gap between exterior cylinder wall and internal finned heatsink head.
One thing I have not done yet is replace the 14AWg with 10AWG. It pulls about 19 amps, but the actual amount depends on voltage reaching it, and how much pressure the unit is fighting.
I recently had a friend buy a Viaair 90p.
Nicely built unit and smaller than expected, my only issue is it rated to draw upto 23 amps, but uses no Relay, just a 15 amp rocker switch. UNloaded it draws 9 amps but draws 21 amps at 100 PSI. I told the owner to start it first then attach to SChrader valve, and when removing it from tire first before switching off to reduce strain on the underrated switch itself.
I added 10AWG to it, and a 60MM high rpm fan to blow over the head that comes on as soon as the alligator clips are attached to battery, whether the switch is on or off. This unit does have a thermal safety switch, but it is in the tail cap, well away from the head, which gets the hottest and where the piston skirt will burn up if it is allowed to get too hot.
The MV-50 is easy to open up and inspect, rather crude and efficient. No thermal safety switch.
I did not want to open up the Viair any more than the tailcap. The Viair90p sucks air in through two 2 tiny holes inside the tailcap. Had to bust out some smoke to find out where the intake was.
The Viair says if the thermal safety switch trips, one will likely have to wait 30 minutes before it will reclose and can be used again.
There is no room inside the tailcap of the 90p for a relay. Getting the 10AWg to fit in there was a pretty good curse fest. The owner needed it to reach much further than the provided 14awg would allow, and I did not want to lengthen the power feed wire without thickening it as well as a motor designed for 12 volts, getting only 9.5 volts is not a happy motor.
The overheating issues/ short duty cycle..... are easily solved with a powerful fan. Look for one which has steering vanes on the hub support, these concentrate the flow into a dense column of Air. whereas fans with just 4 hub supports tend to send air off at 4 wide angled hotspots of flow The 80mm size is perfect for zip tieing to my mv-50s carry handle, the 60mm fan is perfect for the Viaair90ps handle.
Here's the models I use:
60mm fan: DELTA fan model AFB0612DH-9C4........... rated for 50 cubic feet per minute
80mm fan : NIDEC fan model V80E12BGA7-07-T35A1............rated for 109 cfm
These two fans are the most powerful, or certainly in the top 5 most powerfan fans in their size format at this point in time, and are quite loud. If they were inside your desktop computer running at full speed, you'd want it in the next room, and would likely wish it were two rooms away.
Too many people associate computer fan with quiet slow powerless fans. These two fans will suck themselves across the table if you hook 12v to them without stabilizing precautions. They will levitate themselves if placed flow down on a table, at 10.5v.
It's actually very impressive. Watch your fingers.
The quality control was quite poor.
Mine had NO wire strain relief on the 14awg coming out of the tail cap, and inside, the wire crimp nuts, were absolute jokes of electrical connections.
All 4 of the head bolts were various stages of too loose.
The finned heatsink head is too big to touch the walls of the cylinder at more than one spot.
The air inlet holes of the plastic air filter, were occluded with plastic flashing and obstructing airflow to a significant degree..
I retapped the head for 1/4 NPT fittings
I relubed piston skirt with Syl-glide
I used a higher quality airhose and locking tire chuck, drilling a hole in it to make it passive.
I used much better electrical connections and a better Bosch style relay inside the tail cap, and added strain relief to the 14awg.
I added a 80mm high rpm computer fan to blow over the head's finned heatsink, switched by the relay.
I added thermal grease to fill the gap between exterior cylinder wall and internal finned heatsink head.
One thing I have not done yet is replace the 14AWg with 10AWG. It pulls about 19 amps, but the actual amount depends on voltage reaching it, and how much pressure the unit is fighting.
I recently had a friend buy a Viaair 90p.
Nicely built unit and smaller than expected, my only issue is it rated to draw upto 23 amps, but uses no Relay, just a 15 amp rocker switch. UNloaded it draws 9 amps but draws 21 amps at 100 PSI. I told the owner to start it first then attach to SChrader valve, and when removing it from tire first before switching off to reduce strain on the underrated switch itself.
I added 10AWG to it, and a 60MM high rpm fan to blow over the head that comes on as soon as the alligator clips are attached to battery, whether the switch is on or off. This unit does have a thermal safety switch, but it is in the tail cap, well away from the head, which gets the hottest and where the piston skirt will burn up if it is allowed to get too hot.
The MV-50 is easy to open up and inspect, rather crude and efficient. No thermal safety switch.
I did not want to open up the Viair any more than the tailcap. The Viair90p sucks air in through two 2 tiny holes inside the tailcap. Had to bust out some smoke to find out where the intake was.
The Viair says if the thermal safety switch trips, one will likely have to wait 30 minutes before it will reclose and can be used again.
There is no room inside the tailcap of the 90p for a relay. Getting the 10AWg to fit in there was a pretty good curse fest. The owner needed it to reach much further than the provided 14awg would allow, and I did not want to lengthen the power feed wire without thickening it as well as a motor designed for 12 volts, getting only 9.5 volts is not a happy motor.
The overheating issues/ short duty cycle..... are easily solved with a powerful fan. Look for one which has steering vanes on the hub support, these concentrate the flow into a dense column of Air. whereas fans with just 4 hub supports tend to send air off at 4 wide angled hotspots of flow The 80mm size is perfect for zip tieing to my mv-50s carry handle, the 60mm fan is perfect for the Viaair90ps handle.
Here's the models I use:
60mm fan: DELTA fan model AFB0612DH-9C4........... rated for 50 cubic feet per minute
80mm fan : NIDEC fan model V80E12BGA7-07-T35A1............rated for 109 cfm
These two fans are the most powerful, or certainly in the top 5 most powerfan fans in their size format at this point in time, and are quite loud. If they were inside your desktop computer running at full speed, you'd want it in the next room, and would likely wish it were two rooms away.
Too many people associate computer fan with quiet slow powerless fans. These two fans will suck themselves across the table if you hook 12v to them without stabilizing precautions. They will levitate themselves if placed flow down on a table, at 10.5v.
It's actually very impressive. Watch your fingers.
