deanders Posted February 5, 2018 Report Share Posted February 5, 2018 Does anyone know the correct belt P/N for an Inter-av alternator installation? I'm currently using a Lycoming belt P/N 37B19774-374 belt. The problem with this belt is the pulley on the alternator in wider than the belt. Even when I tighten the belt it goes to the bottom of the pulley allowing the belt to slip. I'm told the belt that came with the STC was a Gates belt. I can either change the pulley or the belt. Mooney M20/E Quote Link to comment Share on other sites More sharing options...
BDPetersen Posted February 5, 2018 Report Share Posted February 5, 2018 Had to change belt when I did mine last year. Logbook says Gates p/n 9335XL. Quote Link to comment Share on other sites More sharing options...
nels Posted February 5, 2018 Report Share Posted February 5, 2018 I had a new belt installed on my old E as directed by the mechanic. I had suspected the pulley was worn out but what do I know. I suspect you have the same problem. Does the belt ride ok on the crankshaft pulley? The two grooves, alternator and crank pulley, should be the same geometry. It is expensive to change the belt as the prop has to come off. I was also told that the alternator needed to come off to remove its pulley for the real fix. Instead, I clamped the two sides of the belt together at the alternator and took a half inch impact wrench using a portable air bottle for air and just blipped the trigger and the nut was loose. That saved me a couple hundred dollars in alternator removal labor. It took all of ten minutes. Quote Link to comment Share on other sites More sharing options...
neilpilot Posted February 6, 2018 Report Share Posted February 6, 2018 This probably isn't you problem, but the InterAv unit come with either the standard or wide deck pully. If you happen to have the wrong pulley for your engine you will have the problem you describe. I think your E requires the wide deck pully. Quote Link to comment Share on other sites More sharing options...
nels Posted February 6, 2018 Report Share Posted February 6, 2018 10 hours ago, neilpilot said: This probably isn't you problem, but the InterAv unit come with either the standard or wide deck pully. If you happen to have the wrong pulley for your engine you will have the problem you describe. I think your E requires the wide deck pully. Neil, I'm curious, what is the difference between the two you describe? Does one take a wider belt like 3/8 to 1/2 inch? Quote Link to comment Share on other sites More sharing options...
neilpilot Posted February 6, 2018 Report Share Posted February 6, 2018 When the InterAv on my last Mooney failed years ago, I sent it back to InterAv for an exchange alternator. When the A&P installed that exchange, he found that the belt would not mount onto the alternator correctly. I called InterAv, and they said "You have a M20E, and so you need the wide deck pulley". They sent that pulley, my A&P swapped pullies, and then the belt mounted fine. That was on a 64E, and IIRC that pulley was over $100 about 15 years ago! I think that I may still have the standard pulley that it came with in my hangar. I can't speak to the belt dimensions. I was told by InterAv that the difference between the narrow deck and wide deck is the bracket that is bolted to the crankcase halves, and that my M20E alternator requires a special extended pulley and belt. InterAv is out of business, but you might contact Quality Aircraft Accessories in Tulsa, OK and ask about the correct belt. I've attached a drawing (sorry for the very poor resolution) that lists both pulleys, and may have belt information if you can read it. Also a paragraph that mentions the two deck options for that alternator installation. As I mentioned in my original post, this probably isn't related to Deander's problem. InterAv drawing.pdf InterAv wide deck.pdf Quote Link to comment Share on other sites More sharing options...
deanders Posted February 12, 2018 Author Report Share Posted February 12, 2018 Thanks for the information guys. I'll post the solution when I figure it out. Quote Link to comment Share on other sites More sharing options...
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