---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Sat 07/08/23: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:10 AM - Re: Re: Tach drive (George) ________________________________ Message 1 _____________________________________ Time: 07:10:21 AM PST US From: "George" Subject: RE: Yak-List: Re: Tach drive My 2 cents. If you pull the inner pat of the Russian tach drive, There is a good chance the mating bevel gear has dropped down. We had a client with an almost new TW do this and got it started. The bevel gear chewed trough another shaft and fille the engine with mental. If it is reinstalled already, you can check the air start timing to confirm that it did not move. George Coy -----Original Message----- From: owner-yak-list-server@matronics.com On Behalf Of Robin Hou Sent: Friday, July 7, 2023 10:44 PM Subject: Yak-List: Re: Tach drive Mark, I am installing a M-14p engine that the tach drive had previously been removed then put back without properly engaging the air distributor gear. Is it possible to re-engage the air distributor gear with the tach drive gear without removing the accessory case? If so, can you share your experience on how to do that? Thanks in advance, Robin Hou [quote="mark.bitterlich(at)navy.m"]Yes Doc, and that is what I was trying to emphasize. Tell me exactly which one of those spline cogs is attached to the Tach Drive! It's important to know. The Tach Drive is not stand-alone, it is part of an overall gear mechanism as your picture shows clearly. It does not matter where the actual hole is on the case, what is important for the average engine owner to understand is that the Tach Drive is part of the whole accessory drive MECHANISM, and is a CRITICAL cog. If you pull the Tach Drive Cover Plate clear out of the engine, you can easily cause the Air Start Distributor to come out of time. This has actually happened when some folks converted their Tach Drive systems over to the P-1000 Tach by Horizon Instruments, that uses the Mag P-Lead wire to determine engine RPM. They first pulled the Tach Drive itself out, and then they decided to pull the next cover plate off in order to make a blank off plate. Well, they went a tad bit too far in the "pull and remove" phase, and managed to yank out the gear that goes with into that mechanism you have a picture of, which allowed everything to come out of time. Give it a try and see what happens. :-) I would rather not. I saw it happen after the fact, and had to re-time the Air Start Distributor for the gent, which some folks claim is easy. I guess I am not as good as they are, because for me it was a real task. I am not an M-14 engine expert. Most of what I have learned has been due to the mistakes made by myself and others. Some of those mistakes have ruined entire engines, luckily not by me for the Grace of God! I usually pass those lessons on via the Yak List. This is one of those times. Take care, Mark --[/quote] Read this topic online here: http://forums.matronics.com/viewtopic.php?p=511067#511067 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message yak-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Yak-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/yak-list Browse Digests http://www.matronics.com/digest/yak-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.