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</head><body><p style="color: rgb(51, 51, 51); font-family: helvetica,arial,sans-serif; font-size: 12pt;">Bud & Bob,<br></p><p style="color: rgb(51, 51, 51); font-family: helvetica,arial,sans-serif; font-size: 12pt;">Your going at the ratios backwards. Mark the output flange and tail housing and the input shaft. Turn the OUTPUT flange 1 revolution while counting the input shaft revs. The number of input revs is the ratio. example, 1 output rev has input turning 4 revs = 4.00:1 ratio.<br></p><p style="color: rgb(51, 51, 51); font-family: helvetica,arial,sans-serif; font-size: 12pt;">Not ALL transmissions have a 1:1 4th gear ratio. I build a racing trans that 4th gear can be overdrive, underdrive or 1:1. Spitfires do not have a good selection of differential ratios which is why I designed and built my trans. I can also give you any 1st, 2nd, 3rd gear ratio you want. I use Hewland/Webster gears and best of all it is a bolt in trans for any Spit.<br></p><p style="color: rgb(51, 51, 51); font-family: helvetica,arial,sans-serif; font-size: 12pt;">Ron Krantz<br></p><p style="color: rgb(51, 51, 51); font-family: helvetica,arial,sans-serif; font-size: 12pt;">ReK Racing<br></p><blockquote type="cite">On January 11, 2018 at 8:19 AM Robert Lang via Fot <fot@autox.team.net> wrote:<br><br><div style="color: rgb(0, 0, 0); font-family: Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 13px; background-color: rgb(255, 255, 255);"><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4543">Hi Bud,</div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4423"><br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4424" dir="ltr">Those numbers look fishy. 4th gear should be 1:1, e.g. turning the input shaft one turn should yield one turn of motion at the output flange. The lower gears would turn the output flange less than one turn. A 1.33:1 overall third gear ratio would see the output flange turn 3/4 of a turn per one turn on the input shaft. Similarly, a 1.75:1 2nd gear would result in slightly more than half a turn (.57 to be exact) of the output flange per turn of the input shaft. Note that 1.33 and 1.75 are random numbers shown to illustrate and not actual gear ratios. I think the GT6 used 1.78 and 1.25 for 2nd and 3rd. At least the Mk3 GT had those ratios.<br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4544"><br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4536">What you reported seems to be the opposite of my example.<br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4582"><br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4610">It is possible that you are seeing some sort of "sticktion" where gooey oil in the gearbox is coming into play. But the key is that 4th should always be 1:1 unless there's an overdrive and that O/D is engaged.<br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4683"><br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4813">But the only way to know for sure of what the ratios are is to count teeth and "do the math".</div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4871"><br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4872">Can you remove the top cover and count the teeth on any of the gears on the main shaft? That should make it easier to identify what gear clusters are in there. You probably only need to count the teeth on the main shaft but I know squat about GT6 gearbox internals other than they are more Spitfire-like than TR-like so the lay shaft gear ratios may be fixed as they are on the Spitfire. The point being that there are only so many ratios available that would fit in the gearbox, so it should be fairly easy to figure out what you have there.<br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_7402"><br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_9471">Regards,</div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_9472">Bob Lang<br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_5116"><br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_11690"><br></div><div id="ox-e8fb51fdbb-yui_3_16_0_ym19_1_1515674801482_4422"> <br></div><div class="ox-e8fb51fdbb-qtdSeparateBR"><br><br></div><div class="ox-e8fb51fdbb-yahoo_quoted" style="display: block;"><div style="font-family: Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 13px;"><div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"><div dir="ltr"><span style="font-family: Arial; font-size: small;"> On Wednesday, January 10, 2018 9:09 PM, Bud R via Fot <fot@autox.team.net> wrote:<br></span></div><br><br><div class="ox-e8fb51fdbb-y_msg_container"><div dir="ltr">Listerati,<br></div><div dir="ltr"><br></div><div dir="ltr">I’ve been trying to figure out what gear ratios I have in the gearbox that came with my race car but don’t know how to do the proper math. The PO told me it was a close ratio GT6 gearbox but one never knows until you actual check. <br></div><div dir="ltr"><br></div><div dir="ltr">I at least took some “data” while it was out so I’m hoping someone can tell me how to figure out the gear ratios and if it is indeed close ratio GT6 gears or whatever it might be.<br></div><div dir="ltr"><br></div><div dir="ltr">When the input shaft was turned one full rotation the output shaft turned the following amount.<br></div><div dir="ltr"><br></div><div dir="ltr">1st gear it turned 1/4 turn<br></div><div dir="ltr">2nd gear it turned 1 1/8 turns<br></div><div dir="ltr">3rd gear it turned 1 5/8 turns<br></div><div dir="ltr">4th gear it turned 1 3/4 turns<br></div><div dir="ltr"><br></div><div dir="ltr">Any help on how I should do the math is appreciated.<br></div><div dir="ltr"><br></div><div dir="ltr">Also does anyone know what happened to the minty lamb gearspeed website? It does not appear to be up any longer and I used to play with it a lot. Very useful site that now appears gone. Waaahhhh.<br></div><div dir="ltr"><br></div><div dir="ltr">Thanks<br></div><div dir="ltr">Bud Rolofson<br></div><div dir="ltr"><br></div><div dir="ltr">Extreme Parts Racing (more than just a haircut)<br></div><div dir="ltr"><br></div><div dir="ltr">71TR6 CC57365 (Good 6)<br></div><div dir="ltr">71 Spitfire MK IV Race Car #3<br></div><div dir="ltr">69 Spitfire MK III (back up FE engine/dinghy car)<br></div><div dir="ltr">93 Minnie Winnie Race Support Vehicle <br></div><div dir="ltr">77 Z-50A Hardly Davidson Honda Mini-Trail Bike (Triumph Pit Bike)<br></div><div dir="ltr"><br></div><div dir="ltr">_______________________________________________<br></div><div dir="ltr"><a href="mailto:fot@autox.team.net">fot@autox.team.net</a><br></div><div dir="ltr"><br></div><div dir="ltr"><a href="http://www.fot-racing.com/" target="_blank" rel="noopener noreferrer">http://www.fot-racing.com</a><br></div><div dir="ltr"><br></div><div dir="ltr">Donate: <a href="http://www.team.net/donate.html" target="_blank" rel="noopener noreferrer">http://www.team.net/donate.html</a><br></div><div dir="ltr">Archive: <a href="http://www.team.net/archive" target="_blank" rel="noopener noreferrer">http://www.team.net/archive</a><br></div><div dir="ltr">Forums: <a href="http://www.team.net/forums" target="_blank" rel="noopener noreferrer">http://www.team.net/forums</a><br></div><div dir="ltr">Unsubscribe/Manage: <a href="http://autox.team.net/mailman/options/fot/robertlangtr6@yahoo.com" target="_blank" rel="noopener noreferrer">http://autox.team.net/mailman/options/fot/robertlangtr6@yahoo.com</a><br></div><div dir="ltr"><br></div><br><br></div></div></div></div></div></blockquote><p class="default-style" style="color: rgb(51, 51, 51); font-family: helvetica,arial,sans-serif; font-size: 12pt;"><br> </p><blockquote type="cite">_______________________________________________<br>fot@autox.team.net<br><br>http://www.fot-racing.com<br><br>Donate: http://www.team.net/donate.html<br>Archive: http://www.team.net/archive<br>Forums: http://www.team.net/forums<br>Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/rkrantz77@comcast.net<br><br><br></blockquote></body></html>