jeffc Posted June 2 Report Share Posted June 2 Hello, Just removed my starter motor on my mk iv spitfire to find the bendix teeth very badly damaged - see photo. This starter motor is only a couple of years old so hasn’t had a lot of use. Looking at the one I originally took off the bendix has 10 teeth while the damaged one has nine. I know the Spitfire should have nine but I think the Dolomites had ten as I had a similar problem on my 1500 Sptifire. I removed the starter as it seemed loose but that was probably caused by the bendix not engaging properly. My question is how many teeth should the ring gear have - for both a nine and ten gear bendix? On inspection it doesn’t seem to be damaged. However, I do not know the history of this car so will have to end up counting the teeth! thanks Jeff Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 2 Report Share Posted June 2 First question before we get to the teeth: are you using a spacer? That looks more like wear from a rotating ringgear being too close, than just from starting, especially if it's hardly been used. Link to comment Share on other sites More sharing options...
johny Posted June 2 Report Share Posted June 2 But doesnt the spacer move the bendix gear closer not further away😩 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 2 Report Share Posted June 2 34 minutes ago, johny said: But doesnt the spacer move the bendix gear closer not further away😩 Yep, thats why it looks like the teeth being too close. Remove it and see what it's like. Link to comment Share on other sites More sharing options...
jeffc Posted June 2 Author Report Share Posted June 2 Thanks for the replies. It did have a spacer fitted. So this looks like the bendix hasn’t gone back far enough to clear the starter ring so the ring has effectively machined the bendix gear? I will do some measurements to see if the two were interfering during running. As a design engineer question - is the spacer required for some starters and not others? The Canley site shows a spacer and a shim so should there be an engagement check to set the gears in the correct alignment? Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 3 Report Share Posted June 3 if the things been it constant mesh i hate to think of the starters rpm when you give any throttle yikes Pete Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 3 Report Share Posted June 3 On some Triumphs I've never used a spacer, but just visually matched the teeth on the starter to the teeth on the flywheel, and if the starter clears the ring gear with enough movement to be pulled back to engage on starting then it's fine. My GT6 for example had a saloon flywheel which sat about an inch closer to the gearbox (or away from the engine backplate) than the 'proper' GT6 version so needed all the length of starter it could get - see photo. If that flywheel was closer to the backplate then I'd need to space or shim the starter forwards to be able to engage fully. Shims are available but to be honest I've never needed that kind of fine adjustment. This pic shows what happens with too many spacers and shims, where the flywheel has made contact with the actual bendix body and not just the teeth: Link to comment Share on other sites More sharing options...
johny Posted June 3 Report Share Posted June 3 This is a spitfire so were there various flywheels used for those? Link to comment Share on other sites More sharing options...
jeffc Posted June 3 Author Report Share Posted June 3 Pete - that happened soon after I bought my 1500 Spitfire in 1990. It had a ten tooth starter which jammed - I seem to remember the starter motor squealing and generating lots of smoke! Luckily it happened at the Leicester and Rutland show (which was at Stanford Hall near Lutterworth back then) so I went and bought a second hand starter from a stall, bolted it on in the parking field and all was well 👍 Colin - good photos thanks. I guess the flywheel is designed to run in the gap between the starter pinion and the motor so the ring gear is completely disengaged once the engine has started. Will need to take some measurements and draw it all out to see where things should be. Link to comment Share on other sites More sharing options...
DanMi Posted June 3 Report Share Posted June 3 the 1500 dolomite had a pre-engaged starter so the ring gear is different, not used on other models could you have a dolomite engine? 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 4 Report Share Posted June 4 agree pre engage motors fly the pinion in from the front opposite to a bendix drive which flies in from the back so the ring gear will generally have the chamfered teeth on the opposite sides to suit . Pete Link to comment Share on other sites More sharing options...
johny Posted June 4 Report Share Posted June 4 Easy to mix up if the starter mountings are the same😳 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 4 Report Share Posted June 4 in the past i have fiited pre engaged to previous bendix starter engines (mainly Rootes )and despite the flywheel chamfer being wrong the chamfer on the pinion had always worked well the corresponding improvement in crank up loads always pleasing so it can work out ok . Link to comment Share on other sites More sharing options...
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