The ‘rounded off’ part on the crankshaft nose is called a ‘fillet radius’. It is well known amongst Engineers that sharp edges and corners are stress raisers and can cause cracks, leading to premature failure of parts. Read about the De Havilland Comet aircraft failure in the 50s/60s, where they had rectangular windows. That’s why you will never see a sharp corner, but a small radius to relieve the stress. Great job so far, BTW.
Excellent video Elin.. I have timed in dozens of engines back in my day and never really had the time to work out the finer points .. Watching you do it with such clarity and added editing to show precisely where things are at , guides the viewer through the smoke and mirrors, (or as my old boss used to say "The Black Arts"). It's all very nostalgic for me watching your Rusty Beauties series and takes me back to much harder and more demanding times but with better music, beer and a lot of fun.
Hey Elin I think I finally understand timing without having to take my shoes and socks off! Another "Triumph" of explanation and in UK terms . Keep at it its a pleasure to look forward to the next episode.
Wonderful Elin. I have today ordered a duplex kit, I have been considering this for along time but not sure if its possible. Once again your videos not only answer the question but shows how to. Thank you
Sorry Elin, I forgot to shout when I saw you didnt put the lock tabs on ....... I was out in the backyard playing ball with Rusty😁😁😁. Great video, really good editting to show animated the timing wheel !! Good luck from Spain!!
You mentioned the rounded edge, and not a square edge, on the crank shaft, and not knowing why (requiring the chamfer on the sprocket). A square edge will result in a shaft stress concentration when subjected to torsional loading, which is caused by the abrupt change in geometry (i.e., a sharp corner). The stress concentration can be reduced with a properly sized filet. Therefore, as you noted, the sprocket then requires a chamfer to clear the filet to allow it to seat properly. Without the filet, it would become a likely location for shaft failure to occur.
Elin, thanks for your effort to show the degree wheel positions in the video frame insets; greatly adds clarity to the description! The entire degree wheel process must be done stepwise to insure accurate results; even turning the crank anti-clockwise past the desired stopping point and then clockwise to eliminate the 'backlash' slop/error. Thanks for describing each step of the procedure and the 'why' the next step is taken! "It is always better to be advanced than retarded." Now I know why my mind is going; my 'chain' has stretched over my lifetime! lol
Sorry to change the subject but I noticed you installed an electronic ignition system the other day. I have a TR3A (1960) with a TR4 engine with 87mm bore. I noticed that Rimmer Bros offer different ignitions sets for different bore sizes 83mm/86mm. Is there any different requirements for my 87mm bore? And by the way what an excellent video on timing. Well done,
Elin I don’t understand why the small Duplex sprocket isn’t allowed to float along the nose of the crank, as that would allow it to always self-centre with the revolving thrust of the chain. (It would also automatically compensate for crank end float). I expect you know why?
If Rusty had been there he would have reminded you to put on and bend the tabs, but all that math and geometry isn't really suitably for us dogs. Greetings from Halgrim.
Hi. Thank you for the explanation. I have ome question. I must timing my spitfire. I changed the camshaft for a fast road. Does your 110° is the inlet timing (mine is 103°)? The 50 (thou? =thousandths?) is a random number or corespond to something? Thankyou.
Hi, the procedure for 103 is exactly the same. Just when you add your numbers and divide by 2 you need to get to 103 instead 110. That is all. 50 thou stands for thousands, yes, 50 thousands of an inch or 0.050”. You can do it with another number, as long as it is the same for the clockwise and counterclockwise drop, but 50 is recommended because of the shape of the cam. Many specs even give you a crankshaft position for 50 thou drop. I recommend 50 for your camshaft as well. Good luck!
Definitely the double gear on TR6 and GT6 engines limits you to half tooth increments only. The double row gear on TR2,3,4 though is still reversible so there you can do a quarter tooth adjustment, assuming it was made correctly as it turns out some of the the reproduction gears are a little off and the quarter tooth adjustment is not really possible. I might make a separate video about that. Oh, btw it is 110 ATDC not BTDC. I made that mistake once :)
I am planning to make it available for download on www.rustybeauties.com but I can’t find time to do it so it is not online yet. You can send me an email at elin.yakov@rustybeauties.com and I will reply with the PDF attached
I uploaded it in the files section of our Facebook group Rusty Beauties facebook.com/groups/3028660134022715/files/files If you don't do Facebook, just email me and I will send it to you
The ‘rounded off’ part on the crankshaft nose is called a ‘fillet radius’. It is well known amongst Engineers that sharp edges and corners are stress raisers and can cause cracks, leading to premature failure of parts. Read about the De Havilland Comet aircraft failure in the 50s/60s, where they had rectangular windows. That’s why you will never see a sharp corner, but a small radius to relieve the stress. Great job so far, BTW.
Excellent video Elin.. I have timed in dozens of engines back in my day and never really had the time to work out the finer points .. Watching you do it with such clarity and added editing to show precisely where things are at , guides the viewer through the smoke and mirrors, (or as my old boss used to say "The Black Arts"). It's all very nostalgic for me watching your Rusty Beauties series and takes me back to much harder and more demanding times but with better music, beer and a lot of fun.
Hey Elin I think I finally understand timing without having to take my shoes and socks off! Another "Triumph" of explanation and in UK terms . Keep at it its a pleasure to look forward to the next episode.
Hi Elin wish I had a teacher like you at school I have a MK3 spitfire owned 25 years now with a GT6 engine in it.
Kev 👍🇬🇧
Ah that was great! Thanks for going back thru it a few more times….pun unintended!,
Wonderful Elin. I have today ordered a duplex kit, I have been considering this for along time but not sure if its possible. Once again your videos not only answer the question but shows how to. Thank you
Great work. Looking forward to seeing this car running.
The fillet on the crankshaft prevents it from snapping off !
Regards,
Sandy🔧🏴
I watched till the end!
Sorry Elin, I forgot to shout when I saw you didnt put the lock tabs on ....... I was out in the backyard playing ball with Rusty😁😁😁.
Great video, really good editting to show animated the timing wheel !!
Good luck from Spain!!
Thank you Elin! The 2nd time round it makes more sense!
That was a great video thank you Elin
You mentioned the rounded edge, and not a square edge, on the crank shaft, and not knowing why (requiring the chamfer on the sprocket). A square edge will result in a shaft stress concentration when subjected to torsional loading, which is caused by the abrupt change in geometry (i.e., a sharp corner). The stress concentration can be reduced with a properly sized filet. Therefore, as you noted, the sprocket then requires a chamfer to clear the filet to allow it to seat properly. Without the filet, it would become a likely location for shaft failure to occur.
Nice job Elin, I will refer to this video when I do my TR6. I believe Rusty did not join you because all of the timing numbers confuse him.
It takes some good looking studs to keep an engine together.
Engine jokes are all about timing.
Elin, thanks for your effort to show the degree wheel positions in the video frame insets; greatly adds clarity to the description! The entire degree wheel process must be done stepwise to insure accurate results; even turning the crank anti-clockwise past the desired stopping point and then clockwise to eliminate the 'backlash' slop/error. Thanks for describing each step of the procedure and the 'why' the next step is taken!
"It is always better to be advanced than retarded." Now I know why my mind is going; my 'chain' has stretched over my lifetime! lol
Sorry to change the subject but I noticed you installed an electronic ignition system the other day. I have a TR3A (1960) with a TR4 engine with 87mm bore. I noticed that Rimmer Bros offer different ignitions sets for different bore sizes 83mm/86mm. Is there any different requirements for my 87mm bore? And by the way what an excellent video on timing. Well done,
Elin I don’t understand why the small Duplex sprocket isn’t allowed to float along the nose of the crank, as that would allow it to always self-centre with the revolving thrust of the chain. (It would also automatically compensate for crank end float). I expect you know why?
If Rusty had been there he would have reminded you to put on and bend the tabs, but all that math and geometry isn't really suitably for us dogs. Greetings from Halgrim.
Hi. Thank you for the explanation. I have ome question. I must timing my spitfire. I changed the camshaft for a fast road. Does your 110° is the inlet timing (mine is 103°)? The 50 (thou? =thousandths?) is a random number or corespond to something? Thankyou.
Hi, the procedure for 103 is exactly the same. Just when you add your numbers and divide by 2 you need to get to 103 instead 110. That is all. 50 thou stands for thousands, yes, 50 thousands of an inch or 0.050”.
You can do it with another number, as long as it is the same for the clockwise and counterclockwise drop, but 50 is recommended because of the shape of the cam. Many specs even give you a crankshaft position for 50 thou drop. I recommend 50 for your camshaft as well. Good luck!
do you think the double roller gear set vs. the single is different in it's ability to be perfectly calibrated to 110 degrees BTDC?
Definitely the double gear on TR6 and GT6 engines limits you to half tooth increments only. The double row gear on TR2,3,4 though is still reversible so there you can do a quarter tooth adjustment, assuming it was made correctly as it turns out some of the the reproduction gears are a little off and the quarter tooth adjustment is not really possible. I might make a separate video about that. Oh, btw it is 110 ATDC not BTDC. I made that mistake once :)
Hello Elin
Could you put a link to a pdf of your degree wheel so I could download it?
I am planning to make it available for download on www.rustybeauties.com but I can’t find time to do it so it is not online yet. You can send me an email at elin.yakov@rustybeauties.com and I will reply with the PDF attached
I uploaded it in the files section of our Facebook group Rusty Beauties facebook.com/groups/3028660134022715/files/files If you don't do Facebook, just email me and I will send it to you
Hey Elin, you forgot the loc………..oh.
I knew you wouldn't forget. Great video