Carba1984 Posted July 14 Report Share Posted July 14 (edited) Good morning, I would like to know if I am adjusting the ignition of my spitfire correctly, the manual says 10 BTDC, I attach an image of where I have adjusted it, the image is from Google already, in my car it is not visible, I have set it to 850 rpm , thanks a lot Edited July 14 by Carba1984 Link to comment Share on other sites More sharing options...
johny Posted July 14 Report Share Posted July 14 Looks good. There will be a mark on the pulley which must line up with the one you have shown just when the spark comes. With your strobe light connect to spark plug lead 1 and your vacuum disconnected with the engine idling the flashes should show the two marks together.... Link to comment Share on other sites More sharing options...
Carba1984 Posted July 14 Author Report Share Posted July 14 Ok, thanks! I am trying to solve a problem of unstable idle, my revolutions drop when I stop, I don't know if it is due to a poor mixture but I am not able to adjust the idle, it is difficult in Spain to find information on SU carburetors Link to comment Share on other sites More sharing options...
johny Posted July 14 Report Share Posted July 14 Im not very good on SU but theres been lots of discussions on here so a search of the site should help you👍 1 Link to comment Share on other sites More sharing options...
johny Posted July 14 Report Share Posted July 14 Where are you in Spain Carba? Also why do you highlight your posts😁 Link to comment Share on other sites More sharing options...
Carba1984 Posted July 14 Author Report Share Posted July 14 I highlight my posts because I use a translator so you can understand me better, I hope it is not a problem. I am in Burgos, Castilla y León. Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 14 Report Share Posted July 14 its fine suits me ok keep it up have you tried set timing by Ear turn dizzy to get the fastest idle but retard/slow it back from best or it will be too advanced Pete Link to comment Share on other sites More sharing options...
Carba1984 Posted July 14 Author Report Share Posted July 14 The timing it’s ok by stroboscopic gun, 10 degrees before Link to comment Share on other sites More sharing options...
Josef Posted July 14 Report Share Posted July 14 Other possible things to check. Can you feel play (movement) in the distributor shaft if you hold the rotor arm and try to move it side to side? Are you using points or electronic ignition? If using points are they set correctly? As Pete mentions, it can sometimes be useful to set the timing by ‘feel’. Our engines are old, fuels have changed, and many other factors like that can mean the engine won’t run perfectly on the settings from the manual. So turning the distributor for the highest idle speed, then turning to retard it a little bit, fixing it down and then testing on the road can be worth trying. If it pinks / detonates then retard some more till that stops! Tried to write that so google translate will have a good chance of getting it right! Link to comment Share on other sites More sharing options...
dannyb Posted July 14 Report Share Posted July 14 My 1500 spit is set at 17 deg btdc. This was done on a rolling road. With today's petrol 10 deg is not enough. Danny 1 1 Link to comment Share on other sites More sharing options...
Carba1984 Posted July 14 Author Report Share Posted July 14 I'm afraid of having a problem with the cranks if I go too far adjusting the distributor, but I can try 17 Deegres like dannyb Link to comment Share on other sites More sharing options...
Carba1984 Posted July 14 Author Report Share Posted July 14 1 hour ago, Josef said: Other possible things to check. Can you feel play (movement) in the distributor shaft if you hold the rotor arm and try to move it side to side? Are you using points or electronic ignition? If using points are they set correctly? As Pete mentions, it can sometimes be useful to set the timing by ‘feel’. Our engines are old, fuels have changed, and many other factors like that can mean the engine won’t run perfectly on the settings from the manual. So turning the distributor for the highest idle speed, then turning to retard it a little bit, fixing it down and then testing on the road can be worth trying. If it pinks / detonates then retard some more till that stops! Tried to write that so google translate will have a good chance of getting it right! I use electronic Ignition Link to comment Share on other sites More sharing options...
johny Posted July 14 Report Share Posted July 14 7 minutes ago, Carba1984 said: I'm afraid of having a problem with the cranks if I go too far adjusting the distributor, but I can try 17 Deegres like dannyb Best to increase a few degrees at a time and listen for pinking (rattling noise from engine when accelerating). However I dont think enough advance is your problem.... Link to comment Share on other sites More sharing options...
Carba1984 Posted July 14 Author Report Share Posted July 14 I have to say that I have a rebuilt engine 600 km ago, maybe I will have to wait to refuel before it settles. Link to comment Share on other sites More sharing options...
dougbgt6 Posted July 14 Report Share Posted July 14 The best way is set it by ear slowly turn the distributor till it doesn't get faster and then back a bit. Take it for a run, If you get pinking, that high pitched ting! Ting! Ting noise, back a bit more. As has been said modern petrol isn't as high octain as the old petrol these cars were designed to run on. Also there will be wear in the mechanical system and you will wind up with a setting which is correct, but nowhere near 10 degrees. Doug Link to comment Share on other sites More sharing options...
Carba1984 Posted July 14 Author Report Share Posted July 14 There is nothing better than learning about a classic English car in an English forum. In Europe, England, Germany, France... you take care of classic cars much better than in Spain, in England you still have spare parts for your classic cars. Congratulations. I also tell you that today Spain 5 - England 0 😂 sorry about this 1 Link to comment Share on other sites More sharing options...
dougbgt6 Posted July 14 Report Share Posted July 14 27 minutes ago, Carba1984 said: I also tell you that today Spain 5 - England 0 😂 sorry about this I think you may be right. Doug Link to comment Share on other sites More sharing options...
Carba1984 Posted July 17 Author Report Share Posted July 17 I've set 17 degrees and I think that's much better, Now I have to fight with the carburetters, I have an unstable idle when I stop at a traffic light it falls at 200 rpm and then it goes back up slowly or sometimes it turns off Link to comment Share on other sites More sharing options...
Colin Lindsay Posted July 17 Report Share Posted July 17 On 14/07/2024 at 14:54, Carba1984 said: There is nothing better than learning about a classic English car in an English forum. In Europe, England, Germany, France... you take care of classic cars much better than in Spain, in England you still have spare parts for your classic cars. Congratulations. I also tell you that today Spain 5 - England 0 😂 sorry about this Well, you have better footballers, we have better forums, it balances out! 1 1 Link to comment Share on other sites More sharing options...
Carba1984 Posted July 17 Author Report Share Posted July 17 Yess 😉 Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 17 Report Share Posted July 17 does the carbs still have what we call waxstats on the bottom of the jet . with age these cause grief if you have them simple English solution is remove jet , pry open the crimped bottom cap remove the wax capsule must keep the small metal spacer add 2 x 1p pennies (or equivalent spanish money) keep the spacer re crimp the base and its done ( re set the mixture afterwards . do not buy a conversion kit cost £$£$£ and dont fit well so thats my 2 pennyworth waxstat jet Pete Link to comment Share on other sites More sharing options...
Carba1984 Posted July 17 Author Report Share Posted July 17 (edited) Hi Pete, I don't know if I'm wearing the waxstats, I haven't started disassembling carburetters yet, would you be so kind as to tell me the number in the scheme of what I have to buy? thanks! My carburetters HS4 Edited July 17 by Carba1984 Link to comment Share on other sites More sharing options...
dougbgt6 Posted July 17 Report Share Posted July 17 (edited) The two penies solution is widely used, nobody buys the conversion kit. I have some penies I could send at a very reasonable price! Doug Edited July 17 by dougbgt6 Link to comment Share on other sites More sharing options...
Carba1984 Posted July 17 Author Report Share Posted July 17 Is that the piece I have to change? Link to comment Share on other sites More sharing options...
Steve P Posted July 17 Report Share Posted July 17 If you have waxstat jets then yes. Have you balanced the carbs?, if you have an airflow balancer it`s easier but can be done by ear?. Can cause lumpy idle if they are out of balance. S Link to comment Share on other sites More sharing options...
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