The idea of solid vacuum advance pipe with LUCAS distributors is, that once the distributer is set, it doesn't need to move ever again. The mistake people make is adjusting the timing by rotating the distributor (like normal distributors). Yes it works and I've done it myself. But if you read the manual, your supposed to wind the advance and retard screw on the vacuum knurled knob till the mid point on the vernier scale is reached. which is the thickest line. Adjust the distributer to the correct timing and lock it off. Any adjustment in the future can then be done with the knurled knob when the car is running. Some cars even where supposed to be set to TDC, then a certain number of clicks on the knob would give you the correct advance. BTW at full throttle the diaphragm isn't used on the distributer. The throttle is at WOT therefore there's hardly any vacuum on the diaphragm. The whole idea of the diaphragm is to make the car more economical when cruising (high vacuum). Highest vacuum is on the overrun, when your engine is running fast but the throttle is shut, for example slowing down while going down hill. You will know this is true if you've ever driven a car with vacuum wipers 😂. Race bred engines did away with vacuum advance (like the Lotus Elan's), as they weren't concerned with economy. Some performance engines are timed at max advance like early Porsche's. And require a timing light and the engine running at about 4000rpm. Normal MAX advance on your average engine is 20-30 degrees BTDC. And between 2-8 degrees when fully retarded at idle. Because there is a high vacuum at idle the manual will tell you to disconnect the vacuum line and plug it to set the timing. Always the best way to time an engine is with a timing light not a vacuum gauge. The light will show you exactly what's happening. A vacuum gauge can easily be thrown off by so many other factors and rarely gives an accurate guide.
Thanks Gary for the detailed information! I agree with you on the use of a timing light instead of a vacuum gauge - I've had terrible results trying to set timing with a vacuum gauge.
Thanks Elin for your lesson on advancing of the spark. It seems to me that the weights come into play at high engine rpm, but hit a limiter stop at a certain rpm, and the vacuum advance works only on the advance when the manifold vacuum is at its highest as it comes off idle when accelerating and not at high speed 'cruise'. I recall that you could get different distributor weights if you wanted to modify the 'advance curve' of a distributor. Also, I believe one of the checks on a distributor is to check for play of the shaft inside the distributor housing because if you have a bad bushing there, you can get 'cam wobble' that upsets the spark break timing. I'm no pro, so I don't know! lol
The circlip is the genuine article. You should have counted the number of clicks when you undid the knurled nut so you can return it to the original position. The rubber diaphragms crack over time if not in use. It's possible to repair them if desperate but it's better to get a new one.
Hi Elin Thank you for your patience to explain us so important things about classic beauties. By mistake I bougth a magnatronic lumination ignition for a 25D6 distributeur but my 1969 TR6 have a 22D6 distributeur. May I use it or it´s best to trade it for a specific one? Thank you and regards. José nóbrega Portugal
That engine sounds really sweet compared with the one I have in my 4A; you have done a great job with the rebuild. I suggest that you make a good inspection of the new vacuum unit when it arrives. I bought one not that long ago for my Triumph Stag; it came from one of the usual parts suppliers, but I found that that it was really notchy in operation when applying vacuum by mouth before installing it on the distributor. That unit was returned and I replaced it with one I was able to buy from a distributor rebuild specialist... it was much smoother in operation. I can picture you setting up a test rig to measure retraction vs level of vacuum ! I hope that you have better luck with your replacement than me.
Elin excellent video! I believe on those old Lucas distributors once good time is established the little thumb wheel is good for one degree per revolution.,it’s good for going up in the mountains at higher elevations.
Great video as usual. I might be wrong but in the UK spec cars, the bob weights and springs govern the advance curve at different revs. The vacuum advance mechanism advances the ignition at low throttle openings and higher revs (eg coasting downhill etc). I like the previous comment about a future efi project.
The engine sounds great. Can't wait to hear it tuned. My 64 was really peppy and responsive when everything was in-sync. I'm loving this series! Thanks for sharing, Elin.
I have been advised by so many classic car owners at shows to steer clear of electronic ignition, Troublesome and unreliable? After watching this extremely informative video Wow listening to that run. Not only learnt the advance and retard but also watch and listen to the experts! Thank Elin.
I have Pertronix on my old Beetle, one of the best mods ever. 20+ years now, not a single issue. Repro modern points and condensers are just not worth bothering with.
lots of great comments on timing. I used to tune air cooled VWs in the '70s and the hot setup was to replace the vacuum/mechanical distributor with a straight mechanical set to 32 degrees max advance. I recall a Don Garlits interview where he said they used 50 total on the hemi fuelers, but they only had to run for a few seconds. I am ready to install a Pertronix on TS394LO (TR2) and wonder which one Elin bought ? There are lots on Amazon. Maybe I should just go to Moss.
That sounds so much better and you're not finished yet!! Putting in a new starter sounds a good idea as well. Glad you can still get the vacuum chamber and buy it as a separate part. No Rusty? .... by the fire of course!! Great video, good luck from Spain!!
you can plot the mechanical advance curve from the data provided in the Bentley manual. Some of the Triumph cars maxed out the mechanical advance at 2500 RPM, others maxed out at 5000 RPM. As described, it is required as the time of combustion remains the same but the crankshaft rotation speed does not. technically, the goal is to have peak cylinder pressure occur in the range of 14 - 20 degrees ATDC depending if the engine is under or over square. the statement of time of combustion remains the same isn’t entirely true, only at wide open throttle. less than WOT means less molecules which means longer time of combustion which means you need some advance to have peak cylinder pressure to occur at the proper point for your engine bore and stroke.
Sparkplug gaps are so important because of time taken by electricity to jump the gap and the fatness of the spark .old plugs with big gaps have weak spark and combustion is not lit properly. Every 1000 miles a plug gap increases by 1000th of an inch so you really need to check and gap plugs when you change your oil.
I'm confused how come these motors never had a manifold vacuum port. To test the engine using a vacuum gauge, (which is a very powerful diagnostic tool) is almost impossible. I would be tempted to drill, tap and fit a small port in the manifold somewhere for future testing.
The mechanical advance is an advance, the rotor move counter clockwise so increase the advance. The vacuum must be take in the manifold ( seems your manifold has no input plug ) not in the port vacuum on the carb, port vacuum give in fact the throttle position for the vacuum advance. Regards.
You need the vacuum advance to operate only when the throttle is open, therefore you need vacuum from the carb, before the throttle plate. The manifold is under vacuum at idle and if you plug you vacuum advance there your timing will be advanced at idle as well, which is not what it’s purpose is.
@@RustyBeauties Of course you connect for the vacuum advance to the vacuum carb port but for adjusting the timing of the distributor ( by turning it and searching the highest vacuum) I connect my vacuum gauge to the vacuum manifold plug, so the vacuum is non relate to the position of the butterfly of the carb. Regards Elin.
I strongly recommend only use their plastic feeler guage provided. Never use a steel feelr guage for that; can upset/ break the sensor. Ask me how I know.
Thanks! That is interesting though. They say in the instructions to use the gauge provided or a metal feeler gauge.... Well, it is worth staying safe so, thanks
You shouldn’t put the grease on the Bob weights because with the engine heat and time it will dry out and make them not move freely 😢 Ps good video though and enjoyed it many thanks ☺️
Interestingly the TR6 PI engine does not use the vacuum advance line at all. The line is capped off and doesn't attach to the distributor, so all the advance is done by the bob weights. I think that you are supposed to disconnect the vacuum line from the distributor when you are adjusting the timing with a strobe light.
Thank you Elin for this master class in Electronic Ignition. Your instructions were perfect.
Elin - the best car maintenance/restoration channel on RUclips thank you.
The idea of solid vacuum advance pipe with LUCAS distributors is, that once the distributer is set, it doesn't need to move ever again. The mistake people make is adjusting the timing by rotating the distributor (like normal distributors). Yes it works and I've done it myself. But if you read the manual, your supposed to wind the advance and retard screw on the vacuum knurled knob till the mid point on the vernier scale is reached. which is the thickest line. Adjust the distributer to the correct timing and lock it off. Any adjustment in the future can then be done with the knurled knob when the car is running. Some cars even where supposed to be set to TDC, then a certain number of clicks on the knob would give you the correct advance.
BTW at full throttle the diaphragm isn't used on the distributer. The throttle is at WOT therefore there's hardly any vacuum on the diaphragm. The whole idea of the diaphragm is to make the car more economical when cruising (high vacuum). Highest vacuum is on the overrun, when your engine is running fast but the throttle is shut, for example slowing down while going down hill. You will know this is true if you've ever driven a car with vacuum wipers 😂. Race bred engines did away with vacuum advance (like the Lotus Elan's), as they weren't concerned with economy. Some performance engines are timed at max advance like early Porsche's. And require a timing light and the engine running at about 4000rpm. Normal MAX advance on your average engine is 20-30 degrees BTDC. And between 2-8 degrees when fully retarded at idle. Because there is a high vacuum at idle the manual will tell you to disconnect the vacuum line and plug it to set the timing.
Always the best way to time an engine is with a timing light not a vacuum gauge. The light will show you exactly what's happening. A vacuum gauge can easily be thrown off by so many other factors and rarely gives an accurate guide.
Thanks Gary for the detailed information! I agree with you on the use of a timing light instead of a vacuum gauge - I've had terrible results trying to set timing with a vacuum gauge.
@@geraldschrader8511 I always used a timing light when adjusting my TR4. Made the job so much easier.
You Sir are spot on correct with your comment 👍
Thanks Elin for your lesson on advancing of the spark. It seems to me that the weights come into play at high engine rpm, but hit a limiter stop at a certain rpm, and the vacuum advance works only on the advance when the manifold vacuum is at its highest as it comes off idle when accelerating and not at high speed 'cruise'. I recall that you could get different distributor weights if you wanted to modify the 'advance curve' of a distributor. Also, I believe one of the checks on a distributor is to check for play of the shaft inside the distributor housing because if you have a bad bushing there, you can get 'cam wobble' that upsets the spark break timing. I'm no pro, so I don't know! lol
The circlip is the genuine article. You should have counted the number of clicks when you undid the knurled nut so you can return it to the original position.
The rubber diaphragms crack over time if not in use. It's possible to repair them if desperate but it's better to get a new one.
Hi Elin
Thank you for your patience to explain us so important things about classic beauties.
By mistake I bougth a magnatronic lumination ignition for a 25D6 distributeur but my 1969 TR6 have a 22D6 distributeur.
May I use it or it´s best to trade it for a specific one?
Thank you and regards.
José nóbrega
Portugal
Great explanation of the timing process. I am grateful of your long format videos and the frequency of them.
Are you considering doing an EFI-conversion on one of the cars ? That would be really interesting...
Well done Elin!!!
That engine sounds really sweet compared with the one I have in my 4A; you have done a great job with the rebuild.
I suggest that you make a good inspection of the new vacuum unit when it arrives. I bought one not that long ago for my Triumph Stag; it came from one of the usual parts suppliers, but I found that that it was really notchy in operation when applying vacuum by mouth before installing it on the distributor. That unit was returned and I replaced it with one I was able to buy from a distributor rebuild specialist... it was much smoother in operation. I can picture you setting up a test rig to measure retraction vs level of vacuum ! I hope that you have better luck with your replacement than me.
I agree, that’s how I’ve always understood it….well done.
Elin excellent video! I believe on those old Lucas distributors once good time is established the little thumb wheel is good for one degree per revolution.,it’s good for going up in the mountains at higher elevations.
Great video as usual.
I might be wrong but in the UK spec cars, the bob weights and springs govern the advance curve at different revs. The vacuum advance mechanism advances the ignition at low throttle openings and higher revs (eg coasting downhill etc). I like the previous comment about a future efi project.
The mechanical advance adjusts the timing for speed. The vacuum advance adjusts for load, responding to throttle position.
The engine sounds great. Can't wait to hear it tuned. My 64 was really peppy and responsive when everything was in-sync. I'm loving this series! Thanks for sharing, Elin.
That was a real win. You can really see what a difference ignition makes.
I have been advised by so many classic car owners at shows to steer clear of electronic ignition, Troublesome and unreliable? After watching this extremely informative video Wow listening to that run. Not only learnt the advance and retard but also watch and listen to the experts! Thank Elin.
Wow.. What a difference.. Great tutorial on the in's & out's of distributors.
I have Pertronix on my old Beetle, one of the best mods ever. 20+ years now, not a single issue. Repro modern points and condensers are just not worth bothering with.
lots of great comments on timing. I used to tune air cooled VWs in the '70s and the hot setup was to replace the vacuum/mechanical distributor with a straight mechanical set to 32 degrees max advance. I recall a Don Garlits interview where he said they used 50 total on the hemi fuelers, but they only had to run for a few seconds. I am ready to install a Pertronix on TS394LO (TR2) and wonder which one Elin bought ? There are lots on Amazon. Maybe I should just go to Moss.
That sounds so much better and you're not finished yet!! Putting in a new starter sounds a good idea as well. Glad you can still get the vacuum chamber and buy it as a separate part.
No Rusty? .... by the fire of course!!
Great video, good luck from Spain!!
you can plot the mechanical advance curve from the data provided in the Bentley manual. Some of the Triumph cars maxed out the mechanical advance at 2500 RPM, others maxed out at 5000 RPM. As described, it is required as the time of combustion remains the same but the crankshaft rotation speed does not. technically, the goal is to have peak cylinder pressure occur in the range of 14 - 20 degrees ATDC depending if the engine is under or over square. the statement of time of combustion remains the same isn’t entirely true, only at wide open throttle. less than WOT means less molecules which means longer time of combustion which means you need some advance to have peak cylinder pressure to occur at the proper point for your engine bore and stroke.
Very informative
Don't forget to lube the cam bushing. Normally there is a felt button inserted so a drop of oil can be applied for this purpose.
Thank you for the ignition advance tutorial
Sparkplug gaps are so important because of time taken by electricity to jump the gap and the fatness of the spark .old plugs with big gaps have weak spark and combustion is not lit properly. Every 1000 miles a plug gap increases by 1000th of an inch so you really need to check and gap plugs when you change your oil.
Nicely done!
Very interesting video, thanks
I'm confused how come these motors never had a manifold vacuum port. To test the engine using a vacuum gauge, (which is a very powerful diagnostic tool) is almost impossible. I would be tempted to drill, tap and fit a small port in the manifold somewhere for future testing.
Sounds lovely, I might book myself into you for an overhaul, as I`m the same age as the car and sound a lot worse 😂
The mechanical advance is an advance, the rotor move counter clockwise so increase the advance. The vacuum must be take in the manifold ( seems your manifold has no input plug ) not in the port vacuum on the carb, port vacuum give in fact the throttle position for the vacuum advance. Regards.
You need the vacuum advance to operate only when the throttle is open, therefore you need vacuum from the carb, before the throttle plate. The manifold is under vacuum at idle and if you plug you vacuum advance there your timing will be advanced at idle as well, which is not what it’s purpose is.
@@RustyBeauties Of course you connect for the vacuum advance to the vacuum carb port but for adjusting the timing of the distributor ( by turning it and searching the highest vacuum) I connect my vacuum gauge to the vacuum manifold plug, so the vacuum is non relate to the position of the butterfly of the carb. Regards Elin.
I strongly recommend only use their plastic feeler guage provided. Never use a steel feelr guage for that; can upset/ break the sensor. Ask me how I know.
Thanks! That is interesting though. They say in the instructions to use the gauge provided or a metal feeler gauge.... Well, it is worth staying safe so, thanks
Elin, would this be the same for a TR6 ?
Yes and no :) The ignitor and the magnetic ring are different for a 6 cylinder, but the installation and the principal are the same.
👌🏼
You shouldn’t put the grease on the Bob weights because with the engine heat and time it will dry out and make them not move freely 😢
Ps good video though and enjoyed it many thanks ☺️
Is there anything you cant do Elin only 3 degrees WOW
Interestingly the TR6 PI engine does not use the vacuum advance line at all. The line is capped off and doesn't attach to the distributor, so all the advance is done by the bob weights.
I think that you are supposed to disconnect the vacuum line from the distributor when you are adjusting the timing with a strobe light.