TR6 Ignition Timing using Strobe Light and Vacuum Gauge method

From buying to owning and improving the Triumph TR6 this series aims to give you all you need to know for living with this British classic icon.
In this episode we look at setting the ignition timing on a 1975 petrol injection UK car using a strobe light and then a vacuum gauge to get it spot on for best driving performance

[@ianwilliams4787]

I've always set my MG engine to 10 degs before someone suggested using a vac guage. Using this method it is around 20 degs now ! Runs great too ! Thanks for your vids !

[@mgmidget-thebirthofaraceca4349]

Glad it helped. Thanks for watching

[@codelocust3297]

all very clear, thanks a lot! As i have a 2500pi saloon which i bought with disassembled top engine and it's my first-ever Triumph (only VW and Audi 8v 10v 16v and 20v), well I'm glad i find such informative videos. Hope mine will run soon.

[@mgmidget-thebirthofaraceca4349]

Pleasure. Glad you enjoyed it

[@codelocust3297]

@@mgmidget-thebirthofaraceca4349 the car fired up yesterday, so i'll use all your videos to properly adjust everything. Thanks for your nice vids.

[@clivehaynes2183]

Great video, I have 3 old Bentleys that have the timing marks on the flywheel accessed from under the car behind a cover plate which is a complete pain. As one of the Bentleys (S3) which is a 6.75 ltr V8 has a twin point system which is also a pain to set up so I have purchased an acuspark module which does away with the twin point system and all the other benefits. I was going to set up the electronic system and rotae the distributor for the best running but having seen your video I will be using a vacuum gauge, many thanks.

[@mgmidget-thebirthofaraceca4349]

Thanks for watching and glad you enjoyed the video

[@paulmuff9883]

Very interesting, manny thanks 😊

[@mgmidget-thebirthofaraceca4349]

Glad you enjoyed it

[@lloyddunn1354]

Very informative as I recently purchased a 76 TR6 and need to tune/balance the triple webers, but first want to make sure the timing is correct.

[@mgmidget-thebirthofaraceca4349]

Glad it helped. thanks for watching

[@johnbyrne2890]

Very helpful! thanks !

[@mgmidget-thebirthofaraceca4349]

Glad it was helpful! thanks for the feedback

[@dochkaian]

As always . . first rate, thank you . .

[@mgmidget-thebirthofaraceca4349]

A pleasure. Glad you enjoyed the video. More to come :-)

[@lebojay]

Thank you for this, brother. Jag guy here. 😎

[@mgmidget-thebirthofaraceca4349]

no problem. thanks for watching. appreciate the feedback

[@seidelswalter]

nive vid, i will try your method

[@mgmidget-thebirthofaraceca4349]

Thanks for watching

[@tristanhagerty2006]

Hi there Mr MG, this is a warning, but first, another great video. Ive recently been chasing my tail with the ignition system which I took out the old points system and worn coil and done what you’ve got on your car, an Accuspark system. It was easy to install and as soon as I plugged it in it started at the first turn of the key. It did have a rough idle because the timing was off but after timing it it ran nice…for ten miles. After I switched it off outside my brothers house, after having lunch it wouldn’t restart. The whole system had broken, all of it was kaput. The coil had given up, the kit inside the new dizzy was dead but I presume the leads and the plugs were fine. Everything was set up right but Accuspark said it was a faulty unit but never refunded me even after it got rather heated. So I had to buy a new luminition magnetronic system and a luminition coil and leads and some Ngk plugs. And the new magnetronic module fitted into the original dizzy. So be warned, there has been a number of bad reviews about the Accuspark and I’m now not going near it with a ten foot barge pole, and upon reflection it was very cheap considering it was a whole new ignition system. I would keep an eye on yours and consider changing. But a great vid apart from that Thanks Tristan

[@mgmidget-thebirthofaraceca4349]

Thanks Tristan for the extensive comment. Your views on accuspark noted. My experience so far has been OK after 2 years of use and around 3000 miles. Will keep an eye on it :-). Glad you liked the video and again, thanks for the input. Appreciated.

[@tristanhagerty2006]

@@mgmidget-thebirthofaraceca4349 wow 3000 miles. I’m sure that’s fine then, I wouldnt alter a thing if it’s run for that long.

[@joe-hp4nk]

The exhaust pulls more air through the intake than the piston. Therefore the more efficient the exhaust the more vacuum. Also the more overlap in the cam timing the better the exhaust pulls on the intake. All the best.

[@mgmidget-thebirthofaraceca4349]

Thanks Joe for the input.

[@joe-hp4nk]

@@mgmidget-thebirthofaraceca4349 For what it's worth.

[@sammoj9836]

Thank you for your videos. I live in the USA and I own a 1970 TR6 PI cp, righthand drive. My engine has been sightly bored out, has Fast cam 86 camshaft, and my timing is set to 14 deg BTD. I tried following your method of timing using a vacuum gauge and timing went up to the high twenties with a max vacuum reading of 12.5. Took the car for a drive and heard no pinging. I was hoping you could comment on that. How high is too high of a timing? How do I know what the correct timing should be? Much thanks, Cheers, Sam

[@mgmidget-thebirthofaraceca4349]

Thanks Sassan for the comment and sharing your experience. The The key is to listen to the engine revs as you retard the timing up from approx 10degs . The Vac goes up to its peak (leaner running) and the engine will pick up in its note. At this point lock off and test. I actually advanced the timing very slightly after that point to gain more fueling. Too far and either it will begin misfiring or on test drive it will start pinking on acceleration as its running too lean. I found mine runs best at around 16 deg BTDC (assuming the timing marks are correct). A spark plug soot colour check after a good run will also confirm if the mixture is running ok or too lean. Adjust as necessary. Hope that helps

[@sammoj9836]

Much thanks for your advice. I initially had the timing set to 14 BTDC, my car seemed a bit sluggish. After using the vacuum gauge, as I had mentioned, timing was set to 26. I took the car for a test drive, car drove well, accelerated well, and no pinging throughout the different gears and RPM ranges. I was too afraid and concern that at 26 BTDC It would do more harm than good. I will try 16. Again, much thanks for your videos. There is no one here that I could seek help from (its carburetor or nothing). Cheers.

[@amandasettee8922]

brought my uk tr from england to canada and havnt been able to get it running for years, recently after retireing I have more time to spend on it , its a pi unit which just baffles any mechanic here in canada they have no knowledge of it as all trs were carburated exported to north america, and after thousands of dollars of exspensive canadian mechanic knowledge no further ahead , when back in britain it was serviced by auto injectrics of hornchurch, a young guy who just started his bussiness when I bought the car in 75 ,so all service was done by him and it ran like a dream, so now im trying to gain knowledge of serviceing it myself , I used to do the timing with a strob like your video and worked ok , do you suggest a vacum is a better test as I plan to buy the neccesary gauges and equipment to work on the injection and metering unit pressures trying to learn as much as I can thanks for you video I will be following , sorry for the long message regards Bill Gregory

[@mgmidget-thebirthofaraceca4349]

Hi Bill, thanks for the comment. My approach to setting up the pi system is as follows - i hope it helps. 1. check constant 100-110 psi at the metering unit from the fuel pump then 2, check metering unit diaphragm integrity using the suck method. (ensure holds a vacuum) 3. check and bleed injectors to ensure spraying correctly, 4. set ignition to factory 11deg BTDC, 5. balance throttle bodies using adjustments and carb balancer tool. 6. fine tune timing using the vacuum gauge and test driving to optimise but ensuring no pinking. all very doable by the home mechanic. good luck with the engine tuning.

[@dusanseman9334]

Hi. Great video. I tried to see the setting on my tr6 pi but instead of vacuum 16 there is only 10 on my car. Is it wrong?

[@mgmidget-thebirthofaraceca4349]

Always worth checking for vacuum leaks but assuming it all looks OK, then i wouldnt be too focussed on a number. The principle is the biggest 'bang' from the best timing will give the most vacuum as the cylinders are pushed down. So setting the timing to give the highest vacuum regardless of the number will get the timing in the right place. After that the fine tuning is done by a road test. If the timing is too advanced and shows signs on 'pinking' on hard acceleration the timing so should be backed off until you are happy with the drive. This is the optimum position. It can take time to do and a rolling road tuning would find this much faster of course but it can be very rewarding and educational to do yourself. Good luck with the setup.

[@dusanseman9334]

Super thanks for the help. I'll try to set it up like this.

[@TheEulerID]

The engine bay seems to be left-right mirrored in the video for some reason (maybe green-screened?). Slightly disconcerting. That said, an interesting method and I've sent a link to the video to a friend who has bought a TR6 fairly recently.

[@mgmidget-thebirthofaraceca4349]

using the front camera on an iphone without mirroring the shot. so some videos look like they are reversed but the car is actually a RHD UK car

[@rutgergooszen9774]

You make great video's but technically some things are wrong here. First the 11 degrees is static timing. That is when the engine is NOT running. So with the strobe light you are measuring dynamic timing (with vacuum advance disconnected). That should be quite a bit more like 16-20 degrees at 1500 rpm (depending on the curve and vucuum advance). This is why the vacuum shows late ign timing. It should be advanced a lot more to read in the green zone. There is defenitley something wrong with your engine or ignition that you are not able to push the vacuum beyond 15-16 HG!. Finally you advise to advance the timing should any pinking be experienced in the road test. It is the opposite! Put the car in 3d gear and drive up a hill accelearting from 1500 rpm en should pinking occur then retard the timing a bit.(If you have a distributor with a fine tuning wheel it's easier) What are your thoughts on this? Also look at the Moss motors video kzbin.info/www/bejne/q6W4hHxjf76bjLc&ab_channel=MossMotors%2CLtd.

[@mgmidget-thebirthofaraceca4349]

Thanks for your input. Glad your enjoying the videos. If you read some of the other comments aswell you are absolutely right. when test driving and you experience pinking you should retard the timing. I do it a degree at a time until the pinking stops. Slip of the tongue when speaking to a camera and stringing sentences together I'm afraid. I'm considering updating this video to make it 100% correct but the principle of using the vacuum to initially set the timing on these cars remains sound and hopefully gets people thinking about this as an alternative to just dynamic timing strobe checks. Thanks for the comments - always appreciate good discussion

[@rutgergooszen9774]

@@mgmidget-thebirthofaraceca4349 I agree fully on using the vacuum! I always do it and I am able to reach 18-19 HG/inch. Again this should be a healthy and attianable score. You might have a vacuum leak of some kind. But you are right in saying it is about reaching an optimum value, regardless of the absolute figure.

[@v8pilot]

I want to understand why the maxiumum pressure in the cylinder after ignition leads to the maximum vacuum in the inlet manifold - I don't see how the one causes the other.

[@mgmidget-thebirthofaraceca4349]

The principle is that the bigger the bang through better ignition, the higher the suck on the induction system as the cylinders go down faster, so as 2 cylinders are on their combustion stroke they create a vacuum in the 2 cylinders on their induction stroke (via the crankshaft) pulling air into the chambers with open valves. The better the ignition, the higher this vacuum will be. So to set for the best timing you start by setting the timing to the best vacuum setting and then retard the timing a degree at a time until you get no pinking in hard acceleration in 3rd. At that point you have the car running the best it can. Hope that helps

[@v8pilot]

@@mgmidget-thebirthofaraceca4349 Many thanks for doing your best to explain it to me. I have no problem in understanding the statement that setting the timing to get maximum vacuum (then retarding to eleminate pinking on hard acceleration) is the best setting. That's more or less how I used to set the timing on my Ford 100E as a student years ago. My difficulty is in understanding why the best combustion leads to the highest vacuum. The speed that the pistons descend in their cylinders is determined by the rpm of the engine, so far as I can see - not by the efficiency of combustion. Maybe it is to do with the fact that, for a given rpm, at maximum engine efficiency, the throttle will be providing a greatest restriction of air into the induction manifold. At lesser efficiency, more fuel (and so more air also) will be entering the cylinders, so less constriction of flow by the throttle resulting in less vacuum..

[@mgmidget-thebirthofaraceca4349]

Yes, could be. Its not the complete answer for sure but using vacuum with get you a good starting point for final tuning on the road in the same way a timing gun will. The advantage on a TR6 is that as the timing on the crank pulley is lost due to wear over the years, vacuum is an outcome of the engine performance. Starting here and retarding the timing to remove pinking has never let me down yet. Interesting thread - thanks for the input

[@joe-hp4nk]

You want to be able to adjust the time curve for best performance.

[@mgmidget-thebirthofaraceca4349]

Thanks Joe for the input.

[@nkelly.9]

Close, but no cigar. You're doing it wrong. If you want to use the vacuum method you hold the revs at close to 1000 rpm, then you advance the distributor to get your highest vacuum reading, then back it off 1" of Hg. Still never precise. The manufacturers knew what they were doing, had performed exhaustive testing to arrive at the final product and had to guarantee their products. To pretend that some bloke in a garage knows better than all those clever blokes is a pisstake.. That said, Aston Martin, in the 1950's gave workshop advice regarding ignition timing, with no actual figures. They deemed that after having set the ignition points gaps and spark plug gaps to specifications, to advance the ignition timing and then road test the car. On the road test they said to load up the engine/lug it in low revs in top gear and listen for "pinging/pinking" whereby the timing should be retarded so that pinging was just no longer present if driven similarly. Those cars have no ignition timing marks from factory. Every engine is different. You have been reading too many forums and their un/mis informed old wives tales.