Finding the best ignition values

Engine Oily Bits, Ignition, Fuelling, Cooling, Exhaust, etc.
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Peter Douglas W
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Finding the best ignition values

#1 Post by Peter Douglas W » Fri Jul 29, 2022 6:56 pm

My saloon seems to be lacking in power. Everything from A to Z has been checked even Super Plus Petrol. No improvment. I am just wondering because of the petrol, the year, the miles, the new head, if the ignition point is no longer valid.

Years ago I learnt to advance the ignition until the engine pinks then back it off a bit. This is great when you are doing it all alone and cannot even hear a doorbell ring. So this a no go.

The next one was to measure the engine vacuum and turn the dissy untill you got maximum vacuum then, back it off about 1" of Mercury. This does work so long as you keep on changing the idle speed everytime to keep the idle speed constant. I just wondred as this info is stone age technology whether there is another way. How does a Garage do it nowdays when there is no data over the engine. I don't think they can keep on doing test runs nowdays that will cost a bomb. I don't think a laptop will work on my car. :D :D :D
Peter Douglas Winn
A happy Triumph owner.

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david_lall
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Re: Finding the best ignition values

#2 Post by david_lall » Sat Jul 30, 2022 1:33 pm

Are you on carbs or injection? Has a compression test been done?

The factory standard timing is valid as a starting point and incremental advance with checks for pinking out on the road is as valid as ever!
David Lall

1972 Triumph 2.5 PI Estate Royal Blue
1968 MG 1300 Saloon Connaught Green
1978 Carlight Casetta Caravan
http://carlightrestoration.blogspot.co.uk
1995 Lada Riva 1.5 Estate Cherry

Peter Douglas W
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Re: Finding the best ignition values

#3 Post by Peter Douglas W » Sat Jul 30, 2022 3:05 pm

Carb job. The days of injection have long gone.whereby I always had excellent results and never any problems with the PI system.

You say the book values are a starting point. Great but what do you do when you have absolutly no idea what is under the bonnet? You don*t even know which book to use. I know there are many bastard cars out on the roads.

Unfortunately I have no club members in the near and all my neighbours are way over the hill.
The head is new 5.000 miles, so no I have not done a compression test.
I will have to get my hearing aid out and see what happens.
It was just a thought.
Peter Douglas Winn
A happy Triumph owner.

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david_lall
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Re: Finding the best ignition values

#4 Post by david_lall » Sat Jul 30, 2022 6:37 pm

If you don't have a standard setup then the only way to get optimum performance, which will also ensure that you don't burn any valves out, is to get a rolling road setup....even if that does mean expense and a distance to travel.
David Lall

1972 Triumph 2.5 PI Estate Royal Blue
1968 MG 1300 Saloon Connaught Green
1978 Carlight Casetta Caravan
http://carlightrestoration.blogspot.co.uk
1995 Lada Riva 1.5 Estate Cherry

Peter Douglas W
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Re: Finding the best ignition values

#5 Post by Peter Douglas W » Sun Jul 31, 2022 5:50 am

Did not think about this varient as I have always done everything on my own.
Peter Douglas Winn
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david_lall
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Re: Finding the best ignition values

#6 Post by david_lall » Sun Jul 31, 2022 11:44 am

Every one of my cars is always rolling road tuned after I've finished tinkering.... Interestingly even the Lada which I returned to original Russian spec (UK had ECU, 3-stage automatic choke, single exhaust manifold downpipe and a cat). I did use a genuine Weber (which is still manufactured) rather than the Russian copy and a K&N air filter. The exhaust manifold etc was sourced from Russia.

Now you'd have thought that in virtually identical Russian spec with less than 15,000 miles covered it'd be spot on following factory timing etc... It did run really very well but nevertheless I had it rolling road tuned, one of the Weber supplied jets (don't forget this is their Lada conversion kit) was changed and with a few ignition tweaks it was made even better achieving both torque and bhp figures claimed by the manufacturer!

When I had the Triumph checked out it came back better.... To a large extent the PI metering unit is self calibrating so one might argue there's little point having a rolling road tune but it's important to find a place that also understands ignition curves as you can't really do that at home and in the case of my PI this was tweaked - the engine has an S-head, K&N cone filter and a semi sports Witor exhaust and apart from standard lift roller rockers it's a standard setup.

My MG 1300 is bored out to 1380cc with all the accompanying bells and whistles so the rolling road is a must but in the past I've seen dramatic improvements to a bog standard Austin 1300 GT after the rolling road operator changed the factory standard SU carb needles.

Lastly, I'd suggest to you that you find a rolling road that addresses ignition curves (not all do) and also one that is genuinely familiar with your make of carbs
David Lall

1972 Triumph 2.5 PI Estate Royal Blue
1968 MG 1300 Saloon Connaught Green
1978 Carlight Casetta Caravan
http://carlightrestoration.blogspot.co.uk
1995 Lada Riva 1.5 Estate Cherry

Peter Douglas W
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Re: Finding the best ignition values

#7 Post by Peter Douglas W » Sun Jul 31, 2022 11:47 am

Thanks
Peter Douglas Winn
A happy Triumph owner.

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