Timing

[Mike J]

I've wasted hours trying to set the timing to 12 then 14 then 12. Do it by feel . Mine is now set at about 18+ and is a totally new car. I now love this engine. Forget strobe lights have some one sit in the car gently rev it and set as you feel fit. Fuel consumption will be out the window. There are too many varients to say it must be 14 16 or even 18 Hay Ho.

[nib]

Hi Mike
Wont it run a bit hotter?
Have you got electronic ignition or points?
Mark

[flying farmer]

I generally just keep adding ignition timing until it pinks, then back it off a couple of degrees. I have one engine at 12 degrees, and two at 18 degrees. In my experience the MK1 dizzy gives more pinking problems as it has 13 degrees of centrifugal advance, the MK2 only has 7 degrees. The engine will only run hotter if the ignition timing is retarded, as more throttle is needed for any given speed, which means more fuel burned, hence more heat produced.
Neil

[Sheepdip]

A topical subject as only yesterday was trying to work out how to get TDC through a plug hole to check on pulley. Even a slightly bent timing plate will show a few degrees out. Does anyone have a method or as Mike says just gor for trial and error?

Paul

[Colonel Mustard]

Just a word of caution regarding ignition timing...

...because the fuel/air mix takes time to reach max pressure it is ignited before the piston reaches top dead centre. The ideal goal being to have the maximum force possible to drive the piston back down the cylinder bore. There are so many variables with each engine design surrounding thermal, mechanical and volumetric efficiency that each manufacturer puts a lot of research and testing into deciding ignition timing.

If the timing is slightly retarded there is no doubt that the engine is not operating at maximum efficiency. It will be down on power and probably use more fuel but combustion temperatures are libel to be lower.

If the timing is too advanced the engine is still not operating at maximum efficiency but this time the combustion temperatures are very likely to be higher...perhaps considerably higher than normal.

You are absolutely correct in asuming that any misalignment in the crankshaft pulley will give you the wrong reading with a strobe light. Also a worn distributor with tired springs or a vacuum advance that is not working correctly will also have an effect.

Doing it by ear and listening for pinking is all very well but some engines pink more readily than others. My Stag has never pinked so I can't say whether the TV8 will make that sound as soon as you over advance the timing but I am reminded of a friend who messed about with the timing on his Opel Record many years ago...it didn't pink...in fact it ran very well indeed, but when we opened the bonet we were amazed to see the exhaust front pipe glowing bright orange! (a weak fuel mixture will have the same effect).

Even super unleaded fuel has a lower octane rating than 4 star used to so I'd just be a bit carefull about getting too ambitious with ignition timing...you don't want to melt a piston.

As for manually checking TDC...gosh I haven't done this since the 1980's when I used to rally...but you'll need a dial gauge. Normally you would do this before fitting the cylinder heads with the gauge touching the top of the piston and rotate the engine to determine TDC. It should be possible through the spark plug hole...never tried it on a TV8 so not sure if you can get a rod to accuarately touch the piston. Once you know where TDC is (check it more than once) you can mark the crankshaft pulley.

Hope some of this makes sense.

Chris

[Sheepdip]

Chris, what you say makes sense, I was told retarded could burn valves, advanced could overheat the piston. I guess Neil is closest with advancing until pinking heard then a tad back, after all thats how knock sensors work, only problem is if you don't hear it. I can't see why the static timing should alter that much between engines other than distributor setup and fuel supplier, but open to comments.

Re checking TDC, tried at w/e and its a pig as need a sort of Z on its side, accurately supported then use dial gauge. Then remembered I have an old compression gauge, simply a tyre pressure gauge on a plug adapter. If I connect a thin plastic U tube with some water in it, in place of the gauge then should be able to monitor cylinder pressure as I turn the crank. Thats the theory anyway.....

Paul

[Gresley]

I run mine at an indicated 12 deg BTDC on the pulley (very late MK2) and it runs lovely on super unleaded and runs well on all but one make of 95 octane without pinking.

Brian

[flying farmer]

Once in a while I will get pinking after filling up with a dodgy tank of fuel (maybe once or twice a year), that tells me timing is about right.
There is one way to check top dead center on an engine. Take an old spark plug, knock the ceramic center out of it, then tap a convenient thread up the middle. A long threaded bolt can then be screwed in, and the engine gently turned until the piston hits the bolt.Check the timing marks, it is best to aim for about 15-20 degrees BTDC as there is very little vertical movement of the piston in the last few degrees, then turn the engine backwards untill it hits the bolt again. If the timing marks are correct then it should be the same BTDC and ATDC. if it is 4 degrees different, then the marks are 2 degrees out
Neil

[Mike J]

Fantastic to get so much knowlege. I've now done about 150 miles since reset and loved every min. No pinking. Never a dull moment with a Stag is there. Think I might look out for a spare engine Just in case. Engine rebuild could be my winter project. Wonder if I could get a Subaru H6 to fit. ( Joking)

[pcoleman]

I took the easy way out as car was very sluggish after the winter lay up and didn't want to pull at all,went to a local recommended tune up guy with a rolling road set up and the car is a different beast now as the running is transformed,it even sounds better and goes like stink worth every penny IMHO. I would have loved to have seen the look on the face of the boy racer in his "hot hatch" as he tried to overtake this old guy in his old car on the slip road to our local dual carriageway but the little s**t was too far behind to see,oh don't you just love stags

Pete.c

[big lad]

Pete,
could you let me have ths name and address of the tuner, thanks

Tony

[jbuckl]

Re: long bolt down the spark plug thread:-

This method is ok for engines with plugs inclined closer to vertical than the stag plugs.
I suggest its very/too easy to 'jam the bolt' against the rising piston crown in a stag.