Page 1 of 1

Timing Question - too much advance?

Posted: Thu Sep 15, 2022 5:16 pm
by Chris83
I was hoping someone might be able to help me with a timing question on for my 2.0ltr. It engine simply isn't running right especially for you rev it as it pops and misses and I think it is because there is way to much advance above idle. The static advance is set to 8 degrees and at about 2500rpm is goes to 46 degrees with vacuum attached and about 39 to 40 degrees without vacuum (plugged off). The distributor is an accu spark one and there appears to be no way to adjust it. The reason I think it's too advanced is when the vacuum is disconnect the engine issue is nowhere near as bad. I have put new gaskets on the carb inlet manifold so these are good and a compression test I did shows 160psi on each cylinder so all this side of things is good as well.

I am not a mechanic, but the only thing I can think of is this advance seems way to high. Any help on this would be appreciated. If the distributor is junk any idea where to get a decent electronic one from?

Re: Timing Question - too much advance?

Posted: Thu Sep 15, 2022 5:27 pm
by SCP440
If you loosen the clamp and retard it while its running does it get any better?
You can restrict the total advance by shortening the slots in the distributor, some dissasembly will be needed but you can use something like Araldite.
What fuel are you using? How old is the fuel? E10 can start going off in a couple of months, some brands of E5 are not as good as others but that is a subject for another thread.

Re: Timing Question - too much advance?

Posted: Thu Sep 15, 2022 6:25 pm
by Chris83
Thanks for your reply.

I will try that tomorrow, as in theory it should eliminate it but probably won't idle (or idle badly) as it be retarded rather than advanced at that speed.

What I have done is fag packet measure the mechanical advance by hand with a protractor and I am getting about/ just over 30 degrees, so that ties in with what I was getting with the timing light. Trouble is I can't find what the standard specifications are for mechanical and vacuum advance, as nothing in the Haynes manual and Google comes up with pretty much nothing!

Re: Timing Question - too much advance?

Posted: Thu Sep 15, 2022 7:44 pm
by Mc Tool
I dunno what the full advance timing is ....but a total of 8deg plus your 30 ish doesnt sound toooooo bad .
The popping and banging suggests an intermittent fault rather than a constant fault like off timing .
I would check other stuff .......like plug leads , plugs dizzy cap and rotor .
My crapi idled well and was ok up to about 2500rpm then it would start missing and back firing . Unfortunately I had just "fixed " the carb so I fixated on that ......nearly went mad . In despiration I fitted a million volt blaster coil😁 which fixed the problem .........for about a day. Eventually I put a meter over the plug leads and they were all #ucked ,even tho they looked like they were new.
Hard to say from way down here but one thing I will say ( specially with misfiring )is not to get tunnel vision 🙂.
If you have set the static timing at about 8deg and the thing is advancing properly ....move on to checking something else. As I discovered it doesnt matter how many times you check something ( I had that carb to pieces 3-4 times ) that aint the problem the fault wont go away.
Good luck 🙂

Re: Timing Question - too much advance?

Posted: Thu Sep 15, 2022 8:01 pm
by Peter-S
Is the car new to you or have you had a while and this is a new fault?
Just wondering what you know of the carb and what the emissions are like, is it running way rich perhaps? Is it on a standard cam?

Re: Timing Question - too much advance?

Posted: Thu Sep 15, 2022 9:11 pm
by Chris83
Thanks for the replies.

I had the car a couple of years and it's never run right since I have had it.

I have changed the plugs a couple of times, tired different leads, replaced the PCV, changed vacuum hoses and checked for leaks to the brakes servo. Carb is also new (proper weber 32/36) and whilst this has sorted a couple of other things it's made no difference to this particular issue. All is standard including the cam with the exception of sportex exhaust and K&N air filter.

It has got me really stumped!

Re: Timing Question - too much advance?

Posted: Thu Sep 15, 2022 9:25 pm
by SCP440
What is the fuel air ratio when it is misfiring, a very lean or rich mixture can also cause big problomes obviously. Could you have a big air leak?
What is the voltage at the poistive side of the coil while it is running ? A bad Ballast resistor can lower the voltage. At least 7 volts is what I would be looking for. Rotor arm and dizzy cap can all be problem areas.

As has been said it is very easy to concentrate on one piece of the puzzle but miss something else.

Re: Timing Question - too much advance?

Posted: Thu Sep 15, 2022 11:40 pm
by Mc Tool
Uh ,ok🙂 , I can see why you are eyeing the dizzy/timing with some suspicion🤔 , everything else I would look at has been done .
Tight exhaust valve clearance can give issues but in my experience this show up as a lousy idle with little reaction to fiddling with the idle mix screw.
Is the accuspark dizzy electronic or points ?.......just thinking maybe condenser if it has one .
I spose the thing to do would be to borrow short term a known working dizzy just for elimination purposes ......Im sure Nick would lend you his 😂😂......( Di likes this idea.......and says hi 😀)
If there is a vacuum leak , spraying crc or wd40 what ev around the intake manifold gasket and carb base gasket can cause crc to be drawn into the intake system and this will cause an instantly detectable change in running .......indicating a leak . 😀

Re: Timing Question - too much advance?

Posted: Sat Sep 17, 2022 10:00 am
by Bug
Another thing you can try is go out to it on a dark night, pop the bonnet and rev it up.
Any dodgy connections or leads will spark up and you'll see it.

Re: Timing Question - too much advance?

Posted: Sat Sep 17, 2022 1:59 pm
by Caprigear
Sounds like a dodgy distributer to me. We have fitted these to our builds previously and they don't always run well if you set them to the book settings. We have had to sometimes set them up by ear and do several road runs to get them sorted. These distributors are sold for a variety of motors and I suspect the advance curve isn't quite right for the Capri.

Re: Timing Question - too much advance?

Posted: Sat Sep 17, 2022 4:13 pm
by Chris83
I finished sorting my MOT failures from yesterday on my daily driver and I have had another play with the Capri today and it seems to run better at speed when the static advance (or actually retard) is set to somewhere between -6 to -8, however it runs dreadful at idle! I think it has to be ignition related and probably the distributor. The perfect idle seems to be around 10 ish degrees and then is runs even worse when the engine is revved :doh:

I am also going to try what you suggested Bug and check it tonight when it dark for any dodgy connections such to satisfy this as well.

If I go for a new distributor are there any suggestions so that I don't end up with the same issue that don't break the bank or maybe this is just a faulty one?

Re: Timing Question - too much advance?

Posted: Sat Sep 17, 2022 4:13 pm
by Chris83
I finished sorting my MOT failures from yesterday on my daily driver and I have had another play with the Capri today and it seems to run better at speed when the static advance (or actually retard) is set to somewhere between -6 to -8, however it runs dreadful at idle! I think it has to be ignition related and probably the distributor. The perfect idle seems to be around 10 ish degrees and then is runs even worse when the engine is revved :doh:

I am also going to try what you suggested Bug and check it tonight when it dark for any dodgy connections such to satisfy this as well.

If I go for a new distributor are there any suggestions so that I don't end up with the same issue that don't break the bank or maybe this is just a faulty one?

Re: Timing Question - too much advance?

Posted: Sun Sep 18, 2022 3:16 pm
by D366Y
Last time I looked a standard Bosch (points) dizzy was about £130 Ish which was the whole shabang
May be the best place to start going back to basics/original?

Re: Timing Question - too much advance?

Posted: Tue Sep 20, 2022 1:14 pm
by sierra3dr
Chris83 wrote: Thu Sep 15, 2022 5:16 pm If the distributor is junk any idea where to get a decent electronic one from?
Has it been converted from points to electronic ignition?

Re: Timing Question - too much advance?

Posted: Wed Sep 21, 2022 10:31 am
by Chris83
It an accu spark distributor so it's not an original distributor conversion unfortunately!

Re: Timing Question - too much advance?

Posted: Wed Sep 21, 2022 9:39 pm
by A17 LTF
I fitted a H&H one years back and its been pretty reliable. Heard the accuspark units have their issues.