No Ignition Advance

[bob dunn]

these engines were made to run on  leaded petrol , unleaded petrol takes longer to burn so you have to retard the ignition a bit more than the book says, to give time for the petrol to burn, my mk4 75 spit is 8 deg before in the book and is running at appx 13 deg btdc . turn the engine to top dead centre on the compression  stroke (both valves closed). mark the pully at the top . measure the pully dia . draw a circle that size , 3.142 times dia is circ . circ times 13/360 = distance on the edge of the pully from tdc to 13 deg before tdc . i do not wish to insult your inteligence , i,m only trying to help .  

[Pete Lewis]

you wont strip down a delco centre spindle and weights unless youwant to  wreck it,  
some intial slack in the springs is normal,
just make sure the movingtop plate does rotate when you suck the vac unit hard.
make sure anty screws thro the top plate do not bottom out into the bottom plate and losk it solid.

Pete

[SpitNoir]

Hi Bob. No insult taken (so glad none was offered!) and always happy for pointers and reminders.
I thought unleaded would burn quicker though? But maybe that's only the case for lower octane vs higher. Don't remember hearing one way or t'other regarding unleaded vs leaded. Learn something new every day.
If that's the case though, would you by chance have meant to say "advance" rather than "retard" the ignition? That's what it looks like though, by your stated numbers, so that's the way I'm taking it.
I like running engines with as much advance as they like though, so expect to do some experimentation initially, to see what it likes.

At this point in the game, I don't think I'll bother with the marks unless the existing one turns out to be off. I am going to check the existing one though, to make sure it's accurate enough for me. So I may end up doing it after all.
Reason I don't feel the need to bother with the extended markings at this point is that I have a "dial-back" type timing light, which will let me literally read the advance from the dial on the back of the gun.
Probably not as precise as markings on the pulley, but good enough for now.

Heck, I'm still hoping that my fiddling around with it, has caused the distributor to loosen up a bit and give me some controlled advance at all!

Thanks

Paul

[SpitNoir]

peterhlewis wrote:

you wont strip down a delco centre spindle and weights unless youwant to  wreck it,  
some intial slack in the springs is normal,
just make sure the movingtop plate does rotate when you suck the vac unit hard.
make sure anty screws thro the top plate do not bottom out into the bottom plate and losk it solid.

Pete

Cheers Pete.
So I've found! The plate was definitely not going to come off from the top. Didn't realize that it would be trouble even if I took the whole thing apart though. Now I'm glad I didn't go to the extra trouble.

The initial slack was there as expected, but the issue I saw was that the weights were not fully retracting as I would expect. Seemed to be a bit sticky, so I used copious amounts of carb cleaner and thin lubricant (WD-40) to see if I could smooth out the action. Seemed to help at least somewhat.

I didn't like the initial slack in the secondary spring however. It might be normal, but I would suspect that to allow the weight to start it's journey outward earlier than desirable and then perhaps add initial timing that could never be taken out of the equation.
And that spring was STIFF!
Yeah, I know that's what the design calls for, but I've never seen a spring rated that heavy in a distributor. So I changed it out for a slightly lighter one that gripped the post enough to keep the weight from opening until it was able to pull against the spring.
Not being an expert dizzy-modifier, I'm sure this could be an incorrect way of adjusting things. But I think it will at least be better than what I had.
Fingers crossed...

Here are some pics of the offending unit. For anyone that wondered, after trying to figure out what model this was, the part number is "D200 7953557" with both "Delco-Remy" and AC Delco clearly stamped into the housing.

Don't know how to post pics and text in the same place, so they're all seen below.

Thanks to all. I'll let you know what happens when I get the new plug wires routed.

Paul

[SpitNoir]

Posted larger pics than intended. In the first you can see the original spring on the left, with the new springs I had from a Ford kit.
I used the Purple one as the replacement.

Oh, and the advance plate seemed well and tight, with no screws jamming things up. But I cleaned and re-lubed it anyway.
The vacuum advance does not respond at all to my sucking, but does pull in slightly with a lot of help from my manual vacuum pump. So while it does hold a vacuum for a few seconds before leaking down, it takes quite a bit (more than the engine seems to have at the moment anyway) to get it to work. We'll see if anything has changed when it's back and running.

Added yet another ground to my system by attaching one to the earthing screw on the side of the distributor where the internal earth braid is, and ran it to ground at one of the starter relay's mounting bolts.
Just as a way of making sure the Pertronix Ignitor has the best connections possible.

Paul

[Pete Lewis]

there wont be much vacuum at idle to the vac unit , it developes most at light mid throttle ie like a 55mph cruise

the vac take off is just beyond the throttle plate , it developes vac from air passing over a small port in the throat.

and has nothing to do with manifold vacuum which is great at idle or overun and low with throttle open ...totally different .
in general you can suck ( till a gentle blue colour) to make the vac unoit respond but can get a uick suck of nasty petrol oil mix ,hence the   need of  a whisky gargle .
Pete

[SpitNoir]

Newest update.
It's all back in and tight, but some other things have cropped up.
Naturally, I just couldn't resist the temptation to put in new plugs and wires too. Might not have been a bad idea under normal circumstances, but when you're trying to diagnose some issues, best to try to keep changes to the one-at-a-time variety.
Easier to track what's happening that way.

It barely runs now. Hard to start. Won't start at all if I open the throttle even slightly, but will finally fire if I leave the choke closed and my hand off the carbs. Then it actually runs semi-respectably, but dies within 10 seconds or so.
This is possibly another issue, like a sticky carburetor, but it's hard to know when you've just had the ignition so far apart. Might just need to reset the idle settings on the carbs, now that the advance is in a more normal reading, rather than what I started with.
Sounds like more detectiving in store for me.

When it does see fit to start, it's showing about 15° advance while the starter is cranking and it just catches. When the rpms come up to idle speed (about 700 rpm now, instead of the previous 1100) I can watch the timing rise to about 20° or so. This is with the timing light hooked up and activated before I push the button on the starter relay/solenoid. So I see timing from initial cranking to full idle.
Evidently the springs don't hold the weights back at even minimal rpms. Is this initial advance normal? It's been so long, I can't remember if it starts advancing instantly, or after 1000 rpm or so.
The strobe pulses were very steady and consistent however, so the ignition seems to be doing it's job in that regard.

I could not retard the timing to much below the 15°, as it would die before I got very far. Nor could I give it gas to see what effect higher rpms have on the timing because it would die as soon as I opened the throttle. If I let off quickly however, it would sometimes catch back at idle for a few seconds.
The short run-time could have simply been the cold, as it would idle longer and longer as time went by with multiple starts. This went on for perhaps 10 starts before I had to give up and move on to other things around the house.

Something else that cropped up is very interesting. If you remember, as originally set up, the number-1 spark plug wire was at the 7 o'clock position and number-4 was at the 10 o'clock position, where the 1 wire would normally be located. When I lined the timing mark up again however, the rotor was pointed to 10 o'clock! So, after doing a bang-up job on making new wires to fit just where I wanted them, I had to change them all around to fit into their originally expected positions in the cap. Oh well.
And curiouser and curiouser....

Starter is now making all sorts of nice ringy-dingy rattling noises when it disengages too, so looks like it's time for a new one after all (talked about in another thread). Gives me another reason to stop half-way into one thing, only to start another.
Never ends, does it?

Thanks for listening. Now to go find a little cheese for my whine.

Paul

[Pete Lewis]

one thing if you use a strobe with a hook over pick up many are polarity sensitive, there is noramally an arrow on the back of the pick up to pick to lpugs.
if wrong this can give you some really daft strobe flashes.

two springs on an advance one soft and  one stronger taht normally is a loose fit when not rotating to give low speed and higher speed graph hysterisis.

where the rotor points for no1 depends on where the drive gear is positioned , see manual

apart from in some postions you cant fit the dizzy other than that it doesnt matter , providing the rotor knows where No1 lead is
sounds a bit like you have this a little mixed .   sorry if im wrong here .

to get where is No1 , I sugest take out plugs, stick thumb over no1 plughole,  turn engine slow till air starts to expel past thumb
you may need an assistant here.

continue to turn a little further till the  tdc marks align

now look at rotor , fit the leads in the cap to start with No1 above the rotor( close to) and fit the rest  to get 1342  anticlockwise

[SpitNoir]

Cheers Pete.
I didn't do the finger over the plug hole routine because I'm still "assuming" that the timing marks are correct. If so, then the number one location seems correct between the timing mark, distributor rotor direction, and location of number one plug wire. Now at least.
When it was set up as I received it, number one plug wire was in the 7 o'clock position (as viewed from the side of the engine) which seemed odd, since most I've seen (including in the book) were in the 10 o'clock position. I didn't change it until now however, since it took me that long to find the timing mark and to verify the distributor was functioning. Which is does seem to be.
My original assumption was that the drive gear was a tooth or two off in one direction, which would put the rotor in a different location. If you remember though, this whole thing started with an advance reading of near 35 degrees or so.
This might start to explain things a bit.

Although I was aware of the polarity aspect of the pickup, I did not in fact check. I'll do that next time playing around under there. I've never had issue before, as the light I use has always worked correctly as long as I put the "U" portion of the pickup on top of the wire, as instructed. Perhaps I've just been lucky with other vehicles however, and have just now run afoul of reality.
So I'll check that.

Thanks for the reminder.
Now to try and determine whether the current starting issue lies with the ignition or the carbs.

Paul

[don cook1]

I agree with Pete. Go back to basic stuff. Find TDC on the firing stroke, take off dizzy cap and put No1 lead in the cap directly over the rotor arm. Look in your manual for image of the firing order and move plug leads to suit, taking the cue from No.1 lead, which you know must be correct. Course, you might be ok. Before replacing the plug rock the engine back and forth with the ignition switched on and you should see the plug spark: belt and braces! That should sort out the correct firing order. If the vac advance isn't working by sucking on it then it needs repairing...no/little advance otherwise. Having done this and if it runs then you can always find yourself a hill and drive up it in 4th and increase the advance a little bit at a time until it just starts to pink, then retard it a tad. That's your timing done.

[markcro]

Did you ever get to the bottom of this issue?

[SpitNoir]

Hi markcro.

Nope, not quite. Been out of circulation (car-wise that is) for awhile, and still need to install the new starter motor first. Have to do that before I can get back to the carb/timing issues.

I got the old starter motor out, covered in another thread, but have not yet done the pre-install depth checks and clearances like the service manual states.
It's next on the list though.

I hate delays, but I let lots of life's little mysteries get in my way constantly.
Will post up as soon as there is progress.

Paul

[markcro]

Best of luck Paul and keep us posted.  :)

[piman]

Hello Paul.

just to pick up on your timing at crank and at idle, yes at 700 rpm you may have some initial advance, it depends on your distributor. If you let me know the distributor number stamped on the side (5 digit, not 25D4, that is the type) I can probably tell you what the advance starts at?
15 degrees sounds a bit advanced by the way which won't help starting?

Alec

[SpitNoir]

Hi Alec. Sorry for the delay in replying. I don't get notifications via e-mail, so responding is sometimes a hit-or-miss thing.

Just happen to have the numbers right heah' in fact.
Uh, well, they were here the day before yesterday, when they fell out of the stack on to my keyboard and then got re-shuffled.

Will post up as soon as I find the paper again.

Paul

[SpitNoir]

Bingo. After taking a breather and an episode of Hawaii 5-0 to straighten out my thoughts, I found the paper mid-way down a stack.

The only stampings on the distributor body are:

Delco - Remy
D200  7953557
                                      AC Delco
                                         K8

Brit. Pat. No 79770

Does this shed any light?

Paul

[piman]

Hello Paul,

I'm sorry, I don't have any data for that, only Lucas distributors.

Alec

[drofgum]

Paul,
That is a Mk3 Spitfire distributor. I'm rushing out the door to work at the mo, but can get back with a list of advance figures this evening.
                                                                         Cheers,
                                                                         Paul

[uksnatcher]

Save you a job Paul....and Paul...:)

D200 7953557 Mk3 Spit

D200 7953557 (Emission controlled, 8.5:1 CR)

516 rpm 0 degrees
600 rpm 0 to 2 deg
1500 rpm 19.6 to 23.6 deg
2000 rpm 21.16 to 25.16 deg
3200 rpm 24.88 to 28.88 deg
4000 rpm 28.0 to 32.0 deg
5000 rpm 32.0 deg (maximum possible)

http://www.totallytriumph.net/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=112&forum=DCForumID5

Hope this helps.. ;)

[drofgum]

Gaz,
Thanks, exactly the figures I have though I wasn't getting them from TTN.
                                                                         Cheers,
                                                                         Paul