unbelivable strange timing phenomena

427Swede

Well-known member
Joined
Jan 6, 2011
Messages
369
Location
East coast of Sweden
Facts: Original TI distributor. Prev. owner added ignitor system. Do not know why.
Dist in very good shape.
I set base timing at 13º. At 2800-3000 i have around 36º.
Vacuum shows additional 16º.
Basically a sound setting for my engine, perhaps some more initial but it is ok for now.

The problem: after driving the car for a few miles it starts to get tired. A check of the timing shows it to be retarded -10º on base timing!!!! Letting the engine cool down gets the timing back to good original settings... This can be repeated time after time again.

I have checked that the dist. is fixed an not moving. I have put direct 12v to the ignitor module. I have tried with the original coil as well as with the flame thrower coil. I have even tried a new ignitor module. Nothing changes.

I am at the end now and prepared to throw a big pile of dollars on a brand new msd system or something similar....

Any thoughts or suggestions???

Regards, Daniel
 
the only other thing - and this is unicorn territory - is the coil is building heat and causing it to be late on its discharge. How warm is your coil?
 
Hi SBG,
Yes, if i think about it, both coils are getting pretty hot.
I use the resistance wire for the original and a direct 12v for the flame thrower. I think this is correct. Could it be that both coils are out of order?
 
I'm running the original TI system. Works perfectly- better than the crossbred magnetic pickup/CD box.

Make sure you are using the correct coil for the TI. The replacement coils have too much resistance and will not deliver enough spark (degraded performance is the term used). If I recall, the original coils were embossed with the number "243" and have the correct resistance.

http://www.tispecialty.com/articles/article1.htm

http://www.tispecialty.com/articles/article4.htm
 
The TI was unfortunately removed by some previous owner and replaced with the pertronix. It is not possible for me to get the all the parts for an original TI unit.
Tonight i tested a third coil with no sucess.
 
That is a shame.

I used the TI mag pickup distributor with a CD box for a while. It worked, but just ok. Went back to the TI amp and made lots of difference.

There are several different styles of ignition boxes. MSD, Mallory, Crane, even some house brands from Summit and Jeg's. The box I had was a Summit branded one that looked exactly like a Mallory but was $50 less.
I have ended up with an MSD magnetic pickup distributor, but using it to signal the original TI amp and coil.
Can you borrow an HEI from someone? I realize that you may not have a very large pool to draw from where you are. There are new, complete HEI distributors around here for $80-$90. Maybe drop a different system in there and see what happens.

EDIT>> Thinking about this some more, is it possible the mechanical advance could be sticking when it's cold?
 
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Thanks for your input TimAT.

I have checked the mechanical advance several times. I get full mechanical advance every time. The values are basically the same as with a cold engine but everything is offset. This is also valid for the vacuum advance which shows a perfect function, but offset. When the engine cools down the values are back to normal. This is driving me crazy...
I even bought a new timing light. Made no difference.

This night I have located a new MSD dist. with mec. tach and vacuum adv. including an 6AL box and coil. I'm about to pull the trigger on this set. I'm running out of options...
 
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Might be rotor phasing. Get a junk cap, drill a hole in it and put a timing light on it to see if it is moving. Probably is. Probably the vacuum advance system or bushings...not an expert, but that was advice I was giving related to one of my issues.
 
before spending the pile of dollars I'd try a chep Ebay distributor, these are like $80 or so.... but then you're in Sweden and shipping/customs/tax are going to make it quiet pricey.....
 
The vacuum and mechanical has the correct function. This is regardless of hot or cold engine and resulting base timing difference. Phasing I have not checked but that should not be affected by temperature or?

Yes, I probably could get a cheap dist and try it out. I would have to locate a unit in Sweden then. I know they are around. Then again, a brand new MSD unit seems attractive at this stage... despit the cost.
 
I guess some electronic component (tipically a capacitor) is having a Thermal offset.
Is not uncommon in ectrolytic capacitors .

My thought is confirmet by the total shift of your advance curve, only a capacitor in your module can retard the Whole curve.
 
problem solved...

Finally solved the timing problem. After testing three coils, two pertronix modules, checking all feeding cables for correct voltage, changing to new ignition cables, testing three different timing lights and finally, buying a brand new MSD system, it was the damper...
From the beginning i excluded the damper since the ignition setting was back to normal after letting the engine cool, within a few degrees. Seemed totally impossible that the outer ring of the damper magically could slide back as the engine is cooling down. But it is doing exactly that!
I have been able to repeat this phenomena four times. The latest this afternoon.
I painted small dots of paint on the outer damper ring and on the fan belt hub that is attached to the inner part of the damper. After driving for a few miles and then checking the timing I could see that the marks were offset in relation to each other. After letting the engine cool down for a few hours the marks are almost in line once again!
I may be called an idiot by telling this, not anyone I have spoken to has ever heard of this phenomena... Anyway, I will have to get a new damper and make a new tdc indication on it.

Problem solved, it was time consuming, expensive and not particularly fun.:skeptic:
 
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I've seen them slip before, but not typically as you have described here. What a nightmare! I worked on a 1984 Lincoln Continental several times that had odd timing issues. The camshaft sprocket bolt had backed off some and allowed the cam sprocket to flutter around enough to wallow out the hole where the alignment pin engages the sprocket. Who knew that Ford had variable valve timing on the 302 back in 1984... ;-P

Glad you found it, the Continental threw us all for a loop.
 
I thought you said that it ran poorly after running for a while. If the damper ring slips, that should not cause performance issues.

Maybe there is still something wrong?
 
I thought you said that it ran poorly after running for a while. If the damper ring slips, that should not cause performance issues.

Maybe there is still something wrong?

Yes, that was my impression while i was running the pertronix system. I think that I was actually fooling myself a bit. When I measured the timing to be off i probably got the feeling that the car was running bad while it probably was not... My eye was fooling my "butt feeling" so to speak. Then when i reset my timing with the damper offset and a warm engine, it actually was running bad since the timing was completely off compared to what I was seeing.
However, the MSD system makes the engin behave smoother and it also seems more powerful. I think...
 
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Finally solved the timing problem. After testing three coils, two pertronix modules, checking all feeding cables for correct voltage, changing to new ignition cables, testing three different timing lights and finally, buying a brand new MSD system, it was the damper...
From the beginning i excluded the damper since the ignition setting was back to normal after letting the engine cool, within a few degrees. Seemed totally impossible that the outer ring of the damper magically could slide back as the engine is cooling down. But it is doing exactly that!
I have been able to repeat this phenomena four times. The latest this afternoon.
I painted small dots of paint on the outer damper ring and on the fan belt hub that is attached to the inner part of the damper. After driving for a few miles and then checking the timing I could see that the marks were offset in relation to each other. After letting the engine cool down for a few hours the marks are almost in line once again!
I may be called an idiot by telling this, not anyone I have spoken to has ever heard of this phenomena... Anyway, I will have to get a new damper and make a new tdc indication on it.

Problem solved, it was time consuming, expensive and not particularly fun.:skeptic:

YGTBFSM, talk about totally obtuse, something I would have NEVER guessed either.....nuff to drive you nuckin' futz....:flash::flash::chinese::crutches:
 
Seems like the few things I haven't changed on this car is breaking up..

So, does anyone know if it is possible to change the damper without lifting the engine up in the front?

It is a very tight fit between the damper and front cross member.
Looks like I can get hold of 8" dampers within a day or two here but the original is 7" if i'm not completely wrong?
 
The damper on mine is 8".

Maybe you could ge enough clearance by dropping the transmission down?
 
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