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Discussion Starter · #1 ·
After days of trouble shooting my '78 280, I've narrowed it down to the ignition timing. Does anyone know how to set the timing(crankshaft sprocket, vs. camshaft sprocket, vs. no 1 TDC, vs. distributor alignment). My cheesy chilton manual does very little. Do you line up dots, arrows, notches? Also is it possible for the chain to jump a tooth(or teeth)? Your help has gotten this gearhead this far, so any more help is greatly appreciated....

Thanks in advance. JN
 

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Discussion Starter · #2 ·
The following is based on the '79 thru '83 manual but should still be good for '78.

>Does anyone know how to set the
> timing(crankshaft sprocket, vs. camshaft
> sprocket, vs. no 1 TDC, vs. distributor
> alignment).

After you have the camshaft and crankshaft in time you make sure number one is at TDC (with both valves closed) and then install your distributor so that the rotor is pointing pretty much to the number one terminal on the cap. When the ignition timing is set correctly, with the number one cylinder at TDC and looking from front to back, the rotor should be real close to the 5 o'clock position and the number one terminal on the cap should be real close to the 6 o'clock position. This is because the rotation is CCW and the timing is advanced slightly when properly set.

>Do you line up dots, arrows,
> notches?

There should be marks on the chain, camshaft sprocket and crankshaft sprocket. With the number one piston at TDC You line up the marks on the chain with the corresponding marks on the crankshaft sprocket and camshaft sprockets. It's also important that the camshaft sprocket is positioned properly on the camshaft so if you have removed it be sure you get it back on with the camshaft dowel in the number one sprocket hole.

Also is it possible for the chain
> to jump a tooth(or teeth)?

Yes. Especially in older engines the chain can stretch and jump a tooth or teeth.

Hope this helps.

Bob A.
 

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Bob, I am having problems with my turbo timing. I see that you say when #1 is at TDC the rotor should be at 5:00. The last time I did the TDC routine the rotor was at about 7:00. Is there a difference in the two motors by this or could this explainn ny 40-50Degree BTDC timing. My car is only supposed to be at 30 BTDC. If this is so, and you are right what is the quickest and easiest fix? Is it just a re-inserting the ditributor or the shaft or is it the timing chain? If it is the timing chain can I fix this without removing the front cover?
HELP!!!!!!!!!!!!!!!!!! Thanks Scott
 

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Discussion Starter · #4 ·
> Bob, I am having problems with my turbo
> timing. I see that you say when #1 is at TDC
> the rotor should be at 5:00.

I always try to emphasize that when looking from the front, towards the back, the rotor should be at 5:00 o'clock. I do this because that's typically the way engines are always viewed and the way it's illustrated in manuals. If you are viewing your engine looking across from the left side to the right side of the car, about 8:00 o'clock would be correct. With my '83 in correct time, the number one terminal on the cap is at 6:00 looking from front to back.

The last time I
> did the TDC routine the rotor was at about
> 7:00.

If you're talking 7:00 looking from front to back the timing would be retarded since rotation is CCW. If you're talking 7:00 looking left to right, then your timing would be well advanced.

Is there a difference in the two
> motors

I don't think so, but I'm not familiar with the turbos. I'll do some checking and if I find any difference I'll let you know.

what is the quickest and
> easiest fix? Is it just a re-inserting the
> ditributor or the shaft or is it the timing
> chain?

I can't give you a good answer, again because I'm not familiar with the turbos. What little I do know is that with the turbos there's a different procedure for setting the timing than with the naturally aspirated engines.

If it is the timing chain can I fix
> this without removing the front cover?

No. If the chain has slipped you need to replace it.

Sorry I can't be of any more help.
I will look into it as I have time and if I learn anything I think will be helpful I'll let you know.

Good Luck!

Bob A.
 

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Discussion Starter · #5 ·
Is it just a re-inserting the
> ditributor

Scott

I did some looking in the Haynes manual and found that when installing a distributor on an 81 Turbo you need to align the rotor and cap by inserting a wire through the #1 cap terminal into a hole in the rotor. This then holds the rotor in the proper position. You have to do this with the engine number 1 at TDC(compression stroke).

I also read (in general) where the timing is a function of a lot of inputs into the computer and so your well advanced timing may be caused by a malfunctioning sensor. I know on my non-turbo 83 that there's an electronic advance built into the ignition module that is supposed to cut out at normal engine temperature. If the water temperature switch fails it could cause the timing to remain advanced.

A couple of things to emphasize, always set the timing with the engine idle speed at the correct setting. Most times you need to disconnect and plug the vacuum advance unit. I'm not sure if you have to on a Turbo or not.

I think you need someone who is much more knowledgable of the turbo systems than me.

Sorry I can't help.

Bob A.
 
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