Replacing distributor on '73 Coupe deVille

[cadillac73]

Hello all,
I'm a novice gearhead, going to attempt replacing the distributor in my old girl today ('73 Coupe w/ 472).  Wondering if you have any advice, tips, or tricks for me?  Or if you know of any videos you can point me to?  I'm a little nervous about messing with anything timing related, but determined to do this myself.

Thanks!

[cadillacmike68]

Do you have the shop manual?

[cadillac73]

I sure do!

[35-709]

To make it easy (for me), and assuming you are not going to turn the engine while the dizzy is out, with a felt tip marker I mark the "dizzy" base and the engine flange where it mounts so I know exactly where it was for later.  With the dist. cap off, mark where the rotor is pointing on the edge of the distributor where the cap fits (first rotor mark), then when you pull the distributor you will see the rotor turn, mark where it ends up (second rotor mark).  Then, when putting it back in, line the rotor up with the second mark you made for the rotor, line up the dizzy base to engine flange marks and ease it back in.  The rotor should now be at the first rotor mark when the dizzy is all the way back in and the dizzy to engine flange marks are also lined up.  This way you can be sure the timing is the same and the engine should fire right off, of course you should check the timing to be sure it is correct when you get it running. 
If you are going to (or might) rotate the engine while the dizzy is out then start this whole procedure with the engine at TDC, on the compression stroke, then you have a known starting point to go back to.

The guys that do this regularly may not have to be so fussy and precise with markings, etc. but this works well for me.

[Jeff Rosansky CLC #28373]

The first Jeff rule--- take pictures of everything before you start. Just in case

What is the reason for replacing the distributor?

Jeff

[Scot Minesinger]

35-709 is 100% correct follow his advice, has worked for me many times.  Also read shop manual.

[cadillacmike68]

The first Jeff rule--- take pictures of everything before you start. Just in case

What is the reason for replacing the distributor?

Jeff

Probably because it's worn / loose like mine was.

[TJ Hopland]

I'm with 35-709,  especially with the bit about watching where the rotor ends up as you lift it.    If you don't move the engine you should be able to drop the new one in the same way and it should be close enough to start.    If you were planning on moving the engine like say for a timing chain replacement then I would first rotate the engine till the timing marks aligned and then make all the marks.  The idea there is that when you finish the engine work you will rotate it back to the same spot then drop in the distributor. 

Other things to add is you will need a timing light.   A tach / dwell meter is required for points and nice to have even if its not points.  A hand vac pump / gauge is also a nice tool.    If you don't have these tools or know what they are let us know and we can give you examples of what we are talking about.    You can get a decent meter for maybe $30.   Same with the vac pump gauge which can also help with brake work.   Both the meter and vac pump have many uses around the garage so are good tools to have. 

Before I remove anything I would take readings of what is there now.   I would take timing readings at idle with and without the vacuum disconnected.   I would take some readings at higher RPM's,  maybe up to 3000 with the vac disconnected.   I would then hook up my manual gauge/ pump and take readings at idle at various vac settings.    If its points I would also take a dwell reading.   write all that down or type it into your phone.    The idea here is to know where you are starting so if the new part and factory settings don't improve things you will have a base line to try and return to where you know how it ran. 

Remember on this engine the passenger side is the odd bank which is opposite most other engines. 

[Jeff Rosansky CLC #28373]

Probably because it's worn / loose like mine was.

Yes, exactly. What ate the symptoms of a worn distributor?
Jeff

[cadillacmike68]

^^ Unstable dwell readings which translates into poor idling quality, etc.

[cadillac73]

Thank you all for the excellent advice.  I am replacing it because I have replaced every other damn part of the ignition system AND the carburetor and it is still running like crap under a load.  Stumbling, backfiring, etc...but idles fine.  I know the timing is factory because that's the first thing I did, then did points/condenser, plugs, wires, cap, rotor, coil.  So this is my last ditch effort.

I do have a timing light and dwell meter, but not the hand vac you mentioned...

[TJ Hopland]

I would consider the hand vac pump a must have for a DIY car repair person.   They range from $20-50 so pretty cheap.   Handy for testing vacuum stuff as well as brakes and sucking small quantities of other fluids out of various places.    I'm not endorsing this specific store or model, just giving it as an example.   Mighty Vac is a good quality unit many stores carry including HF.

http://www.harborfreight.com/brake-bleeder-and-vacuum-pump-kit-69328.html 

With stumbles the first place I go is the distributor with my vac pump and run it through its range.   Both points and the HEI can have cracked wires that will loose connection as the vacuum runs through its range.   HEI its the pickup coil wires.   Points its either the ground or the coil lead wire.