Replacing water pump means removing distributor ... help

[450SLC_SPOKANE]

1975 450 SLC ... Replacing water pump.

Part of the process is to remove the distributor.

To prepare to remove the distributor my repair manual says to turn the crankshaft so that the mark on the distributor rotor is aligned with the mark on the distributor housing. The mark on each of these items is very obvious. In addition, the manual states that the pointer on the crankcase should be just above the TDC mark on the vibration damper. I can not satisfy both of these requirements at the same time.

If I get the mark on the distributor rotor to align with the mark on the distributor housing the pointer on the crank case points to about +18 degrees.

What do I need to do in order to safely remove the distributor? Is aligning the distributor rotor mark with the mark on the distributor housing enough?

[Tomguy]

That probably means your timing is WAY off.

Either way, you'll need to retime it when you're done. Just line the crank up to TDC. When you're done, reinstall the distributor with the rotor on the line. It will start like that. The timing wont be exact but you can set it from there. Remember, it should be 5° ATDC WITH the vac line connected. It sounds like someone set it with it removed, and it's a 12° advance with it disconnected normally, so 5° ATDC with the line removed would be 17° ATDC with it on. Your engine must be pretty sluggish at that setting!

[450SLC_SPOKANE]

Tomguy ... thanks for the reply.

I posted the same question on another forum and received the following brief reply:

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"just align the crankshaft TDC first.

then, make a marker on your rotor cap to coincide with the rotor housing marker.
then open the cap and mark the position of the rotor.

somebody must have changed the ignition cable's position. "
******************

After studying your reply and the one above, I have concluded that each response assumes a different reason for not being able to line things up on the distributor and crankcase per my repair manual ... your reply assumes that my car's timing is way off and the other assumes someone has changed the ignition cable's position ... whatever that means ... and the timing is OK (right?).

Perhaps following either path will lead me to the same place and because I don't understand the whole ignition time thing well enough I just can't see it.

At any rate, because of the difference in the two reply's recommended steps to prepare for distributor removal, I am left wondering exactly what to do.

[Tomguy]

If the cables were misplaced by 1, it'd be off by 90°, not 18°. Your mechanical advance springs may be worn or off and it's advancing too much at idle, the timing could be set wrong - but it's not possible that your wires are off by 1 each and your timing is only off by 18°.

I've removed my distributor (same engine) so many times I can almost reinstall it without retiming it now - just by remembering where the screw was. Lining the engine up to TDC is the proper way. If you want to mark where the rotor was on the distributor, feel free to do so. Be aware that the shaft will turn when you pull the distributor out. If you dont touch it (hard to do) you can sometimes just set it right back in at the exact same position. However sometimes the points may cause it to turn even more, or even just setting it down can affect it. Either way, you WILL need to retime the engine when done.

[kbannister]

Since you haven't mentioned anything about your engine's performance, lets assume it was in time. Here is what I always do when removing a distributor. Get your engine to TDC with your mark on the balancer. First, mark the distributor housing to the engine block by drawing a line from the distributor housing onto the engine block. Then remove the distributor cap and mark the position of the rotor to the distributor housing. When reinstalling, make sure both marks line up and you will be real close to where your timing was set.

Hope this helps you

[250 Coupe]

Ignition timing explained, with a cool amimated graphic!

www.howstuffworks.com had some pretty good stuff.

Michael

PS, I do the mark both parts and return to the marks trick myself.