View Full Version : Distributor Movement

08-26-2003, 10:04 PM
I finished the rebuild on a Chevy 454. I am running the MSD billet dist with the mag pickup.

When I first installed the dist., it would not seat tight on the cam gear and or the oil pump drive. The block or the heads were not milled more than .003" to clean them up. I think the new oil pump drive shaft is and or cam gear is holding the dist., slightly out of the block so you can not tighten the dist. down with the hold down clamp.

The timing was bounching around about 2-3 degrees. I installed an extra gasket on the base of the dist., and that snugged it up. You can now tighten it down and it stays in one place. However as the gasket compresses I can see the timing starting to move a little bit like 1 degree or so.

Does MSD make some steel shims for this problem? How do I know what sizes to use? Where can you get them? The 2 gaskets is not the way to go.

08-26-2003, 11:00 PM
The distributor is designed to use only one gasket. If your distributor is not seating all the way to the maifold, then you need to determine why. Check your oil pump shaft to make sure it is not to long or is not coupling to the distributor shaft properly. Pull the distributor out and check the wear pattern on the distributor gear. The pattern should be centered between the top and bottom of the gear when it is installed correctly. Failure to check this may result in damage to the distributor gear. Engines that have had extensive modification to the cylinder heads and intake manifold should be using a distributor with an adjustable collar so that the proper installation height and gear meah can be achieved. MSD offers an installation tool, PN 8599, for checking and setting up proper distributor installations on modified engines.

MSD Tech1

08-27-2003, 07:30 AM
Thanks again. I will pull the dist. and check for the wear patterns. Since I have to use 2 gaskets it is being held out of the block the thickness of the gasket or about .125" and the extra gasket is sucking up the added height. Yes, either the oil pump drive saft is too long ot the gears are not meshing, not much else in there. I need to get the tool you talked about as maybe there is more milling than I was thinking.

BTW - when you first start the engine there is a louder than normal nosie from the dist. area. I am now thinking that either the cam - dist. gear is not meshing properly or there is internal noise inside the dist. either from the shaft or from the cap rotor rubbing. Tough to tell the difference. The noise goes away after warmup which I am equating to expansion of the metals upon heating.

Can you comment on this issue or share ideas to locate the noise?

08-27-2003, 08:43 AM
Pull the distributor right away and take a look at it closely. You need to get the distributor set up correctly otherwise you are going to have many problems.

MSD Tech1