Distributor Install

I've put my distributor in and out many times - both as just a straight replacement and also when the engine got turned with distributor out and I had to start from scratch with finding TDC etc. But...I can't get my old delco distributor (with pertronix) to install into my rebuilt engine. The engine has new timing cover as well as new Melling oil pump.

I could just be incompetent and for some reason I can't get the distributor to sit all the way back in - it will mesh with the gear teeth, but it seems like I can't get it to sit down into the oil pump slot. I've tweaked the oil pump position with a screw driver till I am sick of it and it won't sit all the way down with the distributor housing bottomed out against the timing cover rim. Its gets to within about a 1/4" and stops - basically to just the bottom of the o-ring on the distributor. The distributor shaft is really tight sliding down into the timing cover - I've added just a bit of oil and lubricant to help, but it likes to stick and takes effort to move it up or down by hand.

I have also measured the distance from the top of the timing cover rim to the oil pump slot - its 3.75", and that is the exact same as the distance from the bottom of the distributor gear to where it stops just below the o-ring and needs the last 1/4" to sit down in the oil pump slot. Any suggestions for getting everything to line up - After 2.5hrs I give up. It seems like somehow the distributor gear has the wrong base to mesh with the oil pump - possible?

 

Was wondering about that - need a second set of hands to bump it as well as installing the starter and getting battery power to it. Was wondering if maybe it could be turned by hand from the front with someone pushing down on the distributor to accomplish the same thing. Wife is not home yet...maybe she can help...

 

Gonna try the cleaning the distributor shaft really well with a brillo pad or similar (maybe even a bit of very fine sandpaper) and see what that will do. I feel like its binding in the timing cover as much as anything.

 

Check the 'slot' size if possible. I had a slot that was a bit small and the Distro would not drop down all the way... little filing on the distro slot and it slipped in.

I would not recommend bumping the starter... messes with the position.

 

Note to self - next engine rebuild check the fit of the distributor and oil pump before assembling and sealing everything up. Chalk that one up to a learn the hard way experience. Filing on the oil pump slot probably isn't going to happen as its assembled - or I have to pull it all apart. If cleaning the distributor shaft doesn't free things up, maybe I can look at cleaning and gentle file on the bottom of the distributor gear might provide needed clearance to mesh with oil pump slot? Certainly would have been easier to test fit this before assembly and if needed just file the oil pump slot a bit bigger.

 

Good news - Got the distributor to sit all the way down. I polished up the distributor shaft which helped ease the difficulty of sliding the distributor in place, cleaned and re-lubed the distributor gear and its bottom, and did the same for the oil pump slot as best as I could down through the timing cover. I think the main issue was matching up the oil pump slot. I guess the new oil pump slot fits tight and has to be perfectly aligned whereas my old one was much more worn and the distributor gear never got hung up sliding down into it - it never took me more than a couple tries with a screw driver to get it oriented close enought that everything would slide together. It did take my wife pushing down on the distributor while I turned the engine over by a hand just a bit and it fell into place. According to the timing marks I had to move it about 10 degrees before it fell into place...Either I am getting old and can't see or the old pump was a lot more forgiving getting it lined up. My old marks for rotor position for #1 suggest I didn't miss a gear tooth, rechecked I am on TDC for #1 on compression stroke, so with a little luck it should be ready to fire when the time comes.

 

Walt - you are correct. It has no vertical endplay. Its bound in way too tight. I am actually having trouble removing it now. I originally put shim/spacer rings just above the distributor gear to remove some endplay when I installed the pertronix. Guessing I need to remove one or both of those now. Or would it be better to put a ring spacer between the bottom of the distributor housing and the timing cover?

 

Thanks Walt - I think that makes sense. I had to put the the distributor gear shims in to reduce endplay enough for the pertronix ring and pick-up to keep proper spacing (I did the pertronix install a couple years ago). Even with the shims it still has acceptable endplay when removed from the timing cover...but when installed and pressed down into the oil pump slot, the shaft pushes up a bit and binds. If I removed the gear shims, the distributor shaft can push up a bit and allow for some endplay, but would cause the spacing between the pertonix rotor ring and magnetic pick-up to increase beyond spec (which i could solve with some spacers to lower the ring below the rotor). But it seems like a spacer between the housing and timing cover would solve the problem without affecting the pertronix unit. Will test with feeler gauge when I get home tonight.

 

I couldn't figure out a good solution as it was...so I decided to pull oil pump and see if I could figure something out - maybe a different gasket or something. It also gave me a chance to test fit the distributor gear into the oil pump slot on the bench and take a few measurements. Everything looked good. I put the distributor in with no oil pump and it went in with a little effort - definitely has a sticky spot but can work on that. I then slid the oil pump gear with shaft and slot up into the distributor gear (took just a bit of turning) and everything fits great with good endplay. I also packed the oil pump with vasoline and put everything back together. Kind of nuisance doing it under the vehicle, trying to keep the mating surfaces clean of vasoline, and getting the oil pump and spacer block and two gaskets etc all. So not sure what wasn't working initially...Seems like I might have had something off just a bit. I haven't tried removing the distributor and putting it back in....just buttoned everything back up for now and time to take a break.

 

Okay - this is less of a technical question and more of anecdotal type question about the delco distributor cap for the 225. This question arose from ordering some replacement parts (cap rotor and plug wires). The first cap that I ordered is not the cap I have been using on my 225, but I have come across it before. In the pictures below, its the one on the left in the dual pic and the bottom one of the single photos. I have gotten this cap before when I bought a pertronix set-up from a member here, and they threw in a new cap and rotor. Basically it doesn't fit on my delco distributor - of course my delco distributor is some rebuilt unit from the PO that I have fixed up a bit.

Since my existing cap from the PO was still in good shape I went back to using it with pertronix and had no problems, and prefered the way it all connected. With the engine rebuild, I am trying to upgrade to new parts on just everything I can, so I ordered a new cap and sure enough got the cap mentioned above. After some research and a helpful salesperson at the FLAPS...he found the exact cap I have been using - it was listed for a CJ5a (tux park model I believe). It works great for my set-up....vac can and points window are accessible (though not used with pertronix) and the #1 plug cap works with the actually #1 plug wire. Plus it really easy for my existing markings for where #1 TDC is.

Not that it really matters....just wondering if one of these caps is truly the 'correct' cap. I am going to use the one that works best for my set-up...and the old one is now in my parts kit with an old points delco distributor in case its needed in emergency. Here is the pics:

Tow shown from top - notice the difference in location of the points window with respect to the wire plugs as well as the different clocking of of the cap with respect to the hold-down clips.

This is the one that seems 'correct' to me...well let's say it works well for me. #1 cap is above the window.

The cap that doesn't work so well for me...pointing at #1 cap and #2 cap is above the window