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strad 10-27-2013 01:51 PM

need a little help pinpointing a dist problem 351 PCM
84 351 PCM with a stock prestolite distributor, that has been gutted to install a crane cams electronic conversion. This is a weird one. Most of the time, this engine will fire right up just like it's supposed to. Every once in a while, it'll crank crank crank no fire, or it'll backfire through the arrestor immediately after I let off the starter. One of those times, I popped the dist cap off, grabbed the rotor and rotated it back and forth through the mechanical advance a few times and back to base timing, then popped the cap back on. After that exercise, it fired right up like it is supposed to. I revved a few times, then turned it off, and restarted, and it fired up again just fine.

What I suspect is going on is the springs that spring the dist back to base timing are weak. I've not played with distributors before, so academically I know that the springs are there but I haven't seen them.

There is no side to side play in the distributor shaft, so I think the bearings are fine. Looking on skidim, I cannot find many internal parts for this distributor -- so if it is the springs, how do I get to them, and where do I get new ones? Or is this possibly not a mechanical timing problem but a problem with the electronic module?

thatsmrmastercraft 10-27-2013 02:47 PM

The backfire is a good sign that either the springs are weak or there is corrosion preventing the springs from returning to base position. There was a thread on here where there were some new prestolite distributors on ebay for cheap. If one of us can find that thread, that will be your cheapest route to reliability as there aren't parts floating around for these.

You might try cleaning, polishing and lubricating the insides of your dist. This pic should help.

You will need to remove the base plate to access the springs.

thatsmrmastercraft 10-27-2013 04:02 PM

Here is the thread

And here is a current ebay link

Putting your EI into a new distributor wouldn't be a bad way to go.

strad 10-27-2013 04:08 PM

Haha in the thread he says he got the last one. I cannot read the data plate on my distributor. It's pointed toward the tstat so not enough clearance to read it -- I'd have to remove either the distributor or the tstat housing to read it. I can read the end of the word prestolite but nothing else. Anybody know what model Prestolite distributor this is? If for no other reason so I can go on a fruitless search lol.

thatsmrmastercraft 10-27-2013 04:23 PM

You can turn your distributor to see the tag. Be sure to mark the location before moving it so you can get close before resetting your timing.

The link I posted is a current active lin. I would check with them as they should have distributors if the link is up.

Spork 10-27-2013 05:03 PM

there is a guy locally selling a new Ford Prestolite Marine Distributor E5JL-12100-CA 7020S - 351W Windsor - $70

other options

strad 10-27-2013 07:48 PM

Thanks. I now have another problem lol. My riser gaskets were leaking, so I removed three of four bolts on one side successfully. The fourth one? Well it broke off with about 3/8" sticking out of the manifold. I've been hitting it with penetrant for a few hours now, and it is not wanting to budge. I'm afraid of the next steps heh. I occupied myself chasing the threads on the other three holes -- those are nice and clean now.

I've also gotten the front two bolts on the other side out successfully. The rear two I've been hitting with penetrant. Is there a such thing as an extra short socket? My box end wrench is not giving me a good fit and I'm more afraid of rounding the bolt off than I am of breaking it.

I'll probably just buy a new distributor from one of those guys. Gotta solve the manifold problem though. Aarghh.

Edit: I was able to read the dist tag. It says D3JL-12100-C I'm not seeing that online.

waterlogged882 10-27-2013 08:11 PM


Spork 10-27-2013 08:13 PM

The D3 is a date code 1973. The ones posted will work, just slightly different on octane and initial timing.

D3AZ-12127-A 6 89 31
E2TZ-12127-U 6 89 31
E3TZ-12127-AA 15 89 31
D3JL-12100-B 6 89 31
D3JL-12100-C 6 89 31
D3JL-12100-D 6 89 31
D3JL-12100-E 6 89 31
D3JL-12100-B 2 87 21
D3JL-12100-C 2 87 31
D3JL-12100-D 2 87 31
D3JL-12100-E 2 87 31
E5JL-12100-AA 10 87 31
E5JL-12100-BA 10 87 31
E5JL-12100-CA 10 87 31
E5JL-12100-DA 10 87 31

Ford marine manual.

strad 10-27-2013 08:28 PM

Hmmm. Not disbelieving you necessarily, but I just checked, and my engine turns counter clockwise as viewed from the flywheel end. I believe that is standard rotation? The sellers are saying the E5JL-12100-CA is for a reverse rotation engine. . . I'm lost here.

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