DuraSpark Distributor - Too fat for the hole

[.94 OR]

Picked up a Duraspark assembly on here about a year ago and am now getting it installed, or so I thought. Did my prep work, pulled the old unit out and went to drop the Duraspark dizzy in the hole and it won't go. The shoulder below the O-ring on the old one is 1.497" and the DS is 1.553".

Is this common, or did I get one for a different engine?

Suggestions?

 

[Boss Hugg]

Just the top of my head, you may have to bump the engine to get the gears to line up so the oil pump shaft will line up.


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[sanndmann3]

Not sure what the dimensions are but are you trying to put a 351 dizzy into a 302? there aredifferences between the 2...

 

[.94 OR]

No, I don't think that will work. The shoulder won't even slip down into the engine. It rocks back and forth since it is too large and turning the top of the shaft doesn't change anything.

Is a 351 longer by chance?

 

[Jebus]

IIRC all the guts from the duraspark dizzy fit into the points dizzy?

 

[.94 OR]

IIRC all the guts from the duraspark dizzy fit into the points dizzy?

That crossed my mind too.

The bottom shaft is too big as well. That may be part of the issue.

Points dizzy: 0.450"
Duraspark: 0.515"

Back to square 1 I guess.

 

[Jebus]

I believe I have never pulled the gear and shaft to switch because that is where the differences mostly are in ford distributors. The upper vanes always fit onto the existing points dizzy lower shaft that the cam gear attaches to and the centrifugal advance springs connect them together up above.

I only remember having to square up the wire hole where it exits the dizzy and readjust advance with selected springs and an adjustable vacuum advance....

You probably already know there is a small wire clip that holds the upper rotor from sliding up the shaft in the absolute center of the dizzy, under the felt oiler...

 

[broncnaz]

Sounds like the housing is the 351/400M/460 type which I believe had a slightly larger shoulder than the small block and your shaft appears to be the later style for 87 up engines. You might have a steel gear as well for a roller cam.
The main issue is that most of the ford housings look the same and parts pretty much all fit. but there are minor differences as you've found out.
If this is new/rebuilt looking unit I would consider going to the parts store buying a new/rebuilt unit that fits and then take the one that doesn't fit back to them you may wind up with a refund or a spare dizzy

 

[.94 OR]

I think it is a rebuilt unit.

I'll likely get a replacement. Not sure if they need a core or not since this thing is obviously useless to me I don't need it kicking around.

 

[TDubya]

I purchased a reman distributor for mine from one of the chain auto parts stores several years ago and ran into the same problem. I just took the housing lightly to the bench grinder and its been working fine.

 

[.94 OR]

Cast iron gear for older flat tappet and steel gear for newer roller cam?

 

[Eoth]

Cast iron gear for older flat tappet and steel gear for newer roller cam?

Yes.... That's how you can tell the difference, but there are some dimensions that are different between the two so you cant just swap out the gear from cast iron to steel to reuse a 302 distributor in a 5.0. Come to think of it.... I believe its the issue you are experiencing. I'm pretty sure you have a mismatch. If I remember correctly, I was going to use my old 302 distributor to turn the oil pump on the 5.0 to lubricate everything before startup but I couldn't because it wouldn't fit properly. So if I was a betting man, I would say that you have a 5.0 engine and a 302 distributor..

 

[Broncobowsher]

Not sure what the dimensions are but are you trying to put a 351 dizzy into a 302? there aredifferences between the 2...

Those dimensions look like those between a 302 and a 351. I think you are right.

Probably a mix up in rebuild, packaging, or parts store.

Check the oil pump drive hex. Is it 1/4 or 5/16?

 

[tirewater]

Hmm, interesting. I just replaced my remanufactured unit (Cardone ) - the lower shoulder (directly above the gear) was a friction fit to get it into the block. I assumed it was to center it properly. Leaky vacuum advance, and timing that wouldn't get above 24 total - with 16L arms, notchy stiff breaker plate for vacuum advance, are items I noticed about it.

 

[.94 OR]

I picked up a fresh rebuilt unit with a cast gear. Struggled with it Sunday as it would go all the way in but just shy by 3/32". I fought it and fought it. Walked away. Texting a buddy last night while staring at it, I tried again and it dropped right in. I'm not asking any more questions of it now if it works!

 

[.94 OR]

The hex drive is larger as well.

Safe to assume it is for a 351?

 

[Broncobowsher]

The hex drive is larger as well.

Safe to assume it is for a 351?

Yes.

You could always keep the distributor and change the engine;D

 

[Builtnotbought0]

To fat for the hole.......

 

[.94 OR]

Yes.

You could always keep the distributor and change the engine;D

That did cross my mind. Maybe after I get other projects out of the way.

I'll probably keep it then.

 

[.94 OR]

Well, I got the DuraSpark wired in yesterday. The FiTech 400 fires the engine right up now and is a lot happier. The IAC steps were 0-5 during the times I had it running yesterday and the engine sounded good. It has never started this easy since I have owned it. Now to clean up the wiring and get ready to drive it some.