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Fuel pump eccentric

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
So it's locked down tight and the little bent tang is in it's hole then? No way for the eccentric to turn on the bolt? Hmm, strange.
Or am I thinking about Chevy cams and ours use a locating dowel?
Maybe it's coming down to the crappy quality assurance that lets them have a little too much leeway with original dimensions when making the new Chinese pumps?
But that wouldn't explain why the old one was doing the same thing.

Paul
 
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Shulaps

Shulaps

Jr. Member
Joined
May 12, 2013
Messages
55
Loc.
BC Interior, Canada
I think the eccentric was installed a little off. Maybe with the pump held up when installing it may give me a full stroke on the pump. Cleaning up and doing some painting so I will see if it corrects the problem I a few days.
 

langester

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MASTER OF MADNESS
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Mar 2, 2013
Messages
2,660
The eccentric should have a dowel pin. There are two different pins on long and one short. Make sure you have the right one for your application. If the pin is too short the eccentric will not stay where it is supposed to.
Good luck and keep us posted!
 

amax

Jr. Member
Joined
Mar 10, 2014
Messages
119
I tore mine down and the pin had slid back in and the bolt holding it in place was loose. It didn’t have much movement but I think it was just enough to keep it from actually pumping fuel. Putting it all back together today after painting all the parts before installing.
 
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Shulaps

Shulaps

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Joined
May 12, 2013
Messages
55
Loc.
BC Interior, Canada
AMAX was yours a 1 piece eccentric? Mine was the 2 piece with the bent little tab instead of the pin. I am wondering if mine originally came with the 1 piece and the 2 piece was added after a rebuild. I wonder if there is a difference in stroke between the 2? I have read a bunch on these things and have yet noticed if there is and difference from one to the other.
 

DirtDonk

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Nov 3, 2003
Messages
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I'd be surprised if the two types had different offsets. But I shouldn't be surprised at anything any more!

The 1-piece design was typically relegated to the heavy-duty applications, such as cop cars and ambulances, but could have found their way in to truck engines. In fact at one time I thought they were automatically included in truck engines.
But I believe that was incorrect, and that most of the standard light-duty vehicles (which ours would usually qualify as) would get the 2-piece.

Maybe someone knows if Broncos got one or the other, but I'd still say the offset is the same since it had to run the same fuel pumps for the most part. I think even Ford would have recognized the trouble it would have caused during future maintenance if they'd been different.
Then again...

Paul
 

amax

Jr. Member
Joined
Mar 10, 2014
Messages
119
Mine was a 1 piece. My engine is not the stock 302 so there is no telling what the truck actually came with. The motor had been swapped out before I bought it. It ran good and still does just has to have fuel for that to happen
 

gr8scott

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Bronco Guru
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Jul 1, 2011
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1,823
I had to replace my 2 piece with a 1 piece when I changed out my cam.
 
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Shulaps

Shulaps

Jr. Member
Joined
May 12, 2013
Messages
55
Loc.
BC Interior, Canada
Well quick update, I put everything back together and no luck. Since there is no adjustment I decided to bend the pump arm until I got some action. Didn’t take too much but definitely had to modify the arm. Only thing that I can think of is maybe whoever rebuilt the engine just grabbed what ever eccentric was laying around and put it in? All is good now and it pumps from dry no problem.
 
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