• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

worn fuel pump push rod

shovelluv

Well-Known Member
Local time
2:03 PM
Joined
Jun 13, 2014
Messages
139
Reaction score
38
Location
indiana
Well, over the weekend my 1969 383 fuel pump quit pumping fuel. I removed the pump and rod today to find that the fuel pump pushrod is 1/4" shorter than it was 5000 miles ago. the motor was completely rebuilt with a mild to comp cam. I am running a factory style pump. So my question is... What is the correction for this? I don't want to be here next year with the same problem. I DO want to continue to run a mech, style pump. I wonder about fuel pump spring pressure and what it is supposed to be and if the replacement ones we are buying have a heavier spring pressure than the original spring pressure? I used the pushrod that was in the original engine when I rebuilt it. I am assuming this was a OEM pushrod. If I do run a hardened pushrod, do I run the risk of wearing the cam instead of the pushrod.
 
Last edited:
NOS or nice original are the only ones I trust anymore.
 
Lots of discussions on this topic, there for the finding by using the sites' SEARCH feature:
search box.png
 
Did you take a measurement of the rod prior to the rebuild? Are you using oil with a sufficient amount of zinc?
 
Did you take a measurement of the rod prior to the rebuild? Are you using oil with a sufficient amount of zinc?
Thanks for the reply.. Yes, When I did the assembly after rebuild, I made sure it the pushrod was in specs by using the SEARCH bar as moparedtn suggests.
 
Another sub-par lower quality, product usually sourced from China....
Best to find an NOS one.
Nuff said...

Just my $0.02... :thumbsup:
 
Ok, fair enough. but with all the issues over the past years, there should be somewhat of a consensus on what actually fixes the issue. So, I guess my question is to everyone is.. Who has the most miles on what setup, AFTER pushrod failure, assuming with the right oil?
 
I went through this a couple months ago. I was fortunate enough to find an NOS one but they are not easy to find. Lots of talk about poor steel in new rods and some replies here just assume you put in a new rod even though you said you didn’t. Good grief! Anyways, from what I learned Mancini claims to have gotten a handle on this situation and says they have a good rod of the proper hardness. I’m looking for any old big block that’s sitting around that I can rob a rod out of, so far no success.
 
Ok, fair enough. but with all the issues over the past years, there should be somewhat of a consensus on what actually fixes the issue. So, I guess my question is to everyone is.. Who has the most miles on what setup, AFTER pushrod failure, assuming with the right oil?

I'm not the guy with the most miles on a big block but I've had 440s for over 20 years. I have never worn out a fuel pump pushrod.
What is the correct length? 3 1/4" ?
 
As an aside to the pushrod, the BBM @440 Source fuel pump is sold under another generic name on FleaBay, and I decided to try it out. Same specs, same pump.

It looks like the Edelbrock with the clockable body and threaded fittings, but puts out a steady 4.9psi of pressure per my Autometer fuel pressure gauge. Perfect for my AVS2.

I got the generic one since Source didn't offer the fuel pump on the Canadian eBay site. Oh well.

Quite happy with it so far. It's advertised the same as putting out up to 80GPH. Can keep up with demand.

My Carter only put out 18GPH, and if ya stomped it, the pressure dropped down to under 2psi from an idle 5psi.

Not sure if anyone has tried this pump, but this is my 2c on the subject.
 
I'm not the guy with the most miles on a big block but I've had 440s for over 20 years. I have never worn out a fuel pump pushrod.
What is the correct length? 3 1/4" ?
Just under that, 3.22".
 
I think I would pull the distributor and look at the cam lobes too. If you think that push rod had many miles on it, IMO that really just leaves the oil or the cam at fault.
 
Shortly after I got my 66 Charger w/383 back in 2010, it had just over 78 K original miles on it. I had the push rod issue. Being away from these cars for some 50 years, had to totally re-educate myself as to these 60's era cars. I was dumbfounded as to why it would randomly stall out while other times run perfectly. But since the stall out was quite random, it was summer, but thought it was just vapor lock issue but I had always managed to get it re-statrted and was on my way. One day, out for a ride, it stalled while driving and refused to re-start. Had to be flat bedded to a general auto repair shop that's just down the road from us that use for state inspections and general car repairs. He checked ignition, carb and all OK, replaced fuel pump & fuel filter but still had what appeared as a fuel delivery issue. He wanted to install an electric pump. Told him no..hang on while I started researching this issue on internet. Googling, found many threads and accounts that discussed push rod length in big block Mopars.
Me, not knowing that in a big block, a pushrod is what actually strokes he fuel pump, called the mechanic and told him about the push rod length to check it as might be the problem. He knew that there was a push rod, but not the possibility of excessive wear of the rod that could cause this. He obtained a replacement from local parts store, replaced it and all fixed. In my case, the push rod was worn by well over 1/4" of spec. just barely stroking pump !! In my research, there were accounts of Chrysler having this issue back in the day with push rods that were not hardened properly that made their way into thousands of big block engines. Also much discussion on replacements that weren't much better. The previous owner of my car had done an "engine refresh" in 2008, but don't think the previous owner replaced the push rod at that time.
Hey guys, beware of your length ! Speaking about fuel pump push rods I mean....
 
Last edited:
Best bet is to find an old OEM rod in good shape. I've had a couple of new rods that were OK, but I had a bad new one too. Best test is run a small file across the rod, stay off the areas that contact block and pump/camshaft. If the file will cut the surface the rod isn't hardened.
 
I'd be a little worried about a 1/4" of the rod in the oil pan.
I'd pull the pan and clean it out and inspect the pickup screen.
 
I'd be a little worried about a 1/4" of the rod in the oil pan.
I'd pull the pan and clean it out and inspect the pickup screen.
I thought the same thing, but he said he reused the rod that was in there before the rebuild. I agree, that's a lot of metal to lose from that rod in 500 miles. My guess is it may have already been short.
 
I thought the same thing, but he said he reused the rod that was in there before the rebuild. I agree, that's a lot of metal to lose from that rod in 500 miles. My guess is it may have already been short.
Well let's be careful when discussing a guys "short rod"...
 
Auto Transport Service
Back
Top