worn fuel pump push rod
#1888907
08/10/15 04:45 PM
08/10/15 04:45 PM
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Joined: Jul 2007
Posts: 863 Pinelands , NJ
joelson6
OP
super stock
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OP
super stock
Joined: Jul 2007
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Pinelands , NJ
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i'm a little ticked off right now about this. i have a 383 that i did a top end rebuild on. heads rebuilt, new cam, lifters, valve springs, timing chain, oil pump. put it all back together and had it running for about 2 weeks. all of a sudden, i developed a fuel delivery problem, no fuel coming out of the pump. so i put on a new fuel pump and it didn't even work for a day. i take off the pump and remove the fuel pump push rod, it won't come out. can't get anything in there to get it out, so i take apart the the front of the motor and get the timing chain cover off. i get the rod out and the end is worn about a 1/4" (just measured with digital caliper 2.910", should be 3.220") and the end of the rod is concaved. so i take the rest of the engine apart and get the cam out. the lobe for the fuel pump push rod definitely looks worn. i get my old cam, the cam i originally replaced, set the 2 next to each other, make sure the timing chain dowels are both facing in the same direction, and measure both. no matter what direction i turn both cams, the measurements on the caliper are the same. so what would cause the fuel pump push rod to wear like that? does it spin in the bore like the lifters and for some reason it wasn't spinning? is it only suppose to go in the block one way and i had it in backwards? the fuel pump that was in the car, when i first put it back together, was in the car for 10 years with the old cam, and never had a problem. i'm kind of at a loss with this. the lobes on the cam and the bottom of the lifters all look great, no abnormal wear there. the fuel pump is a stock over the counter replacement, no HP pump. the new cam (.420/.442), lifters, timing chain and valve springs are Edelbrock stuff. this isn't a HP application either. it's in my '70 Newport, 383 2bbl. and i wanna keep it that way too. it seems to be difficult to find stock replacement cam and lifters for a B/RB engine. I know i'm replacing the cam and lifters, i don't want to get it back together and have the same thing happen with a new fuel pump push rod. Howards cams has a .420/.420 lift cam i'd like to try with new lifters and the fuel pump push rod. but i'm not sure if that will fix the problem. any input would be appreciated. thanks, Greg
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Re: worn fuel pump push rod
[Re: joelson6]
#1888919
08/10/15 05:05 PM
08/10/15 05:05 PM
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Joined: Feb 2005
Posts: 4,316 Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,316
Prospect, PA
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It is a wear item and it can happen. It's not that uncommon. Usually after they sit for a while and don't get good start up lube. Can be poor metalllurgical quality as well.
Did you lubricate the pump drive lobe and end of the pushrod with the new cam install?
Last edited by BSB67; 08/11/15 08:56 AM.
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Re: worn fuel pump push rod
[Re: BSB67]
#1888922
08/10/15 05:11 PM
08/10/15 05:11 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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poor metallurgy and or not enough zinc in the oil. Hughes' ones are likely good ones and 440source sells good used ones & those OE ones were reportedly pretty much bulletproof
live every 24 hour block of time like it's your last day on earth
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Re: worn fuel pump push rod
[Re: RapidRobert]
#1888948
08/10/15 05:50 PM
08/10/15 05:50 PM
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Joined: Jul 2007
Posts: 863 Pinelands , NJ
joelson6
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super stock
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OP
super stock
Joined: Jul 2007
Posts: 863
Pinelands , NJ
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poor metallurgy and or not enough zinc in the oil. if that was the case, why just the fuel pump push rod and not the rest of the cam and lifters?
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Re: worn fuel pump push rod
[Re: joelson6]
#1888949
08/10/15 05:54 PM
08/10/15 05:54 PM
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Joined: Apr 2005
Posts: 81 Sweden
MikeN
member
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member
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Posts: 81
Sweden
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A few questions:
When you changed the cam, was there any noticeable wear on the fuel pump pushrod? Any wear when you changed the fuel pump? What type of fuel pump is the new one? Is it easy move the pump lever by hand?
To my knowledge the fuel pump pushrod doesn´t rotate and I am surprised to read about fuel pumps with claimed open spring pressures on 200 lb considering the small area the pushrod has on the camshaft.
Last edited by MikeN; 08/10/15 05:55 PM.
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Re: worn fuel pump push rod
[Re: joelson6]
#1888963
08/10/15 06:14 PM
08/10/15 06:14 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,376
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They're a known wear item and people have been having problems with them since the '70s, or maybe even earlier, and there was plenty of zinc in the oil in those days. I believe they have some hardening on the ends but it must have been a rudimentary process because even new ones back in the day would suddenly start wearing. They usually would wear out on family vacations, at least that's what most of the stories include.
So, you didn't do anything wrong and I believe it's more a "luck of the draw" kind of thing, unless there was something wrong with the fuel pump that wouldn't allow the pump lever to move when the rod kicked it over. The cam/pushrod/lever arrangement doesn't push the fuel out of the pump, the spring in the pump does that. The idea was that the pushrod kicks the lever when it can, probably not on every revolution of the camshaft, and the lever operates the diaphragm that draws fuel into the pump. The spring pushes the fuel into the carb. As the fuel leaves the pump, the diaphragm moves and the lever moves back, so the pushrod can kick it open again.
In your case, suppose the hardened layer on the end of the pushrod was almost gone, and during the last bit of driving it wore off, leaving the softer steel to fend for itself.
I am not a restorer and what you have described is the reason I like electric fuel pumps so much. They either work or they don't, and I have yet to have a Carter P4070 pump fail. They are at the back of the car so they pressurize the fuel line, mostly eliminating the possibility of vapor lock. You can turn them off whenever you want to if you provide a switch or a switching mechanism. They cost less than $100, or at least they did when I was buying them.
R.
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Re: worn fuel pump push rod
[Re: MikeN]
#1888980
08/10/15 06:34 PM
08/10/15 06:34 PM
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Joined: Jul 2007
Posts: 863 Pinelands , NJ
joelson6
OP
super stock
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OP
super stock
Joined: Jul 2007
Posts: 863
Pinelands , NJ
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A few questions:
When you changed the cam, was there any noticeable wear on the fuel pump pushrod? Any wear when you changed the fuel pump? What type of fuel pump is the new one? Is it easy move the pump lever by hand?
To my knowledge the fuel pump pushrod doesn´t rotate and I am surprised to read about fuel pumps with claimed open spring pressures on 200 lb considering the small area the pushrod has on the camshaft. Q: When you changed the cam, was there any noticeable wear on the fuel pump pushrod? A: no, i had one on the shelf and the one from the car, both looked identical with no indication of wear. Q: Any wear when you changed the fuel pump? A: wear on what, the pump or the rod? if your talking about the fuel pump lever, than no. Q: What type of fuel pump is the new one? A: basic stock replacement over the counter pump that you buy at any advance auto/autozone/o'reilly parts store. the wear happened before i replaced the pump. Q: Is it easy move the pump lever by hand? A: as easy as any other pump i've tried. the levers weren't seized or bound up.
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Re: worn fuel pump push rod
[Re: joelson6]
#1889004
08/10/15 07:16 PM
08/10/15 07:16 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
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Posts: 36,041
Lincoln Nebraska
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poor metallurgy and or not enough zinc in the oil. if that was the case, why just the fuel pump push rod and not the rest of the cam and lifters? that's easy, poor metallurgy in the pushrod & acceptable/adequate metallurgy in the cam/lifters, however yes if it was a "zinc" issue it could (& would) affect both (& possibly other items)
live every 24 hour block of time like it's your last day on earth
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Re: worn fuel pump push rod
[Re: joelson6]
#1889251
08/11/15 01:43 AM
08/11/15 01:43 AM
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Joined: Jan 2003
Posts: 17,861 albany ny
05dakota
I Live Here
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I Live Here
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albany ny
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why change the cam/lifters?
5549 post on old board
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Re: worn fuel pump push rod
[Re: 05dakota]
#1889334
08/11/15 09:12 AM
08/11/15 09:12 AM
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Joined: Feb 2005
Posts: 4,316 Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,316
Prospect, PA
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why change the cam/lifters? I think he believes it's the cam's fault
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Re: worn fuel pump push rod
[Re: BSB67]
#1889346
08/11/15 09:59 AM
08/11/15 09:59 AM
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Joined: Aug 2007
Posts: 601 Mass
charge70
mopar
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mopar
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Mass
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why change the cam/lifters? I think he believes it's the cam's fault If the camshaft fuel pump lobe looks and measures ok,I'd reuse the cam and lifters that were in the motor.Just use a quality pump pushrod and you should be good to go. John.
1970 Dodge Charger R/T S.E.
1969 Dodge Dart GTS 440 M-Code
1970 Dodge Charger 500 383/4-speed w/A.C.
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Re: worn fuel pump push rod
[Re: joelson6]
#1889373
08/11/15 11:10 AM
08/11/15 11:10 AM
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Joined: Oct 2006
Posts: 7,369 Iowa
burdar
Owen's Dad
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Owen's Dad
Joined: Oct 2006
Posts: 7,369
Iowa
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why change the cam/lifters? From the original post... so i take the rest of the engine apart and get the cam out. the lobe for the fuel pump push rod definitely looks worn.
Last edited by burdar; 08/11/15 11:11 AM.
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Re: worn fuel pump push rod
[Re: joelson6]
#1889458
08/11/15 01:06 PM
08/11/15 01:06 PM
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Joined: Jan 2003
Posts: 21,076 Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,076
Niles , Ohio
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There was a member that had some NOS ones for like 18 bucks shipped.Got one for my 440.I do have a few from my blocks that are from the 60s and still close to stock.The last new one aftermarket was worn in like 5K miles. Rocky
Last edited by therocks; 08/11/15 01:06 PM.
Chrysler Firepower
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Re: worn fuel pump push rod
[Re: dogdays]
#1889625
08/11/15 05:57 PM
08/11/15 05:57 PM
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Joined: Jul 2007
Posts: 863 Pinelands , NJ
joelson6
OP
super stock
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OP
super stock
Joined: Jul 2007
Posts: 863
Pinelands , NJ
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I read all this and I wonder why we work so hard to keep the mechanical pump. It doesn't make sense to me.
The OP also said he'd measured the fuel pump cam and it wasn't different than the stock cam. I agree why not use the same cam (even if it is the Edelbrock Performer version of a cam that is definitely a chevy lobe, 50 years old design). It's broken in. The price of a new cam and lifters would definitely cover the cost of an electric pump, and then no more worries about fuel pump pushrods!
R. i don't want to go with the electric fuel pump cause that isn't what this car is. i want it 99% completely stock running exactly how it did in 1970. people have been using stock mechanical fuel pumps for years with no problems , so why should i change now.
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