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BB Fuel Pump Pushrod Issue #3065114
08/04/22 10:31 AM
08/04/22 10:31 AM
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Clinton, NJ
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njmopar Offline OP
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I don’t really get this, but just my luck I guess. The past year I went through a 71 440 HP motor. Had broken valve spring, which snowballed into me pulling engine and going through pretty much everything. New bearings, cam, valve job etc. I reused the fuel pump pushrod that was in there already and probably from the rebuild prior to my Dad purchasing in 1990, so assuming it was done in the 1980s. I didn’t actually measure the pushrod when assembling, just looked it over and it “appeared” fine (wish I did now). Some tiny wear marks on ends and I put the cleanest looking end towards the cam. New, not vintage era, Carter 3/8” inlet fuel pump.
Fast forward a few hundred miles on the motor and I noticed fuel starvation at high RPMs and engine stalled a couple times on uphill climbs. Would restart until it didn’t. Figured it was the pump and upon removal along with pushrod, see the pushrod is worn down a good 3/8”. Lovely.

What I don’t get is this is the same pushrod from 1980 something, which I figured was from the era before all the issues. Was I just unlucky and put the side towards the cam that wasn’t hardened properly or could there be something else contributing? I cant find a spec, but the spring pressure on this pump appears to be ok. I can’t really compress easily by palm of hand, but compresses pushing against a hard surface. Doesn’t seem excessive or binding. Cam looks like it survived, don’t see any scratches or anything after going around full circle. I run Mobil 1, but use 2 bottles of ZDDP+ additive due to the 7 qt pan. I did use break in oil and ZDDP additive as well during break in.

Only thing I did different on this assembly was I used engine assembly lube on the pushrod and not my normal glob of grease. Is it possible that the assembly lube was too restrictive in the block bore and bound the rod during the critical break in period?

I am kind of lost on this for cause. I bought a new pushrod from 440 source, which I have used same in my last BB build that was missing an existing part, with no issues. That one I did use regular grease on assembly out of habit. I got a magnetic drain plug and plan to cut open filter to see how much was caught so far.

pushrod.jpg
Re: BB Fuel Pump Pushrod Issue [Re: njmopar] #3065126
08/04/22 11:11 AM
08/04/22 11:11 AM
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Arlington, Texas
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bobby66 Online content
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Hope the lobe on the cam is ok. wrench


B
Re: BB Fuel Pump Pushrod Issue [Re: bobby66] #3065129
08/04/22 11:15 AM
08/04/22 11:15 AM
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Clinton, NJ
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njmopar Offline OP
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Looking down from distributor hole with a super bright light as I turned it over, appears ok. I saw one diagonal discoloration mark, but no deviations on the metal surface.
I am thinking I wore past the hardened surface and just chewed up the rest of the pushrod. I just don't know why.

Re: BB Fuel Pump Pushrod Issue [Re: njmopar] #3065176
08/04/22 02:15 PM
08/04/22 02:15 PM
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Bend,OR USA
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Cab_Burge Offline
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Were did that metal go? work
I would cut the oil filter open and look at a couple of rod bearings now up Just to be safe twocents


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: BB Fuel Pump Pushrod Issue [Re: Cab_Burge] #3065204
08/04/22 02:54 PM
08/04/22 02:54 PM
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Clinton, NJ
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njmopar Offline OP
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Originally Posted by Cab_Burge
Were did that metal go? work
I would cut the oil filter open and look at a couple of rod bearings now up Just to be safe twocents

Hopefully down in the pan and eventually trapped by the oil filter. Ideally large enough to get trapped in the filter, but small enough to not damage oil pump. I will be cutting filter open.
The way I see damage is probably done already as it has strewn throughout the engine in random places.
I will run a magnet drain plug and monitor.

I really just want to know the cause.

Re: BB Fuel Pump Pushrod Issue [Re: njmopar] #3065219
08/04/22 03:37 PM
08/04/22 03:37 PM
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moparx Offline
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is it possible there may be a slight burr in/on the push rod locating hole in the block, causing it to slightly stick in operation ? shruggy
just throwing something out there to look at.
beer

Re: BB Fuel Pump Pushrod Issue [Re: moparx] #3065259
08/04/22 04:46 PM
08/04/22 04:46 PM
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Clinton, NJ
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njmopar Offline OP
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Originally Posted by moparx
is it possible there may be a slight burr in/on the push rod locating hole in the block, causing it to slightly stick in operation ? shruggy
just throwing something out there to look at.
beer


I planned on dry fitting the new one and carefully taking notice of any resistance.
I didnt do any major engine work that would have knicked the bore or anything.

Re: BB Fuel Pump Pushrod Issue [Re: njmopar] #3065277
08/04/22 06:31 PM
08/04/22 06:31 PM
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Benton, IL.
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DaveRS23 Offline
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Been dealing with this issue since the mid 70s. I have always kept 2 items laying around at all times that I had pulled from junk yards. Ballast resisters and fuel pump push rods. I bet I have changed a couple of dozen over the years in big blocks. I got a heck of a deal one time on a numbers matching '71 GTX due to a worn pump push rod. Never had a problem just throwing another one in there.


KOS
Re: BB Fuel Pump Pushrod Issue [Re: DaveRS23] #3065419
08/05/22 09:54 AM
08/05/22 09:54 AM
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Clinton, NJ
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njmopar Offline OP
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Awaiting new pushrod, but magnetic drain plug came, so decided to dump oil. Put the magnet in the exit stream from pan. No chunks, just a little grey coating stuck.
Cut open the filter and found a grey slurry in the outer case. The circle in my photo is from my LED light magnet stuck on the filter. I can see grey and silvery flecks in the oil inside the filter, but very few large pieces. Some random ones stuck in media, like the one I placed on the housing in this photo.
If this is the extent of my damage, I consider myself lucky. Guess I will be doing some frequent oil changes for a while now until confident.

filter.jpgfilter2.jpgfiilter3.jpg
Re: BB Fuel Pump Pushrod Issue [Re: njmopar] #3066188
08/08/22 10:50 AM
08/08/22 10:50 AM
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JohnRR Offline
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Originally Posted by njmopar
Originally Posted by Cab_Burge
Were did that metal go? work
I would cut the oil filter open and look at a couple of rod bearings now up Just to be safe twocents

Hopefully down in the pan and eventually trapped by the oil filter. Ideally large enough to get trapped in the filter, but small enough to not damage oil pump. I will be cutting filter open.
The way I see damage is probably done already as it has strewn throughout the engine in random places.
I will run a magnet drain plug and monitor.

I really just want to know the cause.



Oil passes thru the oil pump unfiltered BEFORE it gets to the filter ... open your pump and see what the inside looks like.

Better yet just replace it and pull the pan and clean it out along with the pickup.


running up my post count some more .
Re: BB Fuel Pump Pushrod Issue [Re: JohnRR] #3068061
08/15/22 08:04 AM
08/15/22 08:04 AM
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Posts: 1,326
Clinton, NJ
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njmopar Offline OP
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Here is an update, as I think I am going to move on from worrying.

I put about 100 miles on an oil change, driving it pretty normally/spirited. Dropped the oil and the magnetic plug had a slight dark residue on it. Super fine, but obviously magnetic. Cut open the filter and it looked way better than prior, still some of that slurry stuff in the media. Zero flecks of any silver bits like prior time.

I borrowed a borescope and went in through the drain plug. This borescope has a super bright light, which was great, but was too large to fit through the dipstick tube. Was hoping to see the pickup inlet area, but that wasn’t feasible from the drain plug, couldn't bend around to that angle. Checking out the entire pan in detail, could not find anything laying down there, except one tiny fleck of silver on top of the pickup tube that reflected in the light. Pulled the distributor and inspected the cam and pump pushrod and surrounding area, which all looked normal. Did a few passes in the camshaft valley and along the lifters to see if there was anything laying up there, could not find anything out of the norm.

So I am just going to let it be and keep checking on my oil change intervals. Probably by the time anything comes to a head, it will be after I am around to worry about it.







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