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Fuel Pump Pushrod Fail --- Damage to engine??

32K views 77 replies 19 participants last post by  Boucher421  
#1 ·
I have less than 500 miles on the motor (406 SBC). Ran fine in Alabama. Drove her onto a trailer, and moved to VA. Couldn't get the motor cranked when pulling her back off the trailer! Went down multiple rabbit trails (fuel tank full, changed filter, swapped carb). Found the pump simply wasn't pulling gas from one jar and spitting it into another. Couldn't feel any auction at the inlet either.

All made sense once I removed the push rod and saw this:
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WTH! I had never heard of a push rod being ground down, until an hour ago after researching the forums. It was a comp cams 4607, bronze tip push rod. I have a mild flat tappet cam. In retrospect, I shouldn't have been using the bronze tip. But...here we are. So here's my questions:

1. Did the tip simply wear down or is there a chance it snapped off and I have a big chunk of metal floating around my engine?
2. Could it really wear down in 500 miles? I.e. Is there some other problem going on?
3. Is my cam trashed?
4. Most importantly...where is all the metal that wore off?!?! I assume I should change the oil before cranking. Do I need to drop the pan to inspect/clean?

Help!
 
#2 ·
1.If it did wear down or break off there is metal in the engine, definitely worth changing the oil.
2. Is it possible you have a big block fuel pump? It would fit but could cause damage like that.
3. After you change the oil you can put in the new rod and just see if the rod moves properly. Cam could be trash but no way to know.
4.The metal is most likely in the pan, so it might be worth the time to drop it(maybe someone else could chime in on that).
 
#3 ·
If it wore down it is embedded in the bearings and in the molybdenum coatings of your rings. If it snapped off (more likely) it bounced around past the crank and fell into the pan. The steel rod is a different story. The spring in the fuel pump pushed the rod up against the cast iron eccentric on the cam wearing both down (the cast iron is harder than the mild steel rod but it does wear) until the spring no longer applied any pressure.

Either way an electric fuel pump is going to be cheaper than a new cam and lifters (assumes you have flat tappet lifters). Even with a roller cam (that can be replaced without replacing the lifters) a new cam will cost close to the price of a decent fuel pump.

Without dropping the pan you will never know. Without knowing you can get a replacement push rod from Comp Cams but it will still be a the same quality as the last one. A brass tipped push rod like a brass gear on the distributor is used only with a steel billet core cam. Which is to say rarely ever used with a mechanical fuel pump and a steel billet core. As few racers rely upon a mechanical pump, only using one to comply with class rules. Theoretically the replacement cam for that class car could use a steel core cam (ground to stock specs) but due to expense most go with a cast iron core.

I doubt without the missing button you will get anything other than a new push rod out of Comp Cams as they will deny everything.

Big Dave
 
#5 · (Edited)
My guess we are looking at the cam end, I do carry a spare but since the last one failed as you see, I pulled the cam out, to find the fuel lobe worn down.
I pulled the motor and for the sake of it, opened it up and cleaned house. I did find the brass button in the pan. This brass tipped push rod is supposed to be for billet cams, but is yours billet.

From there I went to the roller wheel design as the cam was gone. Closer inspection to the cam,( it was a comp cast and I can't think of the fancy name they applied to the material), A lobe started to flake out on one cly. Set all aside and called The Man in Mississppi UD Harlold. Harold took my specs, had someone else cut me up a billet roller with the EverWear dist gear.
Harold referred to the flaked lobe is lifter bounce as I was running the cam recommended spring pressure of 125# . On Harolds billet, he recommended 155#. This is not a race motor.

I put it alll bact together and ran the little fuel pump roller wheel push rod. I ran one Powrtour and pulled it for inspection. All Good.

Better look for more damage.
 
#6 ·
The picture/damage is the cam end of the shaft.

Cam was NOT billet. I now understand I shouldn't have used the brass tip.

From previous comments, step one seems to be to drain the oil, drop the pan, and find that button.

I'm not sure how I can inspect for damage without pulling the motor. (Pulling the motor probably won't be possible for a about a year...but I don't want to cause catastrophic damage just because I don't have the time/know-how to rebuild/inspect the motor).

I have a replacement rod (no bronze tip) sitting on my bench. Is there a way to verify that the cam lobe is indeed wiped? If it's not wiped, is there danger in using the new rod (after an oil change and finding the brass tip)?
 
#7 ·
Not going to be able to see cam fuel lobe, unless you view it from the fuel pump access hole. You might be able to use a bore-scope tool, but chances are , depending on how long you ran it, to find damage. If the cam is cast, my guess that the wear surface is scored. I thought about just installing the stock gm shaft as its harder than cam, but if you have as much money tied into that motor, its a gamble. You still have to pull the pan. Even more, cut the oil filter open and examine.
 
#8 ·
Lots of tiny gold flecks (yellow bronze) in the filter means it wore prematurely. Steel flecks will be shiny silver like the end of the rod. The wear off a cam is dirty grey sooty flecks as the cam is cast out of nodular iron (aka grey iron) for strength.

If the button sheared it will have a small post that broke off that used to sit inside the push rod. That rod post will be jagged, The button will have impact marks from where it hit reciprocating or rotating parts.

Big Dave
 
#11 ·
Looks like the tip separated. Also appears the end of the rod did not get beat on by the cam lobe or does it appear any material was ground off.

I'm with Doug. Flush and run.

The tip is in the pan and won't get past the OP screen. Maybe get lucky and have it come out with the oil change.

Electric fuel pumps are IMO noisy and failure prone. 1st thing I change when I buy a car that has one.
 
#12 ·
John electric fuel pumps have improved tremendously since the days of the old 1960's Carter cocktail shaker (my first pump back in the mid sixties) or the early 1970's Holley blender (which was not only noisy but prone to heat the fuel thanks to it's dead head design). All cars and trucks have used electric pumps since EFI was introduced in 1987 without noticeable noise or failures.

I have been using Aeromotive A1000 external pumps for decades. Mounted to an aluminum plate with rubber isolators (old shock absorber bushings) and the plate mounted to the frame with more rubber shock absorber bushings keeps all the noise from the pump inaudible inside the car.

Big Dave
 
#13 ·
After I lost the push rod and cam, I rebuilt and went to a Carter Silver electric pump mounted at the rear , near and level with the tank. I was always worried it may fail , so I carried and extra, Because of the dead head pressure issue, I went back to a Holley 327 pump with a roller tip rod. I have inspected this periodically and its good, so I build confidence on it.

Some day I may go fuel inj with tank in pump ($1000) but I am still kicking it around as being of age now, some day my son will get this car and I need to make it maintenance free, thus the thought of a LS motor but then , originality goes out the window.

My suggestion still stands, Pull motor and inspect bearings unless you can do it all on your back.
 
#14 ·
Unless you are a millionaire I would pull the engine. The least it would cost is time, gaskets and oil. On the other side flush it and run. You could be spending your whole life savings on repairs. I always lean towards the caution side.
I had a Race engine shop for 18 years. Had a customer call me and said he was installing a small balancer on the crank. He thought the inner key fell in the oil pan and couldnt find it. I said pull the engine and get it out. He said he talked to Joe blow engine builder and he said it would go to the bottom or the oil pan out of harms way.
Guess what, He called me the next day and 2 laps on the 1/2 mile track, the key found the lower timing gear. Several bent valves and 2 pistons. I thanked Joe blow racing engines for the business and the car owner brought it to me.
If at all you have a question about a possible issue in the engine, check it out.

my 2 cents worth. maybe less .
 
#15 ·
You can check if the fuel pump lobe is ok by inserting a new rod and hold it there with your finger while someone manually turns the engine over by hand with the plugs out. If you can find out the measurement, check it w/ a dial indicator too. If the lobe is wiped go w/ electric pump.

I'm with Doug and John, oil/filter change and go. Whatever material came off is either at the bottom of the pan for good (in a street engine) or in the filter. I just thought, if you have the factory bypass on the filter head then there still material circulating in the oil.
 
#16 ·
Not sure what you mean by factory bypass on the head.

Just dropped the oil pan in search of the brass button but NO LUCK. Dang it. I didn't notice any colored flakes in the oil...but I did notice that it feels like gritty sludge on the bottom of the pan. Here's a couple pics, the first is from 10 seconds after I wiped my finger on the bottom of the pan:
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At this point I plan to clean the sludge out of the oil pan, reassemble, oil/filter, new pump rod (without the brass tip) and crank her up.

(For what it's worth...I only have 500ish miles on the motor, but have probably changed the oil 4-5 times. (After break-in, oil pump change, oil pan gasket change, and ANOTHER oil pan gasket change.) Last one was probably 150 miles ago. I don't recall ever cleaning pan or noticing sludge. )

For those that say "pull the motor to be safe," what does that entail? Rebuild? Inspection? New ______?"

Thx guys!
 
#17 · (Edited)
You said 500 mile on this motor? What is the thick sludge? Did you build this motor and is that heavy assembly lube? Never seen sludge unless is was from water but then its not milky.

Since you have the pan off, why don't you pull some bearings? #2 rod and front main?

Looking at your original pump rod, it looks like the brass button broke off. If it did, then that leaves the sharp ends to cut the fuel pump lobe.

You may find more reasons to pull the motor. Chances could be that gritty stuff you found could be part of your cast cam fuel lobe.
When my lobe wore down half its brass, I noticed loss in fuel volume. Your brass time is gone and could I be seeing a wear shread of material on that end?
At the time of my failure, I had not heard of this brass tip wearing down, neither did Comp or maybe they didn't want to say.
The brass tip rod is meant for roller cams, never heard if they meant billet or cast.
I now run billet with a roller tip shaft.
 
#18 ·
The brass tip rod is meant for roller cams, never heard if they meant billet or cast. I now run billet with a roller tip shaft.
I believe the brass tip rod is intended and necessary for billet roller cams, cast cams (rollers included) use a standard fuel pump push-rod.
 
#22 ·
Trash in bearing, embedded , causing surface scrapes into copper? I just feel that its important to at least pull some bearings, to look at what could be going on, this could save you a crank or worst, rod out the side. I may be exaggerating some but if it was my motor , it would surly put my mind at ease. You may get by with a rinse cycle and oil change, but your button is gone, now, I just don't think it would be ground up in the oil pump. BTW, have you checked your oil pump pickup screen cavity?

I lost just half of my brass tip rod and that was enough for me to pull the motor out and clean. I was running a plugged oil filter bypass at the time and I was glad to find trash in the oil filter element after I cut it open. I have never done that until several of the TC members mentioned it.

As for fuel pump arm movement, I would just guess what you mentioned, at least 1/2" as you mentioned, your motor ran then you restarted and could not get fuel, so I believe the pump lost its prime or pump range in the trailer.
I noticed a shortage of fuel volume and I only lost half of the brass tip.

Referring back to what Big Dave said about the grey iron , that the cam is made of, that's what looks like is in the bottom of your pan, a slurry of grey iron and oil. I would guess that a magnet would attract some of this.
 
#23 ·
If it were my motor and I found grit like that in the pan I would pull and completely dis-assemble and rebuild the motor with new cam and crank bearings, hot tank the block etc. It would be a tremendous PIA but all that stuff floating around will have an effect on the motor and that effect will be wear. Not only from embedding in the bearings and rings but also in slowly clogging up the oil passages.
Rebuild it now or rebuild it later.
 
#24 ·
Just putting this out there for anyone who might stumble across this thread down the road - here is what I decided on for my steel billet camshaft, a plastic one. It will also work with a cast cam. Since it's a "race car" part, it makes my car that much faster.

https://www.summitracing.com/parts/hrs-94475/overview/
 
#27 ·
#2 rod bearing is the last to get oil. It may tell you what the others look like. You un-torque the rod bearing nut and it should come loose, might tap on side of cap, of course the crank throw should be looking up at your with the other rod cap.

I mentioned that you might look at the #1 crank main bearing. I also mentioned that you are looking for evidence where this sludge is coming from. I would do you good to remove the cam and inspect the lobes as well as the fuel pump lobe. In doing so you might find a burned cam lobe also.

I am assuming you have stock rods so the rod bolt nut re-torque should be at 45#. You haven't said if the motor is still in the car or out on an engine stand.
 
#29 ·
Instructions for the bottom end are the same but its harder as you will be working on your back and the crossmember maybe hinder how you work in the front area of the bottom end.
Even if you pull the bearings it may not show you where all this sludge is coming from. Any chance the intake and lifters are out? This may show you the cam and lifter are good but nothing on the cam fuel lobe.

I don't think that sludge is coming from the bottom end of the motor but bearing inspection may tell you what other damage you have. I suspect this is getting hopeless for you and discouraged since you have not done this before. If you have the grumption and determination to find the problem then keep going.
I have done this and come to the end of inspection and found nothing but then I had the cam and lifters out with crank and rods in the motor, working on my back , but that was 20-30 years ago until I found it was easier to pull my motor and put it on a stand .
You said the motor had some 500 miles on it , then you pulled the pan and found all this trash and sludge is what concerns me.
I am an old racer, got into oil field manintence long ago working on large recipotating compressors, with crank inspection door big enough to slide into.
I did this for a long time before moving on to oil well consulting , even today I can still get my motor out with a cherry picker and wife on the other end, giving me directions and help to get my motor out on a stand.

Don't give up.
 
#32 ·
Those bearings are good, I would button the crank /rods back up, Still question all the slop at the bottom of the pan. Any chance of doing some cam / lifter inspections? Guess the pump shaft button hasn't been found.