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54 331 fuel pump / eccentric cam ?

Started by Bill Kaufman CLC# 15225, January 18, 2023, 01:41:31 PM

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Bill Kaufman CLC# 15225

Howdy Folks,
My series 62 Sport Coupe 331 V8 idles and drives like a dream until I try to rev the engine or push the foot feed to the floor for passing. It felt like a fuel starvation problem so I performed the fuel pump test as outlined in the 54 shop manual. I am supposed to be getting 1/2 pint per 9 cycles ( squirts) I am only getting maybe a quarter of that. So little fuel in fact that I am amazed that the car runs and drives as well as it does. I pulled the pump , inspected it and performed a bench test and it is working great. I reinstalled it, tested it and still very low volume of fuel. I blew out the fuel line from the tank to the pump and also blew a little air back into the tank to maybe dislodge anything that may be on the pickup screen.. I also installed a fresh new inline fuel filter. I checked ALL fittings from the tank to the pump. Still very low volume. Has anyone ever had to replace the eccentric or push rod ? Is this a fairly common problem w our 331's ? The manual listed the rod wear as a possible cause on low volume. Thanks for any advice.. I am stumped..   
If you ain't Wrenching ...  You ain't Livin.  So get out there and Live a little..  !!

Current Labors of LOVE;
1948 series 62 Club Coupe / 346 L head / Rendon Blue
1954 series 62 Sport Coupe / 331 V8 / Aztec Red
1970 Deville Rag Top / 472 V8 / Nottingham Green

Previous Caddies ;

1969 Fleetwood Eldorado / 472 V8 / Wisteria
1974 Sedan DeVille
1993 SLS / White Diamond
2006 CTS / White Diamond

PHIL WHYTE CLC 14192

#1
Bill, have you checked that the tiny ferrule is there at the point where the fuel line joins the gas tank? If that's missing it could cause the problem you're experiencing. The other test would be to run it from a can of gas instead of the gas tank. Run a hose direct from the can of gas to the inlet side of the fuel pump.

J. Gomez

Bill,

There are a few post that deal with the fuel pump rod which it may or not help you.

I would take a wild guess if the rod itself do wears that bad to limit the fuel pump volume there would be several folks raising the issue here since the same rod was used from 1954 – 1959 (possible up to 1962 ???).
Same goes for the fuel pump lever which may wear a bit more than the rod itself. I know folks here suggest packing the pump lever with grease to keep the lubrication since there is no oil dripping at this place, only lubrication is when you add oil.

Also not sure when you test bench the fuel pump if you move the lever from the full rest to full stroke stop which would not be the same when it's on the engine. The pump lever would be compressed a bit on the rod (when the lobe on the camshaft is off the rod) and a bit before reaching the full stroke stop when lobe is at the top position on the rod (sorry do not have the correct angles/distance the pump lever travels under operation).

You can try replacing each piece pump and rod one at a time and see if that improves your condition.

Good luck..!
J. Gomez
CLC #23082

Bill Kaufman CLC# 15225

#3
Thanks, I will pull the pump again and check the rod length after I run the gas can test and check for the ferrule at the tank that Phil suggested. Thanks J Gomez and Phil.
If you ain't Wrenching ...  You ain't Livin.  So get out there and Live a little..  !!

Current Labors of LOVE;
1948 series 62 Club Coupe / 346 L head / Rendon Blue
1954 series 62 Sport Coupe / 331 V8 / Aztec Red
1970 Deville Rag Top / 472 V8 / Nottingham Green

Previous Caddies ;

1969 Fleetwood Eldorado / 472 V8 / Wisteria
1974 Sedan DeVille
1993 SLS / White Diamond
2006 CTS / White Diamond

V63

With the alcohol blended fuels mandated today I would suspect the fuel pump itself. the alcohol component rapidly degrades rubber parts.

PHIL WHYTE CLC 14192

Bill, I had a problem with a new fuel pump on my 54, the valves stopped working,they went hard and stopped sealing. This didn't fail overnight it got gradually worse over a period of time.

James Landi

Bill,

When you tested the fuel pump off of the car, you pushed the fulcum as far as it will go--- what you failed to notice is that the pivot shaft wears, the fulcum doesn't immediately engage and THAT's your problem...the pump is toast... the cam follower is likely just fine.  In the "old days" knowledgeable mechanics would pack the pump case with grease, knowing that virtually no lubication will reach the pump's wear spots, and as the pump's mechanical parts gradually wear, the fulcum isn't sufficiently engaging the diaphragm   All of the above is base on real world experience on the NJ turnpike with 5 people in the car.   Hope this helps you.  James

Cadillac Jack 82


I can attest to the ethanol in gas messing pumps up.  I replaced my pump in my 55 only about 4 years ago and I feel like I need to replace it again.  Car will run fine but the filter bowl barely fills up which indicates a lack of pressure.
Tim

CLC Member #30850

1959 Cadillac CDV "Shelley"
1964 Cadillac SDV "Rosalie"
1966 Oldsmobile Toronado "Sienna"

Past Cars

1937 LaSalle Cpe
1940 Chevrolet Cpe
1941 Ford 11Y
1954 Buick 48D
1955 Cadillac CDV
1955 Packard Clipper
1957 Cadillac Series 62
1962 VW Bug
1962 Dodge 880
1966 Mercury Montclair
1967 Buick Wildcat Convertible
1968 Chevy Chevelle SS
1968 Plymouth Barracuda
1977 Lincoln MKV

Bill Kaufman CLC# 15225

Quote from: PHIL WHYTE CLC 14192 on January 19, 2023, 03:16:54 AMBill, I had a problem with a new fuel pump on my 54, the valves stopped working,they went hard and stopped sealing. This didn't fail overnight it got gradually worse over a period of time.
I guess I should have mentioned that the original pump failed due to the pivot pin on the lever working itself half way out and breaking the pump housing. This happened last summer. I rebuilt an OEM pump with a kit from Caddy Daddy so all of parts are new. The new kit came with what seems to be a neoprene rubber diaphragm and seals. I have rechecked my work and am very confident that everything is assembled properly. 
If you ain't Wrenching ...  You ain't Livin.  So get out there and Live a little..  !!

Current Labors of LOVE;
1948 series 62 Club Coupe / 346 L head / Rendon Blue
1954 series 62 Sport Coupe / 331 V8 / Aztec Red
1970 Deville Rag Top / 472 V8 / Nottingham Green

Previous Caddies ;

1969 Fleetwood Eldorado / 472 V8 / Wisteria
1974 Sedan DeVille
1993 SLS / White Diamond
2006 CTS / White Diamond

fishnjim

If the pump benches OK, then it's most likely not the pump.
 
So that leaves, suction(inlet), outlet, or mechanical actuation.
If the tank isn't vented right it won't deliver fuel correctly.  Assuming the line is clear as noted.  I'd try to syphon fuel from the line and see how much is flowing.  Try with cap on and cap off.  If the fuel filter was changed, the carb side could be blocked there's likely inlet screen(s).  The accelerator pump could also be weak, if it's not accelerating with pedaling. 
If the FP push rod mechanism is worn, then the stroke is short on the pump which limits delivery.   You'd need to measure that by rotating the engine and measuring the max. displacement.  Not much you can do if the rod and/or cam is worn other than replace them.

Lexi

#10
What follows is text from an earlier post I did with respect to tests I conducted on my 1956 Cadillac fuel pump. Yes, '56, so not sure if the same, but I suspect they are or very close:

1) Volume output - disconnect OUTLET line, (carb side of pump) and place end of line in a container. Run car for 45 seconds to 1 minute at idle. You should get 1 - 1.5 pints of gas if output OK.

2) Crank only test with coil wire off (no engine starting wanted here) for about 20 sec. You should get about 1/2 pint of gas if OK, OUTLET side.

3) Vacuum test at idle with a vac gauge at pump INLET side. Disconnect line here and fit gauge to pump. Start car. A normally filled carb bowl will permit your car to run for at least a minute or more with the fuel pump disengaged. Run car and observe gauge. Normal minimum vacuum should be 10 - 13 inches. I believe the gauge needle indicator should be steady. I believe, (please correct me if I am mistaken). If it fluctuates, especially wildly, again, I believe that is indicative of an air leak.

4) Pressure test at OUTLET side of fuel pump. The reading on your vacuum gauge should be 5.5 psi with engine running at idle, (4 - 6.5 as per 1956 shop manual). I believe there is a separate section to read this on your vacuum gauge dial.

5) Check torque for the approximate 10 hold down screws around the perimeter of your pump (unless yours is a crimped unit w/o screws).

6) Check all connections as well as strainer nut seal, (see my earlier post) and strainer screen for debris. This is EXTREMELY important as is a source of air leakage (without gas leaking). There should be no air leaks here. This is an insidious place for air leakage and often overlooked.

7) Run car from a gas can if you think there is a problem somewhere in the fuel line before the pump or at the car's gas tank, as a test. Check lines for kinks & blow out with compressed air both directions, gently.

8) If all fails consider checking push rod length as might be worn, manual says should be 7.1425" - 7.1475" long, (same for 1954). Stroke said to be .245 - .250".

Tests done with car at room temperature as per manual. If you suspect a leaking well plug in your carburetor inspect your engine oil for odour of gasoline. I also believe a leaky pump diaphragm may cause gas to also leak into your engine. If you remove the pump and push rod, you may have to slightly 'bump' the engine to make it easier to fit the pump back on if push rod on high end of stroke and interferes with pump lever when re-installing.

Again, above mostly for a 1956 Cadillac 365 V8 engine, but should "ball park" for a '54. Clay/Lexi

James Landi

Quote from: Bill Kaufman CLC# 15225 on January 19, 2023, 09:22:14 AMI guess I should have mentioned that the original pump failed due to the pivot pin on the lever working itself half way out and breaking the pump housing. This happened last summer. I rebuilt an OEM pump with a kit from Caddy Daddy so all of parts are new. The new kit came with what seems to be a neoprene rubber diaphragm and seals. I have rechecked my work and am very confident that everything is assembled properly. 

Bill--- don't mean to be a nag, but the pivot pin working out of the pump is a telltail regarding not lubrication. I suspect the fulcum on your latest pump is not engaging as it should--that cam follower only rises under an inch, but when YOU are pushing that lever, you're taking up all of the "problem" slack in the mechanism.  As I mention before, this problem occurs because of the lack of lubrication that quickly wears the several contact points out.  I think Lexi/CLay's idea of testing the pump with an alternate fuel vessel can easily verify whether the pump or the gas lines are the issue. Please take safety care doing this. As I mentioned above, the old time mechanics would pack the pump housing with grease to give these non lubricated parts some additional service life.  Hope this helps

Lexi

#12
Quote from: James Landi on January 19, 2023, 03:49:38 PMBill--- don't mean to be a nag, but the pivot pin working out of the pump is a telltail regarding not lubrication. I suspect the fulcum on your latest pump is not engaging as it should--that cam follower only rises under an inch, but when YOU are pushing that lever, you're taking up all of the "problem" slack in the mechanism.  As I mention before, this problem occurs because of the lack of lubrication that quickly wears the several contact points out.  I think Lexi/CLay's idea of testing the pump with an alternate fuel vessel can easily verify whether the pump or the gas lines are the issue. Please take safety care doing this. As I mentioned above, the old time mechanics would pack the pump housing with grease to give these non lubricated parts some additional service life.  Hope this helps

James hi. What kind of grease did they pack in there, or does it matter? Also, the degree of fuel pump rod travel is very small as you noted. I think it is about 1/4 inch or less, with a range of motion differential of just less than 1/8 of an inch if my calculations are correct. So any deviation due to wear I imagine would show up quickly as less volume of fuel being moved through the pump. Not a lot of room for error. Clay/Lexi

James Landi

Quote from: Lexi on January 19, 2023, 07:18:40 PMJames hi. What kind of grease did they pack in there, or does it matter? Also, the degree of fuel pump rod travel is very small as you noted. I think it is about 1/4 inch or less, with a range of motion differential of just less than 1/8 of an inch if my calculations are correct. So any deviation due to wear I imagine would show up quickly as less volume of fuel being moved through the pump. Not a lot of room for error. Clay/Lexi


It was heavy wheel bearing type grease... I also recall, from the mid 60's seeing a zerk fitting on one of these pumps.  My personal experience follows:  Back in '72 with 4 adults and my 3 year old loaded in the '56 sedan on an early summer morning, zipping up the New Jersey turnpike --a/c blasting, to catch the last ferry to an island in Maine leaving at 6 P.M.  Motor starts to stumble for lack of gas.  Pull over, take off the fuel bowl, and not much gas coming out. Take off my relatively newly replaced AC pump, and manually pump it--- plenty of fuel comes out. Pull out the cam follower, hitch a ride to a local parts store, fuel pump and cam follower in hand. The NAPA store has a new cam follower (!) and a new fuel pump to do a comparison-- alsolutely NO wear on my high mlieage cam follower--"...but how can it be that I can manually pump my relatively new AC pump.  The counter man next to mine says, "Your machanic didn't pack the pump case with grease--no lubrication--you need a new pump and you need grease."  We missed the ferry by minutes .... it was a powerful lesson... sadly I find myself relating it to our CLC members, who are experiencing the same issue I did a half century ago.

Lexi

Quote from: James Landi on January 20, 2023, 08:24:13 AMIt was heavy wheel bearing type grease... I also recall, from the mid 60's seeing a zerk fitting on one of these pumps.  My personal experience follows:  Back in '72 with 4 adults and my 3 year old loaded in the '56 sedan on an early summer morning, zipping up the New Jersey turnpike --a/c blasting, to catch the last ferry to an island in Maine leaving at 6 P.M.  Motor starts to stumble for lack of gas.  Pull over, take off the fuel bowl, and not much gas coming out. Take off my relatively newly replaced AC pump, and manually pump it--- plenty of fuel comes out. Pull out the cam follower, hitch a ride to a local parts store, fuel pump and cam follower in hand. The NAPA store has a new cam follower (!) and a new fuel pump to do a comparison-- alsolutely NO wear on my high mlieage cam follower--"...but how can it be that I can manually pump my relatively new AC pump.  The counter man next to mine says, "Your machanic didn't pack the pump case with grease--no lubrication--you need a new pump and you need grease."  We missed the ferry by minutes .... it was a powerful lesson... sadly I find myself relating it to our CLC members, who are experiencing the same issue I did a half century ago.

Thanks James. Fascinating story. I always enjoy reading your posts. I think at least in early '56 the pump came with a zerk fitting. Clay/Lexi

James Landi

Quote from: Lexi on January 20, 2023, 08:41:28 AMThanks James. Fascinating story. I always enjoy reading your posts. I think at least in early '56 the pump came with a zerk fitting. Clay/Lexi

Clay-- I was beginning to doubt my memory of the grease fitting on the gas pump (so counter intuitive)... such a maddening  design flaw.  And thank you for the affirmation...even at my advanced age (77), I'm doing some challenging  wrenching on my new Allante purchase (since my local go-to young mechanic is afraid to touch it!).  I very much enjoy the exchanges on this site--- best regards, James

Lexi

Yes, these exchanges are fantastic James. You got 10 years on me and I am hoping my memory on this matter is accurate! Happy wrenching buddy! Clay/Lexi

Bill Kaufman CLC# 15225

  Thanks guys for the great wealth of knowledge and troubleshooting tips. I ran a bunch of the test and learned a lot about the fuel system. While the pump was off of the car I inspected the cam push rod. I took measurements of the stroke and observed it in action to confirm that all is good in that department. I then bypassed the fuel lines and hooked up a fuel hose from a gas can to the inlet side of the pump. Although the pump performs perfect while OFF the car the external gas can test still produced low volume. So James , your nagging (lol) proved to be fruitful. I also noticed what you were referring to concerning the play on the pump lever. Probably a good 1/2". I will for sure pack the next one with grease ! Thanks again everyone and I will keep ya all posted.    Bill
If you ain't Wrenching ...  You ain't Livin.  So get out there and Live a little..  !!

Current Labors of LOVE;
1948 series 62 Club Coupe / 346 L head / Rendon Blue
1954 series 62 Sport Coupe / 331 V8 / Aztec Red
1970 Deville Rag Top / 472 V8 / Nottingham Green

Previous Caddies ;

1969 Fleetwood Eldorado / 472 V8 / Wisteria
1974 Sedan DeVille
1993 SLS / White Diamond
2006 CTS / White Diamond

Bill Kaufman CLC# 15225

Quote from: Lexi on January 19, 2023, 07:18:40 PMJames hi. What kind of grease did they pack in there, or does it matter? Also, the degree of fuel pump rod travel is very small as you noted. I think it is about 1/4 inch or less, with a range of motion differential of just less than 1/8 of an inch if my calculations are correct. So any deviation due to wear I imagine would show up quickly as less volume of fuel being moved through the pump. Not a lot of room for error. Clay/Lexi

Just FYI ..I wanted to mention that the return line from the oil filter on my 54 dumps in right on top of the fuel pump lever. That probably helps a little with the cam/rod but obviously does not lubricate the wear points in the pump. I will for sure pack the new one.
If you ain't Wrenching ...  You ain't Livin.  So get out there and Live a little..  !!

Current Labors of LOVE;
1948 series 62 Club Coupe / 346 L head / Rendon Blue
1954 series 62 Sport Coupe / 331 V8 / Aztec Red
1970 Deville Rag Top / 472 V8 / Nottingham Green

Previous Caddies ;

1969 Fleetwood Eldorado / 472 V8 / Wisteria
1974 Sedan DeVille
1993 SLS / White Diamond
2006 CTS / White Diamond

Lexi

#19
Quote from: Bill Kaufman CLC# 15225 on January 20, 2023, 10:29:18 PMAlthough the pump performs perfect while OFF the car the external gas can test still produced low volume. So James , your nagging (lol) proved to be fruitful. I also noticed what you were referring to concerning the play on the pump lever. Probably a good 1/2". I will for sure pack the next one with grease ! Thanks again everyone and I will keep ya all posted.    Bill

Thought I read on this Forum that working the action of the pump when off the car can in some cases impair it's operation. Have not looked for nor tested this myself, so I don't have an opinion. If true, perhaps it may involve over extending the rubber diaphragm in the pump so when re-installed it performs inadequatly? If true, perhaps one possible explanation to explain your results upon re-installation? Any thoughts out there? Other posts on the re-staking of the internal valves may also be of relevance. especially on new pumps that were reportedly made in an inferior manner. Clay/Lexi