Doug&Deb Posted November 11 Report Share Posted November 11 The engine in my 52 Coronet is originally from a 58 D-100 truck. I’ve been having problems with fuel delivery and after looking at the different pumps I’m wondering if the fact that I have a car specific pump is the problem. The actuating levers are completely different. The car is a straight arm and the truck has a downward bend. I’m not even sure how the car pump is working at all. I’m trying to decide whether to order a truck specific pump or just stick with the electric pump. I kind of like having both. I should add that this engine was in a 51 Coronet when I bought it and the pump was already missing. Quote Link to comment Share on other sites More sharing options...
Doug&Deb Posted November 11 Author Report Share Posted November 11 The engine in my 52 Coronet is originally from a 58 D-100 truck. I’ve been having problems with fuel delivery and after looking at the different pumps I’m wondering if the fact that I have a car specific pump is the problem. The actuating levers are completely different. The car is a straight arm and the truck has a downward bend. I’m not even sure how the car pump is working at all. I’m trying to decide whether to order a truck specific pump or just stick with the electric pump. I kind of like having both. I should add that this engine was in a 51 Coronet when I bought it and the pump was already missing. Quote Link to comment Share on other sites More sharing options...
Dartgame Posted November 11 Report Share Posted November 11 (edited) I am not sure if there is a real difference between the two. When you say fuel delivery issue are you saying you added the electric pump to resolve the issue ? You may have a bad mechanical pump. Run a few diagnostic tests. Without the electric pump running, hook in a fuel pressure gauge between the carb and mechanical pump run the engine and see what the result is, most vacuum gauges can be used for this purpose. I did this and found the pressure will vary between 1-4 psi at idle. If there is no reading, probably a bad pump. Remove it and look for a wear mark on the pump arm where it contacts the cam eccentric, no marks? Then obviously the cam eccentric is not working the pump. Is the cam eccentric is worn down ? Maybe there is a difference in truck vs car pumps, I doubt it though. Edited November 11 by Dartgame Quote Link to comment Share on other sites More sharing options...
Doug&Deb Posted November 11 Author Report Share Posted November 11 Sorry I should have been more specific. I’ve had fuel starvation on hills since I put this engine in my car. The electric pump was already on and I used it for priming and vapor lock but it does clear up the problem if I switch it on. The problem has occurred with three different mechanical pumps so I doubt they’re all bad. The lever arms are so different between the two pumps that I’m not sure how the ones I have are working at all. I’m trying to decide whether to buy a truck specific pump or not. Quote Link to comment Share on other sites More sharing options...
Dartgame Posted November 11 Report Share Posted November 11 I see, I'd still try and test the pressure of the mechanical pump. Did you install a different intake/carb set up ? Dual one barrels might cause the starvation? Quote Link to comment Share on other sites More sharing options...
Doug&Deb Posted November 11 Author Report Share Posted November 11 No, stock carb. I did do the test where so many pump strokes equals a certain amount of fuel (done in a vice) and that was fine. I may be overthinking this but this is a nagging issue. Quote Link to comment Share on other sites More sharing options...
Dave72dt Posted November 11 Report Share Posted November 11 (edited) I think there is a pump flow test that can be done. You can do a vacuum test on the inlet side of the pump You could test it all the way to the tank if wanted to ensure no leaks in the line and are not sucking air. The problem with testing pump flow in a vise is you may be taking a longer stroke than the engine does. Edited November 11 by Dave72dt 1 Quote Link to comment Share on other sites More sharing options...
Doug&Deb Posted November 11 Author Report Share Posted November 11 From talking to a mechanic friend he thinks it’s the wrong pump. Since the correct pump is not expensive I’m going to try it. I should add that the screws holding the pump together keep loosening which causes a leak which definitely causes fuel starvation. I’m guessing the cam is just different enough that the lever is getting pushed too far and never completely returning to get primed. I’ll follow up once I get this sorted. Quote Link to comment Share on other sites More sharing options...
andyd Posted November 11 Report Share Posted November 11 As far as I know, it doesn't make any difference where the pump arm locates against the fuel pump cam, the camshaft rotates and the pump cam lobe rotates and pushes against the lever making the lever operate the pump diaphram and suck & pump fuel........if you have had the same problem with 3 different pumps then I'd think the issue is not the pump/s......have you checked the float level in the carby, etc? Quote Link to comment Share on other sites More sharing options...
kencombs Posted November 11 Report Share Posted November 11 44 minutes ago, andyd said: As far as I know, it doesn't make any difference where the pump arm locates against the fuel pump cam, the camshaft rotates and the pump cam lobe rotates and pushes against the lever making the lever operate the pump diaphram and suck & pump fuel........if you have had the same problem with 3 different pumps then I'd think the issue is not the pump/s......have you checked the float level in the carby, etc? Agree with Andyd, the eccentric on the cam cares not what angle the arm contacts. contact on the side, bottom or top is OK as long as it contacts without excessive clearance on the low point . I've seen at least two types listed for sale, both for cars and trucks with no differentiation between the two. Quote Link to comment Share on other sites More sharing options...
Doug&Deb Posted November 12 Author Report Share Posted November 12 The float level is good. My concern is if the cam was changed between 52 and 58. There must be a reason why the levers are so different. I still have the original engine for my car and the mounting point for the pumps are the same. All I know is the pump I’m currently using is the one that was on the original engine and I had no fuel issues with it. Plenty of other things but not fuel delivery. Quote Link to comment Share on other sites More sharing options...
Doug&Deb Posted November 12 Author Report Share Posted November 12 I have a 52 Coronet but the engine is from a 58 D-100. It has the correct ancillary equipment to work in a car. The problem I’m having is fuel starvation on hills. I’ve tried three different pumps and they all have the same problem. The one on there now always worked fine on the original engine. I should add that part of the problem is leakage from where the pump is screwed together. After looking up the pump for the truck I realized it’s completely different from the car application. I’m wondering if the cam is different and it’s trying to stroke the pump farther than it should. I’ll try to include pictures to show what I mean. I’ve ordered a truck pump to see if it works. Quote Link to comment Share on other sites More sharing options...
kencombs Posted November 12 Report Share Posted November 12 My old Hollander interchange books show a full interchange, all flathead 49-60 cams, as long as the sprocket set matches the cam. Quote Link to comment Share on other sites More sharing options...
Doug&Deb Posted November 12 Author Report Share Posted November 12 Now I’m really confused. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted November 12 Report Share Posted November 12 (edited) compare the throw of the lever to the pump body, not lever to lever...the above picture are not the same profile and thus not representative of the overall pump Edited November 12 by Plymouthy Adams Quote Link to comment Share on other sites More sharing options...
Doug&Deb Posted November 12 Author Report Share Posted November 12 Are you referring to the length of the stroke from one to the other? Quote Link to comment Share on other sites More sharing options...
TodFitch Posted November 12 Report Share Posted November 12 Other things that can cause issues pumping: An air leak on the suction side of the pump. Collapsing flex hose. Clogged fuel line from tank. Clogged filter in tank. 2 Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted November 12 Report Share Posted November 12 (edited) This^^^^^^^^! Possibly cam lobe severely worn , doubt it or back to pump/arm. Edited November 12 by Dodgeb4ya Quote Link to comment Share on other sites More sharing options...
Doug&Deb Posted November 13 Author Report Share Posted November 13 The tank and lines are new. The air leak is caused by the pump screws coming loose possibly because the pump is wrong for this engine. The cam lobe may be worn by now. The engine was recently rebuilt by me and I didn’t notice any wear nor did the machine shop but I’ve put around 3500 miles on it with probably the wrong pump so who knows. I’m waiting on the hopefully correct pump to come in and I’ll see what the cam lobe looks like. Quote Link to comment Share on other sites More sharing options...
Sniper Posted November 14 Report Share Posted November 14 12 hours ago, Doug&Deb said: The air leak is caused by the pump screws coming loose possibly because the pump is wrong for this engine. The pump application should not have any bearing on the screws coming loose. Some locktite should fix that. Quote Link to comment Share on other sites More sharing options...
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