JACK M Posted December 8, 2023 Share Posted December 8, 2023 My neighbor is trying to start this old street rod that has been parked for a long long time and we have no history. He thinks its a 400 from the 60s or 70s. It will fire with a prime but doesn't pump fuel. I get fuel when I put a little pressure in the gas tank. (the pump has three nipples, I think one might go back to the tank as a vent). We have the pump off and I can feel up in there and can feel what I presume is the eccentric (along with a kind of loose timing chain.) My question has to do with the eccentric. It feels like I can turn it with my finger tip, Is there a bearing on a sleeve that the pump shaft rides on? If so then maybe it just needs a new fuel pump and be done with it. I suggested maybe stick a long dowel or the likes up in there to see if the eccentric does indeed push the dowel up and down when cranking the engine. Am I on the right track? I forgot to mention, when we took the pump off it is so stiff that we can't move the arm, I would think that would mean that it is compressed already, but that didn't dawn on me right at the moment. We put the project off so that I could bring in all my knowledgeable friends on this fantastic site for some more educated opinions. Thanks in advance. Link to comment Share on other sites More sharing options...
joe_padavano Posted December 8, 2023 Share Posted December 8, 2023 The third line on the pump is fuel return to the tank, not a vent. Replacement pumps are cheap. Link to comment Share on other sites More sharing options...
JACK M Posted December 8, 2023 Author Share Posted December 8, 2023 1 hour ago, joe_padavano said: The third line on the pump is fuel return to the tank, not a vent. Replacement pumps are cheap. Makes sense, if it were a vent it would only vent back to the tank because I could pressurize the fuel fill. He has a new pump, we just want to do some testing of the eccentric before we put it on. Not being a Pontiac guy I am curious about whether it should feel loose (spin) on the front of the camshaft. The best look is in my Motors manual, but cant tell from the picture in there. Link to comment Share on other sites More sharing options...
joe_padavano Posted December 8, 2023 Share Posted December 8, 2023 The eccentric on a Pontiac actually has a separate ring that goes over the outside of it. This is likely what you feel spinning. The eccentric itself has a tab that keys it to the cam gear. 1 Link to comment Share on other sites More sharing options...
JACK M Posted December 9, 2023 Author Share Posted December 9, 2023 4 hours ago, joe_padavano said: The eccentric on a Pontiac actually has a separate ring that goes over the outside of it. This is likely what you feel spinning. The eccentric itself has a tab that keys it to the cam gear. Perfect, this is what I was thinking. Thanks. 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now