When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
If you think its the fuel pump, take the fuel pump off and then start the car. It's not the fuel pump. Pan back off. Check all 5 mains, and all 8 rods. You will find the problem.
I changed the oil and put in 10-40 with a new filter. This quieted down the knocking substantially. I also change the wires and then got the engine tuned much better. It will idle now at 900-1000 rpm. But it is still flaky about it. Vacuum is 15lbs at idle and with the vacuum gauge I was able to get the timing just right. It smoothed out quite a bit but it still is not what I would call "running like a sewing machine". But no more back firing out the carb and no more popping out the exhaust. The idle mixture screws are at 1 1/4 turns out.
I am in contact with Lars and will be sending out the carb for his review and improvement. I am also going to look into the spark plugs.. The current ones are autolite F 26's that are new. I will also consider a new coil as the one in there looks original.
It just shouldn't stumble in my view and I cannot get it to run perfectly. ignition or fuel mixture.. not sure.
I didn't feel like messing with the fuel pump any more this weekend. In my mind, I know the bearings are good so I will sort out that noise at some point.
Thanks for all your feedback guys. It's good to have a place to share your ideas and frustrations!
Take it for what it’s worth – From reading all the post, you did not check all the rods and all the main caps? If you did no need to worry about the bottom end because of the visual. I had a 82 boat a few years ago with a chevy 305, Same vintage as your 350. It had the same sound as yours and it was a bad single rod bearing that went out. Oil didn’t look bad, but when I started removing each rod cap I found it. All the rest of them were good.
On your fuel pump there is a threaded hole in the front of the motor to hold the fuel pump rod in place while changing it out. Need to check that rod tho – could be why its running so rough because of not enough fuel pressure. Just an FYI – Hope you can find the problem. Good luck
I may not have the carb sent to Lars for a once over. It's not idling like a 2019 vehicle but then again I doubt it was ever that consistent at keeping the idle at 900rpm exactly. I can't get it to stay at 750 rpm.. it will stall. 900 makes it happy.
It is very quiet now. 10-40 oil. I am convinced it is the fuel pump and will get to it eventually. I can feel it in the fuel line that comes off the pump. As the oil thins it gets louder and it is very consistent. Not as loud as before the oil change.
I would cut the Oil Filter and look for bearing debris inside. I would also plumb another Oil Pressure gauge in and see if it agrees with the original.
As long as you use very light throttle it may last a while. You have a rod knock. Dropping pan and cleaning up the journal and replacing the bearings may buy you more time. But that crank is coming out of that block. Your choice: You disassemble it or it will do the job for you...
Last edited by derekderek; Mar 23, 2019 at 04:50 AM.
The oil pressure comes from the main bearings not rod bearings . If anything check the fuel pump. It's not all that hard + they are cheap at the auto stores.
I have the carb with Lars and a new fuel pump that needs to go in. Once I get it all back together I hope I will for sure know the answer to that question. But I can feel the knock on the pump and pump lines. Just by holding them. I don't know for absolute certainty yet but I will in a few weeks.
Well the results are in!! First lets take a look at that knocking problem. See image. I think perhaps there was some issues getting the engine running and it was not lubricated on assembly.
I got the carb back from Lars and he did an excellent job as usual. He really had to work on it too. It had a number of issues.
Cold run
Well the results are in!! First lets take a look at that knocking problem. See image. I think perhaps there was some issues getting the engine running and it was not lubricated on assembly.
I got the carb back from Lars and he did an excellent job as usual. He really had to work on it too. It had a number of issues.
A massive difference from where I started with this little set of issues. Thanks for all your help guys.
So, can't hear as well as some folk ..
So ... what was it?
Thanks for all your help guys.
