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tap tap tap, fuel pump?



Tap tap tap at half crank speed toward the front of the motor, thought it was the valvetrain for a long time, finally adjusted that, still there. I'm thinking the fuel pump has gotten weak and it isnt bouncing back following the lobe on the cam as it should. Normal for a 350? How hard is it to get to on a 74?
Any chance that it is the cam walking back and forth?

I hope not.

If it is the fuel pump, it is not too bad to do, jusk kind of hard to reach depending on the accessories you have on the motor.

There is only two bolts holding the pump on, then you have to pop the plate off that will have two more bolts in it. The old rod will slide out. Now you can compare your rod with a new one, and look at the fork on the fuel pump for wear. Hopefully that will answer your question. There are two tricks during the reinstall. One, get some good axle greese, put it all over the new rod, and push it up in the hole. Work quickly to put a new gasket on the cover, the two bolts, then the pump with new gasket and the other two bolts. Most of the time it will stay in place.

The other trick, if you notice on the front of the block there are bolts going into the block about where the fuel pump rod runs. you want to pull the bolt out and get a longer one. Run the rod in, then hand tighten down on the longer bolt until it makes contact with the rod. It will hold it in place while you finish the reinstall.

Good luck!
wolf walker

Here's something else you might investigate, it's pretty easy to do and will at least confirm or eliminate this source as your noise. One at a time, on the suspect side of the engine, remove a spark plug wire. This is best done with the engine off, put the wire out of the way so it can not ground and fire, and then re-start the engine. Replace the wire and move on to the next one. If your noise disappears when a wire is removed, sad to say, you have a worn wrist pin. Many 350 engines developed this problem as they aged, regardless of year of manufacture.
Will look into it, thanks for the info guys.
fuel pump noise

just remove the bolts from the pump,pull the pump out of the block,leaving the fuel lines attached and start the engine to see if the noise goes away. the fuel in the carb will run the engine
That's a good idea, will try that.

I havent gotten back to work on the thing yet, been busy.

Haveing vette grease withdrawel.. :(
Motorman has a good idea,,,,,,,,BUT,,,,,,,,,, use something to cover the hole where the pump was bolted in or you will loose LOTS of oil. Duct tape might stay in place long enough to check the pump if you clean the area with gumout.

Another recommendation is to purchase or borrow one of those engine stethoscopes with the long rod that will allow you to listen to noises that are hard to pin piont. I have one and I can pin point a noise down to a single set of lifters or a bad bearing in a water pump or alternator. You can even pin point a cylinder knock. :cool The thing is great and cheep! It may save you some time and money.

I also have a regular medical stethoscope and if you use the little megaphone fitting on the end it does a real nice job finding vacuum leaks and general noises like AIR LEAKS around windows and doors. When your not driving or fixen the engine you can listen to your heart! :D

Bill C
fuel pump

if you leave the push rod in place you will have little or no oil come out
Update, pump was the noise, also found a bolt on the front of the block that can be used to secure the pushrod. Sounds much better now...

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