Thread: 350 Chevy popping sound

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A friend of mine went to the local salvage and picked up a 350 SB for a good price. It was very low mileage and was a pre 80 SB that was rebuilt they said. We installed it and it runs great except he has a popping sound on the one side of the exhaust. It's not a miss but pop- pop. I told him I think it's a valve. What do you guys think?Thanks for your help.

Any response from a mail-order diagnosis is going to be a longshot. There are so many variables that can cause engine misfires or noises so any suggestions are worth what you pay for them.

Instead, you should do some basic troubleshooting....troubleshooting 101....has worked for many, many years. Have you done a compression test? Looked at the plugs? Verified the timing and valve lash? Inspected the plug wires and distributor?

Dig in and find the problem...exhaust all the common causes...
before you ask for a list of "possibilities".

First off I would check your wires.

Replaced wires and cap and rotor and checked plugs. Compression check is in consistant. Get different readings. Didn't need a lecture just wanted some help. Won"t ask any thing again from this site.

Wasnt intended to be a lecture...read your original post...appears that you had done zero trouble shooting and you wanted someone to fix it over the internet.

I would check adjustment on valves , and preform a leak down test on the engine all cylinders. check firing order. My two penny's. I dont mind helping you out try looking at these things first.

Don't get all upset, Robot was just laying out some things he felt you should check. It is very hard as he said to diagnose problems over the internet as there are so many possibilities and we all describe sounds differently.

You say the compression is inconsistent..........that is your first clue. What were the readings exactly? Anything more than maybe a 10 percent or so variation should be cause for concern. I also tense up a little when someone who is selling something says is has been "rebuilt". That can mean anything from a spray can job to a completely remanufactured item.

Give us more to go on, we really like to try to help but need all the pieces of the puzzle we can get to do the best job possible.

Don

Could be flat cam

X 2 Flat cam