Thread: knock, with backfire thru carb

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Hi!

Yes this is my first post.

I have just obtained a 1983 Camaro with a rebuilt 350, it has a mild cam, but I got it cheap because it has a loud knock, and back fires through the carb.

Suggestions on how to troubleshoot between rod knock, and really bad lifter?

Thanks!

Mike ( me)

I would pull the valve covers and look at your rocker arms when the car is running.
Sounds to me like a valve is stuck or not opening, maybe a bent valve or a cam lobe went flat. That could also cause your rod knock!!! It could also be a piston came apart and some debre is holding the valve open.
Let us know what ever you find.
Kurt

Thanks Kurt.

I will have it apart this weekend. If I don't have to pull the engine, that would be best for me, but, "what will be, will be"

After looking in the valve galley, I can see number 8 cylinder exhaust valve does not move.
I am most of the way along pulling that head.
Can you just have the one valve fixed, and then put that head back on?

I really think the previous owner over revved and engine with a mild cam, and stock lifters/rockers, and floated the valve.

Hopefully the piston is OK.

check the camshaft the small block chevy has a short cam life.if you have more than 130,000 on the engine change the cam and lifter. have the heads rebuilt to save you heaqdaches in the future.

Less than 5k miles on the engine.

Except for the one valve, runs great.

I still have not seen the piston though, may be a lost cause.

I'll know tomorrow.

Reminds me of when I was a kid my step dad just bought a Plymouth duster with a slant 6 that had a stuck valve. He took a block of wood and a sledge hammer and straightened the valve while still in the head on the car. that car ran for years after that without any problems. If you remove the rocker arm and turn the motor over by hand will the push rod move up and down? Is the push rod bent? You may get luck and just have to fix the one valve.

Well let us know what ever you find please. Kurt

Flat exhaust lobe on the cam cylinder #8. Comp cam installed in 2007. Bad connecting rod on #4. Heads look OK, but I do not know about the valve.

I am going to replace the long block, and keep the Edelbrock Performer intake and carb.

The distributor is an HEI, with a large 4prong plug, that would make it computer controlled?
Can I just replace it with an non computer HEI distributor?

Sorry you didn't have a little more luck with that Buddy.
But maybe you can save some of the stuff for another project in the future.
Thanks for letting us know what you found, just wish the out come would have been better for you.
Kurt

If it only has 5000 miles on it maybe it would be worth it to turn the crank, put a new rod and cam in it and use it?

Just brought home the new Long Block!

350, 40over, comp cam, Edelbrock Performer intake, edelbrock matching carb.

Now I just need to put it in............

I must be getting old, putting in a motor by yourself is work!

Ahhh well, that's part of the fun ain't it?

WOW!
That has got to be the easiest install I've ever done.
OK, I've only done less than 20, so maybe I don't have a broad range of experience.
I was having trouble getting the pins to align with the bell housing. I took a break, and went in to recruit my son to help, (he's 6'4" and could probably bench press the block) when we came out to work on it, the hoist had settled a bit, and the pins were all in place!

Or maybe it was the little people............

That always makes it easier to have stuff fall in to place. and the second set of hands does not hurt either.
Kurt