Uneven exhaust question

[jnikolas]

I have a 400 sbc motor that I just replaced the mufflers on. The old mufflers were completely rusted out so I installed 2 new Flowmaster super 44s. I checked carefully for any leaks and sealed the one I found on the driver side. I found none on the passenger side. The driver side exhaust is very even now. The passenger side exhaust is choppy. When I put my hand to the tailpipe I get two to three strong blasts then one beat of no exhaust coming out at all, maybe even sucking. This is at idle, I have not tested at higher RPMs. The engine runs well except I do notice a tiny loss in power at one point in rotation. I am guessing one of my cylinders is having a problem on the exhaust stroke, but I have no idea. What can I do to test this and to repair. I appreciate any help.

[VWBeamer]

Classic sign of a burnt/bent/leaking exhaust valve.

[brianthelion02]

Time for a compression test!!

[jnikolas]

Will a compression test verify this? Is there any other test I can perform that will help me narrow it down or will I have to visually inspect?
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[terry b]

The compression test is the way to go. You could remove the valve cover on that side and take a look tho i don't know what good it will do you.

[brianthelion02]

Yes ,compression test is the best way to verify if a valve is burned or not! Also how long has it been since a valve adjustment?

[ole dollor]

yep...they told you right...that is where you want to start....

[jnikolas]

Originally Posted by brianthelion02

Yes ,compression test is the best way to verify if a valve is burned or not! Also how long has it been since a valve adjustment?

I have no idea about the valve adjustment. I have a 69 c20 but the motor is not the original as it is a 400 sbc. It was supposedly recently rebuilt, but I have no idea when. I bought it less than a year ago from my brother-in-law and he only had it a few months. I want to fix what I can to prevent any type of failure but have a limited budget. This is my daily driver (about 6 miles each way). Any suggestions on what I should do if valve is bad? Just replace it? Should I give the rest of the head any attention while I am there?
Posted via Mobile Device

[ole dollor]

the cheep way would be to pull that head and fix that one valve, if all the rest have good compression . you can check the rest on that head and lap the others if they need it, if you do both heads and raise the compression then you could start using oil if the rings are weak...so to save money this would be the cheep way. i have had to do this a number of times to save myself money and keep it going. and i have done this for others that were in the same boat i was in, that would buy you some time to save up and keep driving every day....

[terry b]

If you do find a dead cylinder you will need to take the valve off and check rockers and push rods. crank the motor and see if everything is moving as it should. If it is you have to figure you have a bent or burnt exhaust valve. If you are short on cash that is all you need to repair. Remove intake-distributor and bad head. Take it to a machine shop and have the bad valve replaced.

[Sport/Truck]

Originally Posted by jnikolas

Will a compression test verify this? Is there any other test I can perform that will help me narrow it down or will I have to visually inspect?
Posted via Mobile Device

A Leak down test will diagnose multiple problems including what we already suspect with the valve.

Here's a good article to understand how it works.
http://www.carcraft.com/techarticles...r/viewall.html

s/t