Redneck Rev-Up (Carb Question)/ Cam shaft replacement

[78 k5]

I fell victim to peer preasure at a rodeo this weekend and reved my engine beyond belief. I blew some oil out but I don't think its a big deal... The truck started a small clicking shortly after the event and became really loud on the way home. After towing it back to the house I figured I had a rod trying to come through the valve cover but after removing both valve covers I found that both sides were fine. I cranked the truck and removed the air cleaner and found that the knocking was coming from the carb???WTF It is an Edlebrock 650 (I think) What did I do? Anyone had this problem before?

 

[Hogback Fabrication]

If you didn't break a valve spring or rocker arm (you could see this with the valve cover off), it is a bearing knock. Pretty common from overrevving (stock oil pump can't keep up with really high RPM's). The noise you think is coming from the carb is probably coming from much lower in the engine (the harmonics of steel can make finding a noise deceiving). You are probably in for at least a new set of bearings all the way through.

 

[stevewix]

it's valvetrain...

when a cam goes flat it exhibits this 'popping sound' through the carb under any kind of throttle. except idle in most cases.

 

[M-1028]

My old jeep did that, it ended up being a flat cam. When you round off an exhaust lobe the exhaust gasses can't go any were but through the intake valve and up through the carb.

 

[78 k5]

So what are we talking about here...big problem or not? I'm pretty savy around axles and suspension, but I'm pretty much a newb when it comes to engine work. I will have a mechanic friend that will probably be doing the work for me, how much damage am I looking at $$$$$$$$$$ a couple hundred or big money??

 

[mouse]

You're going to need to pull the valve covers and check for valves that are not moving. This should tell if you've got a lobe or two rounded on the cam. This is the easy thing to fix - change the cam (and maybe lifters while your there). If its bearings, its going to require a little more work, but you can probably do that with the engine in the truck.

 

[Hogback Fabrication]

It definitely could be that cam as well (these guys are probably right), but it is a result of starving the engine of oil from over-revving it.

 

[clarkjw24]

Are you sure its from the carb? Could you have blow out a header gasket? Just some wishful thinking for you.

 

[78 k5]

Anyone have a jegs or AutoZone part# for a replacement cam for my sb350??? Any writeups or pictures of a cam replacement to help me along my way? Thanks in advance

 

[trailblazer86]

If you have the rocker covers off check to see if you have any loose rockers.
If you are luck you may have just bent a push rod or bent a rocker arm.

The sound of a knock can also give you some idea. The sound of a connecting rod is different than a wrist pin or a valve train knock.

Sometime high revs in an older engine can also break the skirts off the pistons. This of course will also sound different than the others.

If the valve train seems ok, pull the oil pan. It is amazing how much aluminum can be in the bottom of the pan or in the oil pick up and that poor old engine may still get you home.