Thread: Got a problem...

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So as some of you know i've been trying to get my big block 396 going, has a decent sized solid lifter cam. Broke it in at 2000-2500 rpm's. Used Castrol HD30 oil and a bottle of GM EOS. So I started the engine a couple days ago and it seems that a little while after cam break-in the engine started popping out the carburator. I noticed a sparkplug wire that had came off, but that didn't turn out to be the problem. Could this be a cam lobe that wiped out, or is it possible that it is carburator related? The pops are pretty loud and annoying, about 1 pop per second at idle, engine runs good at idle until you rev it up then pops get more closer together. Any ideas? I'm just hoping I don't have a big problem on my hands...

From what I've seen lately there is a good chance you wiped a lobe or more. Seems to be more prevalent these days. Did you use soft springs to break it in? Did you use cam lube (moly lube like) on the lobes and lifter bottoms? Might want to check the valve lift out everywhere. Drain oil and look for metal in pan and filter for evidence, but the valve lift will tell the story.

Kitz

I'm going to readjust the valves right now since I haven't done that yet, and see if there's any valves that are way off.

And yes I used the Isky breakin lube on the cam, and I called Isky about using softer springs and they didn't recommend it. They said the cam was not big enough to worry about it.

Used push rods? BBC's will bend stock reused pushrods during cam run in proceedures quite often. If you're running stock guide plates, look for a cracked or broken pushrod guide.

there should be on need to go thru the lifters if so you may wipe the cam if poping it sounds like you may have wipe a lobe. i would not think you crack a guide plate if so that is a new one on me

Must be a Midwest to Southwest thing Pat . As dumb and inconcievable as it seems, It has happened a few times in the last two years to me (and in the previous builds) when the customer wants a mild cam and old OEM plates were used. I don't know why, maybe age or deterioration, and I would love to figure it out, but I haven't and unfortunately, it happens once in while. Go figure. I have theories but can't place a finger on an exact reason. Very frustrating sometimes.

i know the new darts will crack at the nut and bolt were there are adjustable to hard

Well i just readjusted the valve lash, I will never use the stock crimp nuts that come with the Comp Magnum rockers again. I installed some Crane lock nuts on. Number 5 and 8 exhaust valves were VERY loose. Probably not even opening. I'm going to put her back together and start her up, I'll let you guys know if that fixed it.

Yep, that was the problem. No popping, runs good. Gosh Dang! This thing runs good!!! My whole street sounds like we are at a dragstrip when the thing is idleing! The only thing I think I need to do now is tune the carburator and maybe timing. The motor doesn't like a lot of throttle yet. That might be cuz I have a 50cc accelerator pump on the primaries. Probably go back to a 30cc and see how it runs. A lot of throttle response though!! Revs like a 327 and sounds like a monster!!

Congrats!

Kitz