Fool's in deep :pokinit: now

[brainlessfool]

So, I'm driving home for lunch getting on the freeway shift out of 3rd and into 4th. foot on the gas truning about 3K. A car goes by
and I think "man, is that car knocking bad!" AWWWW hey, it's not that car, it's MINE!.  started knocking like a cooffe can full of rocks.
butt only when I'm on the gas. if I rev. it a little it sounds just fine. so I get off the freeway and cost up to the stop light. DANG! it's running on three.   as the light truns green and I try to get it to go she's a banging bad, as it gets going and I can let up on the gas it stops  and sounds ok. agin if I rev. it sounds ok.    so, lets make some bets. what do you think I'll find when I take the head off? bad head gasket? droped valve? that bolt for the air cleaner I never could find? piston go to pices? O/P is fine so rod I thinks out. plus the fact I drove it aboout 4 miles home, at 30 mph. any faster and it did not like it at all!.

so post up and take a seat, I'll know more this week end 




I may have to look again at a 4.3 swap if it's realy bad.

[Willy Mammoth]

[WHITE_TRASH]

Id go for either a cracked piston/ringland or a wristpin.  When you pull the fill plug on the valvecover how much smoke comes out?

[BigMike]

Come on BLF, relax, odds are that its nothing serious..

The only way a serious problem would give you this symptom would be a cracked piston, and the engine would be drinking oil silly. And you aren't getting any blue smoke (yet ) so I'm sure its not that.
Anyways it sounds fine when reving so its not the pistons or wrist pins, etc..

Odds are a blown head gasket won't cause this either. If it was blown between the cylinder and water port, then it would be using water and you engine would overheat.. Or if it was blown between cylinder and oil (unlikely) then again it would be turning out blue smoke, and I doubt either of these would cause preignition. Or if you had a cylinder to cylinder leak, it would be a power-to-exhaust stroke overlap and that wouldn't cause any preignition either only under power and it would run poorly at any throttle %.

No I bet it's something simple. Like...

I dont know so much about carbs, but how about the anti dieseling solenoid? Or you got debris in your jets and its going lean under load. Or your fuel filter is plugged and the carb is going lean.. What about the secondary? If its vacuum controlled, maybe its not opening correctly and the engine is suffocating under load?
How about your spark plugs? Have you checked the color (indicates cylinder temp)? What if an electrode broke off or something.. Spark plug wire rested against header and melted the insulation and its arching?
What about your timing? Did the dissy bolt come loose and the dissy advanced a bit?

....this really sounds like a timing problem my man

BigMike

[KYOTA]

Im betting ignition also. Fried plug, bad wire, loose dist. or cracked dist. cap.

[brainlessfool]

Well I pulled the coil wire and cranked it, got at lest one dead hole! 
I'm hoping the head gasket blow up beteen two clys.

[scheid6996]

hey, start it, and one by one pull off each plug wire untill the knoking stops, i bet its a rod bearing

[79coyotefrg]

dang brainy   to be honest it sounds like you broke a adjuster, or rocker, if you have compression  and fire in the wires pull the cover,  gotta do that to get to the head bolts anyway  

[brainlessfool]

well working on the house took up all my time this week end so I geass I'll be driving the bi9g chev one more week than planed.

any how there's def no comp. in at lesat one hole.

and if I spin it to 3k with on load it sounds fine, so I don't think it's any thing to bad.
My $ is on a blown head gasket beteew #3-4.
butt it will be alest one more week before I'll be able to try to take a look.

good by 17 mpg, hello 11.