boogerschnot

So Ive been working on the wife's 67 Fastback today. The 289 has 68k miles on it and I removed all of the emissions stuff, replaced the "D" carb with a 4160 rebuilt by me. Today the carb was having some issues with the accelerator pump. Something is clogging the inlet to the pump so when I hit the accelerator pump arm all I hear is air.. no fuel.

Anyway. I was working on getting it sorted out and while running, all of a sudden, it sounds like there is a bolt or something bouncing around in a combustion chamber. I shut it down immediately and tried to figure out what the noise is..... I dont know. I checked the obvious, pump squirter screw and squirter jets, they are still there.

Here is my list so far, let me know what else I should check and what order..

1. pull the valve covers, check for a dropped valve
2. pull the intake and see if I can find something sitting in a inlet to the head
3. pull the heads and see what I might find.

I dont know what else could cause this sound. The motor kept running smooth so I guess its not a valve. Sounds like something randomly bouncing around inside the engine.

What do you think.

Gun Jam

do the easy stuff first. Like pull the plugs if you dont see anything from the valve cover side it be worth trying to track down a bore scope. but you could also just look for marks on the plug and things like that.

boogerschnot

.... and thats why they pay you the big bucks! thanks Gun. Ill give her a look tomorrow. It just sucks.

rmodel65

last time i heard something like that i had an electrode shoved up inside of a spark plug. pull the head and found i was missing an exhaust valve. the stem was still in place. cracked the cylinder wall and ruined the new forged piston..

boogerschnot

Thats not fun. Lets hope its something stupid but not expensive..

bop11

Are you sure it is not in the oil pan?
You can actually buy a bore scope from Harbor freight for about $90.
You say you removed the smog stuff from a '67 'Stang but I thought that smog equipment was not installed until '68 except for a pcv valve. Although the Gov made laws in early 60's, I believe the first emission test , except CA, were not required until '68. Our '67 in NJ does not need to meet an emission test. Being from CA, what did you remove?

Starfury

CA cars from 66-67 had air injection systems and hot air chokes on the air cleaners, in addition to PCV.

boogerschnot

I checked the plugs and everything was fine. Then I checked under the valve covers and though dirty nothing seemed out of place. I do need new valve stem seals and I found a few chunks in pieces under the covers. And a couple of what looked like seeds from animals living in the air cleaner a while back. I guess the intake needs to come off. Maybe I'll just wait and start on body work instead.. then I'll have a reason to get her running.

Gun Jam

Crank it over by hand does it feel smooth?

Try to use a flashlight and mirror to look into each combustion chamber.

do a compression test on each cylinder perhaps and listen for obstruction

perhaps its related to the carb issue...an accelerator pump that pumps air but not fuel when the floats are full is highly suspicious and may indicate a carb issue much greater than a bad accel pump and just maybe somehow it caused the engine to ping due to improper A/F ratio....

-Gun

boogerschnot

Think it would ping that harshly? That would make sense. The left bank isn't responding to the needle adjustment and maybe I have the timing so far off that it just might be a combination of the two. Hmm.. feeling hopeful again. I'll get a compression checker. But I'll screw with the carb and timing a little first. ..

Thanks gun