engine problems

[General Mayhem]

hey guys i need your help, i was trucking my pickup today (350 carb) and i i went to open her up when it started poping and misfiring, now it only does this around 1500 to 2000 rpm's when accelerating, then it seems to clear up as the rpms go up, so I was thinking it is either i got a valve out of wack or maybe a electrical problem, any thoughts

Thanks

Tom

 

[Chevy305]

check your timing and go from there

 

[RIPPEDK5]

its all in the timing and how you set your carb or fuel system

 

[RustyParts]

Pull your valve covers and check the rocker arms and pushrods, I had a 350 that a rocker arm rubbed a slot into the stud and let the pushrod slip out, it was doing the same thing yours is.

 

[General Mayhem]

well today i checked my timing and it was way out so that fixed that problem then i adjusted my vavles (loose till tick then tighten untill tick stops plus half a turn while running) now under heavy load i hear a knocking sound?? it starts at 2500 and makes it till about 4500, so is the way i adjusted my vavles wrong? cause i can't find anything that could make that knocking sound, like i thought my exhaust was hitting my frame at first

 

[sled_dog]

where did you set the timing?

Sounds like you set it too advanced and now it is "Spark Knocking" or "Detonating". Factory spec on my 84 with a 305 was 4* I believe. This could be engine damaging so double check!

What you are describing sounds like classic spark knock. 2500 is right about where the mechanical advance curve would really be kicking in and if you had base timing set too high, its just way too much timing for the octane of fuel you are likely running. If you set the timing fine, then try puting some 92 or 93 octane(whichever you have) in it and see how it runs. If it goes away, the problem is definetally too much advance. Could be worn out springs on the advance weights.

 

[General Mayhem]

ok i got it set at 6 right now so i will try 4 tomorrow morning, cause i have been running low octane lately because the cost of fuel is preaty high right now, and i know it has a advance kit in it to run with the cam so all the parts in the distributer are just a few months old, so i will let you know how that works out and go from there,

 

[Chevy305]

ok i got it set at 6 right now so i will try 4 tomorrow morning, cause i have been running low octane lately because the cost of fuel is preaty high right now, and i know it has a advance kit in it to run with the cam so all the parts in the distributer are just a few months old, so i will let you know how that works out and go from there,

Make sure you are setting the timing with the vacuum advance disconected...

I've made that mistake before!

 

[General Mayhem]

Make sure you are setting the timing with the vacuum advance disconected...

I've made that mistake before!

i did forget to disconect it, well i think that preaty much is my problem thanks for the help guys so about the vavles is the way i did it ok?

 

[sled_dog]

yea that sounds fine.

 

[General Mayhem]

ok i pulled the advance and put the timing to 4 now she has no knocking, but i have lost a lot of power so i will try 6 and run some higher octane fuel, but thanks for all the help guys

Tom

 

[vortec]

tried adjusting the carb? i got my timing to where my k5 runs great at cruise, and pretty well in hard accelleration, but the idle totally sucks. so, i'll have to go after the idle screws, i guess. maybe you need some skinnier primary metering rods, to richen the mix just a tad.

oh, btw, i'm nothing remotely similar to a carb expert . i just figure that if your timing is about right, then maybe it's a minor fuel issue.

 

[sled_dog]

with an advance kit you will need to run higher octane to see the max gain. I'd run 93 and dial up the timing to 6+. If it doesn't knock at 6, try going to 7 or 8 and see what happens. Can't hurt to try and see where you get the max power, especially if you are willing to run some higher octane.