GM spark,fuel,compression, no start. WTF!! (1 Viewer)

[ak40]

TLDR= getting fuel, spark, has compression, no start.

1974 chevy 350 with a edlebrock performer intake, carter quadrajet, mallory distributor, stock internals.

Had my FJ40 With the 350 since 2002, everything worked great together,about 8 years ago i added intake and timing gears and mallory distributor (dizzy was bad upgraded to HEI) I had stored it for a few years and didnt change the oil when i pulled it out of storage ended up throwing three pistons out the oil pan. So i bought a clapped out 40 with a 350 that i was told had a dead lifter. I assumed that i could just replace the cam and be good to go. Not the case the number 5 cylinder was missing a big chunk of the piston and one of the heads was cracked on the exhaust valve. I did the cheap/bad thing and only replaced the bearings and piston for #5 and honed just that cyl. had my heads from my bad motor cleaned and decked (used the intake too) installed a new mild cam lapped the valves, set lash using EO/OI using the rock 1843 adjust 6572 then the opposite. slapped it all together installed it, no spark. Found out coil was bad so replaced the coil and the module just to be sure. turns out i was 180 out. fix the 180 out. no start, no spark still, figure out battery cant handle the load. but charger with start assist on battery boom fires up runs a little rough need the throttle to keep it going go to reach for the dizzy to adjust and boom spits a fire ball out the carb and dies before i could do anything with timing. It also pisses fuel out of the accelerator pump and vent tube. I go buy a new battery and carb kit. rebuild the carb install new battery still no start check spark and its a go. plug was wet so i know it has fuel (also it spit fuel out the hole the pug wasnt in). Get pissed and walk away. decide to start from the beginning. Pulled all the plugs and wires and valve covers verified TDC on combustion stroke with rotor pointing at #1 went to cylinder 6 adjusted the lash to were i could just spin the push rod then went through them, #1 TDC adjust #6, #8 TDC adjust #5, #4 TDC adjust #7 and so on and so one till it came back around. i then went through it again to make sure nothing was hanging up and everything was good. put it all back together and nothing. thought maybe i hadnt got fuel enough yet so i manually primed the carb till i was certain it was spiting fuel. had my wife try to start it while i adjusted timing slowly and it started. Ran great for about 40 seconds and then spit a fire ball out the carb and died then fuel came out the accelerator pump and the vent tube again.

What do i do next?
Is my new cam already screwed because of trying to start this POS for the last three days?

 

[ak40]

and it will not start again just to be clear

 

[BILT4ME]

TLDR= getting fuel, spark, has compression, no start.

1974 chevy 350 with a edlebrock performer intake, carter quadrajet, mallory distributor, stock internals.

Had my FJ40 With the 350 since 2002, everything worked great together,about 8 years ago i added intake and timing gears and mallory distributor (dizzy was bad upgraded to HEI) I had stored it for a few years and didnt change the oil when i pulled it out of storage ended up throwing three pistons out the oil pan. So i bought a clapped out 40 with a 350 that i was told had a dead lifter. I assumed that i could just replace the cam and be good to go. Not the case the number 5 cylinder was missing a big chunk of the piston and one of the heads was cracked on the exhaust valve. I did the cheap/bad thing and only replaced the bearings and piston for #5 and honed just that cyl. had my heads from my bad motor cleaned and decked (used the intake too) installed a new mild cam lapped the valves, set lash using EO/OI using the rock 1843 adjust 6572 then the opposite. slapped it all together installed it, no spark. Found out coil was bad so replaced the coil and the module just to be sure. turns out i was 180 out. fix the 180 out. no start, no spark still, figure out battery cant handle the load. but charger with start assist on battery boom fires up runs a little rough need the throttle to keep it going go to reach for the dizzy to adjust and boom spits a fire ball out the carb and dies before i could do anything with timing. It also pisses fuel out of the accelerator pump and vent tube. I go buy a new battery and carb kit. rebuild the carb install new battery still no start check spark and its a go. plug was wet so i know it has fuel (also it spit fuel out the hole the pug wasnt in). Get pissed and walk away. decide to start from the beginning. Pulled all the plugs and wires and valve covers verified TDC on combustion stroke with rotor pointing at #1 went to cylinder 6 adjusted the lash to were i could just spin the push rod then went through them, #1 TDC adjust #6, #8 TDC adjust #5, #4 TDC adjust #7 and so on and so one till it came back around. i then went through it again to make sure nothing was hanging up and everything was good. put it all back together and nothing. thought maybe i hadnt got fuel enough yet so i manually primed the carb till i was certain it was spiting fuel. had my wife try to start it while i adjusted timing slowly and it started. Ran great for about 40 seconds and then spit a fire ball out the carb and died then fuel came out the accelerator pump and the vent tube again.

What do i do next?
Is my new cam already screwed because of trying to start this POS for the last three days?

I doubt your cam is screwed. That will not be affected by what you have described.

The running then backfire through the carb would indicate a valve timing issue.

When you installed the cam/chain, are you 100% positive you got the cam timed to the crank properly?

Did you pump up the oil pressure prior to running it?
How did you adjust the valves for the initial start-up? If you tightened them down too much with no hydraulic pressure, it could cause a similar issue,.

There are a lot of things to narrow down here, as you have touched every part of it and it sounds like maybe you got into a hurry a couple times.

 

[ak40]

I doubt your cam is screwed. That will not be affected by what you have described.

The running then backfire through the carb would indicate a valve timing issue.

When you installed the cam/chain, are you 100% positive you got the cam timed to the crank properly?

Did you pump up the oil pressure prior to running it?
How did you adjust the valves for the initial start-up? If you tightened them down too much with no hydraulic pressure, it could cause a similar issue,.

There are a lot of things to narrow down here, as you have touched every part of it and it sounds like maybe you got into a hurry a couple times.

I had a bad distributor, i trouble shot it down to my pick up coil wasnt producing enough AC voltage. went to replace it and once installed the dizzy would not spin right and come in contact with the collar on the shaft. I replaced it and it fired up with a minor tweek to my timing. unfortunately for some reason my fan sliced my lower rad hose and it started to spit anti-freeze right away i only got about ten minutes into the break in before it was too hot to keep going. BUT SHE RAN!!!!

thanks for the help

 

[BILT4ME]

I had a bad distributor, i trouble shot it down to my pick up coil wasnt producing enough AC voltage. went to replace it and once installed the dizzy would not spin right and come in contact with the collar on the shaft. I replaced it and it fired up with a minor tweek to my timing. unfortunately for some reason my fan sliced my lower rad hose and it started to spit anti-freeze right away i only got about ten minutes into the break in before it was too hot to keep going. BUT SHE RAN!!!!

thanks for the help

Interesting. We went through (3) Spectre HEI distributors that were bad and finally bit the bullet and bought a Mallory. This was for our 70 GMC K2500.

Good luck!

 

[pb4ugo]

1st of all, fuel spewing from the carb acc pump and vent means something is wrong with the needle and seat or float or float adjustment. Especially, after a rebuild. Sounds like too much fuel.

I dont understand your vavle adjustment procedure. You say at tdc you adjust #1 cyldr and then #6 cylder? #6 would be on the exhaust stroke and an adjustment shouldn't be made. Put it on tdc on the compression stroke for #1 cylder, and adjust valves:

Exh 1,3,4,8, int 1,2,5,7. Now rotate the crank 360 degress(1 revolution to timing mark) and adjust valves; exh 2,5,6,7 int 3,4, 6,8. Be sure to remove the push rod lash b4 adjusting. Also double check your firing order, 1,8,4,3,6,5,7,2.

 

[ak40]

1st of all, fuel spewing from the carb acc pump and vent means something is wrong with the needle and seat or float or float adjustment. Especially, after a rebuild. Sounds like too much fuel.

I dont understand your vavle adjustment procedure. You say at tdc you adjust #1 cyldr and then #6 cylder? #6 would be on the exhaust stroke and an adjustment shouldn't be made. Put it on tdc on the compression stroke for #1 cylder, and adjust valves:

Exh 1,3,4,8, int 1,2,5,7. Now rotate the crank 360 degress(1 revolution to timing mark) and adjust valves; exh 2,5,6,7 int 3,4, 6,8. Be sure to remove the push rod lash b4 adjusting. Also double check your firing order, 1,8,4,3,6,5,7,2.

I had a bad dizzy, once i replaced that i had no issue's. I believe the backpressure issue's from bad timing caused the carb to not operate properly. my set up has worked in this rig for at least 15 years. the method i used to set lash is called EO/IC i got it from the a video from Summit racing, and also several other places. i am not saying its the easiest way but its the method i used. not trying to be snarky and thanks for your help but i have seemed to solve my running issues now on to charging issue's.

 

[pb4ugo]

Congrats!