at wits end

[sweatybetty]

#1 piston at tdc, silver link on timing chain on #1 on sprocket, v-notch on cam sprocket lines up with the little line, timing mark on the crank pulley at 0*, and the rotor is centered on #1 plug wire with the distributor centered in it adjustment range. i cannot get this pig to run without back fire through the exhaust, unless i advance the timing to around 35-40 degrees at idle. with the timing set at 15* at idle, and i run the rpms from 2200 and up, i get continuous back-fire in the exhaust. any ideas??????????

ill post a video tomorrow

thanks all  sb

[cbuczesk]

The first two cam lobes are pointed up? Can you see/feel #1 piston at TDC? Plug wires are in correct order? What's the history on the car? Any recent changes? How does the distributor look inside? Cap and rotor? EFI or carbs? How are your plug wires? I'm thinking ignition issues right now.

Chuck

 

[Diseazd]

TDC compression stroke? Big difference.... like Chuck said.....first two cam lobes pointing up when piston is on TDC (compression stroke).

[240260280]

Sounds like you are not advanced enough.  Depending on the distributor mount, your reference for where #1 on cap is located can vary.

Quick check would be to rotate your plugs in the distributor by 1 then retry.

It could also be the oil pump spindle out of alignment with the distributor.

 

 

 

Edited April 6, 2017 by 240260280

[Zed Head]

13 hours ago, sweatybetty said:

 i run the rpms from 2200 and up, i get continuous back-fire in the exhaust. any ideas??????????

Maybe an exhaust valve stuck open?  Is it like pop pop pop pop pop ....?  "Continuous" implies that the same thing is happening every series of cycles, unlike the somewhat randomness of ignition misfires.  A compression check or leakdown test might show something, or a very close examination of the valves and rocker arms.  Double-check the lash.

[sweatybetty]

7 hours ago, cbuczesk said:

The first two cam lobes are pointed up? Can you see/feel #1 piston at TDC? Plug wires are in correct order? What's the history on the car? Any recent changes? How does the distributor look inside? Cap and rotor? EFI or carbs? How are your plug wires? I'm thinking ignition issues right now.

Chuck

 

yes, yes and yes. new wires, cap and rotor. everything i have read on backfires, points to ignition. if i advance the timing to 35-40 degrees at idle, it runs fine..

[sweatybetty]

6 hours ago, 240260280 said:

Sounds like you are not advanced enough.  Depending on the distributor mount, your reference for where #1 on cap is located can vary.

Quick check would be to rotate your plugs in the distributor by 1 then retry.

It could also be the oil pump spindle out of alignment with the distributor.

 

 

 

with everything at tdc, the rotor is pointing dead nuts to the correct cap terminal as shown in the fsm

[Diseazd]

TDC compression stroke....is the little half moon exactly at 11:30 facing forward? Also, I'm sure you know the rotor rotates counter clockwise......not clockwise.

[240260280]

It should be just past #1 by the amount of advance,

Did you confirm the spindle tang alignment with the oil pump?

[sweatybetty]

2 hours ago, Zed Head said:

Maybe an exhaust valve stuck open?  Is it like pop pop pop pop pop ....?  "Continuous" implies that the same thing is happening every series of cycles, unlike the somewhat randomness of ignition misfires.  A compression check or leakdown test might show something, or a very close examination of the valves and rocker arms.  Double-check the lash.

i did re-set the valve lash after posting here.

my cam calls for .010 hot on both valves, so after the initial start-up and maybe 1 hour of run-time, i reset them at .008 cold. i think i may try going back to .010 cold.

[sweatybetty]

thanks to you all!

[sweatybetty]

1 minute ago, Diseazd said:

....is the little half moon exactly at 11:30 facing forward?

i will re-check that.