At my wits end

[Jan_280Z]

Hey mates

 

This past weekend I did a motor swap in my brother's 620 pickup. I pulled his very old and poorly running l20B out and put in a "newer" rebuilt one I purchased from a friend. The removal and reinstall went well up to the point when I had to get her running.  I mechanically timed the motor per spec given in the FSM and on this website. When done the motor looked like the picture below. Also ran the valves - adjusted them - per spec in the FSM

 

 

 

The distributor looked similar to the picture below except that the vacuum advance is near the block opposed to away from the block like the picture shows. (I didn't have a camera handy so I'm stealing pictures off the net thanks to ratsun)

 

 

Went to start the truck. Nothing just kept cranking. When I pressed the accelerator I finally got her to fire up. The second I let the pedal go though she dies. I've spent hours trying to figure out what the problem is. I marked the crank yellow paint at TDC - to use the timing gun on - and found that when she runs at 1000 rpm the timing seems to be at + 5 (ATDC) degrees. So I mechanically timed the motor again via all the photos and descriptions I could find. Same result. With the car at 2000 RPM or so the timing mark reads -15 (btdc). Im at my wits end here. What am I doing wrong? Any advice would be lovely.

 

Thank you

Jan

[]2eDeYe]

The body of the dizzy being 180 out might be an issue. Did you use the original pedestal that was in the truck or the one that came with the motor?

[Jan_280Z]

I used the original pedestal that came with the old engine along with the dizzy that came off it.

[izzo]

also. what carb are you running?  you may have said, but i didn't read it all the way. if it is a stock carb it may have an cut off solenoid. it needs power when the key is on to keep the carb from trying to keep the motor from running. helps keep the motor from run-on after shut off.

 

 

the dizzy looks 180 out. Just unbolt it, rotate the bottom portion 180. then double check your firing order on the cap.

 

 

the cut off solenoid looks like this in the picture, with the red wire hanging off. there is a 620 in my driveway now with two of these things on it (i don't knwo if they are both cut off solenoids or not i didn't really dick around with it much)

 

 

 

 

in your picture also, is the motor at current TDC on #1? if so that rotor looks a little off but could be wrong its been a while. the little half moon shaft under the dizzy should be about 11:20 position

[jwerty1]

dizzy looks wrong

[datzenmike]

The dizzy may look wrong, but if it runs, it's good. You can run it in many positions by removing the oil pump/dizzy drive spindle and putting it back in on a different tooth. I believe there are 20 teeth so 20 positions around the clock. One every 18 degrees. Many probably won't work because the rotor will end up between cap wires and the adjustment range won't bring it on. It's safe to say that there are at least 4 positions that work each 90 degrees from each other. 
 

 
If this is (above) at TDC #1 then moving the drive spindle 90 degrees counter clockwise and all the cap wires one position to counter clockwise will work also. Also 180 and 270 degrees. This is often done to move the vacuum advance can away from the thermostat housing or the matchbox module away from the exhaust manifold side. There is no wrong if it runs and you can set the timing properly. 
 
Most people set and keep the drive spindle at the 11:28 o'clock position. Everyone is then on the same page when trouble shooting.
 




 

Went to start the truck. Nothing just kept cranking. When I pressed the accelerator I finally got her to fire up. The second I let the pedal go though she dies. I've spent hours trying to figure out what the problem is. I marked the crank yellow paint at TDC - to use the timing gun on - and found that when she runs at 1000 rpm the timing seems to be at + 5 (ATDC) degrees. So I mechanically timed the motor again via all the photos and descriptions I could find. Same result. With the car at 2000 RPM or so the timing mark reads -15 (btdc). Im at my wits end here. What am I doing wrong? Any advice would be lovely.

Thank you
Jan

First make sure your idle is about 750. OR if not sure, turn as low as possible and have the vacuum advance hose off... no you don't have to plug the carb end. Too high an idle may add vacuum advance, it shouldn't if the idle speed is correct. Either way you don't want it massing up your setting.

Set timing at 12 degrees BTDC.

To be sure... the top tooth is 0 (ZERO or TDC) so when the notch on the pulley reaches this point, the crank is at TDC.

 

Each tooth below that is +5 degrees advance ahead of TDC (0) and.... +5, +10, +15,+20
.

 

The notch on the crank pulley should be set just below the third tooth or point +12 degrees.

[banzai510(hainz)]

year of 620 would help if point dizzy or a true matchbox EI set up would help as you said the photos are not really yours on one of them(dizzy photo)

 

 

looking by your photos it looks timmed. 1 3 4 2 Counter Clock wise fire order???????

now when you put the dizzy in at TDC the rotor should line up to #1 plug wire right??? if yes.

then what I would do is start it and keep the dizzy somewhat loose so you can dial it in. as if should be real close to fire up once the carb is primed.

Now if the motor stay running with the key in start and dies with the key On immediatly than it could be the Hot start BYPASS wire not hooked up.

Or the anti deiseling selinoid to the carb. another way to keep it running would be just keep pumping the gas real fast and it should make a good attemp of still running as your dumping gas in from the accel pump.

 

re ck tighten for everthing carb /manifold intake ect....

 

[banzai510(hainz)]