71 521 w/ a l20b

[kingsizechuck]

New guy hoping for a little info here. Just brought home a 71 521 project ( avg. cond, not running ). marking on the block says L20B, which from what I can tell is not the original motor.......

 

According to the previous owner, when he got it and started to troubleshoot it there was no spark. Said he pulled the dist. and cranked it over and the little spindle that turns the dist. ( not sure of the correct name ) didn't spin.

 

I'm just starting to tear into it now. Is this a common problem?? Is it difficult to fix? Any great advise??

 

Thanks for any help, Chuck

[hessianben]

Welcome Chuck- you're in luck! (hahaha rhyme)

seriously, these motors are really simple to work on, so- it shouldn't be too hard to work out.

First off, if the distributor is not spinning, go ahead and pull the whole distributor off of its pedestal so you can see it's drive shaft.

then, turn over the crank and see if that shaft is turning.

We'll go from there...

 

PS: EVERYONE here likes pics- you know to put a face to a car/truck

you'll get faster help with pics too!

[kingsizechuck]

Ok, with the dist removed I put a ratchet and socket on the crank pulley. The spindle always turns. When I put the dist. back on, it only spins part of the time. I took a pair of pliers and pulled on the spindle, and it has a slight amout of play ( maybe 1/8" ) but seems ok. So I measured the depth of the spindle in the hole in the block, and the depth of the dist where the two should touch/interlock. At the best they would only overlap like 1/8" ( pretty sure but really hard to measure ). It just doesn't seem like enough. Any other ideas.

 

I'm still waiting on the key so I'm limited on what I can do. Also, I'll get some pics up soon, don't have my camera right now.

 

Thanks, Chuck

[hessianben]

Ok- the shaft turns, which means that your oil pump is still being driven as well...good. moving down the line-

 

 

 

 

 

sounds like there may be some play in the dizzy itself... does the rotor shaft have a lot of slop? Also, sometimes when people switch out distributors, they dont keep the pedestal that bolts to the timing cover with the proper dizzy- they put the one from the old dizzy back on, ect...

 

 

 

 

if it's not the same pedestal that was with that particular distributor, you could have clearance issues.

Try this. Put the distributor back on as well as the rotor. Try to spin the rotor by hand. (don't use force) See if you can wiggle/pull it and get it to turn by skipping over the drive shaft blade. If you can get it to jump and turn, you know you've got a dizzy with issues.

If it happens to be an old points-type dizzy, you would do well to upgrade to electronic ignition dizzy/coil combo anyhow.

 

Edited August 18, 2009 by hessianben

[kingsizechuck]

Where would I find a electronic ing.? How Much? Is there any way to tell if my dist. has the wrong base???

 

Thanks for the help, Charlie

[kingsizechuck]

Ok I bolted the distributor back on and when i crank the motor the dist. turns with it. if I grab the rotor ( center of the dist. ) with a pair of pliers and turn ( don't worry, i was gentle ), if i turn it right it will not move. if i turn it left the dist. will spring back off of the pedestal just slightly and then spin.

 

Where should I go next? Thanks for the help.

 

Chuck

[hessianben]

so, before, it was not always turning? try to fire it up and turn the dizzy to set the timing by ear. or get a timing light and set to around 10*btdc. (remove vacuum advance before you set with light)

[kingsizechuck]

The not turning came from the previous owner. So far everything I have done says that is not right. I probably won't mess with it till mon. ( headed to the lake for drinking, etc.)

 

The only question is removing vacumn advance? I imagine it's a vacumn line? Where would I locate it??

 

Thanks, Chuck

[hessianben]

The vacuum advance is the vac cannister attached to the dizzy with a hose to the carb. under vacuum, it pulls more advance on the distibutor in addition to the mech. advance inside the dizzy... just unplug the hose from the carb, plug it to eliminate vacuum leak, and set to timing the motor...

 

search : "how to set timing" ect...

[kingsizechuck]

 

heres a pic.....