Timing Adjustment 5.7 Vortec Slow Crank

Joined
Jan 4, 2021
Messages
74
Just bought a 2007 Larson LXI 208, originally a 5.0 2bbl, now has a remanned 5.7 2bbl. Starting out with basic maintenance trying to eliminate a slow crank. New battery, cleaned or repaired all connections to switch and starter. Checked base timing at idle = 16-18 advanced, grounded ignition timing lead = 22-24 advanced..........is that reacting correctly?? I have not adjusted the timing yet to 10 advanced, as I have to grind down my distributor hold down wrench to clear the tab on the distributor housing. I am thinking that the advance is making the engine hard to crank?? It is either that or the starter is worn out. I can hit the key and it turns over really slowly, let off and hit the key again and it seems to turn over much faster. Thoughts, advice...thanks in advance.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,054
Having that much advance can slow the rotation, and more so if it grunts during the rotation. When spark hits before TDC and trys to spin it backwards.

If not doing that then cable connections, battery, starter. Place a voltmeter on the battery and see if the voltage drops below 10V when cranking
 
Joined
Jan 4, 2021
Messages
74
Been a several week delay on this due to work schedule, bad weather and obtaining parts, but I finally sorted out my problem. I had already done some of the suggestions stated above from alldodge before I posted the original question. Since then I installed a new water separator/fuel filter, distributor cap, rotor and spark plugs. Tried to fire up the engine to set the timing, but each time I tried cranking, it just kept turning slower and slower. Pulled the starter, it was the original one dated 2006, still looked clean on the outside, bendix gear looked good, shaft shiny and clean. I took it apart and found that the brushes were toast.....two of them were worn down and the other two were burned and stuck in their holders. I cleaned the commutator surface and surprisingly it was not burned or pitted. Installed a new brush/holder assembly and it works great now. Engine fired right up and I was able to set the timing. Just wanted to follow up on this in case others have the same slow crank problem.
 

boatflipperz

Cadet
Joined
Jan 30, 2021
Messages
29
It's great when you find the culprit that's been causing the headaches.
Good for you! Good job.

Been a several week delay on this due to work schedule, bad weather and obtaining parts, but I finally sorted out my problem. I had already done some of the suggestions stated above from alldodge before I posted the original question. Since then I installed a new water separator/fuel filter, distributor cap, rotor and spark plugs. Tried to fire up the engine to set the timing, but each time I tried cranking, it just kept turning slower and slower. Pulled the starter, it was the original one dated 2006, still looked clean on the outside, bendix gear looked good, shaft shiny and clean. I took it apart and found that the brushes were toast.....two of them were worn down and the other two were burned and stuck in their holders. I cleaned the commutator surface and surprisingly it was not burned or pitted. Installed a new brush/holder assembly and it works great now. Engine fired right up and I was able to set the timing. Just wanted to
follow up on this in case others have the same slow crank problem.
 
Joined
Jan 4, 2021
Messages
74
It's great when you find the culprit that's been causing the headaches.
Good for you! Good job.
Live and learn..........I spent a lot more time than I needed to literally standing on my head in the engine compartment trying to figure things out. Next time I'll check the starter out first when I run into a situation like this.
 
Top