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Username Post: Ignition timing        (Topic#361980)
1965C-10 
Very Senior Member
Posts: 7471
1965C-10
Age: 42
Loc: San Tan Valley AZ "Phoeni...
Reg: 11-18-01
08-01-20 12:30 AM - Post#2800053    

I put the 396 BBC and TH400 in the 1965 C10 truck in 2004, at the time I set timing at 8 degrees btdc, with my craftsman dial back timing light, I think using the dial.

At the time I didn't know about total timing etc, but have read over the years.

Read lots from ignition man, summer 2011 took light springs out of a performance weight and spring kit, said stick with gm HEI weights, only use light springs, this is what I did.

Also made a stop for vacuum advance, but never got around to playing with timing.

4th of July 2020 (just got truck back on road after being parked for several years) I pulled off the flex fan after work to check timing, about 11 at night but the truck idling shouldn't bother neighbors since loud fireworks.

Ignition man said don't use dial back feature, so I left it off or zero, I was thinking it would be at 8 btdc like I set years ago, but timing mark was far left (counter clockwise) from timing tab.

I lowered idle speed as slow as possible but still it was not at timing tab.

It got hot(I got hot not engine) and late so I put it all back together.

Drove it and just off idle it had a stumble, also in drive with foot on brake truck would jerk surge like it was fighting to go.

Next time after running truck for errand and feeling the off idle low rpm stumble and jerking at red light, just listened to engine and played with timing by ear, went both ways until it ran crappy and got it in a spot the engine sounded and felt smooth.

Took for test drive and the off idle stumble was gone, no more jerking at red light, it starts real easy.

Would you say it was under advanced for it to do those 2 things at idle and off idle?

I was having a problem advancing (if I remember right) the vacuum advance can would hit something on the intake manifold when twisting HEI counter clockwise.



Edited by 1965C-10 on 08-01-20 01:03 AM. Reason for edit: No reason given.

 


1965C-10 
Very Senior Member
Posts: 7471
1965C-10
Age: 42
Loc: San Tan Valley AZ "Phoeni...
Reg: 11-18-01
08-01-20 12:45 AM - Post#2800054    
    In response to 1965C-10

I need to buy or make a piston stop, the dampner may be way off, the engine is a 1968 C10 396 310 hp and 400 ft lbs gross, I think it's stock, might have a mild cam.

Also wondering if craftsman timing light is screwy, it's been moved from California to Texas, to Arizona and several moves in Arizona with other tools.

When it cools down probably after Halloween, I'm going to install the Edelbrock pro flo 4, that has a new distributor, supposed to set timing at 12 btdc, then the ECM takes over timing after it's up and running.

Just want to get it right for the Edelbrock pro flo 4 mainly.



 
1965C-10 
Very Senior Member
Posts: 7471
1965C-10
Age: 42
Loc: San Tan Valley AZ "Phoeni...
Reg: 11-18-01
08-01-20 12:49 AM - Post#2800055    
    In response to 1965C-10

I forgot how much the vacuum advance stop was for, seemed there was one for mild and one for more, seems mine was for mild.

It's getting full manifold vacuum from fitting on back of intake, T with vacuum hose coming from TH400.



 
TAT_2 
Member #26 "19th Year" Silver Supporting Member
Posts: 36606
TAT_2
Age: 67
Loc: "UNDER THE BOARDWALK"
Reg: 10-29-00
08-01-20 08:17 AM - Post#2800070    
    In response to 1965C-10

HAD A PROBLEM WITH MY 78,I WOULD TIME IT,THEN SOMETIMES IT WOULDNT START ETC,THE TIMING WOULD CHANGE,FOUND THE ADVANCE PLATE WAS STICKING EVERY NOW & THEN.

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IgnitionMan 
Valued Contributor
Posts: 3771

Reg: 04-15-05
08-02-20 09:20 AM - Post#2800138    
    In response to 1965C-10

Nope, not even worth getting involved with, it would only bring out the singular worst person on these boards to cause trouble, and wrongly imply I am lieing.



 


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