Timing help

[DPinilla]

First time posting here. A couple of months ago I bought a 69 C10, I have been doing a lot of work to it to make it run right. I am a novice and hoping to learn from it. I recently changed the fuel pump, carburetor, spark plugs, installed a fan clutch and a much better fan. I want to check and adjust if needed my timing, I've never done it before and I need some help. While looking at my marks I see two sets as you can see on the picture. My timing is where the Red line is, is my timing that far off? Or am I looking at the wrong marking? I was told I needed to disconnect the vacuum advance but that didn't make a difference. What should I do?

[medgabeh]

In order to set initial timing, you do need to disconnect (and plug) your vacuum advance. With my initial timing set at 12 degrees BTDC, mine runs at about the same location yours is when my vacuum advance is connected. I just have a cheap timing light, so I can't tell exactly what the timing is when it goes beyond the the timing tab. My rough guess is about 22, but my 350 runs best about there.

[crazy longhorn]

Yes, 12-14 initial.....more important, is the total@ 2800-3200 rpms. I would go around 34, vac unhooked/plugged. More info, on the rest of the set....you will want around 10 -12 degrees(crankshaft), on the vac advance. You may need to "play " a bit, to get it right on, but you should be in the ball park? Longhorn

[RodnRudy]

It looks to me that the larger timing tab has been added on for some reason and the smaller tab is the one to use. It looks original to the timing cover and the mark on the balancer should be read off it. I'd clean off the small one and set the timing off it 10 to 14 degrees BTDC.

[hamjet]

You will have to find true TDC by means of a piston stop, then you'll know for sure which timing tab to use...

[DPinilla]

Hamjet, please explain what you mean by piston stop.

[hamjet]

http://www.jegs.com/i/Comp+Cams/249/...hXkaAh0a8P8HAQ heres one.. its for a FO%D though....

[swamp rat]

If you don't know this:

When you use a piston stop, rotate the engine by hand one direction untill it contacts the stop, mark the balancer, then rotate the opposite direction untill the piston contacts the stop again, then mark the balancer again, now divide the distance between the two marks in half to find true top dead center. probably a good idea to remove the plugs first.

The timing mark off to the side is for a sbc350, its exactly like the one i have which is stock, not sure about the other mark as it looks to be rivited to the timing cover from factory, what engine do you have? 327? 400? 350?

[geezer#99]

Here's a wiki for you on tdc.
http://www.crankshaftcoalition.com/w...op_dead_center

If you use a piston stop it's also a good idea to loosen both rockers on #1 so the valves don't move. Depending on cam timing sometimes the valves can hang up on the piston stop.

[GASoline71]

The one riveted to the timing cover is from a mid 70's and later small block with a long water pump. You had to shoot the timing light behind the water pump to time the engine. So if someone used a short water pump and that timing cover, they wouldn't be able to see the marks.

Or it's possible someone used the later model timing cover with the tack welded timing tab on an earlier block, and then just used a tab that bolts to the cover at the 2 o'clock position.

So many bastardized parts can go on a SBC it's not even funny.

Gary

[swamp rat]

Originally Posted by GASoline71

The one riveted to the timing cover is from a mid 70's and later small block with a long water pump. You had to shoot the timing light behind the water pump to time the engine. So if someone used a short water pump and that timing cover, they wouldn't be able to see the marks.

Or it's possible someone used the later model timing cover with the tack welded timing tab on an earlier block, and then just used a tab that bolts to the cover at the 2 o'clock position.

So many bastardized parts can go on a SBC it's not even funny.

Gary

If thats the case with the other timing tab than the dampner could be origional OR possibly switched with an earlier model like from my 72... long water pumps started about 73 if i'm not mistaken.. lots of possible variables....

[DPinilla]

Thanks guys for all the help. Now I just have to find the time to tackle it. As far as I can tell the truck has an 1980 c10 350.

[greywurm]

I just stick my finger in #1 plug and turn the crank by hand... Am I missing something by not using a piston stop? It gets it close enough to dial in with the light, but I'm no pro..

[swamp rat]

Originally Posted by greywurm

I just stick my finger in #1 plug and turn the crank by hand... Am I missing something by not using a piston stop? It gets it close enough to dial in with the light, but I'm no pro..

Yes he does not know which timing marks to use or even if its the correct dampner, he needs to verify where TDC is on the dampner and which timing tab it lines up too.

[geezer#99]

Originally Posted by greywurm

I just stick my finger in #1 plug and turn the crank by hand... Am I missing something by not using a piston stop? It gets it close enough to dial in with the light, but I'm no pro..

You can be off twenty degrees on your timing tab/balancer. THat's why a piston stop makes it accurate.

[pwdcougar]

You can make your own piston stop with an old spark plug too. Remove the porcelain and tap it for a good size bolt. Use a grinder to round the end of the bolt where it contacts the piston.

Paul

[swamp rat]

Just make da.mn good and sure that bolt won't fall out. Epoxy. J.B. weld. Or weld it.

[greywurm]

Got ya. Thanks for that info
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