First79vette

Ok guys bear with me here... :crazy: Rebuilding my 350 in my 79 and took the timeing cover off, Ok, first I have TDC, on #1, both push rods are turnable with my fingers and the balancer mark is on Zero. With the cover off I see the crank sprocket mark is at the twelve o'clock position, the cam sprocket mark is at the twelve o clock position with the cam pin at the 9 o'clock position..whats up??The rotor is pointing right at the thermostat close to #1 cyl. :confused: :confused: Shouldnt the marks be oposed to one another and cam pin be at the 3 o'clock position?? Thats what you have to do when you put in a new one correct? I used to have a rebuild sb chevy book about 10 years ago and now I cant find it I've done this before with no problems but this is throwing me. I going on memory here :banghead: This motor was done before by the way. :cheers:
Thanks

SLine78

Correctly installed, the cam will have its alignment pin at 3:00 and the timing dot will be at 6:00 with the crank's dot at 12:00. I have heard other do it the way yours seems to be. It will work, but that does not mean it is right.

If you rotated the engine, to line up the timing marks correctly, you would see that your rotor would be 180 degress from where it is now. You could then remove the distribuitor and reinstall it so the rotor is again pointing at cylinder number 1.

Mike



[Modified by SLine78, 3:00 PM 3/17/2004]

cardo0

I never really paid attention to where #1 cyl was when using the alining marks on the timing gears but have install several camshafts and will try to help you here. :(
Now remember #1 is at TDC at the same time #6 is TDC for both power and intake/exhaust overlap stroke - just one is at power with both valves shut and the other is in overlap with both valves part open.
I think where your at now you should verify valve timing. Remember the firing order is 18436572 and every 90 degreees of crank rotation (clockwise when looking at the dampner from the frt bumper) two pistons will be at TDC. So when the dampner says 0 degrees and both #1 cyl valves are shut (both pushrods will gently rotate by fingering) and #6 cyl valves are partly open (both pushrods feel solid) - your TDC on #1. Whats next? Turn that crank only 90* CW and check #8 cyl valves shut while #5 vlvs both open (and both pistons are TDC). Next 90* will be #4 vlvs shut and #7 vlvs open. Another 90* for #3 vlvs shut while #2 vlvs open.
You can just follw this firing order roundy, roundy until you feel comfortable/convinced your timing matches the firing order. :lol:
Hope this helps. cardo0 :seeya


[Modified by cardo0, 8:30 AM 3/18/2004]

lars

Your aligment is correct. When at TDC on the compression stroke, both dots point straight up to the 12 o'clock position. Since the gears rotate at a 2:1 ratio, the gears can also be installed pointing towards each other (crank gear at 12:00 and cam at 6:00), but this is TDC on the exhaust stroke. Many manuals state to install the gears with the dots pointing towards each other since it's easy to tell if they're aligned that way. But this is the reason many people end up with their distributors installed 180 degrees off after cam gear installation.... For trouble-free installation, put the gears both at 12:00 and drop the distributor in pointing to #1. This is the corret way to do it.

First79vette

Thanks :cheers: I talked to a guy who has rebuilt Pontiacs and he said that put them just the way it is now 12 'oclock and 12 o'clock and fire it up... :lol: I can remember now once... I did do the 12 and 6 put the dist. in to line up with #1 and blew the power valve out :eek: backfire bigtime..pulled the dist turned 180 and started up ok. :lol

cardo0

I apoligize for posting the wrong crank angle of rotation. I first posted only 45 degrees of rotation but should have posted 90*. I already modified/corrected the original post.
Sorry. cardo0 :D