Author Topic: TDC on my small block is not at cylinder 1!!!  (Read 28019 times)

Offline buddy84GMC

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Re: TDC on my small block is not at cylinder 1!!!
« Reply #30 on: May 18, 2008, 04:29:31 pm »
Got spark now..but no start.  I have the coil cover off while trying to start and there is a blue spark right over the coil where the 2 wires are for the BAT and the other one.  I looked for bad wires, all look good and I replaced a few just in case with some extra wires that were good as well.  I held a screw driver up to distributor and had the other end on the intake and it did spark.  Thats when I saw the blue spark on around the coil like its grounding out.  Any ideas?  Thanks
1984 GMC K1500 8" lift, 39" MT Baja Belted tires, 400 small block
2006 GMC Sierra 1500 SLT 4x4 L33 5.3L Special Edition
1967 Lincoln Continental Coupe Hot Rod, 462 big block

Offline VileZambonie

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Re: TDC on my small block is not at cylinder 1!!!
« Reply #31 on: May 18, 2008, 08:04:27 pm »
How are you checking this? Do you have an HEI? If so the coil needs to be mounted on the carbon button and the coil housing needs to be grounded. the primary should receive b+ from the bat terminal and the - terminal is connected to the ignition module. Check for spark from one of your wires.
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline buddy84GMC

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Re: TDC on my small block is not at cylinder 1!!!
« Reply #32 on: May 18, 2008, 08:33:06 pm »
I checked for spark from the wires and no arcing onto the block or headers where I tried.  The coil is mounted on the button and it is grounded and hooked up correctly.  The only thing I can think of right now is that the button is surrounded by that round rubber spacer with a hole in it to let the button through.  The new coil cam with one and I used it but its a tad bit too small but from what I can see it still lets the spring loaded button touch the coil.  I can check it and try the old one again if you think its not making contact.  It is HEI by the way.  Thanks and let me know if that button not making contact would cause a spark on top of the coil itself.  I had the coil lid off to check so maybe it just arced off the nearest wire on the distibutor? 
1984 GMC K1500 8" lift, 39" MT Baja Belted tires, 400 small block
2006 GMC Sierra 1500 SLT 4x4 L33 5.3L Special Edition
1967 Lincoln Continental Coupe Hot Rod, 462 big block

Offline SUX2BU99

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Re: TDC on my small block is not at cylinder 1!!!
« Reply #33 on: May 20, 2008, 05:10:34 pm »
I see it's already been discussed but I thought I'd add in about when my mechanic was doing my heads and cam I was talking to him about finding TDCC and he showed me an easy way to tell is to see that both rockers are in the up position (valves closed) and the rockers will wiggle a little as there will be no pressure on them. I thought that was kinda neat.
85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.