Help please...base timing '87 TBI 305

[Leevon]

I just got through with the lovely task of replacing the intake manifold gasket on my '87 305 TBI.  The truck runs fine, but I am trying to set base timing to 0* per factory specs.  I found the tan/black wire that controls timing advance just below the bulkhead connector and unplugged it.  I can't get the truck to idle all the way down to 0* connected or disconnected.  It dies at about 8-10* even with some throttle. 

[VileZambonie]

Are you sure you're checking off of the #1 cylinder wire?

[Leevon]

Vile, it's funny you ask that because I started to wonder if I was going crazy and had it wrong.  Found out the balancer was off, this is the third sbc in a row I've had this problem with.  I use a piston stop to find TDC, it's not perfect like a degree wheel, but pretty darn close.  She ran like a champ and the ESC was advancing correctly.  Only problem is it still leaked.  PISSED off!  Then I had to take it down the road today and it died at the sandblaster's shop.  There it sits, I feel like me and the truck are getting divorced or something. 

[VileZambonie]

How are you using the piston stop? You can visually see TDC with the spark plug removed. Where and what is it leaking? Oil or coolant?

[Leevon]

I put the piston stop in place of #1 plug, then roll the engine over by hand until piston contacts the stop.  Mark balancer at 0' then turn the other direction, mark 0' and split the difference in 1/2, mark true 0', set dist to #1.  The back of the intake was leaking oil, I had already done the rear main, oil pan, plug, and pressure sending unit and could see the leak at the manifold or so I thought.  Is it possible for oil to leak from the back of the head gasket without any typical head gasket symptoms? 
 

[VileZambonie]

Did you use the intake manifold end seals or did you use RTV?

[Leevon]

I used the black O2 safe RTV supplied with the felpro gaskets, laid down a nice bead up about 3/8 onto the gaskets.  I also "dragged" the bead slightly back down into the corner at China wall / head to get a little grab.  Climbed in with engine and set the manifold straight down, torqued to spec (35ft./lbs).  My only second thought was that the areas around the coolant ports were kind of pitted both on heads and manifold, maybe the gasket didn't seat well and I should have laid down a thin layer around them. 

Could the manifold be warped a little?  The funny thing is that although the engine was full of carbon and crap, the old RTV beads looked great, well seated and uniform. 

I think I'm gonna clean it up real well and try to pinpoint the exact spot. 

[VileZambonie]

Good idea.

Tip. when you replace the intake gaskets and clean up all of the mating surfaces, use a prick punch along the level areas of the block at the front and rear. Lay a bead of RTV (use the right stuff by permatex) and use teflon thread sealant on the bolts. Torque them evenly and in sequence. Repeat the sequence several times. Make sure you don't use the end seals just throw them away.

[Leevon]

thanks Vile! it's almost like live tech support!

[78 Chevyrado]

A problem I had on my 87's 305...  It wouldn't make it to 0 on the timing and it turned out to be the harmonic balancers outer ring had slipped in reltation to the inner part that mounts to the crankshaft.  I had to find tdc with a piston-stop and then marked the balancer with a cold chisel for my new 0 degree mark.  Do what was said above and if all else fails try this.  It doesnt happen often but can, all that holds the inner and outer pieces together is a piece of rubber, which can slip.  Good luck!