Wacked compression after top-end swap.

[Azrael]

Tore everything down to the block and rebuilt it with 3400 heads (no idea if they've been milled before I got them) with SI valves and LS1 springs. I used lower mileage lifters, roller rockers and pushrods.

Tried to start the car and all I got was "Whiiiiirrrrr". Gauge cluster showed some rpm and oil pressure building up so the cam/crank are turning. Broke out the compression guage and this is what I see:

Cyl1 = 0psi, Cyl 2 = 125, Cyl 3= 185, Cyl 4 = 185, Cyl 5 = 115, Cyl 6 = 90.

My 3/8's torque wrench is suspect for overtightening after breaking bolt holes on 2 upper intakes, so is it likely I just overtightened the rockers as well or am I looking for something deeper?

[Superdave]

you sure you don't have the pushrods mixed up on cyl 1?

[Azrael]

I'm sure I double-checked but I'm willing to assume I didn't at this point. The plan was to pull the valvecovers and back off the rockers slightly on cyl 1 to see if it gains any compression so it won't be out of my way to check.

[Azrael]

Pushrods are in the right order. Backed off the rockers for #1 by about 30 degrees and saw about 15 psi of compression. Backed off a little more and 0 again. I tried backing off rockers for #2 by 30 degrees and I lost compression completely in that cyl.

When a cyl is at tdc firing position and you're tighten the rockers, should the springs be compressing any?

Also springing to mind, some of the lifters felt tight going in. Is it possible they're just stuck?

[Azrael]

Solved the case of the missing compression. After reading this thread here: http://60degreev6.com/forum/showthre...-new-guy!-lol? the lightbulb finally lit up. The lifters I used had been sitting on a shelf for a year.

Yanked off the LIM, loosened a rocker, and tried to compress the lifter with the pushrod and found absolutely no give to it. I grabbed one of the old ones and was able to compress it a little. Cleaned all the old ones, swapped them for the ones I installed and cyl 2 suddenly got 195 psi. I'll have to test the rest to be completely sure though.

It goes to show that there's no such thing as being too observant of the parts you put into an engine.

Learn from my fail!

[Azrael]

It's all together again and runs. It runs a little rougher than I remember (from the stiffer valvesprings?) but it runs. I'm getting a bit of smoke out the exhaust too. Not enough to know if it's coolant or oil. Or is a little smoke normal after a headgasket change? I did cleanup the piston-tops a little with a scotchbrite disk so maybe it's just some freshly exposed carbon burning?