Rebuilt 318 Refuses to Start

95dakotadude said

nm9, I didn't replace the chain because it's almost new. It only had maybe 1/4 of play on the slack side.

GTS, how did you go about measuring your pushrods then? I had previously broken all of my pushrods before I spun the bearing because I guess they were too long? So, I remeasured them by getting one of those extendable pushrods and put it on the #1 rocker arm while the lifter was at the base lobe of the cam and then tightened it were it should, and extended it just a half turn more for lifter preload. My new measurement was only .1 shorter. Granted, my engine is far from stock. Is there anyway to tell if I got it right this time? Before, when I had the valve cover off looking at the valves I tried twisting the exhaust pushrod while at TDC because you're supposed to be able to do so, I could. Is that a good enough insurance? I'm pretty sure I measured them right, but your comment puts a seed of doubt in my mind. Does it matter if I checked them on #1 or #6?

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OK, good on the chain, even a new one will have a smidgen of slack on the passenger side. Sounds like you're OK.

BTW, 1/2 on the checking pushrod turn probably means you have around .020" preload: the threading on the checking pushrods that I have seen are 24 TPI, which means around .040" length change per turn.

Twisting the push rod is not always good enough as the pushrod could be too loose (too short), or even too long if the lifter happened to leak down some since the engine stopped. You can find waaay too loose (obvious slack) or waaay too long (pushrod bound up) with the pushrod check. But you can be very close to one end of the piston range in the lifter and still spin the pushrod, and then when things heat up, something expands and things go out of the piston movement range.

The way I like to do it is look at the lifter tops closely when the rocker shafts are all assembled and torqued in place. When a lifter is on the base of the cam, then the piston inside the hydraulic lifter should be down from the retainer by approximately by the amount of the preload. This means you have to rotate the engine over and look at each lifter pair when it is for sure on the base of the cam lobe (at TDC of the compression stroke). To see this gap accurately between retainer and lifter piston, you need to have the intake off. (You can even insert thin wire gages into the retainer-lifter piston gap to get an accurate measurement.) It is a check to do just prior to putting on the intake.

Unfortunately, measuring the pushrod length on just one valve/rocker position could lead to issues as that one particular valve.rocker set could be off from the rest. Which I suspect is why you want to check....