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The amazing part is having 160-170 psi of compression in a cylinder without a functioning inlet valve.

I would look down the push rod hole in the head and see if the lifter is still in place and not laying up in the lifter valley.

 

I have a local buddy who's a John Kaase disciple that builds some pretty hot Ford big blocks. When I spoke with him earlier he definitely agrees that Ford put too small of a pushrod in these engines. He thinks I would have been in bad shape if it had been an exhaust pushrod, but while telling me I really *should* pull the intake and find the old pushrod, also agreed that I've put enough miles on the engine with the misfire that IF the pushrod was likely to do any further damage, it already would have done so. Chances are it's lying somewhere in the valley and will stay there until the engine is totally dismantled.

My current hypothesis is that I did have a bad, leaking injector. It filled the number one cylinder with fuel and created a hydrolock before the intake cycle. The cam tried to open the intake valve against the cylinder full of fuel and the pushrod was the weak link. It bent, enough so that the valve spring pressure no longer kept it in place and managed to rattle down into the valley. I can see the lifter in its bore. It doesn't look cocked or otherwise damaged.

I figure I'll put a pushrod in and turn the engine over by hand a few times. So long as I can see that the valve is opening I'm not going to really bother myself with anything else. Best case scenario, I'm good there. Worst case scenario I'll be either pulling the intake to replace a lifter as well... or pulling the engine to put a new cam in.

Fingers crossed a new pushrod gets me back up and running.

As always, thanks to the community for all of the suggestions. I doubt anyone else had: "ejected a pushrod" as the reason for the misfire. I think I exhausted my possibilities before pulling the valve cover and discovering the root of my issues.




Jeremy

 

The lifter is still in its bore. You can see it through the pushrod guide hole. Which tracks. It's a stock engine with stock cam, so most likely the lifter is sitting in the bore *just* above where the cam lobe will even touch it. Hopefully.

I guess there's enough exhaust overlap to draw some air into the cylinder through the exhaust valve.




Jeremy

 

Well, at least you know part of the problem!