Engine Rebuild Day 4 - Monday July 21

In true soap fashion you were left with a cliff-hanger last night - will the riddle of the bore sizes be resolved? 
I measured the bore sizes and they were just right at 4.030, so why were the pistons sloppy, when you eliminate the impossible whatever is left, however improbable must be the truth (who said that) - i.e. despite the box saying 4.030 pistons they must be 4.000!  So I have called for a new set of the right size.

My objective at present is to get the rotating assembly to the machinist ASAP for balancing - he will also check the bores to match the new pistons.

This is a trial fit of the head.  I used the old head gasket to give the right spacing.

I timed the engine according to the Edelbrock instructions but the intention is to check it with a degree wheel.

Since I needed to check if there is clearance between the piston and valves I put a layer of plasticine over the valves. I subsequently moved this to the top of the piston, but didn't want too much under the flat area which meets the head.

I put a couple of lifters above the cam (using suitable lube) and tried the roller rockers.  The poly locks have socket key grub screws to lock the rockers in place.

Another shot of the new rockers.  Extruded aluminium, anodised.

Here you can see again the misplaced spring on the upper valve.  I removed the valve and realigned the spring.  It's obvious that the Edelbrock checks are not brilliant and that anything you can inspect or double check needs to be done.

I also noticed that the timing chain has sharp edges on the teeth and that inside the heads some drilled holes have swarf still attached.  I will clean these up before final fitting.

Again the pushrod guide plates are mis-aligned although in the manual it says they will be ("bolt on and go" - I don't think so!)

I slackened the studs and aligned the plate to set the roller on the rocker centrally over the valve stem.

 

Here I am preparing to check the piston/valve gap - though this set-up is not right.  Its very difficult to work out the worst case of piston and valve position to check if there is clearance - and how much.  It not TDC or anything obvious, you have to calculate the formula for each movement and resolve the equations - I probably will do it as an exercise, but even then you have to set the components in the right place. 

Easier and more reliable is to turn the engine and check the plasticine.  Unfortunately I tried this and found the lifters bleed down.  I have to make rods to use as solid lifters - another delay.

Finally I am setting the position of the degree wheel to be ready when I make the lifters.  It wasn't easy.  I need a fresh start in the morning!

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