Engine Rebuild Day 5 - Tuesday July 22

Various other activities interfered with the build today, like the need to get my road car MOT'd.  It failed of course and needed various new bits to get it through - but this couldn't be more uninteresting!

I wanted to degree the camshaft.  The first job is to set the degree wheel to TDC.  Although recommended practice is to put a piston stop in and average the angle for each direction of rotation to the stop, I couldn't get this to work - probably as my piston stop was just a screwdriver it kept coming up with different values.  As I could see the plasticine through the spark plug hole I was able to accurately identify the TDC this way at the top of the stroke.   I used a piece of flat ally, held under the distributor clamp as a convenient mounting point, for the timing pointer.  The wheel is twisted against the crank until it reads TDC at TDC.


I had to make a dummy solid lifter as hydraulics collapse under test and therefore are no use for this purpose. Fortunately a neighbour has a Myford lathe and I decamped to his garden shed at lunchtime.

Not the best bit of turning I have done but it does the job and fitted the lifter bore a treat.

I made sure the height of the lifter with the pushrod inserted was the same as my new hydraulic ones.

The indent just below the top is to make it easy to retrieve the lifter from the bore with a finger nail.

I then removed both valves from No.1 cylinder and setup the dial gauge over the pushrod with the dummy lifter in place (lubed of course - but not too much to affect the reading). 

I zeroed the dial and turned the crank round to see the lift at the cam, it was exactly to the Edlebrock spec namely .310"

I swapped to the exhaust which was .325, again spot on.

I then noted the degree wheel position for the .050" lift open and close of each valve.  I have to check this 100% but I know from memory that the intake open position and exhaust close are right.

The 050 lift is used as the start of the lift is very hard to determine.

For good measure I measured the valve opening on top of the spring but unless the rocker ratio is wrong it had to be right, and was.  I turned the engine over a few times with the intake and then the exhaust valve gear set up to check for piston to valve clearance.  I removed the head and checked the plasticine in the chamber. I used the small end of my digital calipers where the prong sticks out matching the gap in the jaws.  I pressed it into the plasticine up to the piston top with the flat end level with the surface (sorry no pictures).  The smallest gap I could find was about .214", this is very comfortable clearance - it should be minimum .080 intake and .110 exhaust.

In the meantime I was waiting for the replacement pistons to arrive, but as they only came at 4pm there as not chance to go to the machinist today.

I stripped the block down and loaded everything in the car, except the block, for an early start tomorrow when I am satisfied the pistons are now right.  I will have to try and get the crane under the car roof, or it will be one man and a boy power to lift it in!