Machining Head 2008
March 19, 2017


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It took a while to accumulate all of the parts and find the right machine shop,
but everything is now done, there's nearly 1,000 miles and the engine runs great.

Mason's Racing Engines in Rhode Island is one of the finest engine machine shops
on the East Coast.  The business is run by Bob Mason and truly is a family owned
and operated business that is spotlessly clean and as well equipped as you will ever find. 
State of the art equipment,including in house Dyno services, as well as the expertise
to do any type of specialty engine machining makes this shop stand out above the competition.

**** Viewers are warned that if they attempt any mechanical repairs or modifications,
or follow procedures referred to here, they do so at their own risk, and no liability will
attach to either myself or Mason's Racing Engines.****

This is what we started with when it got to Bob's shop.  I'm showing before and after pictures
to show the types of cleaning that can be done to a block after it is disassembled.

The heads just got a quick cleaning and then the plugs were removed before hitting
the acid tanks for the final clean up.  As one can see, the guides are new from last fall.

The Dupli-Color Ceramic 1200 degree paint does not come off easily.  It took a
long time in the acid tank to get it all, but it did come out perfectly clean.

This is what you get most of the time, but it's not quite good enough to get the remaining
rust and potential crud that may be lurking in the oil galleys or coolant passages.

The head will go through the  hot acid tank cycle to remove everything else.

A lot of checking and machining is done on this machine.

The head will be resurfaced on another machine after the guides are completed.

The guides are checked to be sure that they are installed correctly and each new
valve is matched to a guide and the clearances and movement is checked.

After everything is measured and verified, the guides will be cut for seals.

All set and ready for phase two, which will be resurfacing or "shaving".

The head will be shaved or resurfaced to remove sufficient metal to
raise the compression to 9.5 to 1.  This head had .080" removed last fall, but will
need an additional .040" removed even with .008" being taken from the block.

All setup work is done via CNC and verified before the machine is even started.

It will take several cutting passes over the head to remove the proper amount of metal.

That looks a lot better and just about ready for the valve seating work and CC'ing.

Perfectly smooth and perfectly square.

Next the valve job begins. 
The seats and valves have been cut to match and the valves are being lapped in.

The new springs have all been tested for compression and height and are ready for assembly.

But first, it's time to fit the new seals to the newly machined matching guides.

These are not Teflon seals.  Bob will no longer use them.  But what's missing?

Notice the newly machined shims that will fit under the springs to prevent
any cutting into the head and the subsequent chatter and failure that will occur.

A close up of the assembled springs over the shims.  What can't be readily viewed
are the spacers that go between the inner spring and the guide to keep the
spring from walking around on the head at high RPM's.

The CC'ing of each chamber is next and all are matched across the head.

It's an elaborate setup with a very tall graduated cylinder for the filling.

All assembled, but a few sharp edges to polish off and some clean up on the chambers.

Done and ready to go home for painting.

That looks a lot better and will perform a lot better when installed.

That's a really nice and neat job by Bob Mason.

Some masking tape and a warm sunny day is all you need to paint it properly.

Two light coats and one medium coat done within an hour and three days
of no touch drying and this paint cures and lasts very well.


The clear coat will be applied to the entire engine after final assembly..

Next, the engine assembly.

Another fine job by Bob Mason of

Mason's Racing Engines

53 Hartford Avenue

North Scituate, RI 02857

Toll Free 888-235-1622 2017

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This site was last updated 03/19/17