[alfa] new head

["Scott Johnson" <scott@xxxxxxxx>]

First, if you haven't already get or make some cylinder hold-downs. Alfa 
made "real ones", but you can build them yourself out of some washers 
and metal pipe. DO NOT turn the motor without the head on any more if 
you don't have hold-downs in place. There is a very real chance a piston 
will raise a liner, which will require pulling the motor to fix. Slide a 
few really wide washers down the head studs, then drop the pipe on it, 
then tighten the pipe to the washer with the head nut.

Next, remove the head and get a metal straightedge to make sure you 
haven't ALREADY lifted a liner. Just make sure they're all nice and even.

After all the cylinders are firmly held down, set the #1 piston at TDC 
on the compression stroke (make sure the disty is pointing at #1). 
Remove the hold-downs and don't move the motor again until the head is 
on it.

Remove the camshafts from the head by gradually loosening the clamshell 
nuts (I work in a cross-wise pattern, top-1, bottom-2, top-3, bottom-4, 
top-4, bottom 3, top-2, bottom-1, etc.)

Carefully place each bucket/valve shim combo in a labeled bag, one each. 
Also make careful note as to which cam clamshell goes where, and which 
way they're pointing (they're numbered, just make a quick sketch).

IMO there's no need to mess with the roll pins... just put new o-rings 
on and off you go.

Place the head on the motor. It should seat down just perfect. If not, 
check the cylinder liners again. Replace all valve shims & buckets. 
Torque it down to spec, then place the cams on the head. Make sure the 
#1 cam lobes are both pointing directly away from their respective valves.

Place the cam clamshells on one cam (I start with the exhaust, but 
that's just me). Make sure they're in the right order, facing the right 
way. There will be a mark on the front clamshell that's supposed to line 
up with a mark on your camshaft. Line these up as close as you can for 
now. Place the washers down on the studs and then hand-tighten all the 
clamshell nuts. Note you may have to press down pretty hard on a few of 
the clamshells to get enough thread to start the nut.

Now, find something to hold the camshaft in place. I use a 22mm wrench 
(I think that's how big it is anyway) to hold the nut on the end of the 
cam sprocket. Move the cam until the marks line up perfect, then start 
tightening the clamshell nuts in the same cross-wise pattern you 
loosened them. Keep tightening until they're all snug, but not tight. 
Get a torque wrench (buy one if you have to) and torque the clamshell 
nuts to 16 lb-ft. Make sure you hold the camshaft still the whole time, 
because it'll want to squirm as things tighten up.

Now repeat with the other camshaft.

Connect the timing chain and manually rotate the engine through a 
complete firing sequence. If something binds, back off and try and 
figure out what went wrong. If it spins properly (likely), continue on 
with the motor assembly to finish the job.

Hope this helps, and apologies if you already knew all about it.

Scott Johnson
71 1750 Spider
Alfa Spider FAQ Author
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