Camshaft Removal Questions

I am trying to replace the camshaft seal on my 1991 Honda Civic LX. At this
point I am not seeing that I can literally pick it out, with, say, an awl, sharp
screwdriver, and pliers. To do this right, the manuals say one must remove the
camshaft. To get at the camshaft, the rocker arm and shaft assemblies must come
out. After disconnecting the negative terminal of the battery and removing the
valve cover, the next steps of the procedure state:

"3. Loosen the adjusting screws two turns at a time, in a crisscross pattern, to
prevent damaging the valves or rocker arm assembly."

4. Unscrew the camshaft holder bolts and remove the rocker arm and shaft
assemblies. Leave the rocker arm bolts in place... "

Are the "adjusting screws" in step 3 those that are adjusted to set valve lash
(that is, the 16 screws with 10 mm hex socket fit locknuts)? If so, what does
"crisscross" mean here?

My Civic has four valves per cylinder, and so four screws (with locknuts) per
cylinder.

It also has 16 other bolts (12 mm hex socket fit), which I hope are instead the
bolts for both steps 3. and 4. above, and for which I see a specific torque
sequence for re-installation in the manual.

 

Caroline wrote:

it means a loosening sequence of the rocker arm assembly, the bolts that
hold the whole deal down, just like you'd use a patterned torquing
sequence for head bolts. you use a criss-crossed opposites pattern to
ensure the working surfaces of the rocker arms stay relatively square
against each other and don't damage, or get damaged by, the camshaft.
you should also loosen the valve lash adjusting screws, but you can get
away without that most of the time.

theoretically, it is possible to pull the seal without disassembly, but
you need to sacrifice a screwdriver by grinding a hook into it and using
it with a slide-hammer - tricky and liable to damage the sealing surface
of the cam if you're not very careful. so, full disassembly is the
"preferred" route even though you install the seal after the head is
reassembled again.

 

Caroline wrote:

it means a loosening sequence of the rocker arm assembly, the bolts that
hold the whole deal down, just like you'd use a patterned torquing
sequence for head bolts. you use a criss-crossed opposites pattern to
ensure the working surfaces of the rocker arms stay relatively square
against each other and don't damage, or get damaged by, the camshaft.
you should also loosen the valve lash adjusting screws, but you can get
away without that most of the time.

theoretically, it is possible to pull the seal without disassembly, but
you need to sacrifice a screwdriver by grinding a hook into it and using
it with a slide-hammer - tricky and liable to damage the sealing surface
of the cam if you're not very careful. so, full disassembly is the
"preferred" route even though you install the seal after the head is
reassembled again.

 

[snip]

Do NOT pull the camshaft just to replace the seal! The seal can usually be
popped out by using a small straight blade screwdriver. Carefully slide the
blade of the screwdriver under the lip of the seal next to the cam. Then
carefully pry the seal out. The size of the screw driver that I usually use
for this task is 7/32" wide x 0.032" thick with a length of 2 7/8" (Snap-On
part # SDD20 though any similar size driver should work). Note that I use
the same method for the front crank seal though these can be a little more
troublesome as you've discovered. I like to avoid using a hook and slide
hammer as it's much too easy to damage the outer seal journal.

Good luck, Eric

 

[snip]

Do NOT pull the camshaft just to replace the seal! The seal can usually be
popped out by using a small straight blade screwdriver. Carefully slide the
blade of the screwdriver under the lip of the seal next to the cam. Then
carefully pry the seal out. The size of the screw driver that I usually use
for this task is 7/32" wide x 0.032" thick with a length of 2 7/8" (Snap-On
part # SDD20 though any similar size driver should work). Note that I use
the same method for the front crank seal though these can be a little more
troublesome as you've discovered. I like to avoid using a hook and slide
hammer as it's much too easy to damage the outer seal journal.

Good luck, Eric

 

Thanks Jim and Eric. I let all this sit over night, thought about Jim's hook
suggestion as well as studied seal puller tools available commercially. I
decided to try a can opener (the kind that comes on a scout knife) and a
corkscrew (from my days removing packing from around valve stems, where a
corkscrew-like tool worked great). Saw Eric's message this morning, thanked God
;-), and didn't touch any of the camshaft etc. screws or bolts.

I had the camshaft seal off in less than 10 minutes with the cork screw. The
crank seal came off within 20 minutes with the can opener. If I hadn't really
mangled the crank seal yesterday, the corkscrew might have worked fine.

Eric, the pop bottle material 2" x 3" (or so) sleeve, with oil on the inner lip
of the seal and a thin coat of Ultra Grey Silicone on the outside circumference
of the seal, worked great.

I'm back on track and aiming to have everything back together by early this
evening...

 

Thanks Jim and Eric. I let all this sit over night, thought about Jim's hook
suggestion as well as studied seal puller tools available commercially. I
decided to try a can opener (the kind that comes on a scout knife) and a
corkscrew (from my days removing packing from around valve stems, where a
corkscrew-like tool worked great). Saw Eric's message this morning, thanked God
;-), and didn't touch any of the camshaft etc. screws or bolts.

I had the camshaft seal off in less than 10 minutes with the cork screw. The
crank seal came off within 20 minutes with the can opener. If I hadn't really
mangled the crank seal yesterday, the corkscrew might have worked fine.

Eric, the pop bottle material 2" x 3" (or so) sleeve, with oil on the inner lip
of the seal and a thin coat of Ultra Grey Silicone on the outside circumference
of the seal, worked great.

I'm back on track and aiming to have everything back together by early this
evening...