[s-cars] [A4] A4 head rebuild, Part 4

[Igor Kessel]

PART 4 - head reassembly.

*WARNING*
My notes below are NOT meant to be a substitute for not reading your
Bentley! They are only a supplement, ought to share some tricks and
hidden obstacles with you.

25. Turn the head upside down, wet the valve stems with fresh motor oil
and insert them into their original guides according to the numbers that
you have put on the valves in paragraph 20.

26. Turn the head right side up. Watch the valves, you don't want them
to slide out and fall on the floor.
Find the new valve guides and the protective installation plastic
sleeves that came in the head gasket kit. Wet the plastic sleeve with
motor oil and slide it onto the first valve stem. It will protect the
tender valve oil seal lip from being damaged over the valve keeper
grooves during the installation. Wet a new valve seal with motor oil and
insert into the installation tool from paragraph 10. Gently push the
tool with the seal over the valve stem until it is sited onto the valve
guide. Lightly tap the opposite end of the tool with a hammer until you
feel that the valve seal is seated all the way on the valve guide. You
will hear the change in the sound from rubber over metal to metal
against metal when the seal is fully seated. Repeat the procedure for
the remaining 19 valves.

27. Insert the valve springs into the valve wells. Put the washers on
top of the springs. Compress the first spring with the spring compressor
from paragraph 8. Grab a valve keeper with the curved tweezers and
carefully put into the grooves in the valve stem. Since you have oiled
the stem in paragraph 25, the valve keeper will stay put due to the
oil's surface tension forces. Insert the second keeper in the same
grooves and release the spring compressor. The spring should now be
locked on the valve. Repeat the procedure for the remaining 19 valves.
*Note* - Pay special attention to the proper orientation of the valve
keepers. They are conical in shape and the narrow tapered end should
point downwards in order to properly wedge in between the valve and the
washer, thus locking it in place.
*Note* - Either use the non-magnetic tweezers or a very narrow flat
screwdriver with a bit of thick wheel bearing grease on the tip to which
you stick the valve keeper. Otherwise you will be forever struggling
with the keeper chasing the magnetised tweezers tip all over the washer.

28. Install the spark plugs into the head.

29. Flip the head upside down. Level the head surface in the true
horizontal plain with a carpenter's level. Shim the head cover studs if
needed.
Wipe dry any assembly oil from the intake and the exhaust ports with a
dry rag.
Carefully fill the combustion chamber with the cheapest brake fluid you
can find. I pride myself with finding the one for 97 cents/200ml in
Walmart. Let it sit for a while. If you failed to do a good job at
lapping the valves the brake fluid will find the way to leak out,
marking the seal between the bad valve and its seat with the wet trail
inside its respective ports. If this happens to you, I hate to break the
bad news but dude, you are going back to the lapping part of this
dissertation.
If after say 30 minutes the meniscus of the brake fluid in the
combustion chamber stays at the same level and there are no fluid runs
in the ports, carefully remove the brake fluid from the combustion
chambers with a turkey buster and knock on the wood coz your valves are
closing hermetically.
*Note* - Observe all the necessary precautions associated with using of
the brake fluid. Keep in mind that if it gets on the car paint (even in
minimal amounts) you will be looking at a paint job. It WILL lift the
paint in a few seconds.

30. Turn the head right side up. Wet the valve lifters with oil and
insert them in their original valve wells according to the numbers that
you have put on them in paragraph 14.

31. Check for wear on the two segmented brown phenolic tensioner boots.
They shouldn't have any deep groves in them worn by the chain. If they
do - replace the boots. I don't know if they are available separately.
Mine were perfect after 40kmi and 100% Synthetic oil, but I saw a used
head whose owner neglected to change the oil regularly and those boots
were worn rather deeply. Install the still compressed chain tensioner
over a new tensioner gasket. Don't forget to put some gasket paste in
the locations specified in the Bentley. I couldn't bring myself to spend
$42/tube for the Audi stuff recommended in the Bentley so I've put the
generic high temperature Ultra Blue RTV Silicone Gasket Maker made by
Permatex, which I had in my garage. Let's hope it doesn't leak.

32. Find a couple of wooden blocks and put them under the head on either
side of the combustion chamber so that there is some clearance for the
valves to travel. We will be pushing the valves into the OPEN position a
couple of steps below.

33. Wet the first camshaft and its bearing caps with assembly lube. I
personally use regular motor oil on camshafts, since  I never had to
assemble the engine and let is sit for a long period of time on the
shelf. Insert the camshaft's gear into the chain so that the link marked
in paragraph 12 is sitting over the TDC notch in the camshaft. if you
zip tied it, don't forget to cut it off. Lay the camshaft squarely all
the way into the bearing beds. Put the bearings caps over the camshaft
journals. Insert the screws into the caps and finger tighten them.
*Note* - The camshaft won't go all the way in coz some of the valves
will have to be pushed down into open positions.
*Note* - Watch the bearing numbers. Remember they are numbered
backwards, from the back of the head to the front.
*Note* - Watch the orientation of the bearing on its respective bed. One
out of the two screw holes (or of four in case of the Intake camshaft)
has a little bushing pressed into it on the bed side. The correlating
bearing cap has a countersink for that bushing on one of the screw
holes.

34. Very carefully tighten the caps for this camshafts in the sequence
and to the torque values outlined in your Bentley. Pay very close
attention to the exact procedure, of you will be risking cracking the
hollow cast iron camshaft.

35. Repeat paragraphs 31 and 32 for the second camshaft. Remove the
chain tensioner. Now the head should be ready for installation onto the
engine block.

(to be continued)

--
Igor Kessel
two turbo quattros