Date: Thu, 24 Oct 2013 01:50:05 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: off with her heads
In-Reply-To: <CAFNeVpHFyZYM-eq92tFJzY4e=PoZM1Mg=bPeDW50A_b_Y6N71Q@mail.gmail.com>
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Please take this as training. At the point that compression test was taken
that engine should have been taken out of service and further evaluated. All
the cylinders are down and the one with 60 psi indicates a failure. If you
had an emissions test program it should have failed. The catalyst is most
likely shot. More concerning is while that cylinder was down the remaining
three had to work harder to compensate. This often translate to increased
wear on the rod bearings. The oil contamination from unburned fuel doesn't
help things. Before taking the engine a part a leak down test would help to
diagnose if you had a valve or a ring problem.
Now that the heads are off there are some easy checks you can make. Put the
spark plugs in and set the heads with the combustion chambers facing up.
Fill the chambers with some light liquid like WD-40 or even carb cleaner.
You will find leaking valves real fast. The exhausts should not be ground.
If the seat are cut or the valves ground the stems should be shortened and
the springs shimmed to compensate. This is to maintain spring pressure and
rocker geometry. Adjusting screws should always be replaced. If the valve
guides are worn it is likely time for new heads. These are a heat the head
to 400 and cool the guides in liquid nitrogen fit. Otherwise they tend to go
in off center and the seats will need a lot of cutting to compensate. Back
when VW rebuilt these heads they almost always ended up drilled out and
fitted with oversized guides. A lot of labor. Make sure the intakes get the
oil seals. ETKA does not show them but they should be there. I have a bunch
in stock. They will keep oil from getting sucked down the intake guides.
You need to remove that carbon ridge at the top of the cylinder. The new top
ring can get broken hitting it. If honing the cylinders remove as little
material as possible. A few more thousandths and you will have an engine
with piston slap noises. With the cylinders out at least measure the rods
for play and bearing wear. The rods and bearings can be replaced without
splitting the case, (this sucks but do-able).
Good luck,
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Tom Carchrae
Sent: Wednesday, October 23, 2013 4:21 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: off with her heads
I checked a compression test that was done on the van a year and a bit ago.
It had a reading of 60/115/120/140. If I read that right (those readings
are for 1/2/3/4 cylinders) then the one that was stuck on is #1. Perhaps I
did not break that piston ring after all? (also, presuming that cylinder
#1 is the one closest to passenger in north america)
I'm also wondering if I should disturb the valves at all. It seems like a
logical thing to approach while I am in there, although I'm not clear on how
much benefit would be gained vs the extra work and chance of messing it up.
I realize I'll need a spring tool if I take them apart. A new set of valves
and guides seems to be around $100 - and in my novice mind, new valves would
seem to be important for compression. I've done quite a bit of googling but
can't find much on valve maintenance, bar the adjustment and nosiy lifter
discussions.
My current plan is clean it up as best I can, install all the new gaskets,
and then back together. Once I clean it then it'll be more apparent if I
can get away with that or not.
Tom
84 1.9L
