Date: Mon, 28 Nov 2011 18:58:49 -0800
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Head and valve condition
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Hi Gregg...
nice long detailed post - nice..
I don't know what 'oil cavities' are though ..
the area below the rocker arms ?
Small crack between the two valves . Very normal. Very 'vw' . Five
million aluminum vw heads are in service with a small crack there. Usually
nothing to worry about.
You can have the head pressure tested.
and some people peen those cracks closed. Usually they are just left along.
You probably have a VW head, as opposed to an AMC brand head.
Supposedly the VW heads are prone to cracking ..but I have not had a problem
ever.
if it's an AMC head ..it's not original, and they are known for not that
great valves.
I really deluxe waterboxer engine rebuild will sometimes have new AMC
heads..
with the new valves, or at least the exhaust valves replaced with new better
valves.
I don't see that you have checked how well the valves seal.
On every high miles 2.1 head I take off ..
if I stand it on end and fill the exhaust port with gasoline to test for
leakage.
( do all the valves of course ...test them for leakage )
I commonly find an exhaust valve or two that leak a little.
So I'd remove the valves for sure.
the mushroomed valve tip bothers me a little too.
I might ask a machinist what they think of it ..
or just replace both exhaust valves with new ones.
Personally I do not think the type of coolant used is much of a factor at
all. More like how often it's changed.
On a 20 year old waterboxer..
once a year would not be too often.
You never get all of it out anyway.
When changing it, unless you just go nutty to get all the old out ..
or dilute it with water after the first draining, then drain that ..
you only are changing about 60 or 70 % at the most I'd say.
I use conventional green anti-frz. Mixed 50/50 with water ..
and a small cup or so of machinist's cutting oil..
a water soluble oil that makes a fine water pump lubricant and rust
inhibitor.
I have done this to many hundreds of car and vanagon cooling systems for
about 20 years ....even longer than that maybe. It flat works.
I also add Water Wetter ...particularly in the summer.
I like an 87 C t-stat for winter, and an 80 C for summer .
I like to put the bare head on ( metal rings on top of the barrels ) without
the rubber gasket and measure that gap where the outer water gasket goes.
Yours are likely ok, dimension-wise since it ran a long time without
pinching the outer gasket.
I have seen heads that squeezed the rubber gasket too much ..
and sometimes not enough ..
and sometimes a head that sits tilted , which can't be too good.
I think the rubber gasket is 4.5 mm thick..
and I aim for a gap of 3.5 mm . You're probably ok is my hunch.
Scott
turbovans
----- Original Message -----
From: "Gregg Carlen" <gregg.carlen@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, November 27, 2011 6:27 PM
Subject: Head and valve condition
> Hey folks,
>
> I'm looking for some advice about reusing the head I just removed from my
> 2.1l (1990 Westy 2WD). 185k on the engine and the heads and engine have
> never been rebuilt as far as I know.
>
> The PO had been running the incorrect coolant, which I changed out this
> past summer with Sierra, however, it was too late. Had a slow head leak
> (more like seeping through the gasket) starting already. Finally got
> around
> to pulling the head this past weekend to prepare for a gasket replacement
> (and green o-rings on the cylinders, all other usual gaskets replaced,
> etc).
>
> When I pulled the head, I was initially pleased with the condition.
> However, upon closer inspection, I notice a few things that make me wonder
> if I can re-use the head as-is, make a few repairs, or have to replace it.
> This is the passenger side head.
>
> My initial observations were:
> - the gasket surface was in very good condition. Only a few small spots of
> the slightest pitting.
> - The oil cavities only had the slightest tarnish from oil. Wiping with a
> cloth removed it.
> - All of the coolant and oil cavities seemed to be clear and clean.
> - There was only the slightest bit of carbon in the combustion chambers.
> - The head gasket was the source of the leak, not corrosion on the head's
> mating surface. - - The gasket had essentially turned to putty and started
> to deteriorate and like an old sponge (I could see the 'spongy' look from
> the outside before I pulled the head).
>
> Upon closer inspection, there were a few areas of concern I noticed:
> - Between one pair of intake/exhaust valves, was a very small crack. I'd
> say it's not quite wide enough to insert the edge of a piece of paper.
> - Between the other pair of valves, I noticed a hairline fracture if I
> look
> at it from just the right angle. Not a crack, just a fracture.
> - Lastly, the contact surfaces between the valve adjustment screws and
> valves looked good, with the exception of one. The contact surface between
> one exhaust valve and the adjustment screw had lost its original shape
> just
> slightly. Almost didn't notice it at first. The adjustment screw has the
> slightest mushroom effect on it and the contact surface of the valve end
> isn't mushroomed, but doesn't have the crisp edges like the other 3 valves
> do.
>
> So, all that being said, I'm thinking I'm okay to clean it up and
> re-install (I hadn't removed the valves and wasn't really planning to). I
> am, however, a little concerned about the 'almost mushroomed' valve end
> and
> adjustment screw. I'm going to replace the adjustment screw since its a
> simple thing to do, but wondering what would cause this condition to occur
> in the first place.
>
> In the back of my mind, I wonder if the crack (and hairline fracture)
> between the valves will get worse and make the head unusable and have to
> do
> the job again (I'd prefer not to spend another $500 on a new head). Or, is
> the almost-mushroomed valve going to cause a problem (or be a sign of
> future impending doom)? I hadn't experienced any valve tapping in the
> past.
> Given that this head gasket leaked, am I just avoiding the other side? (I
> did notice this head leak was a 'seeping' leak whereas the other head is
> bone dry.
>
> Thoughts? Comments? Advice?
>
> Gregg
> 90 Westy (BlueBerry)
