2.0 Head Gasket delete? Options

[torakki]

I've read where it's a good idea to remove the head gaskets and re-assemble without them. Something about, they crush and cause an issue. Is there anything else you need to do or change, in their place? Like a different head design?
Thanks

[technicalninja]

Ok... I am going to climb up on my soapbox here....

The VW bulletin everyone seems to refer to relating to this does NOT apply to 914 engines. Here is the link to it: https://ratwell.com/mirror/www.dolphinsci.com/techbull.html

"Subject: VWC Remanufactured 2.0l Air-Cooled Engine Group: 10"

"Models(s): Type II/Vanagon 1975 - 83 MY Date: May 31, 1990"

"Engines, P/N 071 100 031AX, 039 100 031 B/C/DX, have been modified to improve heat transfer an increase durability. These changes effect Engine codes: GD, GE, CV." (emphasis mine).

None of those were delivered or factory installed in a 914. And this bulletin is for a Factory Reman engine, not something put together in a garage behind a house in Bakersfield.

Also, in regard to lapping in the jugs to the cylinder head. How can you be sure your deck height on both cylinders on that side of the motor are the exact same height? Can you measure, with repeatable accuracy, to .0001 tolerance? Nobody with a home garage can do that! It takes very expensive machine shop tools and a surface table to do it. And the cases, the jugs and everything have to be spotlessly clean.

And how do you insure that the flycut heads are cut to the exact same depth? I have received heads from the machine shop with the spigots close to .05 difference between the two sides.

Production machine shops are not Raby's shop. They do the absolute minimum, and pay the machinist crap. So they only do what they have to do. Stuff like making the spigots the exact same depth to a tolerance of .0001 is not in their world. One sneeze and you have enough of a difference to have a loose jug if you don't use the head gaskets.

Hand lapping a jug into a head is questionable at best. How can you be sure to get the jug in straight? Are you applying equal pressure on the jug? Did you lap both spigots to the same depth? When you put it together, did you mix up the jugs and get them in the wrong hole?

That is way too many variables for me.

The head gaskets are designed for use in engines that have been, shall we say, less than accurate machine work. If you want to spend the money investing in the proper tooling, and the time to learn how to use it, and the time to do it like the factory did when they did a reman engine, then yes, eliminate the head gasket.

Otherwise leave it in. The difference in compression is minimal. The failure due to a loose jug can be catastrophic.


Getting off my soap box now.

Clay

Actually, he's right!
And I have a surface table.
And really accurate tools.
And a BUNCH of experience.
My LIMITS are at the .0001" range NOW!
Determining depth difference of two fly cuts?
I'd expect my accuracy to be TEN times worse (.001)
And that's with a 3K surface table...

1 out of 50 machine shops I trust, and they've made SERIOUS mistakes that I caught before assembly.
"Some employees should not have been hired" is in every machine shop's history.

If I was "in the field" without my equipment I would use the fire rings as well!

I don't really care about the TSB.
I make mods for durability or performance reasons.
I will not use fire rings on my builds but I have a chance of "pulling it off".
Most don't.

On a stock car, with stock performance goals, keeping the rings is "best practice", especially if you are re-using the heads or jugs.
(IMG:style_emoticons/default/ninja.gif)

P.S. @ClayPerrine I'm betting you might have use someday for a loaner surface table.
Feel free to hit me up if you do...