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

[914Sixer]

If you leave them out, lap your barrels in.

[rick 918-S]

Just be sure the head mating surfaces are true and leave them out.

[technicalninja]

Check deck height!

The upper surface of the piston crown has to be at least .040 DOWN the bore.

Most stockers are this far anyway but if you don't check and a piston gets too close to the head (does this shit at high RPM!) entire loss of the engine is possible...

It IS an improvement to have them run close. Quench action is improved by reduction of deck height right up the point of contact.

Contact equals the Grim Reaper!

Head surface and jug surface that form the seal have to be FLAWLESS for it to seal well.

New jugs and fly cutting the heads are the normal way to achieve decent sealing.

If I was trying to re-use old, I'd "lap" the jugs into the heads with fine valve lap compound as 914Sixer suggested.

There is more to this than just leaving the fire rings out...

[ClayPerrine]

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

[930cabman]

I built my 2056 a couple years ago (still running great) and used small pieces of Plastigage at quarter points of the top of the cylinders and torqued the head(s) down. The results showed near equal dimensions at all locations. I do recall reading the factory recommended to eliminate the head gaskets and the engineering regarding the cast iron barrels and the aluminum cylinder heads. I did not use head gaskets, but a paper gasket at the case/cylinder connection.

[rick 918-S]

Since Clay responded I need to clarify my post. Stock cylinders - pistons and heads. If you check the cylinders to verify the registers are not collapsed and the heads are only in need of new guides you can the heads to make sure you have a clean mate up and gain a slight compression increase by leaving out the head gasket. It may or may not be the recommended method. But I have done it successfully.

[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...

[emerygt350]

I kept them out of my 2056 build. I ended up only putting a single spacer between the jug and the block on mine. Can't remember the size now. I was very careful about measuring the .04 distance.

[ClayPerrine]

I do recall reading the factory recommended to eliminate the head gaskets and the engineering regarding the cast iron barrels and the aluminum cylinder heads.

OK. Please show me the factory bulletin that refers to the deletion of the head gaskets on a 914/4 engine.

[ClayPerrine]

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...

Rick,
I have access to a surface table, a height gauge, and a full machine shop. And I know how to use everything in there. But I still use the head gaskets. I know I am not good enough to build a motor without them. Jake Raby is, but he is the exception, not the rule.

Thanks for the offer.

Clay

[930cabman]

I do recall reading the factory recommended to eliminate the head gaskets and the engineering regarding the cast iron barrels and the aluminum cylinder heads.

OK. Please show me the factory bulletin that refers to the deletion of the head gaskets on a 914/4 engine.

These days I am lucky if I can find anything, but I do recall seeing a TSB to the deletion of a head gasket. My 2056 rocks without head gaskets

[torakki]

OK, way more responses than I thought and way more opinions. I originally broke a valve spring and replaced all of them. I was advised to leave the head gaskets out and no other instructions beyond that. A local friend, that rebuilds 914's (has an award-winning car) also agreed, just leave them out. After putting all back together, car runs very rich. I'm hitting that age where I have trouble working on cars, so I took it to a VW expert, and he was questioning the head gasket removal. He found an air leak on the throttle body, but I wanted to ask about the head gasket.
I will pass on the voluminous information and go from there. I appreciate all the responses and info.
Thank you and Happy Fathers day to those fathers.

[emerygt350]

Is it still injected? D-jet? I would be looking to the mps if I were running rich
A shot diaphragm produces a rich condition. Air leaks don't do anything but raise the idle.

[914werke]

All it took for me was one engine tear down exposing the failure of those MULTI LAYER compression rings.
The resulting compression leak burned a hole through the step of the head.
Expensive.
All this talk of the precision machine work is IMO wasted, if you have the resources absolutely use them to machine the concerned components to the gnats ass of perfection.
But most of the engines the regular guy is building it wont make enough of a difference one way or the other.
IMO its one less item to fail that has been proven (& blessed by the manufacture) not to be essential.

[r_towle]

I don’t believe a leak at the head/cylinder would create a rich condition with a manifold pressure system (MPs—djet)

If you broke a spring, you may have bent a valve…that happens.
These car are designed to run slightly rich, and by todays standards they run very rich…but that keep the engine running cooler.

[r_towle]

This site may help if diagnosing djet

https://members.rennlist.com/pbanders/DJetParts.htm

[930cabman]

OK, way more responses than I thought and way more opinions. I originally broke a valve spring and replaced all of them. I was advised to leave the head gaskets out and no other instructions beyond that. A local friend, that rebuilds 914's (has an award-winning car) also agreed, just leave them out. After putting all back together, car runs very rich. I'm hitting that age where I have trouble working on cars, so I took it to a VW expert, and he was questioning the head gasket removal. He found an air leak on the throttle body, but I wanted to ask about the head gasket.
I will pass on the voluminous information and go from there. I appreciate all the responses and info.
Thank you and Happy Fathers day to those fathers.

A head gasket (or not) seal and a very rich condition are not in the same ball park. I cannot see a connection between the two

[emerygt350]

I don't think the two are associated (I don't think the OP is saying that either), but a change in compression could result in a change in necessary timing and the quality of the burn. However, there are much more parsimonious explanations for richness to hit first.

[914Sixer]

I used the gasket on my 2056.