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914World.com _ 914World Garage _ 2.0 Head Gasket delete?
Posted by: torakki Jun 15 2024, 11:10 AM
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
Posted by: 914Sixer Jun 15 2024, 11:37 AM
If you leave them out, lap your barrels in.
Posted by: rick 918-S Jun 15 2024, 11:38 AM
Just be sure the head mating surfaces are true and leave them out.
Posted by: technicalninja Jun 15 2024, 12:18 PM
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...
Posted by: ClayPerrine Jun 15 2024, 02:16 PM
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
Posted by: 930cabman Jun 15 2024, 02:52 PM
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.
Posted by: rick 918-S Jun 15 2024, 03:11 PM
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.
Posted by: technicalninja Jun 15 2024, 03:18 PM
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.
P.S. @http://www.914world.com/bbs2/index.php?showuser=1143 I'm betting you might have use someday for a loaner surface table.
Feel free to hit me up if you do...
Posted by: emerygt350 Jun 15 2024, 03:19 PM
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.
Posted by: ClayPerrine Jun 15 2024, 03:21 PM
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.
Posted by: ClayPerrine Jun 15 2024, 03:25 PM
P.S. @http://www.914world.com/bbs2/index.php?showuser=1143 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
Posted by: 930cabman Jun 15 2024, 04:15 PM
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
Posted by: torakki Jun 16 2024, 02:12 PM
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.
Posted by: emerygt350 Jun 16 2024, 02:48 PM
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.
Posted by: 914werke Jun 16 2024, 03:49 PM
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.
Posted by: r_towle Jun 16 2024, 04:36 PM
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.
Posted by: r_towle Jun 16 2024, 04:38 PM
This site may help if diagnosing djet
https://members.rennlist.com/pbanders/DJetParts.htm
Posted by: 930cabman Jun 16 2024, 05:27 PM
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
Posted by: emerygt350 Jun 16 2024, 05:47 PM
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.
Posted by: 914Sixer Jun 16 2024, 07:08 PM
I used the gasket on my 2056.
Posted by: ClayPerrine Jun 16 2024, 08:41 PM
(& blessed by the manufacture)
I still want to see the Porsche documentation that says to do this. The only thing I can find is a VW tech bulletin that does NOT cover a 914/4 engine.
Posted by: emerygt350 Jun 17 2024, 05:36 AM
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
Here is an old thread with the bulletin and some pretty good points made.
http://www.914world.com/bbs2/lofiversion/index.php?t215407.html
Posted by: emerygt350 Jun 17 2024, 05:37 AM
Dbl post
Posted by: ClayPerrine Jun 17 2024, 09:05 AM
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
Here is an old thread with the bulletin and some pretty good points made.
http://www.914world.com/bbs2/lofiversion/index.php?t215407.html
Still having the same argument over a decade later.
Will this bullshit misinformation NEVER end? The Tech document refers ONLY to the revised 2 liter heads. Period. Perpetuating misinformation does no one any good.
The Cap'n
The listed thread makes the same point I have been trying to make. The tech bulletin does not apply to the 914 engine. The tech bulletin applies to the engines with the revised head design.
The key words here are "REVISED HEAD DESIGN". The 914 motor does not have it.
Posted by: 914werke Jun 17 2024, 11:04 AM
http://www.914world.com/bbs2/lofiversion/index.php?t215407.html
Does not have what? with all due respect to John.
Sorry Clay but you are making a specious argument. First no one will argue (I think
) that the T4 motor is a VW design & that Porsche's contributions to it related to the 914 centered around the 2.0L & redesign of its heads. Arguing the VW bulletin cited isn't applicable may be splitting the finest of hairs.
Perhaps you can define what you think the specific features are that differentiate the "Porsche" vs the "Volkswagen" versions described in that bulletin, and how they are germane to this discussion about the use of compressible multilayer metal head gaskets?
Posted by: 914werke Jun 17 2024, 11:12 AM
My understanding is that VW manufactured the T4 engine not Porsche?
Posted by: ClayPerrine Jun 17 2024, 11:34 AM
Look. . this is real simple. Do what you want with your engine.
But please READ the tech bulletin in detail. It specifically mentions only the later Vanagon engines by type. It does not apply to ALL type IV engines.
Posted by: Nogoodwithusernames Jun 17 2024, 11:52 AM
Pardon my lack of knowledge in this area, but what specifically changed with the later T4 heads? Obviously there are some differences between the 1.7, 1.8, VW 2.0 and 914 2.0 heads but I did not realize there were changes from earlier to later versions.
In my vast knowledge and experience rebuilding VW motors (a whopping 1 T1 motor and 1 T4 motor 
) I have taken this to be ubiquitous to take the head gaskets out on all T4 heads. Based on the VW bulletin and Jake Raby's suggestion. I have heard of doing metal o-rings with a groove cut in either the cylinder or head for it for super high performance engines. That is a whole different ball game though.
I am not trying to argue either way, but would like to learn more from both schools of thought. To my line of thinking, it would logically make sense that it would apply to all T4 motors. They are all basically the same, and how much of a difference can a head redesign really make? Perhaps though it is just the extra heat and load from the breadboxes on wheels that was the primary cause of the issue?
Posted by: mmichalik Jun 17 2024, 12:35 PM
![popcorn[1].gif](style_emoticons/default/popcorn[1].gif)
Posted by: 930cabman Jun 17 2024, 01:39 PM
Possible/probable the folks at Porsche never had a TSB eliminating the head gasket, but I am running with my own experience and that of Jake.
For any /4 I may/will build in the future I am not using a head gasket, but will make sure things at the cylinder/head connection is tight.
Posted by: thomasotten Jun 17 2024, 06:39 PM
Not wanting to enter a debate that clearly needs an Ecumenical Council to resolve, I would point out the following:
The document, written in 1990 is stating that these changes have been introduced as improvements to their remanufactured engine program. "The following improvements have been introduced as of remanufactured Engine number 89000". It is information applicable to a certain year range of Vanagons, but is silent on all other models. This doesn't mean that it is not applicable to other models with type 4 engines. But generally, it is not wise to offer recommendations on changes to other complex systems unless you are reasonably sure that the changes won't have some other effect not considered. Also, do we even know if, in 1990, there was a remanufactured 914 engine program?
I would not say that this bulletin was meant for all type 4 engines, but only for their remanufactured engines. That does not mean, however, that the changes may not be applicable to your particular engine.
Posted by: Al Meredith Jun 18 2024, 10:57 AM
I stayed up last night reading a bunch of articles about type 4 rebuilds by Jake Raby and FAT and KB pistons and Mark Stephens,Len Hoffemen in Dune Buggies and HOT VW and VW TRENDS . Everything I read does not use head gaskets in their rebuilds. All are very clear about a .040 clearance . I have built several 2056 with carbs and have not used head gaskets . I have a 2056 in my 912E and a 1911 in my 914 all at 9 to 1 CR and never had a problem in 15 years of use . We need Jake to comment on this subject.
[attachmentid=914174] [attachmentid=914174]
Posted by: 914werke Jun 18 2024, 12:11 PM
BTW #5 should be performed on ALL T4 builds (using stock rods) 
... IMO
Now back to the argument about head gaskets 
Posted by: 930cabman Jun 18 2024, 12:17 PM
BTW #5 should be performed on ALL T4 builds (using stock rods)
... IMONow back to the argument about head gaskets
I was unaware of this modification and missed it on my last 2056 build. The reasoning is to cool the underside of the pistons?
IIRC Jake has spoken with regards to the use/non use of head gaskets
For me, they go in the recycle bin
Posted by: 914werke Jun 18 2024, 12:18 PM
correct. Poor mans oil squirter!
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