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

If you leave them out, lap your barrels in.

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

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...

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

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.

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.

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

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.

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

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

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

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.

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.

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.

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.

This site may help if diagnosing djet

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

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

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.

I used the gasket on my 2056.

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.

Here is an old thread with the bulletin and some pretty good points made.

http://www.914world.com/bbs2/lofiversion/i...hp?t215407.html

Dbl post

Still having the same argument over a decade later.



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.

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?

My understanding is that VW manufactured the T4 engine not Porsche?

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.

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?

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.

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.

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.
Click to view attachment Click to view attachmentClick to view attachment

BTW #5 should be performed on ALL T4 builds (using stock rods) ... IMO
Click to view attachment
Now 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

correct. Poor mans oil squirter!

The only time to use the factory T4 head gaskets- is NEVER.

I disagree. If you look at that tech bulletin, it clearly says "These changes effect Engine codes: GD, GE,CV."

None of those engines were used in the 914 at all.

Jake, you can do the required machine work to make it work without the gaskets. Ordinary guys working in their garage cannot do the precision work you do. They cannot machine heads with enough accuracy to be able to eliminate the gaskets. I would bet 98% of the professional machine shops out there cannot do the quality of work you do. The head gaskets are there to compensate for the less than dead nuts on machine work that comes from most shops.

Seems to work fine on my GA without them. I don't race seriously (autocross, occasional Watkins Glen) but I push the poor thing pretty hard (daily). Didn't even lap the heads to the sleeves. It's just another shim, just extra thick. 6000 miles so far in 3 months driving.

Question:

The update states improvements were made but does not say what they were unless I missed it in my speed read. What was done to accommodate the change?

Re-read, the stated actions are the improvements.

Some various ponderings on this topic.

-So we have various options of copper gaskets and aluminum gaskets for a lot of automotive applications. What is the difference between using a separate copper head gasket or using the aluminum head as its own gasket?

-The T1 doesn't use a head gaskets, the T4 cylinder to head connection is basically identical. Why does one require a gasket and not the other?

-Why can't my local auto machine shop cut heads flat? Sure you might get someone being lazy on a Friday afternoon, but can I not measure them and verify prior to assembly that everything is as it should be?

-Also nobody has said what the actual differences are between the engines in the bulletin and those not mentioned?

Not to stir the pot or anything

My last build (2056) I did not use head gaskets, but I did make a trial assembly of the cast iron cylinders/heads with a small 1/2" long piece of Plastigage at quarter points of the sealing surface. Tourqued everything together and then broke it down and noted the readings of the Plastigage. This was what I had available, and I feel this gives a reasonably accurate picture of the joint. Two years and 7,000 miles later all is good

Cost= almost zero and a decent level of accuracy

similarly not to stir the pot but simply to point something out, and why i am inclined to agree with @ClayPerrine .

the type1 (and type 3 pancake version) have magnesium cases.

the type 4 has an aluminium case (apart from the very early V engines of 1968/9 not sold in the USA).

it all could have something to do with thermal expansion of engine.
not quite sure how.

bear in mind back in the late 70s and 80s i was taught by my german mechanic to disconnect the auto chokes in my type 3 and gently warm the engine for at least 5 minutes from cold.
then drive off. this gave the engine a chance to reach its proper dimensions before stressing it. magnesium has a greater rate of thermal growth and expansion than aluminum. the old type 1 engine had quite a few different alloys in it and was designed to be self sealing at engine operating temp. when cold not quite so.

i was also trained or schooled to let it idle after a long highway drive on hot days for about 5 minutes to allow it to cool itself down a little before switching off.

with an aluminium engine case its a whole different kettle of fish. or at minimum slightly different to the type 1.

i am sure VW would have had a reason for the gaskets in the type 4.

possibly with expert machining they can be deleted but likely in the form they came from the factory with engineered tolerances they are meant to be there. i'm thinking they perform a role when the engine is stone cold rather than warmed to operating temp.

mind you thats just a guess off a hunch.

I re-read the stated actions. Just because the bulletin does not list the type IV does not mean it would not benefit from the upgrade as well. I was thinking there was some sort of a metallurgic change that our type IV's don't have therefore would be a negative if you tried it.

Type IV rods can be notched, Cylinders can be honed out for increased clearance, and the shims can take the place of the base gasket. Don't see the problem.

I tend to agree.

With respect to pistons: modern hypereutectic pistons will have their own special piston to cylinder clearances that will be determined by the piston suppliers. Forged pistons will have their own larger clearances vs hypereutectic so that #1 action on the bulletin can be taken with a grain of salt.

The other actions in the bulletin are focused on increasing heat transfer. First by the poor man’s oil squirter (notched Con-Rods) to get heat out of pistons and into the cylinder walls. Second, by eliminating the insulating effect of the cylinder base gasket ( paper) which gets changed to aluminum (due to thickness) but also because the aluminum allows better heat transfer from the cylinder into the case. Finally, by elimination of the head gasket so that the cylinder has a better heat transfer to the head.

With respect to cylinder to head sealing, Wonki nailed it. All the VW air cooled engines seal rather poorly when cold. When they come up to operating temperature they seal much better. Why?

The difference in thermal expansion is why. Aluminum is expanding much faster than the cast iron cylinders and the steel head bolts. As the head dimension grows but the steel studs grow much slower. This means, you get increased sealing the hotter things get up until studs break or pull out of the case (2.7L 911 sound familiar - cough - cough ) ever notice how Nickies (aluminum cylinders) require the use of (stronger) ARP head studs instead of OEM head studs. There you go.

Final thought: how many here have a Dyno and have done the development work & testing to argue this further than mere personal opinion or based on the results of onesie, twosie, engine builds with limited mileage accumulation? Gonna’ roll with Mr Raby on this one.

All of us need to thank Jake for his generosity to share the information he has gained.

Most likely the tops in the field of T4 and other engines. I am also siding with Mr JR

This isn't about choosing sides.
I can't believe that in 2024 we are still having this debate.
You know why we are?
Two reasons:
-Because the factory screwed up and installed the head gaskets in the first place
-Because the gasket sets bought today still come with them, when they should not.

Porsche didn't care about these engines, to them it was VW's job to design and support the 914-4 engine. Since VW used these engines up to 1983 in the Vanagon they had to make changes to keep more engines from failing, so they released the factory bulletin calling for omission of the gaskets. This did not occur until 1990, 14 years after the last 914 was built. Porsche should have followed suit, but they didn't care since the engine was from VW with just a few small changes to make it more suited for something other than a VW Bus.

These gaskets fail today. matter of fact someone had a failure of a head gasket on a 914 in the past week and posted to the 914 Facebook group. He thought that he had an exhaust leak, but once he explained when and how the failure occurred, I went straight to the head gasket. A couple of other did as well- we were all correct. He confirmed this is a combustion leak.

There's no circumstance where the stock gaskets should be utilized. Matter of fact I ended up with my 912E because of a failed head gasket back in 1999 and I still have it today. That engine went 160K miles in 8 years without those gaskets, and it is still alive today after being freshened up in 2010, but not touched since.

I can share hundreds of stories about how head gaskets have caused issues, but not a single one about how omitting them has caused a problem.

That said, the new casting heads come with this note from the manufacturer, yet people buy the gasket set, and use the gaskets anyway. Then they have a problem, and question why.
None of this is new information, it shouldn't be debated anymore. Since VW themselves stated they should be omitted 34 years ago, it should not even be discussed in 2024 and onward.
This is discussed in our "4th Dimension Type 4 Performance Group" on Facebook as well. It pops up every few weeks, and in the heat of summer these head gaskets give up more than any other time.