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O-ring heads... tehcnical info..worth it?

5K views 24 replies 2 participants last post by  eschaider 
#1 ·
I'm looking for technical info about o-ringing heads. I'm fully aware that HG's are a fuse to what goes on in the cylinders so I don't want to get into this debate. I also know there are things that I could probably change to help minimize back pressure between the turbos and heads but this thread is started so I can realistically understand the technical design of o-ring'd heads, what limitations there are, best components or design for mod-motors, etc.

The best sealing would probably be to do the block and heads but I don't want to pull the block out. After inspection if it looks like the whole block needs to come out then I will entertain different paths.

Quick run down:
2V
Cobra Iron Block
Heavily ported PI heads w/ studs re-torqued 3 times.
40psi boost
950RWHP - 1200-1300hp crank..?

Looking at the video it let loose exactly at the time he let out of the throttle at the 6200 RPM limit so I think it's close to holding but this is simply speculating on my part. Tune/plugs looked absolutely perfect so we think it just needs help in sealing..

ks
 
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#2 ·
Here is some good Kentucky Windage and Tennessee elevation type information Kevin. The images below are from SCE gaskets. Other than one website image, which I have spoken to them about, and they agreed was incorrect but still have not corrected it, the other stuff they show is accurate. I'll flag the upside-down image when we get to it.

This is a general guide to what to use for various engine boost levels. Boost is a broad but, also good indicator of how heavily you are working the head gaskets.
Rectangle Font Parallel Screenshot Brand

As you can see, SCE recommends MLS or their ICS Titan Gaskets up to about 25 lbs of boost. Above that boost level they recommend either their Titan or Pro Copper gaskets. Your boost is solidly up in the Titan and Pro Copper space.

The ICS Titan gasket uses an o-ring made of stainless wire that it is embedded in a cut channel on the ID of the gasket's bore. The gasket sandwiches the o-ring, so it is squeezed into the upper and lower layers of the copper gasket surrounding it. This is a nice gasket design and although they show it as identical to an MLS for sealing capability, I have found it to be slightly better than an MLS but not as good as their Titan or Pro Copper alternatives. This is what the business side of the ICS Titan gasket looks like;
Human body Font Window Circle Automotive mirror


The SCE Pro-Copper and Titan-type Gaskets are the gaskets we historically have associated with supercharged alcohol and fuel engines. They are simply dead soft copper sheets cut out with bolt holes, and cylinder bore holes for use in highly boosted applications. They require the use of a stainless wire that is fitted to the head for compressing the copper into a corresponding receiver groove in the block, more on that in a minute. The Titan gaskets have additional seals for oil and water passages in the heads and block. The Pro Copper gaskets do not, they are for pure race applications.

The Pro Copper and Titan gaskets are the gaskets that SCE shows the o-ring being located in the block rather than the head. When I spoke to SCE at the last two PRI shows, they told me the o-ring should be located in the head and the receiver groove located in the block — which is the way I have always used this type of gasket. When I Informed them that their website showed just the opposite, they were initially unbelieving. When I took out my notebook and showed them the page they said it should be the other way around i.e., receiver groove in the block, wire in the head. They said they would look into correcting the imaging. As of today, it remains uncorrected.

This is the prep and dimensional information for this type of receiver groove for the stainless wire;
Line Font Parallel Gas Circle


This picture is the pic that is incorrect. It illustrates the stainless wire being located in the block deck when it should be in the cylinder head — especially on Aluminum heads. If you put the o-ring in the block and the receiver groove in an Aluminum Head the harder copper gasket material will mush out the receiver groove in the Aluminum Heads and ruin a set of otherwise perfectly good heads. The damage is irreparable, and the heads must be replaced.

The sizing metrics for the wire are correct. For the Boost levels you are running the 0.041" wire will be unsuitable. You will need the 0.062" wire to seal up your chambers.

This pic shows an 'assembly' view of the gasket, stainless wire, and what should be the head but is illustrated and labeled as the block
The correct assembly sould locate the stainless wire in the head and the corresponding receive groove in the block. If you do it the other way around you will destroy a set of otherwise perfectly good heads
Line Font Parallel Circle Logo

Other than the misdirection for the proper location for the stainless o-ring wire in the picture, everything else is correct.

When you modify an engine for this type of gasket usage/sealing tech, you need to have the o-ring receiver grooves in the block and the o-ring anchoring grooves in the head properly positioned for registration and sealing. To do this, the shop needs to use a Bridgeport or other similar precision machining center to accurately locate the receiver, and o-ring grooves in both the head and block or they will not seal, and you will torch a head and block.

This is a dimensioned drawing of where the grooves must be located for a 100 mm bore center block like a Modmotor. The dimensions are for an 0.041" wire o-ring. If you intend to do this, I can provide you the correct dimensions for an 0.062" wire o-ring.

Font Rectangle Symmetry Parallel Circle

If you give this drawing to the machine shop, take the extra effort to insure they know how to cut your o-ring grooves. Once they are cut wrong, you can not 'uncut' them, and you will need a new set of heads. Properly installed in your heads, the o-rings will look like this, except they will be Modmotor heads and not T/F heads.

Motor vehicle Automotive tire Alloy wheel Hubcap Audio equipment


This is a pic (below) of a set of new SCE Titan copper gaskets showing their proprietary coolant seals and how the stainless o-rings force the gaskets into the receiver grooves as you torque the heads down. At this point, the depressions are the result of only lightly tightening down the head. The engine below is AJ's, (Mofasta), and you can clearly see how the o-ring begins to push the copper into the receiver grooves at the top of the block, creating an interlocking seal.

Crankset Automotive tire Motor vehicle Bicycle part Gas


When everything is said and done, this is a lot of expense and effort to seal up an engine. It is also improbable you can hook up all the power this engine is capable of producing, on the street. Of course, the easiest and least expensive way to address this problem is to turn down the boost — although I also recognize how hard a decision that might be :)
 
#13 ·
This is a general guide to what to use for various engine boost levels. Boost is a broad but, also good indicator of how heavily you are working the head gaskets.
View attachment 176460
As you can see, SCE recommends MLS or their ICS Titan Gaskets up to about 25 lbs of boost. Above that boost level they recommend either their Titan or Pro Copper gaskets. Your boost is solidly up in the Titan and Pro Copper space.

The ICS Titan gasket uses an o-ring made of stainless wire that it is embedded in a cut channel on the ID of the gasket's bore. The gasket sandwiches the o-ring, so it is squeezed into the upper and lower layers of the copper gasket surrounding it. This is a nice gasket design and although they show it as identical to an MLS for sealing capability, I have found it to be slightly better than an MLS but not as good as their Titan or Pro Copper alternatives. This is what the business side of the ICS Titan gasket looks like;
View attachment 176461
The table is a bit misleading using boost to define the limits separating the different gasket designs since boost is a measure of the air not getting into the cylinders. Seems to me that it should be the power per cylinder.

Crudely calculating the power of my motor I think it's making 1200-ish FWHP = 150hp/cyl...?

ICS Titan: I like the idea of the SST ring imbedded within a single layer of material around the cylinders. This design is relying on the head clamping torque to seal the combustion process and the lack of separate layers keeps the combustion gases from weeping through any layers.

The table lists 25psi as the limit of this gasket but how much power per cyl is this understood to be?

I sent them an email asking them the power limits of this particular design so maybe they will come back with some interesting data for us.

ks
 
#3 ·
Perfect info and exactly what I was looking for especially on the different wire thicknesses which is what I was curious about.
I texted my friend/engine builder and quickly highlighted what I wanted to learn and he also mentioned I needed MLS gaskets.

I agree that having a receiver groove would be the ultimate in sealing.

I'm not sure exactly what he is describing in his reply text but he said:

"You can either do just a oring in the head and use MLS gasket or you can machine it for hoops but that requires installing a hoop in the head and a receiver groove in the bock... However you will need to have the heads welded up if you ever do hoops in it."

I've heard of people just doing orings in the heads with no receiver groove in the block but I can't see this making any difference w/o a receiver groove but in another of his text he implied that this would also help and he does it on high boost Mitsubishi motors that he also builds.

Is there any merit to thinking that using an oring but not using a receiver groove can also help over not using an oring at all?

What about his comment of needing to weld the heads to do hoops? Is there areas on the 2V heads that don't allow clearance for the machining for the oring?

I'm assuming "hoops" means the wire oring although his comment allows me to think he is talking about two different types of processes/materials?

I think with the power it made yesterday I would succeed in my track goal so all I want to do now is to sustain it as-is and not push it any farther.

ks
 
#4 ·
Hoops are a yet different type of sealing. They are a race-only technique and require yet more special machining operations on engine components to make them usable. Once you use them, you can never go back to regular gaskets because of the special machining required for hoops.

Do not ever run a stainless o-ring without a receiver groove. You are courting a stunning disaster.

While some people have run MLS gaskets with an o-ring, it is equivalent to running an o-ring w/o a receiver groove — again, a stunningly bad idea!
 
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#5 ·
Good info, Thank You!
Based on what you've said I will do a lot more research on all design options and if the requirements start spinning out of control then lowering the boost will be my choice, no problem. Now I need to make sure I understand the limitations of all options and have a realistic idea of what to expect from each.

Still thinking out loud... I believe I read that the stock head gaskets were recommended as capable for our cars so I think that's what I used when reassembling it lats time.

But if I was to put it back together w/o orings, etc is there a head gasket that you would recommend, of course performing the recommended re-torquing of the heads, etc..?

KS
 
#6 ·
The last time I used OEM Ford gaskets, they were multilayer, perhaps even made by Cometic for Ford and branded as Ford.

The best gauge for the limitations question is the Supercharged /Turbocharged chart I posted in my post #2 above. You basically have two options in head gaskets. Option #1 is an MLS gasket. Option #2 is an annealed dead soft solid copper gasket. Option #2 gets close to race car gasketing and usually is not a happy street experience because of fluid leakage. SCE has blunted some of the leakage problems with their proprietary sealing barriers around water and oil passages. While much better than a plain soft copper gasket, this approach is far from as good at sealing fluids as Cometic's. FelPro or Ford's MLS solutions.

You could try a thicker MLS gasket but that can be a frustrating challenge. The additional thickness blunts some of the conformability of the thinner gasket. The conformability of the thinner gasket helps to seal the combustion products in the head. The thicker gasket has stronger inner layers but a higher stack height which means it is subject to higher lateral forces attempting to breach the seal.

Generally speaking, when you get much above 25 psi, you are moving into race engine class cylinder pressures and sealing challenges. Sometimes you can get lucky, and everything works — other times, not so much. Right now, you seem to have a pretty solid footing in the not so much space.

If you choose not to go the solid copper route, which I think would be a good thing to not do, you would need to back down the boost. If you don't wish to do that, then you only have two choices: go the solid copper route with the appropriate machining required for their use, or on a lark, put the MLS gaskets back in and give it another try. I suspect the latter would play out the same again.

In the end, your easiest, least expensive, and most cost effective bet is probably to bring the boost back down to street driven car levels. I know that is not what you were hoping for or wanted to hear, however, the choices before you are very limited.
 
#7 ·
Yep, that's how I was gauging the options just wanted to make sure I was reading the tea leaves properly.

I'm going to start tearing it down Sunday while pondering my options including pulling the block and adding receiver grooves.

KS
 
#8 ·
I'm going to try and find anything I can on oringing heads and I came across a vid where Modular Head Shop used copper orings in the heads without receiver grooves in the block on Andrew Lavender's 7 second, 40psi boosted 2V:



I also found some articles mentioning copper oringed heads w/o receiver grooves:


Any experience or info using copper rings in heads? I really like the idea of this but I can also see issues if not done correctly..

Heads did not get torched so I'm feeling good now.

ks
 
#9 ·
Very good info in the Engine Labs video. Don't forget their engine is a race only engine. Yours is a dual purpose with most of its life on the street.

The idea behind copper o-rings is that the copper distorts under the clamping load of the head studs producing the seal between the block and the head. This is not incorrect, but three essential considerations are not addressed by this method.
  • First, after the copper o-ring distorts, it must be replaced to properly seal before the next assembly,
  • Second, When assembled, the head will stand clear of the block by the compressed thickness of the copper o-ring. This is a coolant and oil leak issue,
  • Third, The stainless o-ring solution gets its impressive sealing capability through the interference fit that occurs as the stainless o-ring forces the copper gasket material into the o-ring receiver groove in the block.
The interference fit, using stainless wire, is by far the most secure seal possible (other than hoops) for an assembly that sees combustion pressures like those present in a supercharged engine. In the FWIW bucket, you could run the copper wire in the heads and also use a head gasket. The copper wire life span would be greater than no gasket and the sealing issue for the fluids would, for the most part, disappear. The life span for the copper wire would only slightly increase. When the failure comes it will be impressive!

The supercharged race engine head gasket sealing technology has been around for almost 70 years, and with the exception of the recent Hoop Technology approach to sealing up the block/head interface, there have been no changes to the basic technology or approach to sealing that have performed better, and there have been many attempts.

In the '70s, I had a blown alcohol car with an engine using Veney heads. Ken had built the heads so that either a copper gasket or no gasket could be used. When you went the no-gasket route, the stainless o-ring in the head would be forced into the receiver groove in the top flange of the cylinder liner. The seal was as good as the copper gasket approach until you took the heads off, and some of the stainless o-rings would stick in the liner and be pulled out of the heads. Then you had to re-o-ring the heads before the next round. That was impossible because the o-ring register in the aluminum head was damaged when the stainless o-ring was pulled out, so you needed a second set of heads.

The damaged set of heads had to have the o-ring grooves welded up and re-machined. When you weld 6061 T6 aluminum the location you weld loses its temper and is reduced to the aluminum's annealed state, which is very soft. O-rings in annealed aluminum had a single-use life span and, if you were unlucky, would be blown out while the head is still bolted down and you are racing! The block and head damage was impressive!

In the end, this is your engine and your money, so there is no one more qualified to decide how you build your engine and spend your money. I would encourage you to embrace proven sealing technologies and not try to develop alternatives or create new ones. The time, effort, and monies involved in developing new technology is impressive, to say the least.

In the case of your engine, you have an iron block, ideally suited to receiver grooves, and virgin heads ideally suited to embedded stainless o-ring wire. If you choose not to turn down the boost, then the best sealing technology, other than hoops (which are expensive to purchase and install) is a 0.060"/0.063" stainless wire in the heads and a corresponding receiver groove in the block. An adequate sealing technology at a lower boost level would be MLS gaskets.

Blown engines have some unique operational idiosyncrasies that n/a engines do not have. One of them is a very flat and broad torque curve which can get you into trouble. If you hook up the tires at low speed and lower engine rpm, the in-cylinder pressures skyrocket in a supercharged engine. At, say, 3,000 rpm, the gasket has to seal against those in-cylinder pressures for twice as long as it has to at 6,000 rpm. During that increased time, the head gasket in a supercharged engine will blow out. Same thing if you short-shift the car and lug the engine under boost — kiss the head gaskets goodbye.

I am still of the opinion that the prudent solution is to reduce the boost for a street-driven car. Race car — different story but even in a race car, remember not to heavily load the engine at low speeds (engine and/or car), or you will still blow out the best gasket sealing technology available today.
 
#10 ·
If I can do receiver grooves in the block while it's still in the car then I'm all in, but I cannot see how it can be done with the precision required to make it work, depsite the "block" tools I've seen. But at this time I have no desire to pull the block out of the car b/c it becomes a domino affect of where do I stop... If the block comes out then I might as well build a teksid block, then I might as well get new pistons, rings, rebalancing, etc and it won't stop until I have a complete new motor.... not gonna happen at this time.

If there is a proven process that works without receiver grooves in the block then I want to look into it but I need to understand what makes it work and what are the limitations and I'm not getting a warm fuzzy feeling based on what I think I know..

You've zero'd in on my concerns with the copper orings and no receiver grooves:

- Second, When assembled, the head will stand clear of the block by the compressed thickness of the copper o-ring. This is a coolant and oil leak issue.

So how is Modular Head Service getting this to work? According to the video by Andrew Lavender they recommended a Cometic gasket. Does this gasket have a softer/copper top layer that is displaced easier when using copper orings and no receiver groove or is the sealant on the gasket thick enough to accommodate a few additional thousandths of clearance created by the oring?

In addition - how flexible is that process for a street car vs race car?

I did send MHS an email so hopefully they will respond with some info..

I doubt anyone except MHS has these answers but thought maybe someone here has some thoughts on why it does work, b/c it does seem to work...

KS
 
#11 ·
If I can do receiver grooves in the block while it's still in the car then I'm all in, but I cannot see how it can be done with the precision required to make it work, depsite the "block" tools I've seen. But at this time I have no desire to pull the block out of the car b/c it becomes a domino affect of where do I stop... If the block comes out then I might as well build a teksid block, then I might as well get new pistons, rings, rebalancing, etc and it won't stop until I have a complete new motor.... not gonna happen at this time.
The precision with which the receiver grooves must be cut to work correctly precludes any of the in the car sorts of processes that are so frequently suggested and simply do not work.


If there is a proven process that works without receiver grooves in the block then I want to look into it but I need to understand what makes it work and what are the limitations and I'm not getting a warm fuzzy feeling based on what I think I know.
None that I am aware of ...


In addition - how flexible is that process for a street car vs race car?

I did send MHS an email so hopefully they will respond with some info..

I doubt anyone except MHS has these answers but thought maybe someone here has some thoughts on why it does work, b/c it does seem to work...
I would not use that process at all. It is like using a metric socket on an SAE bolt because they are a pretty good fit. It is wrong, and eventually, it will bite you.
 
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#12 ·
It sucks that I'm not getting a warm fuzzy feeling with that process but I'm kinda glad too. Still going to research it as much as possible so prepare for more questions but something better start "mechanically" adding up to why it seems to work.

Thanks again!

ks
 
#14 ·
Summary of what I have read thus far in the archives:

ICS gasket (Formerly “ICS Titan”).

These are solid copper with an oring embedded in the copper around the bores and sealant around passages.

There are several older threads mentioning these gaskets being used over MLS gaskets. I couldn’t find anything making a comparison of before/after results.

One comment that was popping up from a few people was these tend to weep around the oil drain back holes. It was suggested/recommended to use Hondabond and Yamabond to seal around passages.

Several people that did not re-torque the heads had leaks.

Block/Head surface finish needs to be right for these to work properly.

A few comments mentioned that these gaskets re-sealed even after “lifting a head”.

No specific info/results on how much power these were holding.


Titan gasket: Copper gasket with sealant around passages. This can be used with a SST oring in head and receiver groove in block. Multiple thicknesses available.

Not much info from people going this route since most people aren't pushing power levels that require this design.

Can’t use receiver grooves in the Aluminum blocks (receiver grooves may wear from the copper being harder than aluminum) so the aluminum blocks need re-sleeved with sleeves with wide shoulders and the receiver grooves machined into the shoulders.

Cutting receiver grooves in the iron blocks is OK.

Best results when re-torqued...highly recommended.

Should use ARP2000 or better head studs.

May require additional sealant around passages.

Ultimate design in combustion retention for full race vehicle.

My Own personal observation with the Titans from my research:

There are different diameter SST wires that can be used but there isn’t much material between cylinders. Is there a limit or desired wire diameter for these Mod Motors to make sure there is enough material between cylinder bores?

Wire diameter may be determined by gasket thickness: thick gasket with thin oring may not seal well, etc. I’m sure there is a ratio/spec but I will look into this later.

Not sure what issues, if any, there would be if used on street vehicle. Even though these are copper, and copper expands a lot when heated, it seems to me that as long as the passages are sealed then this design should be fine for street use.

I think the MLS gasket I was using was around .037thk but for the Titans there are .050”, .043” or .032” to choose from…I’ll figure this out later.

I’ve opened Pandoras door to possibly machining this iron block with receiver grooves because I’m not getting a warm fuzzy feeling with the ICS gaskets due to the lack of data about how much power they were holding and comments about the gaskets “resealing” when a head was lifted.

Due to the lack of documented results even if the ICS gaskets held at 39/40psi it would drive me crazy waiting/expecting them to go sometime down the road.

But..can the Titan gasket with oring/receiver groove be reliable on a street car if additional sealant is located around passages and if the heads are re-torqued a few times..?

Still researching…

ks
 
#16 ·
Summary of what I have read thus far in the archives:

...

My Own personal observation with the Titans from my research:
There are different diameter SST wires that can be used but there isn’t much material between cylinders. Is there a limit or desired wire diameter for these Mod Motors to make sure there is enough material between cylinder bores?
Yes but larger bores like Coyotes and 5.0L Boss blocks have reduced material between the bores and increased gasket failures because of this. Driver driving stye is also a very big factor in how long gaskets witll live.


Wire diameter may be determined by gasket thickness: thick gasket with thin oring may not seal well, etc. I’m sure there is a ratio/spec but I will look into this later.
A good wire diameter for 0.043", 0.050", and 0.060" thick gaskets, at the boost you are running, is the 0.060" / 0.062" wire depending on where you get it. My personal preference is the thicker wire over the 0.041" / 0.043" wire.


Not sure what issues, if any, there would be if used on street vehicle. Even though these are copper, and copper expands a lot when heated, it seems to me that as long as the passages are sealed then this design should be fine for street use.
This is a race gasket being forced into proletariate service. It will disappoint you maybe not right away and maybe not in a year, but it will, and when it does, you will be pissed off that you chose that path.


I think the MLS gasket I was using was around .037thk but for the Titans there are .050”, .043” or .032” to choose from…I’ll figure this out later.
When you use the dead soft copper gaskets the thinnest you want to go is the 0.043" gasket. The 0.050" and 0.060" gaskets work well also. Thinner and thicker begin to work progressively less satisfactorily, especially in a street application.


I’ve opened Pandoras door to possibly machining this iron block with receiver grooves because I’m not getting a warm fuzzy feeling with the ICS gaskets due to the lack of data about how much power they were holding and comments about the gaskets “resealing” when a head was lifted.
Block receiver grooves are as important to the final sealing solution as the stainless o-ring is. They provide the mechanical interlock between the gasket and block deck required to seal up the combustion gasses.


Due to the lack of documented results even if the ICS gaskets held at 39/40psi it would drive me crazy waiting/expecting them to go sometime down the road.
ICS gaskets are a nice idea but they fall significantly short of the sealing capabilities of the Titan gaskets. They are for the guys who are too lazy to o-ring the block and heads.


But..can the Titan gasket with o-ring/receiver groove be reliable on a street car if additional sealant is located around passages and if the heads are re-torqued a few times..?

Still researching…

ks
The answer in a word is no!

The reason is, you will be driving the car at non-race track speeds, on the highway, and want to accelerate quickly. You will push down on the throttle without downshifting because the massive torque the engine produces allows you to easily accelerate the car this way. Once you discover that you get lazy about keeping the engine speed up under load. The massive increases in in-cylinder pressures, at low engine speeds, begin to whittle away at the gasket. Sooner or later, it will fail as surely as the sun rises.
 
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#15 ·
Your instincts with respect to the broad brush effect of the head gasket usage chart are spot on Kevin.

If you have a racer that leaves the line above 5000 rpm and the engine speed accelerates briskly upward from there he is not likely to experience gasket failures. On the other hand, if you have a racer that grabs the crank fairly aggressively at 3000 rpm or less he is going to see gasket failures others simply do not. Similarly, if you leave the line at the 5000 rpm threshold or higher but begin to rattle the tires or worse smoke them and then the driver upshifts to stop the shake or wheel spin the load you put on the crank and in particular the head gaskets will push out a gasket in a New York minute. There are no hard and fast rules about what gasket to use when or where but you can depend on gasket failures the heavier and lower in the engine rpm that you load the crank.
 
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#17 ·
You are definitely confirming all my suspicions on all the options available so I seem to be understanding the general principals and design requirements of how/what each gasket was made for.. (y)

ks
 
#18 · (Edited)
Did a lot more searching but just came up with more questions. I sent SCE a few emails but no replies and I couldn't find a Tech line to call.

Concerning copper gaskets with orings/receiver grooves:

Ed,
If I can be humored for a bit I'd like to know what you feel is the limitations that steer you away from these for full street use. There are a lot of threads with people using these on limited street use vehicles but one thing that popped up every so often was the leaks from the passages (oil and coolant). Not everyone had issues but I would say it was 50/50 (not good) and these were on limited street use vehicles to full on race cars. No info on Long Term street car use could be found.

So, is your main concern the difficulties sealing around the passages or the combustion ring seal failing over time or something else?

If it's the oil/water passages then I can see why they leak being a purely flat gasket, even with a sealant sprayed on the surface. Even the Titan gaskets with the adhesive around the passages are not designed properly if all they have is a seal located on the gasket surface without any relief for the sealant to be located in which, IMO, is a design flaw and easily remedied.

I halfway suspect that the combustion seal can deteriorate over time being that copper doesn't have any/much spring to it, but this is where I lack facts so haven't studied the results of what the gaskets look like over time.

ks
 
#19 ·
The age old why can't I do the same things with my performance vehicle that I drive on the street always comes down to one thing in the end. Both daily drivers and race cars are purpose-built vehicles. These vehicles, irrespective of which one you look at first, are each the result of tens (probably hundreds) of thousands of hours of design and development work to optimize them for their particular work environments. Both optimizations target longevity, and one also targets performance.

When you subject the performance targetted vehicle to proletariat daily driving service all the daily driving service longevity engineering that was eliminated from the performance-designed vehicle comes to roost at your doorstep in a particularly unhappy way. Similarily when you subject a showroom stock vehicle to a drag strip performance regimen things that would not fail on a race car begin to fail on the daily driver.

The simple bottom line is purpose-built vehicles are built that way for, not surprisingly, a purpose!

That is exactly what you are running into with this head gasket sealing issue and more fundamentally with the boost level you are trying to run on the street. The boost level is simply a race car level of boost. Can you run it on the street? Absolutely! Will you have problems? Absolutely!

Why? Because you are using a hammer to put in screws instead of a screwdriver. After you smack the screw down flush with the surface it looks the same as if you had screwed it in. It just doesn’t have the same holding power.

Lets talk about the copper head gaskets for a moment. They are what is called dead soft copper. That means they are unusually conformable to the surfaces being gasketed. It also means they have no memory — they will not spring back to any previous shape or form. That means once compressed they will not change back to anything like their virgin condition.

The failure rate of these dead soft copper gaskets on street vehicles is actually 100%. The difference between the 50% you found and the 100% I just stated is the gaskets that did not leak after their first assembly and could not be used again in subsequent assemblies.

Can you use them on the street — yes. Will your maintenance regimen have to incorporate regular replacement prior to failure —very, very highly recommended. When will you tire of the elevated maintenance regimen? Only you know.

Now while we are still on the race vs street use argument, I am going to beat you up on boost. The boost you are running is a race car level boost number. I have a friend who sadly passed away recently from Covid. He has a AA/A that only runs 28 lbs of boost but runs 5’s at nearly 245 mph. You have substantially more boost — but why?

It is impossible for you to hook up that kind of engine power on the street, even with slicks. This begs the obvious question, then why are you doing it?

You have reached the crossroads all of us at one time or another come to. Do you want a streetcar, or do you want a race car? Whatever the answer, that car is then the car you should build without any compromise for the other in design or engineering.

You are attempting to fit a square peg in a round hole or maybe a round peg in a square hole. It doesn’t matter which one it is, the sooner you stop, the happier you will be.
 
#20 ·
I know I am beating a dead horse in your eyes, sorry. I am a designer by trade that's what I do. I am given a new product design specification and required to design something to meet the spec's which requires a lot of research, thinking out of the box and testing.

I apply this mentality to this car project and throughout this project I have found a lot of off-the-shelf items that do not meet my requirements and when this happens I make them myself or have them made to my specs.

Yes, this is a street car but I am building it to run and hopefully survive on the street and at the track at this level of performance. When designing I see limitations and understand a lot of why they are limitations, but not all of them, so I am researching and trying to understand and to determine IF they can be improved. If not then I make a decision based on the factors presented.

I have never said that I expect to apply this type of power on the street and hook up...never.

Every thread and post I have found ALL recommend to use copper gaskets even on a "street" car. But I have far more respect of the facts you offer over those postings even though you are the only one that doesn't recommend it so I look for the technical issues which goes a lot farther with me.

I suspected the lack of "spring" that the soft copper has is one of the principals that cause issues but I needed verification b/c nobody details the "why" anywhere. Most people just follow and never question anything which can lead to unexpected results.

No more questions on head gaskets but Thank You!

Best Regards
ks
 
#21 ·
Kevin, I am not discounting your initiative or your insightful perseverance. It is just that the path you are pursuing is not new; it has been traveled by many of us before with a similar outcome. My observation about hooking up on the street is cautionary. I doubt you would attempt to use all the power the engine is capable of on the street. However, that said, a boosted engine, properly tuned, has a torque curve that is pancake flat from the moment it hits max boost all the way out to max rpm.

Granted, turbos need to spin up, so off idle and up through, say, 3000 rpm or so, the boost and torque will still be building. However, once the boost hits your boost-controlled target numbers, the torque curve is pretty much table flat from that point on out, and it will be quite impressive. It is also much more than can be hooked up by any street tire.

Once you get to the table flat portion of the torque curve, engine rpm is no longer as significant a factor, in terms of traction, as engine torque. That massive engine torque will light up virtually any tire on the street in the blink of an eye. This and mechanical reliability are the impractical aspect of a high-boost version of the engine on the street. Even off-the-showroom floor examples of the Terminator would light the tires from a roll in almost any of the first three gears. Your torque is substantially more than an Eaton-equipped Terminator. The build strategy does beg the question, why build a race car engine for a 99% street-driven car that can not use the power it is capable of producing, the overwhelming majority of the time?

I am impressed with your tenacity, and I would like to see you find that magic mix that allows both sets of engine attributes to reliably exist in a single engine. However, after so many have unsuccessfully reached for that brass ring and missed, I believe that particular goal, at least in the near term, is unattainable — without spending a lot of time and money. You have a stunningly impressive street-driven car. It would be no less impressive and potentially a lot more reliable at an ever so slightly lower boost level.
 
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#22 ·
UPDATE:
4/4/23


After digging around on a lot of MFR'ers websites I came across some Cometics that looked interesting. They offer a MLX version (extreme MLS) where one of the middle layers is folded back around each bore essentially giving the gasket a .005thk ring around each cylinder producing additional sealing but it's still a multi-layer gasket with 4 layers. I contacted them this morning and we discussed this gasket along with custom making a set for my application but ultimately they felt that if the existing MLS gaskets were holding 32-34psi then this MLX gasket should easily hold more.

So this is what I will try and I am confident that this will work for me:
Sample image of one of the middle layers:
Helmet Kitchen utensil Electric blue Personal protective equipment Metal


ks
 
#23 ·
Like it was to you, that gasket is a new item to me also. I like the idea of the folded layer and the extra sealing capabilities it brings to the installation. I would try this before attempting the dead-soft copper solutions we talked about. We are on the same page here, Kevin. Remember, with the boost you are capable of it is easy to accelerate the car, on the road, without increasing engine rpm. That is a gasket killer, even for this type of gasket. Whenever you lug the engine under load, you are loading the gasket at stunningly high cylinder pressures for longer periods of time than they can safely handle and risking a gasket failure.

I am optimistic about the new Cometics you found. They look like the best alternative commercially available right now.

BTW excellent Sherlock Holmes work ...
 
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#24 ·
Yea, in my mind I kept thinking an extra compression ring .005-.007thk around the cylinders could help which prompted me to research more. I researched using orings with MLS gaskets but again just didn't like the idea for obvious reasons and when I saw these I figured it was golden.

I offered them to think outside the box on a custom gasket for me using a thicker layer or different material or additional oring in the heads, etc especially based on the lower RPM loading my car sees so we discussed several ideas but the path came back to their off the self part so we both concluded that it would be the best.

I usually retorque them three times at a minimum so I can't wait to start getting things moving forwards again.

I now have a warm fuzzy feeling!

ks
 
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