Going forward with masi valve cover gaskets!

[Reaper1]

In "theory" if the half-moon pieces were in place, you could use spaghetti o-ring material in the valve cover groove. It would have to be pretty thick material, though and honestly I don't know if it's made as thick as would be needed. Add on top of it that this valve cover already is notorious for leaking because the clamping force isn't as even as it should be (the preproduction ones have a LOT more fasteners holding the cover down) and that idea might just be another recipe for how to douse your engine bay in oil.

[acannell]

In "theory" if the half-moon pieces were in place, you could use spaghetti o-ring material in the valve cover groove. It would have to be pretty thick material, though and honestly I don't know if it's made as thick as would be needed. Add on top of it that this valve cover already is notorious for leaking because the clamping force isn't as even as it should be (the preproduction ones have a LOT more fasteners holding the cover down) and that idea might just be another recipe for how to douse your engine bay in oil.

thick and probably a very soft durometer...even a 1/8" thick 1.5" diameter oring can take 100lbs to compress correctly..if there already warping issues youd probably want to select something very soft

[joelzip]

That is why the gaskets I'm having made were reduced in width for compression. I was told that for it to compress at all I would need to take an equal amount out of the width for the amount added in height for the volume of rubber to squish width wise when it was clamped down. I would have never thought of that myself, I just went in asking for them to be .030 taller than my original because mine was flattened to deck height. Would have been great to see a NOS gasket that had never been clamped on but I don't think we have any at this point. I also requested that they be made with a 50 durometer rating for reduced clamping requirements so we're not cracking our valve covers. There was also an issue with o-ring material as I was trying to use an off the shelf o-ring for the spark plug holes. I don't have the cover in front of me but I think it was that the width of the valve cover path was narrower than the height needed so a circle shaped gasket would not work. It needed to be a rectangle as it needs to be taller than it is wide. I tried a number 324 and 325 O-RING without success.

[Reaper1]

I understand what you are trying to accomplish, but the stock gasket is already really narrow. Anybody have a NOS TIII valve cover gasket they can measure? I'm curious what its dimensions are. It really doesn't take a lot of compression to seal o-rings. They just need to have a good contact area and even pressure. Most fixed o-ring type joints I'm used to that use a reciever groove in at least 1 of the parts end up with the 2 parts either touching or being very close to touching. Maybe I'm overthinking things or I simply don't have the knowledge on how to properly design an o-ring joint (very possible as I can't recall ever covering anything like that in my classes...kinda worries me actually, not that I use it in my job). In any case, I'm still happy that this is actively being persued.

[acannell]

I understand what you are trying to accomplish, but the stock gasket is already really narrow. Anybody have a NOS TIII valve cover gasket they can measure? I'm curious what its dimensions are. It really doesn't take a lot of compression to seal o-rings. They just need to have a good contact area and even pressure. Most fixed o-ring type joints I'm used to that use a reciever groove in at least 1 of the parts end up with the 2 parts either touching or being very close to touching. Maybe I'm overthinking things or I simply don't have the knowledge on how to properly design an o-ring joint (very possible as I can't recall ever covering anything like that in my classes...kinda worries me actually, not that I use it in my job). In any case, I'm still happy that this is actively being persued.

orings can take plenty of force to compress..depending on durometer, cross section, and length of the oring..

the little 1.5" diameter oring in my 4th cyl kit (about 1/8" cross section) takes about 100 lbs to compress the 20% for the standard face seal.

the second chart is hard to read because its so small but really has some awesome information

[joelzip]

Its being made narrower than the slot so that when its compressed it fattens up to the full width in the valve cover. It needs to be made tall and skinny before being compressed so that it has somewhere to bulge when it gets clamped down. The rubber doesn't really compress to a smaller volume it just squishes to an empty cavity, that cavity being the wider valve cover slot than the original uncompressed gasket. Kinda like compressing a water balloon, its doesn't get smaller it just bulges out the sides. I was enlightened by the engineer that the gasket needed to be made skinnier than the slot in the valve cover so that it could squish full width into the cavity after it was bolted down. My original idea was to make it just as wide as the slot to begin with which wouldn't have worked out as well. The tolerances aren't very good in my valve cover let alone comparing it to others. This narrower and taller gasket is probably how the originals looked before they were bolted down and ran for 25 years. It allows the gasket to seal with the differing tolerances and adapt to the head and valve cover by being able to become taller or shorter depending on where on the valve cover its located. On taller compression areas it won't bulge as wide in the valve cover slot and in shorter compression areas it may bulge to the full width. This is whats unique about having a rectangular gasket instead of an o-ring. The o-ring is relying on two perfectly flat surfaces or a slot that was milled out not cast. Then factor in what our valve cover does after bolting it down, it probably looks like a pringle chip....

[135sohc]

I understand what you are trying to accomplish, but the stock gasket is already really narrow. Anybody have a NOS TIII valve cover gasket they can measure? I'm curious what its dimensions are. It really doesn't take a lot of compression to seal o-rings. They just need to have a good contact area and even pressure. Most fixed o-ring type joints I'm used to that use a reciever groove in at least 1 of the parts end up with the 2 parts either touching or being very close to touching. Maybe I'm overthinking things or I simply don't have the knowledge on how to properly design an o-ring joint (very possible as I can't recall ever covering anything like that in my classes...kinda worries me actually, not that I use it in my job). In any case, I'm still happy that this is actively being persued.

T3 valve cover gaskets are not an O-ring at all. They are sort of wedge/rounded rectangular shape on the cross section

[joelzip]

I heard 4.3 chevy valve cover gaskets can be spliced and glued together for a replacement on a t3

[Reaper1]

orings can take plenty of force to compress..

I understand it can take quite a bit of force to compress the o-ring. What I was saying is that it doesn't take too much force to seal the o-ring. Of course that is dependent of all kinds of things, but given equal pressure on both sides of the joint and good sealing surfaces, the actual act of sealing doesn't take much. I do understand that in order to keep the o-ring in place and to make sure the joint reliably stays sealed that it will take more force so as to increase the contact area of the o-ring and that the displaced volume has to go somewhere. No arguments there.

T3 valve cover gaskets are not an O-ring at all. They are sort of wedge/rounded rectangular shape on the cross section

I know they don't have a circular cross section, but the way they seal compared to what we are dealing with is similar. I'm curious as to what the dimensions of that seal versus its groove are in the natural relaxed state. I think it might be educational to see how an OEM tackled this problem. It could be argued that the TIII valve covers are pretty resistant to leaks.

I heard 4.3 chevy valve cover gaskets can be spliced and glued together for a replacement on a t3

I've heard the same thing. I honestly can't remember if the person that tried it had success or not. I do know that the splicing technique is somewhat common, so there must be some form of success in order for people to keep doing it.

BTW, here are two websites I found in a quick search that have a good bit of information on o-ring joint design.
http://www.parker.com/literature/ORD...g_Handbook.pdf
http://www.applerubber.com/

[joelzip]

Got an email today that said March 24th they will be ready to ship the sample. Slower than I had expected but at least its happening.

[Wastelands Warrior]

4.3 Chevy valve cover gaskets work very well when modified to work with the T III valve covers.

[4 l-bodies]

Joel,
IIRC Larry Carlson had a NOS valve cover loaned out to Chris @TU. It would have been ideal to have that in hand when you took the reins on this project. Glad to hear you are still making progress.

[joelzip]

Good news, center spark plug gaskets are done! Still waiting for the 1st prototype valve cover gasket that should be done the 26th. Here are pictures of the new spark plug hole gaskets that will work in conjunction with the full valve cover gasket.

[joelzip]

Some item I am selling that may interest you guys. Everything is NOS. $80 for all 4 exhaust gaskets, $80 for a pair of intake gaskets required for a single motor, $40 for 4 valve cover spark plug gaskets. The NOS valve cover gasket and the additional 4 rings are mine for now.

[2.216VTurbo]

Some item I am selling that may interest you guys. Everything is NOS. $80 for all 4 exhaust gaskets, $80 for a pair of intake gaskets required for a single motor, $40 for 4 valve cover spark plug gaskets. The NOS valve cover gasket and the additional 4 rings are mine for now.

I'll go $150. shipped for the Ex gaskets and two IN gaskets. Pm me a paypal addy...

[joelzip]

Checked out four valve cover sample gaskets today and brought my NOS gasket with me, the valve cover and cylinder head. We made a few last changes to the mold including a .020 bead to the entire perimeter for better sealing and agreed to a shore 65 hardness material. Hopefully won't be long at this point. I'm anticipating an installation method of a thin film of silicone to hold the gasket in place to the roof of the valve cover while placing it and another thin film on the head for perfect sealing. The material and shape should be superior to the factory piece. I was surprised at how well it came out even before the last modifications.

[joelzip]

Second round of samples came and there are errors. I didn't have the NOS gasket when we started so we were adding onto an old junky compressed gasket for the new ones and it wasn't working out too well. So long story short the first tooling is going in the trash and we are starting over by duplicating the OEM NOS gasket that we now have in hand. I know its for the best. Here's a teaser pic of the samples, probably the most gaskets you will ever see in one pic until the real ones are done. These are off to the trash!

[2.216VTurbo]

^Ouch

[Reaper1]

Well...that kinda blows all around. What exactly was wrong? Were they tried on a head?

[joelzip]

The factory one has a taller profile with the bead they couldn't add to the current tool, has ears that hold the gasket into the valve cover while you flip it over to install, I had compression issues in the corners come to find out the factory ramped the corners to pack them in there, I wasn't thrilled with the .030 compression height as it wasn't accommodating enough for all valve cover tolerances or warpage, and they screwed up the hoops on the cam caps as they tapered for some reason when I told them to add the material to the entire perimeter it was only added in one direction so it ended up thicker on the top than the sides. Too many issues to sort out. Way easier to copy the original that I now have. I wish I had this NOS one before I started but I didn't and it bite me. I have to pay for new tooling but I can't risk them not working at this point I'm too deep.