1166 engine head gasket saga

[Wuts11]

I posted a couple of weeks ago about a wiseco supplied MLS head gasket which failed badly right away. Head and cylinder flaws contributing to the failure have been ruled out. I was told by cometic/wiseco that a composite gasket was no longer available, which I was hoping to use instead. I have since located an old stock composite for an 1166 from a different supplier which was the last one they had. The impression I get from talking to cometic and wiseco is that they are having issues with the product, But thats just my take on it. I am alittle dismayed however that given the popularityand cost of bore kits, there seems to be little support or alternatives available. I am a very new user of this forum and don,t want to get anybodys shirt in a knot, but reading older posts, this seems to be an ongoing problem for some. I love working on bikes but I like to ride them a hundred times more.When a head gasket is purchased and properly installed ( whatever that is because the manufacturer does not supply any instructions or any surface preparation specifications) It should work and seal properly without having to come up with trial and error solutions.So at the moment I have two gaskets on the way, the composite and a replacement MLS, both cometic products. Neither gasket I am told requires any seperate o'rings or need for sealer. ( Do I believe this ). I would be very gratefull for any comments from Individuals that expect to install a simple gasket and not have to deal with it again for 25,000 + miles. GS's are supposed to be reliable. When the gaskets show up I will have to choose. GS product consumers should expect more from reputable suppliers!
Please excuse the long winded rant but I'm frustrated having already lost considerable time from a short riding season. Thanks.

[posplayr]

Glue the "F"ings composite gasket and give the MLS the boot. Copper coat, yamabonmd or such.


EDIT:
Actually not sure why you bothered to ask a second time?????

http://www.thegsresources.com/_forum/showthread.php?t=143288&highlight=MLS

[rapidray]

Get a STOCK 1150 head gasket & trim it where needed with a pair of aviation snips & be DONE with it! Ray.

[posplayr]

Ray,
He been done told that ; maybe tell twice he listen?
Who know

[Wuts11]

My mother always had to tell me twice, slow learner. But once I get it I'm usually pretty good. I will not use the MLS. Thanks for the push !

[posplayr]

Wuts11,

So who did you buy the 1168 kit from and did you ask them "Wuts"-Up?

Big Jay still has not provided anymore info on "prettiness", although the Cometic say RA 50 (whatever that means).

Pos

[gs1197]

This will explain what Ra 50 means:

http://www.actdenver.com/pdfs/Surface_Finish_Measurement_101-Rev_1.pdf

[posplayr]

This will explain what Ra 50 means:

Sorry no it doesn't. That explains one of the theoretical definitions of RA (apparently there are different conventions) but it has not quantitative definition of what RA 50 is and further. Further even if it did , I doubt my local machinist knows what RA 50 really means.

According to the definition, you could deck your head and it checks out to e less than 0.001" out of flatness using a straight edge and you would fail the RA 50 spec, because the cutter ran to fast and left a pattern on the surface. So now we are talking about how shiny the surface is (how close the cutting grooves are together).

RA is a wonderful theoretical measure, but I'm not sure it means much to a machinist. Any machinists out there wanna give your take?

I know I can't measure RA with a feeler guage and a flat edge.

[chef1366]

Way to go Jim. Take all the air out of another thread.

[gs1197]

Sorry no it doesn't. That explains one of the theoretical definitions of RA (apparently there are different conventions) but it has not quantitative definition of what RA 50 is and further. Further even if it did , I doubt my local machinist knows what RA 50 really means.

According to the definition, you could deck your head and it checks out to e less than 0.001" out of flatness using a straight edge and you would fail the RA 50 spec, because the cutter ran to fast and left a pattern on the surface. So now we are talking about how shiny the surface is (how close the cutting grooves are together).

RA is a wonderful theoretical measure, but I'm not sure it means much to a machinist. Any machinists out there wanna give your take?

I know I can't measure RA with a feeler guage and a flat edge.

Wanna take a wild guess how I've made a living for 20+ yrs?

Surface finish and flatness are NOT measured the same way nor do they mean the same thing.

[tejasmud]

Easy now....

GS1197, no offense, you neither Jim.

It could have a flatness of 0.00000001mm and still not pass RA 50 if there is a scratch deep enough.

IE.. someone's head has a screw driver gash across a critical surface, but the flatness is 0.00mm

Yes, RA is very subjective upon the measurement area, RA is usuall measured within a 1 inch or so path with most measuring equipment.

Pretty? uh...ummmm. yea...

I can get any part to pass if I subjectively select the surface I measure.

That is why they make "glue".

Gaskets sealing dry does have an issue with the material they are made from. Surface as well.

Compression set is one issue. Torque specification and sequence is another.

Torque adjustments after an engine has been run at high or operating temperatures. Another.

Over torque of bolts and flat mating surface gaskets do not mix well either.

IE.."put a little more torque on it!!!"

No.

More torque usually never fixes a leak, unless it was under torque specs to begin with.

I deal with gaskets, o-rings, diaphragms, RA, flatness, and all types of sealing components every day in design.

And, I do machine a lot of things also "in my day job."

Things that deal with gas, super heated steam, wierd chemicals, beer, you name it...

In opinion, get a better gasket.

[posplayr]

Surface finish and flatness are NOT measured the same way nor do they mean the same thing.

Maybe I was being obtuse; but that was my point.

[posplayr]

This is what gribes my A$$; there is an unobtaininum of precision alluded to to make this dry hard gasket work. But it is the perfect head gasket if you ever can get it to work. From a practical standpoint this is wishful thinking engineering.

http://www.cometic.com/faq.aspx#q7

What is MLS?MLS stands for Multi-Layer Steel. MLS head gaskets are comprised of three layers of stainless steel. The outer layers are an embossed viton coated stainless steel providing a superior seal with excellent rebound characteristics and are corrosive resistant. MLS head gaskets reduce bore distortion and withstand extreme cylinder pressures.


What surface finish is required to us an MLS head gasket? A surface finish of 50 RA (roughness average) or finer, is recommended for a proper gasket seal. Anything rougher may conflict with the gasket design.

Why does Cometic recommend MLS gaskets to be installed dry? Cometic Multi-Layer Steel (MLS) head gaskets go on dry because they are coated with a sealant. Each MLS head gasket is coated with a .001" thick viton rubber that is bonded to the outer stainless steel layers. Adding an additional sealer can hinder the performance of an MLS head gasket.

Can MLS head gaskets be used with motors setup with o-rings or receiver grooves around the cylinder bores? No. MLS head gaskets require smooth, flat and true head and deck surfaces to seal. Most of the time with o-ring setups the wire and groove fall where our gasket’s combustion seal is located; therefore, the wire will hold the gasket and not allow proper compression while the receiver grooves allow combustion gases to escape.

[chef1366]

I'm gonna get me one of those.

[Nessism]

There are hand held measuring tools available that measure/calculate Ra. Most machine shops have them, or should.

Regarding machine work on heads and such, Costa Mesa R&D has some good videos on YouTube. Well worth watching... http://www.youtube.com/watch?v=YVFE0hVcuLs