I have noticed that Payen has changed the silicone bead on the latest BW750 gasket from "red" to "blue". I have always wondered why and have tried to find a answer to this without any luck. I have done a search for different standards of silicone material, and it seems to me that the blue silicone on the latest gasket migth be a "florusilicone" quality. This silicone is more resistent to oils, coolant and other chemicals than the more commen "red" type, but its temperature rating is not as high as for the "red" type. For all we know, detoriation of the red silicone bead over time due to chemicals, migth be one of the reasons why this gaskets suddenly fail at age, and thats why Payen has changed it??
Anyone here that knows more about this subject?
I did ask a gasket supplier (which seems to be pretty serious) about this question a while ago, here are the email conversation:
I have noticed that the latest version of this gasket has a blue colored elastomer seal while the old one has a red silicone seal. I guess that the latest blue one has better properties than the OEM red. I see that the gasket on the picture has a red seal, but does the one you sell have the latest blue elastomer?
You are correct, however the manufacturing fault rate found in this new version is 80% !!!!!
So we will not include them in our sets until Payen sort the production problems in their Eastern European factory.
I have to admit that I was not aware off
that fault rate!! I allready have a "blue" Payen gasket on the shelf which
I intend to use as a backup solution together with your 0,5mm thick
headsaver shim if my 1.8 for some reason fails. I am currently running on
the MLS gasket but am off the impression that these tends to weep a little
coolant externally (done 3 different engines with this "by the book" and
all has some minor weeping). I guess that the elastomer gasket is of a
tighter design and is a very good solution together with the head saver
shim. Do you know if there was any production batch of the blue elastomer
gasket that was worse than others?
If you check either No1 or No4 cylinder, the
faulty ones have a badly
folded/crimped cylinder fire ring, usually only
one but it could be either 1
or 4 depends on which way around they put it
on the assembly jig !