I dont know if someone already posted this but Cosworth will release a new FSL metal heasgasket for the KA24de on a bigger bore and different thicknesses.

Here is the link:

http://www.cosworthusa.com/news/article.asp?idpage=62

Good! more options other than Cometic for a layered steel one!

I am sold son, pretty much if it has cosworth on it its worth it. The pressure film test however seals the deal for me. mls huh must mean cometic lol I know of several people with blown cometics.
Good find

I wondering if the machining requirements are the same as the Cometic...which is super fine finish on the head and block and the dreaded re-torquing?

It would almost be a shame to buy one and then cut the timing hoop off to fit it on a SOHC.

I actually called cosworth the other day searching for a "high compression head gasket". Needless to say ill just hit them up next time i need a question answered very informative conversation indeed!

Their thinnest gasket is almost identical in thickness to a oem headgasket. 1.1mm i think?

cosworth: "It wouldnt be a good idea to run a thinner gasket since its already pretty thin and a compromised seal would neg. very small gain to be made."


Anyways now thats out their if anyone was wondering but me, wrong side of the street here at kat.

I also asked about the recommended ra rating and if it was comparable to cometic. I told them i used a cometic on my rb20 2 years ago with arp headstuds detorqued and torqued to arp's specs. I never had any problems at all I sold the car after 6 months of abuse a whole year later guy that bought it off me called me to tell me he wrecked my car. <<<<he never had one problem pulled motor out and put it in his track car..........
I informed them i never had anything resurfaced and scrapped off the oem graphite gasket myself.
cosworth: "Obviously if there is any imperfection it will compromise the seal. This is the most common case in that during assembly and what not it gets imperfections. If you are worried about the sealing surfaces you can take a large flat steel block and use very fine sand paper to verify no surface imperfections. 1200 grit sand paper or so would work well."



Ive heard of people doing it before but if i remember right they got knocked pretty hard on forums. I guess ill wait for feedback on that

I bought the 0.60 over 1.1mm cosworth, just waiting for the motor to come back from the machine shop..

lexcrob wrote:
I also asked about the recommended ra rating and if it was comparable to cometic. I told them i used a cometic on my rb20 2 years ago with arp headstuds detorqued and torqued to arp's specs. I never had any problems at all I sold the car after 6 months of abuse a whole year later guy that bought it off me called me to tell me he wrecked my car. <<<<he never had one problem pulled motor out and put it in his track car..........
I informed them i never had anything resurfaced and scrapped off the oem graphite gasket myself.
cosworth: "Obviously if there is any imperfection it will compromise the seal. This is the most common case in that during assembly and what not it gets imperfections. If you are worried about the sealing surfaces you can take a large flat steel block and use very fine sand paper to verify no surface imperfections. 1200 grit sand paper or so would work well."



Ive heard of people doing it before but if i remember right they got knocked pretty hard on forums. I guess ill wait for feedback on that

Funny, I did the same exact thing on my RB20. I even pulled the head, reused the bolts and the gasket multiple times. No sealing issues. I also used my own torque value and a different method of seating, something we do on helicopter rotors etc. Just a multi step torque process with timed intervals after the max torque for reseat/retorque until no movement is achieved on every bolt. I usually have to go through every bolt 3-4 times after the final torque before I get no movement. For cleaning I used a brass wire wheel brush mounted on my Makita hand drill on both the block and head every time until they shined. Hit the head with a buffing wheel and slapped them together. The problem is, you'll get some dudes out there leaning on the wire wheel, removing material from the head and ruining it. Or using a metal scraper...all kinds of things can go wrong. I'm comfortable with shade tree work on MY stuff and I've gotten pretty good at it.

RB20 FTMFW...

I was looking at these and I've heard nothing but great things about Cosworth but if I was boring out my motor to .020 over would these gaskets be to big for that?
They seem to only come in a 90.5mm, I've been told you want the head gasket .5mm larger than your bore size but would 1mm be too much?

lexcrob wrote: I also asked about the recommended ra rating and if it was comparable to cometic. I told them i used a cometic on my rb20 2 years ago with arp headstuds detorqued and torqued to arp's specs. I never had any problems at all I sold the car after 6 months of abuse a whole year later guy that bought it off me called me to tell me he wrecked my car. <<<<he never had one problem pulled motor out and put it in his track car..........
I informed them i never had anything resurfaced and scrapped off the oem graphite gasket myself.
cosworth: "Obviously if there is any imperfection it will compromise the seal. This is the most common case in that during assembly and what not it gets imperfections. If you are worried about the sealing surfaces you can take a large flat steel block and use very fine sand paper to verify no surface imperfections. 1200 grit sand paper or so would work well."

Ive heard of people doing it before but if i remember right they got knocked pretty hard on forums. I guess ill wait for feedback on that

I have never heard of using sand paper and a steel block lol. Seems pretty haggard compared to the way it's done at a good machine shop. I'd also like to hear stories of how this has gone over.

I bought one and installed in january. I'm bored .20 over which is 89.5mm , I'm using the 90.5mm bore and 1.5mm thick cosworth with no problems. On a side note the headgasket I recieved was not that new fls style (folded layer) they advertise. It was standard stacked metal later like my old cometic.

Good to know it worked out for you. I have one sitting in my garage waiting to be put on the ka i'm building. Mine is also just stacked layers which kind of disapointed me but i know these gaskets are great regardless.