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Kdx headgasket thickness

Posted: 10:40 am Sep 13 2023
by JZ05220r
I’m curious what the stock head gasket thickness is for a kdx220. I am going to try to have a copper headgasket cut for my 220. Thanks

Re: Kdx headgasket thickness

Posted: 03:15 pm Sep 14 2023
by kdxdazz
surprised nobody was able to reply to this given a few posts ago was about squish band and compression, from memory its 0.20mm
but before making any head gaskets i would check your squish clearance first then you can customize it

Re: Kdx headgasket thickness

Posted: 04:15 pm Sep 14 2023
by pumpguy
You may want to check if the gasket you get has been annealed. Being rolled to that thickness, the copper could have become work hardened. If so, it won't deform to comply with the joint faces and seal the joint.

You may be able to anneal it yourself by heating to a glowing red color, but I'd be concerned about warpage.

Contrary to common belief and often published advice, quenching in water or just letting the copper air cool has no effect on the annealing process. Its the heating that does the annealing.

Re: Kdx headgasket thickness

Posted: 04:53 pm Sep 14 2023
by JZ05220r
kdxdazz wrote: 03:15 pm Sep 14 2023 surprised nobody was able to reply to this given a few posts ago was about squish band and compression, from memory its 0.20mm
but before making any head gaskets i would check your squish clearance first then you can customize it
I think a lot of the guys on here have heard enough from me, and I wouldn’t blame ‘em. Just took my 1991 200 for a ride and it was awesome, just having such bad luck with this 220. Thanks for the info

Re: Kdx headgasket thickness

Posted: 04:55 pm Sep 14 2023
by JZ05220r
pumpguy wrote: 04:15 pm Sep 14 2023 You may want to check if the gasket you get has been annealed. Being rolled to that thickness, the copper could have become work hardened. If so, it won't deform to comply with the joint faces and seal the joint.

You may be able to anneal it yourself by heating to a glowing red color, but I'd be concerned about warpage.

Contrary to common belief and often published advice, quenching in water or just letting the copper air cool has no effect on the annealing process. Its the heating that does the annealing.
Thanks for the info. I’ll see if they can make it for me, and make sure to ask if it is annealed.

Re: Kdx headgasket thickness

Posted: 02:30 pm Feb 08 2025
by Chuck78
I came to the KDXR search function looking for the same info, being too lazy to go out to the shop and find an OEM gasket and measure it's UNcompressed thickness...

https://www.cometic.com/products/C7298

Cometic's 70.00mm KDX220 head gasket is stated to be 0.254mm or 0.010" thickness, rubber coated stainless steel (Multi-Layer Steel shim pack "MLS" gasket?) head gasket composition. They still list a 73.0mm bore composite head gasket (for the NLA steel sleeved 240cc big bore kits) even, as most everything that's not a frequent seller is made to order from Cometic.

Still curious as to the OEM head gasket thickness, if it's the same.

Re: Kdx headgasket thickness

Posted: 05:35 am Feb 09 2025
by kdxdazz
Chuck78 wrote: 02:30 pm Feb 08 2025 I came to the KDXR search function looking for the same info, being too lazy to go out to the shop and find an OEM gasket and measure it's UNcompressed thickness...

https://www.cometic.com/products/C7298

Cometic's 70.00mm KDX220 head gasket is stated to be 0.254mm or 0.010" thickness, rubber coated stainless steel (Multi-Layer Steel shim pack "MLS" gasket?) head gasket composition. They still list a 73.0mm bore composite head gasket (for the NLA steel sleeved 240cc big bore kits) even, as most everything that's not a frequent seller is made to order from Cometic.

Still curious as to the OEM head gasket thickness, if it's the same.
OEM head gasket thickness with the silver coating removed

Re: Kdx headgasket thickness

Posted: 11:39 am Feb 09 2025
by Chuck78
Oh wow, I'm surprised to see you with inch sized tools, also surprised by the thickness.

After reading a lot of positive reviews here on the forums about Cometic gaskets who are based out of my home state here in Ohio, USA, I will probably exclusively by their top and gasket kits with their viton-coated stainless steel gaskets, as I think that will definitely be as good or better than OEM and seal coolant in much better. It says rubber coated on the website but I am assuming that is Viton.

Re: Kdx headgasket thickness

Posted: 09:14 pm Feb 09 2025
by kdxdazz
Chuck78 wrote: 11:39 am Feb 09 2025 Oh wow, I'm surprised to see you with inch sized tools, also surprised by the thickness.

After reading a lot of positive reviews here on the forums about Cometic gaskets who are based out of my home state here in Ohio, USA, I will probably exclusively by their top and gasket kits with their viton-coated stainless steel gaskets, as I think that will definitely be as good or better than OEM and seal coolant in much better. It says rubber coated on the website but I am assuming that is Viton.
Lol. I collect vintage micrometers so they are all in inches, I have 15 in my collection, Starrett being the highest value,

the OEM head gasket has a silver coating then on op of that there is a sticky coating, almost like wet silicone, I've reused this one many times by scrubbing it clean then using the lightest smear of three bond 1211 which is designed for head gasket use

Re: Kdx headgasket thickness

Posted: 11:58 pm Feb 09 2025
by Chuck78
Interesting, I did not know that 1211 was acceptable for use on head gaskets