what gaskets for a 416 kit

[crashinmatt]

ok guys i know this topic has been beat to death already, but there is a couple things i need to know. i am going to get the JE 10.8 to 1 416 piston. i am also getting the white bros track cam. now, to get the correct CR or close i have read that u can use an XR head gasket and then use silicon around the bottom, instead of a gasket. Is this what i should do? if so, what type of silicon and how big of a bead do i need to run around the base? or should i just get some aftermarket gaskets and be good enough? could someone please answer these questions for me?

[crashinmatt]

bump

[Leo]

I used an XR400 headgasket, and the base gasket out of a cometic kit (it was slightly thinner than the base gasket in my Honda gasket kit..)

This was while installing my "10.5:1" stock bore JE piston..

I've yet to get a compression reading because I'm lacking the correct adapter for my gauge..

Leo

[VegasEx'r]

The base gasket for the 416 kit is very thin. I would say use that & skip the silicone. Terry @ Marcum's agreed with that, but I think that Mickey Dunlap @ FST said to use the silicone. If you do, use a high-temp type selant. The xr gasket is thinner, and appears to compress better than the gasket that comes from Cometic, I tried the cometic gasket, then switched to the xr gasket, & didn't really notice any difference. Hope that helps.

[mental1]

I'm confused (and still learning), what's all this about using different gaskets to get the correct comp. ratio? I trying to find things out before I do the wrong things myself and end up wasting money I con't have.

[VegasEx'r]

Originally posted by mental1
I'm confused (and still learning), what's all this about using different gaskets to get the correct comp. ratio? I trying to find things out before I do the wrong things myself and end up wasting money I con't have.

A thicker head gasket will increase the combustion chamber, thus lowering the compression ratio. Using a thinner base gasket (like the Cometic base) makes the cylinder sit lower. The piston still has the same range of motion, so with a thinner base, it will sit higher in the cylinder @ TDC. This will increase the CR. Clear as mud now?

Using a thin base gasket & head gasket will make the combustion chamber smaller, thus increasing the CR. The Cometic base gasket & xr head gasket are two of the thinnest you can get, so they work well together.

[crashinmatt]

from what i understand the cometic gasket kit(top end), only comes with the head and base gasket. is this correct and what about the head cover gasket? do i need to buy this separately? i need to know cuz i am gettin this done on monday and need everything so that i canh have it broke in and ready by saturday. my local dealer is a little slow, so if i need to order this gasket then i need to do it as soon as i can. thanks, u guys are a great help.

[JhallettEX]

From what I have been told you can re-use the head cover gasket, this is what I have done.

[deansfastway]

IF YOU ARE NOT USING A GASKET ,USE HONDABOND OR THREEBOND SEALER THE STUFF IS LIKE GLUE. FASTWAY MOTORSPORTS

[crashinmatt]

thanks guys. i guess ill try to reuse it, if i cant then i will try that sealer stuff

[patrick delao]

If you reuse your stock head gasket your at .047 thick (loosing) your new compression. I ordered sepretly the XR head gasket from Comitic for my 440 that is .027 thick that will get you closer to the compression you want. I will say the thickness on the package.hope this helps.Pat

[crashinmatt]

pat i was talkin about the head cover gasket. the one that holds the cam in and has the rockers in it. but thanks anyway. thats exactly what i did. i bought a xr gasket separate from the gasket kit.

[deansfastway]

We reuse the cam cover gasket ther is some good stuff called copper coat that you can spray on that gasket to help it seal its made by PERMATEX its gold .They also make spray HI TACK its red. Honda paper gaskets are real durable, I know of quite a few Racers who have trick FASTWAY motors and they regularly check their clutch without replacing the R/S gasket , it takes forever to scrape the old one off. Try not to use Die Grinder 3M cookie cutter wheels (gasket removers) on these engines, it eats up Aluminum. I have had more than a few people bring me cylinders to bore and when i looked at the sealing surfaces they neede to be resurfaced. We use RAZOR BLADES. COMETIC sells a cam cover gasket in paper or fiber (very thin) . I think that the Honda Steel is the best. FASTWAY

[Ex'rMike]

Ok..... Humor me... If I use the Hondabond HT on the base and a XR 400 head gasket, Do I need to check any clearances? Or do you guys know this will work fine? I have a friends in peices right now and need to make up our minds. Thanks
Ex'r Mike

[Leo]

Originally posted by deansfastway
Try not to use Die Grinder 3M cookie cutter wheels (gasket removers) on these engines, it eats up Aluminum.

3M makes a new 'white' plastic bristle style gasket cleaner that doesn't remove aluminum (when run at low speeds)..

The yellow also work well, but you have to be very carefull and run them at a slow speed..

You need to be darn carefull with a razorblade.. it's VERY easy to gouge aluminum..

FWIW Chrysler finally approved the white rol-loc's for powercleaning aluminum.. prior to that the only alowable method was a plastic or wooden scraper :) The aluminum they use in there cylinder heads is some of the softest stuff I've ever seen.. You can literally carve your name in it with a screwdriver, like it was plastic or something.. :D

Leo

[deansfastway]

EXr MIKE probably doesnt need to chock any clearances providedthat he has never had the bsae or top of cyv milled or had the head resurfaced . Its easy to do though you just bolt on the cyl and head and use oplay dough or silly putty or clay between the comb chamber then bring the piston up to TDC . Take it back apart and measure how thick it is with a vernier caliper or a small hand mike youll want @ .024 at least unless youre building a real tight race motor then you will know what you want for yourself. WE like to use HONDA steel headgaskets or the Cometic stainless steel .Cometic now makes the S/S gaskets in overbore sizes, but you have to special order them . I just had them run some off for us. It seems like the fiber graphite gaskets like to be retorqued after they heat up & swell , then they cool down & shrink. Its not aneasy chore to retorque on a 400 EX . We have also seen quite a few cases where the cyl head studs pull out of the cyls. We are working with ARP FASTENERS to make oversize stud kits . You can also use deep 10 x 1.25 helicoils in the cyls and stock studs. Anytime you have the cam cover off you should readjust the valves. ATHENA brand gaskets are real good also , the gaskets are real thick & sturdy like Hondas.... GOOD LUCK FASTWAY

[Ex'r Marlin]

Originally posted by Ex'rMike
I have a friends in peices right now and need to make up our minds. Thanks
Ex'r Mike
I'm glad that you consider me your friend!:D

My goal is to continue using pump gas. There has been great responses on here as to use a 10.8 to 1 compression ratio or lower to continue using "pump" gas. I'm nervous if I decide to eliminate a "base" gasket, and seal it with a sealer, that my compression ratio will be higher than a 10.8 to 1. Please correct me if I am wrong.

Note: I have the "416 JE Piston and plan on installing the Cometic "XR400" Gaskets.