Headgasket change question

[huntin5L]

i have a greddy and it doesn't have any rubber coating.

 

[Toycoma]

I personally didnt machine either the block or head, and am going 15,000 miles and still running strong. The one thing i did use is the liquid aluminum bars leak, which fills in any gaps that the MHG doest seal. WORKS GREAT! My local supra shop (well its a performance shop that specializes in supras) said they NEVER do a MHG install without bars leak.

thats good to know, i have my head off because the gasket just started to leak and i am putting a HKS one in. guess i will use the brake queit and the bars leak since i bought i bottle of it a while ago incase my hg blew. funny thing is it blew and i just said the hell with it and pulled the head anyway.
and where can i get some exhaust manifold studs and nuts from??? for a 7mge if that matters.

 

[p5150]

you can go to your local hardware store or just order them from toyota. Dont use bolts unless you want to strip out your head.

 

[89Turbo]

Last time I checked, FEL Pro did not produce MHGs for the 7M series. I think what you have is a standard composite head gasket. Not a METAL head gasket. THere is a difference. Composite HGs are more forgiving to imperfections because they are softer. However they will not hold up as well to abuse. Be sure to check on that

quoted straight from Fel-Pro:

"Fel-Pro PermaTouqueMLS multi-layer STEEL head gaskets. These advanced gaskets feature multiple layers of full-hard stainless steel, precise sealing beads and a proprietary coating that accomodates to a wide range of surface finishes."

 

[IJ.]

89Turbo: Thanks for the new info!
(Always liked FelPro Gaskets)

Wonder what their RA needs are?

 

[89Turbo]

89Turbo: Thanks for the new info!
(Always liked FelPro Gaskets)

Wonder what their RA needs are?

no prob:icon_bigg

RA?

 

[IJ.]

Roughness Average,

a number they use to define how smooth the block and head need to be.

Cometic can get away with a less smooth surface than say a Greddy or HKS.

 

[shaeff]

here's info that Adjuster gave me on using Permatex Brake Quiet. it's also in my buildup thread, and the link is in my sig:

Yep, I've used the brake quiet spray on a few HG's for the 7MGTE. (Mine, and two others, plus a few guys here on the boards have done it with good results too.)

I was told about it by Tony, the guy with the Orange MK3 making 800+rwhp in Vegas. (He did a MHG change for me at a SILV one year, and this was one of a few good tips he gave me.)

The brake quiet spray is nice and tacky, seals up the gasket really well, and is very heat resistant. (Burns off around the cyc edge I'm sure, but not anywhere else.)
I've seen heads pulled off later after using the brake quiet, and it is still intact, sealing up the coolant and oil passeges nicely.

I don't know the Cometic gasket, but I've used a Greddy gasket on 4 motors now. (Same gasket, no failures, but the engines went down for other reasons. #4 is running strong however.)

Here is the easy way to use this stuff.
Clean everything very well with brake cleaner and some rags. (No oil is best.)
Then hang the gasket so you can spray both sides. I use a bungie cord off the track for my garage door.
Spray both sides of the gasket, putting a nice coat with minimal runs. (They are no big deal if you do get a run, but you want a nice thick coating, so two coatings per side is a good idea.)
Let this hang for 10 to 15 min and get nice and tacky. (Dry out some.)

Make sure you do not have head studs in place yet. I've found putting the head into place with studs on is a total PITA, and you have to back out the studs to get the washers into place anyway.

Now, you have cleaned up the block with brake cleaner and clean rags. There is no oil on the block. (or any other debris.)

BEFORE you lay down the gasket, put two small beads of "The Right Stuff" sealer (or other sealant) at the point where the front cover it attached to the block. IF you don't seal this up with sealer, it will leak oil later. (Or if you did not machine the block with the cover in place, it will be too high, and you will need to file down the front cover to the height of the block deck.)

Make sure you have the right side of the gasket, and lay it down on the block in place. (Only fits one way, but if you try and put it on upside down, it will screw up the brake quiet coating, and you will have to clean it all up, and coat the gasket again.)

Get a friend to help place the head onto the block. (Or do it yourself, I've had no issues on a few engines this way.)
Do not lay the head down, and then slid it into place. It needs to drop onto the alignment studs/dowels with very little if any sideways movement once you contact the metal head gasket. (You don't want to mess up the brake quiet.)

Use the moly lube on each stud, and the washers. I've found that sliding the washers down the studs is the easy way to drop them into the right place on the head. Make sure you have the Allen head up on the stud. Then put the stud into place finger tight. (Do no tourqe it down.) Do this for all the studs/washers. Then lube the nuts, and put them into place, also finger tight. (I used a 12 point deep socket to help after getting the nuts started to make sure nothing was cross threaded.)

Start your tourqe passes. I go to 50lbs first. Then 70, 90 and finally end up at 100 ish. (Current ones are at 103lbs.) Follow the TSRM pattern, going from the center, working to the outsides in a cross pattern.

You MUST tourqe down the head when you place it onto the engine before the brake quiet fully sets up. (I'd say you have about 45 min or so after you spray the stuff on. Really more like 30 min if you let it get tacky for 15...)

Good luck, and enjoy the power and fail free operation of a good MHG.

 

[IJ.]

Did a bit of research on the FelPro MLS and the news is good!

I think Cometic will work at 50 RA.

Select PermaTorqueMLS gaskets feature a special coating specifically formulated
for the aftermarket’s repair environment. While most MLS gaskets require a surface
smoother than 40 Ra (400 Rz), these Fel-Pro PermaTorqueMLS head gaskets will seal
a surface finish as rough as 60 Ra (600 Rz).

 

[lanternman]

^ That's good to know. Too bad I don't still work for FM or else I could have gotten a discount on those. I don't have need for one right now anyway, but for future reference I might have to check them out.

 

[shaeff]

yes, IJ, you're correct on the Cometic. that's what i'm happily using!

-shaeff

 

[huntin5L]

Well my neighbor already has permatex headgasket sealant from a previous job. So i told him just to stick with that since that is what it is made for. Ill let everybody knows what happens.

 

[huntin5L]

He did hear about using the brake quiet though so i wouldn't doubt that it works.

 

[IJ.]

Sheff: I used one in my last build and have a new 3mm one here for the new motor!

I'll keep the FelPro in mind for any future motors though!

I wonder if any of the manufacturers have considered replacing the 2 outer layers with Copper so it will conform to the Head and Block with less need for low RA's .....

 

[huntin5L]

Probably pretty expensive to produce if they did that. It would be something if they did.

 

[Toycoma]

this brake quiet stuff, are you spraying it on the head gasket on both sides or onto the block? and how much are you using? putting my head back on tomorrow and i was going to spray it onto the gasket but wasnt sure what was the best way.

 

[IJ.]

Only ever used the Copper Spray or GM Headbolt sealer but I assume the Brake Quiet would work the same just a thin even coat on each side of the gasket, let it go tacky then install making sure you don't move the head once it's down.

 

[Toycoma]

Only ever used the Copper Spray or GM Headbolt sealer but I assume the Brake Quiet would work the same just a thin even coat on each side of the gasket, let it go tacky then install making sure you don't move the head once it's down.

ok, guess i will have to cross my fingers too. the 85 ft-lb on the arp studs should help but you never know with these motors.

 

[IJ.]

crossed fingers are ALWAYS a good thing with 7M's