Metal headgasket surface prep ?

[fatmobile]

I'm real happy with how smooth the block is.
 I am worried about how well it will seal around the prechambers.
 They are standing up a little proud of the surface.
 I've read on here that the prechambers have a different expansion rate and are supposed to be 10 thou" higher than the surface.
 
 Opening this engine up revealed a history:
 It obvious the timing belt broke, they put used stock pistons in and ground out the slot for the piston squirters.
 On the top; they put a new/rebuilt head on it. There is no slop in the valves at all and only a couple cracks between the valves and they are very small.

 When I got the car; the glow plugs were burnt off,..
so it might have run away on them after they got it put back together
or bad injectors are known to burn glowplugs off and cause prechambers to pop out  so it might have just been bad injectors.
 Whatever it was, it might have made the prechambers pop up higher than they are supposed to be.
 Here's a pic of them,.. they don't look too bad in this pic but I wasn't really focused on the prechambers,...
 was documenting the silicone beasts I pulled from the water jacket, ha.


 I did almost no cleanup on this head before the picture, the gasket looks new. They didn't put many miles on it after the rebuild.
I'll get another pic from a better angle so you can see how high they stand up.

So:
 no light oil on the surfaces?
and maybe some sealant?
 That metal gasket does have a coating of some sort? So it wouldn't actually be metal-on-metal? That makes me worry less about corrosion.
 What does the aviation gasket stuff come in? A spray can?
 I've seen/used the copper stuff before,.. on an NA head. I think it's still running for him.

[53 willys]

yes most all MLS gaskets have some sort of sealer already on them. (most the time it's viton)



I used this on mine....like I said before it only takes a very small amount.

http://permatex.carshopinc.com/product_info.php/products_id/42270/80019

[fatmobile]

I think I'll try the copper spray.
It should help hold the gasket in place too.
 I finally saved up enough for some headstuds but the gasket still has room to move and this gasket isn't much bigger than the pistons (80mm, 1.7 pistons).
 I've worked with that aviation stuff before and can't imagine me putting it on in a thin even coat,.. the link says 400F limit, I'm sure most of the head and block don't get that hot.
 Better picture of the prechambers:

 I might put a piece of plastic over them and smack them, see if they sink any,.. then peen them.
 It looks like they were protruding after the last rebuild, by the way it is cleaned up around them, and it's not a rough transition where the headgasket crosses...

 Gotta get this part right

[sdwarf36]

OMG! Beware of that head surface! It looks cookie wheeled to death. (You wouldn't believe how many heads I 've had to resurface after "we just did a head gasket" and the cause of the problems the second time was from damage those abrasive wheels do.) Wanna see how bad it is? Find a sharp fine file. Scribble some magic marker on the surface-so you can see the low spots-now slide the file back + forth a few times-anything with marker on it is low.I think you'll be suprised how many craters there are.

[kaneb]

I'm starting to wonder if i should use something with my metal HG when i put it together.  (1.9L HG on 1.6L with arp head studs)

Also, I know Arp says final torque with the head studs should be 90 ft/lbs.  Just wondering if thats what everyone  is torquing them too, or if other's have been torquing them differently? 
 

[Kantdrivefast]

I'm starting to wonder if i should use something with my metal HG when i put it together.  (1.9L HG on 1.6L with arp head studs)

Also, I know Arp says final torque with the head studs should be 90 ft/lbs.  Just wondering if thats what everyone  is torquing them too, or if other's have been torquing them differently? 
 

I torqued mine to 120ft/lbs

[53 willys]

mine leaked at 90ftlbs....it took 110ftlbs to seal mine....

[fatmobile]

Think the head is bad? you should see what they did to the block with one of those sanding discs, dips on all the edges of the water jacket holes.
I'll take the head in tomorrow and have it checked for straightness. I had new valve seals installed but didnt ask them to check for straightness.
 I'll try the color and file method on the head too.

[fatmobile]

I took the head to my machinist today.
 no warp to speak of,
 a .004" feeler wouldn't fit under it.
 He uses multi-layer metal gaskets often and speaks highly of them.
 He also sprays a thin layer of copper on each side.

[FineFrank]

I took the head to my machinist today.
 no warp to speak of,
 a .004" feeler wouldn't fit under it.
 He uses multi-layer metal gaskets often and speaks highly of them.
 He also sprays a thin layer of copper on each side.

Dry, brother. anything you add will likely only hinder the seal. The shop I worked at never added anything to the sealing surface of the aluminum head/ iron block builds, and we didn't have HG comebacks.

[burn_your_money]

I read in a very detailed Toyota Diesel service manual that precups are allowed to protrude above the surface of the head. I can not recall the spec they gave though.

[Kudagra]

Yea its been dead for a year but I found this good article.

http://www.hensonracingengines.com/Head_Surfacing.html