TonyG

DanD

Make sure you get the block and the head very very clean. By the looks of the pic.. you've got some work to do! :-)

TonyG

DanD

Already done. Not polished, but clean.. Thanks for the tip. The cylinders actually look better too. Scotchbrited the whole thing..
Dan

Duke

Does this mean I should coat the GURU gasket or not!?

AlexE

Since I did not get an answer I searched the web..... I found every site referring to the cometic gasket not to use any sealant. The MLS has a viton coating. They also specify that the sealing surfaces must be incredibly clean and dry...... I did not run into one MLS comment specifying to use any type of sealant.

So if cometic made the gasket it does not refer anywhere to 2 types of MLS gaskets surface coatings..... but I may just call them from work today.

David Floyd

Danno told me to use copper spray on my Guru gasket and I have had no problems.

Danno

There's really no black & white, all-or-nothing answer to the coppercoat spray. It will seal 100% against combustion-pressure with no sealant necessary. The compression-ridges molded into the top & bottom spring-steel layers will have enough pressure on them to seal.

The issue comes in with coolant sealing. Depending upon the AR-average roughness of the surfaces, you'll have microscopic scratches in the surface that can leak water. Even using a gasket scraper to clean up the head & block can introduce scratches that can leak water. The copper-coat spray just takes care of those tiny sources of leaks.

Duke

So if I put it this way, is there any drawbacks with using copper coating?

I just want to make sure so I don't get milkshake for the third time in 1 ½ year

Jon Schepps

As a follow up: After finally have a chance to put a few miles on the engine since installing the Cometic gasket, I backed out the rear bolt from the water passage and yup, coolant came out from the hole. I dried it out, coated the bolt with high-temperature RTV, and put it back in.

Never had water in that bolt hole with the stock or wfr gaskets.

jls.

Asarus

I put the Guru metal head gasket WITH copper spray (as suggested by Danno) last week. We also look carefully to avoid any overlap. Here are the pictures

Dave E

A quick search turned this up on a NASA site..
Galvanic corrosion is an electrochemical action of two dissimilar metals in the presence of an electrolyte and an electron conductive path. It occurs when dissimilar metals are in contact.

It is recognizable by the presence of a buildup of corrosion at the joint between the dissimilar metals. For example, when aluminum alloys or magnesium alloys are in contact with steel (carbon steel or stainless steel), galvanic corrosion can occur and accelerate the corrosion of the aluminum or magnesium. This can be seen on the photo above where the aluminum helicopter blade has corroded near where it was in contact with a steel counterbalance.

Galvanic Series In Sea Water

Noble
(least active)

Platinum
Gold
Graphite
Silver
18-8-3 Stainless steel, type 316 (passive)
18-8 Stainless steel, type 304 (passive)
Titanium
13 percent chromium stainless steel, type 410 (passive)
7NI-33Cu alloy
75NI-16Cr-7Fe alloy (passive)
Nickel (passive)
Silver solder
M-Bronze
G-Bronze
70-30 cupro-nickel
Silicon bronze
Copper
Red brass
Aluminum bronze
Admiralty brass
Yellow brass
76NI-16Cr-7Fe alloy (active)
Nickel (active)
Naval brass
Manganese bronze
Muntz metal
Tin
Lead
18-8-3 Stainless steel, type 316 (active)
18-8 Stainless steel, type 304 (active)
13 percent chromium stainless steel, type 410 (active)
Cast iron
Mild steel
Aluminum 2024
Cadmium
Alclad
Aluminum 6053
Galvanized steel
Zinc
Magnesium alloys
Magnesium

Anodic
(most active)

The natural differences in metal potentials produce galvanic differences, such as the galvanic series in sea water. If electrical contact is made between any two of these materials in the presence of an electrolyte, current must flow between them. The farther apart the metals are in the galvanic series, the greater the galvanic corrosion effect or rate will be. Metals or alloys at the upper end are noble while those at the lower end are active. The more active metal is the anode or the one that will corrode.

Control of galvanic corrosion is achieved by using metals closer to each other in the galvanic series or by electrically isolating metals from each other. Cathodic protection can also be used to control galvanic corrosion effects.