How to seal cam tray to head

[Spetz]

I have the top end of my 6A12 MIVEC motor from a Mitsubishi FTO disassembled.

The head is split into 2. One part that bolts onto the block that houses the valves etc, and another part that goes on top (the cam tray) that holds the cams etc. I am sure people here know this but I didn't know they came apart until recently.

Anyway, I wanted to know:
1. What type of sealant do I use? I assume permatex RTV oil resistant sealant should work well?
2. How much do I put? From what I can tell I should use very little or else it will pour inside the engine once squashed
3. Should I put the sealant then tighten to spec, or do I wait until the sealant dries a bit?

 

[Trav]

Don't use RTV on this application you need to use a anaerobic sealer, it will not clog any passages if any happens to seep in as it only hardens in the absence of air.
Put a thin bead around the head and around all bolt holes.

https://www.amazon.com/Permatex-51531-Anaerobic-Flange-Sealant/dp/B000HBGL6O

 

[Spetz]

Thanks Trav,
Will that be ok in high heat conditions and won't degrade from oil?

Also any ideas on question 3?


Pics for reference:

 

[Trav]

Its spec for this exact application by many manufacturers and stand up to heat, cold, oil, chemicals, etc. The surfaces must be 100% clean and oil, grease, dirt free. You put the parts together and torque it right away, letting it sit does nothing as it only cures in the absence of air.

Clean the parts spotless then wipe the mating surfaces down with alcohol on a lint free cloth, let dry, apply the sealant and assemble and torque, its done.
Some of the main reasons for using this is its oil resistant, it flexes, will not clog oil passages and unlike RTV has a minimal effect of assembled thickness which for a cam holder is critical.
I have been using this for over 30 years without issue in this sort of application when it was OE spec for the GM 2.0 OHC.

Edit: This is only for applications where no gasket is specified. If the original uses a gasket then it would need Hylomar.

 

[Spetz]

Thanks Trav for helping out.

There is no gasket there so it should work well.


Does it cause issues with plastics?
Would I use this for the cam oil seal and crank main seal or would I use something else?

 

[Trav]

Its harmless to plastics. This is best on metal to metal parts for seals I generally use Hylomar or on the outside of the seal. If the seal shell is bare metal and a tight fit then yes the anaerobic can be used.

http://www.newmantools.com/chemicals/hylomar.htm

 

[mehullica]

Toyota/Lexus uses the same design & their black FIPG works great. I've used it for at least 200 reseals after doing the infamous IS250 piston ring/carbon misfire rebuilds with no leaks from the cam housing or anywhere it's used.

 

[nthach]

Looks like Mitsu in fact used an RTV here. You can use Loctite 518 with no ill effects, that's what I did for a Subaru oil pump even though it called for their version of ThreeBond 12xx/Honda Bond HT. A thin bead will do you.

 

[Trav]

I also use the 518 and on Subaru oil pumps its a lot safer than RTV. I don't like RTV and almost never use it unless its a must for some reason.

 

[Spetz]

Thanks guys.

There are some parts of the cam tray that seal onto plastic though, specifically there are some half moon seals on one end and the cam seals on the other end, also a small plastic square that has wires for the MIVEC solenoid going through it.
Anaerobic sealant is still ok with this?

 

[Trav]

RTV is probably the better way to go in that case. Look for Hondabond HT at any Honda dealer, its good for metal to metal and metal to plastic. Anaerobics are better suited to metal to metal only surfaces.