Intake Exhaust Manifold Gasket or RTV

[Dat73z]

I'm doing the final preparations on a turbo motor before dropping it in and wanted to solicit some opinions on using a gasket versus RTV for the intake/exhaust. 

 

On my Rebello built turbo stroker motor, it was recommended to me to run grey RTV for the intake, Red RTV for the exhaust. If both surfaces are true there should be no leaks. I've attached a picture of what the head looked like after removing the manifolds, the motor was run in on the dyno so likely only ran at most for some hour(s). Leaks are either due to improper rtv application or flatness. I'll do finals checks for flatness and get things decked as needed. 

 

In my parts bin I have a new spare Nissan OE intake/exhaust gasket with the metal inserts for the exhaust side. If I run this I could probably put some copper rtv on the exhaust side to ensure a good seal if there are any surface imperfections. 

 

This will mostly be a street motor with some track days perhaps a couple times per year so a few 20 min sessions across a couple days, canyon drives, etc. Probably no more commuting with this car. I have run RTV only on motorcycles bit the service iterval for me was measured in hours so I don't know how well RTV holds up over time to the extreme turbo temperatures. 

 

Any thoughts on if it's better to run RTV or the OE gasket? For those running RTV what is your service interval and how do you drive the car? 

[AydinZ71]

I personally would not run RTV. Quick search says it can handle 650f in intervals. You have probably seen pictures of them glowing red. The turbo manifold can get much hotter in some cases. I would stick to a metallic crush gasket. If you have issues sealing, I would have the manifold and head surfaces milled flat. 
 

you can try the RTV, but if/when it fails you will be back at it. 

[Dat73z]

When I pulled the setup apart I was surprised to find the RTV on the head still looked reasonable. Maybe because the head is water cooled. On the turbo hot side all of the rtv had turned to dust. I agree long term (more than a few hours?) there would be no RTV left so the seal would need to exist from both sides perfectly flat. 

 

Im leaning towards running the gasket. And on the turbo side it'll all be stainless crush gaskets. I'm still curious if any turbo hybridz members run RTV and how that holds up over time. If this was a race only engine and my service intervals were a few hours I would actually prefer the RTV since there is virtually no cleanup after inspection before resealing. If this was a non-turbo motor I would probably also consider the RTV.