Sealing an engine

[iluvmyjato]

Quick question; do all new engines need to be sealed? If not will it say if it is sealed or not? Is it absolutely necessary to seal your engine if it isn't already?

 

[Racer 1966]

All engines come with factory seals(0-rings or gaskets) but the problem is the way they are mass-produced. On some they can't hold tight enough tolerance for the seals to work properly.

Some people will go through and seal an engine with rtv right from the get-go just as a preventative measure. It's not necessary if the engine tunes in easily and I usually don't break open a new engine until it proves it needs it.

So it's really up to each person to decide if they want to do it or not. It's not really a major issue, if you do it's either doing an unnecessary repair or you repair a problem before it exists. If you don't, maybe you will have to later if the tune stays very erratic.

 

[moe7404]

well by rights rtv is not compatible with nitro. how ever to many people, including me, have used it successfully, and iam not about to say dont use it. racers edge has a sealant rce10115 carb sealant, that is compatible with nitro. its red in color

 

[Scrogg]

You have to use Oxygen sensor safe high temp silicone. It's non corrosive to aluminum, I've never seen R/C fuel degrade it. You have to scrape it off. Once you put it there properly, it's there until you scrape/peel it off.
As long as the engine runs and tunes fine, don't seal it. If it starts up screaming at factory settings or is completely untuneable, it's a leaker.

 

[iluvmyjato]

Thanks guys. I appreciate the help

 

[olds97_lss]

Personally, I tear every engine apart even when new to inspect it, then I RTV them and put them back together. I've only went from box to truck with one engine so far. The other 10+ I've had, I've torn apart, cleaned out really well with DA, lubed the internals and RTV sealed before installing.

You'd be surprised how much aluminum dust is inside a brand new engine.

 

[Scrogg]

Personally, I tear every engine apart even when new to inspect it, then I RTV them and put them back together. I've only went from box to truck with one engine so far. The other 10+ I've had, I've torn apart, cleaned out really well with DA, lubed the internals and RTV sealed before installing.

You'd be surprised how much aluminum dust is inside a brand new engine.

Very true, I do the same and have seen tons of engines with machining debri left in them.
I only recommend doing this IF you are confident in you engine assembly/disassembing skills. If you are not, the next bext thing is to flush the engine out with fuel or WD-40 while you have the glow plug out. Do this before you mount it to the car/truck.

 

[iluvmyjato]

What would I do to flush it out? Just soak it or hook it up to the fuel tank and pull the pull start a couple times?

 

[Scrogg]

Don't soak it...ever. Prime it, then a few quick pulls on the starter with no plug in it will flush it pretty good if you already mounted it.

 

[iluvmyjato]

Thanks man. i'll make sure i do that when i get it.

 

[olds97_lss]

I only recommend doing this IF you are confident in you engine assembly/disassembing skills.

Yeah, that's a good point. Should have mentioned that.

I remember when I had my first engine... I was so terrified of taking it apart and possibly putting it back together wrong. The last time I did engine work, I had 4 apart on my parts table with the parts all scattered amongst each other... barely had any extra parts left when I put them all back together!

 

[Scrogg]

Yeah, that's a good point. Should have mentioned that.

I remember when I had my first engine... I was so terrified of taking it apart and possibly putting it back together wrong. The last time I did engine work, I had 4 apart on my parts table with the parts all scattered amongst each other... barely had any extra parts left when I put them all back together!

LOL, been there! I was never scared though....not too much intimidates me on the mechanical side of things. I ruined one or two in my day....