engine leak

[Rs4 drift]

my car has a leak under the head I've already put a new seal in the head twice any suggestions:fro:

 

[abadk9420]

Maybe the surface where the to parts meet is warped on one piece or the other, and thats what is causeing the leak, if that is the case you would probly need to replace that piece. just a guess but I am sure someone with more nitro knowledge might be able to give you some more info...

 

[Monkey Wrench]

What engine do you have and what percentage of nitro have you run? How much fuel have you run through the engine? What kind of car/truck is it in? Do you have an idea as to what your engine temp's. have been?

Answering these will help pinpoint possible culprits.

 

[Rs4 drift]

its a .15 nitro start from hpi its only been run about 7 times and i run 20% maxi fule

 

[Monkey Wrench]

Hmmm....how do you know it's leaking at the head?

Just so you know, the seals you are referring to are actually shims used to adjust the head height based on the percentage of nitro you are running. They aren't technically seals, but they do seal the gap between the head and the crankcase. Usually you don't see leaks there unless, as references, either the head has become warped or the crankcase has been warped. Both are kind of rare, but it can happen if you run the engine too lean and it overheats.

Have you taken the head off? If so, what did the piston look like?

 

[Rs4 drift]

Hmmm....how do you know it's leaking at the head?

Just so you know, the seals you are referring to are actually shims used to adjust the head height based on the percentage of nitro you are running. They aren't technically seals, but they do seal the gap between the head and the crankcase. Usually you don't see leaks there unless, as references, either the head has become warped or the crankcase has been warped. Both are kind of rare, but it can happen if you run the engine too lean and it overheats.

Have you taken the head off? If so, what did the piston look like?

the piston looked clean a little blue from running blue thunder I'm guseing but only on the top its smoth and clean. I'm not sure if its leaking out of the head but a little gas runs down it but not flowing fuel from it

 

[Monkey Wrench]

My suggestion is to seal the exhaust port because I think that's where the leak is coming from. Here's what you do:

1. Take the engine out of the car/truck.
2. Take the exhaust pipe off the engine. If memory serves, there are two long bolts that hold the pipe to the block.
3. Clean the pipe flange and the exhaust port on the engine with some denatured alcohol. You need to make sure both surfaces are clean and free of any debris so they're nice and smooth.
4. Take some blue sensor-safe RTV sealant (can be found at any auto parts store) and spread a little on both the exhaust port and the pipe flange. If you still have the exhaust gasket (usually a little paper gasket) put the sealant on the flange, then put the gasket on the sealant.
5. Reattach the pipe to the engine and make sure you screw the bolts that hold the pipe to the engine on tightly and evenly.
6. Give that sealant a good 24 hours to cure and you should be set!

Another hint is to use that sealant to seal the backplate to the engine and the carb to the engine as well. That'll prevent air leaks in the future.


My guess is that the fuel is leaking around the exhaust gasket and showing up around the head, meaning you may be a tad rich on your needles as well. Once you get this done, may want to work on tuning your engine a bit as well.

Good luck! Let us know if it works or not, we'll get it solved!

 

[Rs4 drift]

My suggestion is to seal the exhaust port because I think that's where the leak is coming from. Here's what you do:

1. Take the engine out of the car/truck.
2. Take the exhaust pipe off the engine. If memory serves, there are two long bolts that hold the pipe to the block.
3. Clean the pipe flange and the exhaust port on the engine with some denatured alcohol. You need to make sure both surfaces are clean and free of any debris so they're nice and smooth.
4. Take some blue sensor-safe RTV sealant (can be found at any auto parts store) and spread a little on both the exhaust port and the pipe flange. If you still have the exhaust gasket (usually a little paper gasket) put the sealant on the flange, then put the gasket on the sealant.
5. Reattach the pipe to the engine and make sure you screw the bolts that hold the pipe to the engine on tightly and evenly.
6. Give that sealant a good 24 hours to cure and you should be set!

Another hint is to use that sealant to seal the backplate to the engine and the carb to the engine as well. That'll prevent air leaks in the future.


My guess is that the fuel is leaking around the exhaust gasket and showing up around the head, meaning you may be a tad rich on your needles as well. Once you get this done, may want to work on tuning your engine a bit as well.

Good luck! Let us know if it works or not, we'll get it solved!

its not on the side of the exsaute its all around the head.

 

[flandersander]

well it might be running from the exhaust to the rest of the head. Or is it higher than the exhaust? Fuel can't run up or atleast I don't think it can...

 

[revo26max]

other than the fuel leak, does the motor run good?

 

[Monkey Wrench]

its not on the side of the exsaute its all around the head.

Have you even tried it yet?

 

[Rs4 drift]

well it might be running from the exhaust to the rest of the head. Or is it higher than the exhaust? Fuel can't run up or atleast I don't think it can...

the heads higher

yea i have

it runs great

 

[Monkey Wrench]

Well then, I'd say the engine is tanked. Go buy a new engine.