I recently rebuilt a 408 stroker motor and now that it is running I am noticing an oil leak that I believe is coming from the front of the intake gasket. Oil pools at the top of the timing chain cover. I am wondering what could be causing this so your suggestions are appreciated.

Things I have considered so far:
1. engine not breathing/venting well
2. intake was milled and may not have the proper fit. The gasket does not appear bulged out and engine builder pays close attention to details
3. your thoughts here...

thanks!

You might try applying some (regulated) compressed air to the crankcase and spray some soapy water on suspected areas then watch for bubbles to detect the leaks. You will need to seal off breathers, PCV inlets, etc, and keep the air pressure fairly low or else you'll do damage to other seals.

It could be blow-by and excessive crankcase pressure that pushed out a seal. Have the rings seated yet? I like to run a Pan-Evac to reduce crankcase pressure, improve ring-seal and crankcase windage.

If it is the intake, perhaps New gaskets and some sealer in the problem area will solve it, or you may need to have parts machined to correct.

Motor has about 200 miles since new.

Even if crankcase pressure drops after break-in, finding/fixing the leak is still worth doing unless the leak is very minor.

I have had the same thing for a bit on a 318 I assumed it was the valve cover gaskets just dripping over to that flat spot. I have not swapped them out yet to see. I do not think its the intake cause you can see that seal pretty good although only true way to tell is leak down as above.

pull the intake & get a new gasket set & check it as some of the front/rear cork seals are too thick (tall) mockup the intake side gaskets & see what you have for gap (front/rear) & compare that to the cork gasket heights. with that resolved make sure you use some cement in the corners where the sideways ends of the cork gaskets meet the front/rear ends of the main side gaskets & as you know that includes the manifold corners right there also

clean the area with some brake cleaner...put some RTV on your finger and squeeze it into the gap...

Definitely try that first

Consider one of these if you are uncertain where leak is coming from


http://www.amazon.com/Spectronics-TP8621...PE3VQ9DXGVCAXM4


Or less dough but no light

http://www.amazon.com/Tracer-Products-TP34000601-Fluorescent-Detection/dp/B000JFHNTM

We had two small block race cars. Might sound crazy but we had issues so we scrapped the front & rear gaskets and used "The Right Stuff" gasket maker. No leaks and easy clean up when removing the intake. We also added those simple crankcase evacuation systems.

Spoke with engine builder and he suggested the same thing you did. He says he'll do that if I take the car in, but I'll do all or some of the leak check suggestions listed here first.

thanks!

the even worse problem is that with alot of the cork gaskets are too tall it keeps the intake from being pulled down properly so that over time the two front cooling ports at the head/intake junction start to leak. You want the clamping to be on the side gaskets not so much on the end corks. I agree on tossing the corks & using the right stuff. Just clean the metal sqeeky clean with brake kleen so it wont come undone

Nobody has mentioned yet one of the more common reasons for small block end seal leakage. Did you use the end rail gasket retaining/locating pins & is the intake drilled to receive them? Many aftermarket intakes don't have the receiver holes drilled in the end rails, so the intake sits on top of the pins and doesn't compress the end seals.

Personally, I do as others have mentioned and omit the end seals and use Right Stuff to seal the ends, or at least a premium silicon. I wipe the end rail areas with rubbing alcohol several times and dry thoroughly before applying sealant.

I fought intake manifold end gaskets for years. Then I started throwing them away and using The Right Stuff...expensive but worth it. It is not silicone. It is an anaerobic sealer. It sets up immediately when the two parts are tightened together and oxygen denied.

Literally I have installed an intake manifold with it, put the wrenches away and driven off for a long trip with nary a drop of leakage.

One thing about it, it will not tolerate gasoline. It'll foam and act weird. So, use it on the intake manifold ends, water neck or thermostat housing but not under the carb.

There's a reason it's used by the manufacturers.

R.

I haven't used end gaskets in years, just copper silicone.