I've always that the series 4 engines had a problem with an oil seal in the front failing due to a design flaw in the engine. I heard many fixs for this problem, but which one is best for a high RPM/horsepower application?

 

I had this problem on my series 5, where the paper gasket blows out because there is a long run where there are no bolts that go through the front cover. The FD's have this problem more commonly. The fix is to make sure there is no pressure in the front cover (maybe you capped off something you shouldn't have? like the "crank case" vents on the oil filler neck.

Alternately I would imagine you could use a metallic gasket with a good amount of RTV.

Edit: I don't know of anyone that makes a front cover gasket out of metal for an FC, however I have seen them for 13b-REW front covers.

 

The problem I'm talking about is the 10-C15 o-ring which is at that cross over point between the front cover and the front housing. Apparently the new gasket mazda gives are thinker than the old gaskets and don't crush the o-ring enough. I've heard of drilling out that o-ring seat 0.020 to get it to fit, I was wondering if there was anything else people have tried?

 

Never heard of that problem. The problem I was referring to is more common I believe.

 

not even close, the problem you are referring to is people who remove the rats nest without properly ventilating the crankcase, i'm sure it is becoming a larger problem as more less knowledgable people start modding their engines.

there is no real solution to the fron't cover o-ring issue, the best i could do was use some tacky adhesive to both sides of the o-ring while assembling the front cover, if the o-ring groove has been machined previously then your only alternative is to find a larger o-ring or omit the gasket alltogether.

personally i hate the design, they should have just cast the passage into the front iron and had the exit on the iron itself rather than the front cover..

the o-ring can fail at anytime, anywhere and there is no foolproof method anyone has come up with to cure it yet.

 

There is, but it requires a lot of work..

 

I've got time and I might as well so it while the engine is apart, what's the method?

 

It requires the engine to be apart, and unless you have a shop I wouldn't attempt it.

 

Negative Ghost rider. I had the problem with stock emissions equipment and a fresh rebuild. I still can't narrow down a specific reason as to why it happened.

 

I have access to a shop...
Is it the method of using a 0.650" end mill, cutting ~0.200" into the 0-ring seat and using RTV instead of the gasket?
I heard of someone using a piece of pipe and press fitting it in, does that work?

 

blockage in the PCV system or excessive blowby due to out of spec clearances, usually the blowby is caused by running higher than normal boost pressures with a mildly clearanced motor without proper crankcase ventilation.

milling the iron is not a foolproof method, i still had a blowout of an o-ring in my engine with a milled front iron, personally i would like to see someone try a square cut o-ring in place of the round cut one, the added surface tension i would think should help it seal and keep the o-ring from tearing.