Need Help w/ Fhead oil Leak

Percival's got an oil leak we can't track down and we need some help . . .

Fresh rebuild from a reputable guy about 1800 mi ago.

Oil leak only shows up when rig has been run at highway speeds for ~ 1 hr or more (4.27s w/OD, so I'm not flogging the old guy too badly)

Puddle shows up under the rear of the engine, like its a rear main seal - but that's already been replaced, with no impact on the leak.

Engine doesn't smoke, etc. and there is no appearance of blow-by.

I was thinking about checking the relief valve in the oil pump to see if that's stuck, and if that's not it, I'm out of things to check.

Are there any fittings, etc on the rear of the engine that might be leaking? I need to get this fixed before I have to replace the clutch due to the oil contamination-

Thanks in advance for your help-

Eck

 

Hey there,

Yes, but you'll need to pull the bell housing, clutch, flywheel and sheet metal cover that covers the front of the bell housing. There's a plug in the rear of the engine that is at the end of the oil galley. I just got my F head running too, but ran it before bolting on the tranny/xfer case. I got lucky and noticed this was leaking even though the rebuilder had used a sealer on it. The original plug was far enough in, that I just cleaned the threads up and added another plug behind it with lots of non hardening sealer. Haven't had it on the road yet, but I'll betcha I slowed it down a whole lot if not completely! Hope this helps....

 

Oh yeah, that could do it if it was leaking at the head....Also check the valve cover gasket.

Leave it to me to think of the worst possible scenario.... 8)

 

Thanks guys -

I meant to mention that I checked all over, and that there was no sign of leakage from the oil pan gasket, and the valve cover. It appears to be in the back, covered by the bell housiing.

The oil galley plug sounds like it could be the offender . . . at prolonged high speeds, there's enough pressure, etc. . . . damn. I just hope it can wait until after hunting season.

 

John, I had the similar situation to yours... Fresh rebuild, and a leak from the rear of the motor. It was the oil galley plug that was leaking.

You might be able to put off taking it apart. Just keep plenty of oil in it, and bring some with you..

 

Did you have the same symptoms - leak after high speed operation? Just curious - thanks

 

Isn't there also a camshaft plug at the back of the engine where it's thru bored?

 

Yes, there is also that plug, but it sounds like the fix is the same for either one of them. I think I'll be dropping the transmission and pulling the fly wheel at some point in the future . . .

 

This is intresting , I have my motor in the floor now do yall think it would be worth the efford to change that plug out and put some sealler on it.There was some oil in the bell housing that I figured was rear seal drool but now Im wondering.

 

It might be easier to remove the engine rather than drop the transmission.

You'll have to drop the bell housing as well, so why not yank the engine?

That would seem to me to be easier especially since the exhaust was just recently assembled..

As for the guy who has the engine on the floor and suspects the oil gallery plug. You have it this far apart; this is clearly a situation where a stitch in time saves nine. Or saves removing the engine later in this case.

You don't have to replace the plug, just remove it and reinstall with sealer.

The oil gallery plug is a female plug with an odd dimension. What I did was to grind down the sides of a 3 / 8 inch socket extension just enough to get into the plug.

I painted the extension red so that I'd know that it was the modified one and not try to use it in a standard socket.