Leaking head gasket?

[Downer]

Hey guys gotta issue with a leaky head gasket I think. I have a little bit of oil on my fins that looks as if its coming from the head gasket also the base gasket is a bit oily also.

But... I've done a compression test and I'm getting 140 on the left and 150 on the right

So my question is can I have a leaking head gasket but good compression? I have my motor pulled out of the frame right now should I replace the head gasket witch I don't mind doing I just don't wanna if my compression is good Any thoughts on this would be great thanx in advance

 

[ippytattoo]

There are a couple of places you could get and oil leak between the cylinders and head without it affecting the compression. You could try a retorque of all the head fasteners, especially since you are seeing some weeping at the base gasket as well.

 

[Downer]

Thanx for the quick response I have re torqued but no changes but I do have another question about the washers on the big acorn nuts the rubber ones that everyone does away with are saposed to be on the four inside or outside? Also if I replace them should I get the brass or copper ones and could those alone fix my leaking with a re torque?

 

[ippytattoo]

They are supposed to be on the outside studs. I replaced mine with the brass washers from Mikes and put them on all 8 studs. I know you don't have to put them on all 8 but I put my motor together from pieces in milk crates and figured I might as well. I don't know if just replacing them will stop your leak but it may help to maintain the torque.

 

[5twins]

The rubber washers go on the outside 4 studs. Those drain oil back to the bottom end. The inner 4 are dry holes so no seal washer is needed. Changing the washers may not stop the leaks. The rubber ones can be made tight enough, they just don't stay tight. Are you using 30 ft/lbs instead of the 25 or 26 factory spec? That's what you usually need to do to stop the leaks, sometimes even a bit more like 32. Also, be sure to do the bolts under the spark plugs. They are part of the head gasket sealing pattern. It's best to remove and clean them, then re-torque. They can get stuck on their threads and read tight when they may not really be. Also, those are smaller bolts and don't get the 30 ft/lbs (you'll be in trouble if you try that). Spec on them I think is 14 to 16.

 

[Downer]

Thank you ill look into getting the brass ones from mikes or a hardware store if I can find em

 

[5twins]

Those washers are rather thick and need to be or the acorn nut may bottom out on the stud before the head is actually torqued down tight enough. So, in other words, just any old plain washer may not do. It needs to be a bit thicker than most normal ones.

 

[Downer]

Ok ill just order from mikes I guess ill try re torque and see how it goes

 

[nj1639]

Throw on the power brake booster valve too for your breather-if you don't have one yet.

 

[Downer]

I do have the brake booster on too but thanx for the heads up