Hey everybody, it's me again. Same '84 FXSB rebuild, new problem. Actually it's kind of an old problem that I have put on the back burner. I rebuilt my motor using a new S&S 80ci kit that had the cylinders, pistons, rings, heads. I also plunked down the cash for the fancy S&S rocket boxes. I assembled them with the utmost care under the direct supervision of a seasoned professional shovel mechanic who had rebuilt many motors. After going through a very careful break in process as stipulated by S&S for just under 500 miles, I found that I was fouling plugs every 100 miles or so. I had chalked that up to carb tuning issues and went through hell rejecting. I also had an intake leak that came and went. So, to keep this long story long, i removed my front head to reposition it to try to cure the intake leak and noticed oil pooled in the valve recess on top of the piston. I then removed the rear head and was dismayed to see the same thing there. I called S&S who had me take them (the parts) to an authorized service guy. He just today called and said that he found nothing wrong with the S&S parts. My original mechanic buddy that helped with the rebuild is out of the picture with significant health problems. Any idea how the hell i get so much oil on top of the piston? The S&S guy is saying the heads/valves, cylinders, pistons/rings are all in spec and fine. I don't get it. Should I get a second opinion or should I just put it back together and see if the second time is the charm?

thanks!

 

the valve seals are the tin ones and as such allow oil to by pass, S&S would never admit they suck, so have the new guy swap the seals out to the blue rubber ones

 

I will give that a shot. Thanks for the tip. Inexpensive advice is always nice!

 

Did the same upgrade with my 81'. I too had plug issues that I was chasing with different plug manufacturers and heat ranges. Rear cylinder looks good while front cylinder looked too rich. The only thing I kept from my old build was the valvetrain. Thinking that maybe with the S&S springs my used and possibly worn out hydraulics had something to do with it I pulled the trigger on a JIMS Powerglide upgrade kit (issues with that as well, I'll leave it for another thread.

Could you PLEASE followup with how you are making out with your issue, I'd really appreciate that!!

Mikey

 

I will keep everyone updated for sure. I will be replacing the valve seals as recommended. I do remember now tearing the little clear plastic thing you put over the valve when installing the seals. I am embarrassed that I forgot about that. At the time I brushed it off because I convinced myself that it was ok (looking back I think it was my last few valve seals and I didn't want to take them back off and order more.... that and i didn't have anymore of the little plastic things. I kept using the torn one. impatience doesn't pay but you dont always realize that until it's too late). My hope is that the seals were damaged at that point. Yes the heads came fully assembled from S&S but I checked the valves and how they were seated and wasn't impressed so I lapped them to where they were seated well enough to hold alcohol while CC'ing them. It's funny looking back how I was very meticulous on the complicated parts of the build but got impatient on the valve seals. I am hoping that this is the fix.

 

I have heard that the older shovelhead heads pooled oil in the head casting at the exhaust valve and that the pooling would be high enough to infiltrate a bad or worn valve seal. So when you do disassemble the top end it is common to have fresh oil pooled on top of the piston.... All the more reason to use the better vitron seals.... I believe that is what I've heard....

 

don't beat your self up too much that has been done so may times you need comer's