Author Topic: Pan Cover leak  (Read 680 times)

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Offline fourthgear

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Pan Cover leak
« on: May 28, 2016, 06:45:54 AM »
    I had a post a year or so ago on my front Pan ( Valve ) cover leaking , no matter what I did or Gasket I used ( except Cork ) (I even tried the James Rubber thick ones ) it leaked at the front , right above the front Exhaust pipe , of course . I did find a very minor crack above the Flange, Gasket seating area & I thought that was it. ( crack was toward the intake end of the Cover )
  I purchased a new set of S&S Covers to put on when motor was done with rebuild , checked all Gasket surfaces & made sure new Covers had flush flanges for gasket & set them on the completed Heads ( with out Gaskets ) to make sure they would not hit any Rocker studs or anything , I redid all threaded holes with Heli-Coils to make sure I had good threads also
. This time I used Cometic Gaskets , the new type & I got the same leak as before , same place . I started to think it was a Porous Head Casting & it may be . Totally frustrated with a new Motor & it leaked in the same place , I had to miss something , some where .
   What I did was removed the two Bolts in front , the middle one & the front left corner ( as seen from sitting on the Bike ) cleaned the holes with Brake cleaner & then Acetone , blew the Holes out & used " Seal-all" on the Bolts threads & Shafts , re-installed Bolts & let it set for 24 hours & so far no leaks , at all . I don't have many miles on the motor yet , but by now I would have had a puddle in front & now nothing .

   I at first thought that I did something with the Heli-coils , but it was leaking before the Thread repair , so could I have a Porous casting ? Has anyone had something like this before ?

  I could see a gasket not seating properly & leak , but with all the Gasket types I tried , including putting RTV & Letting it set up before installing , it would have taken care of it . I don't think a Cork Gasket would have helped , because I no longer believe it was Gasket related .

Offline drifter

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Re: Pan Cover leak
« Reply #1 on: May 29, 2016, 01:56:06 AM »
Sounds like you are not having fun!  I remember your earlier post, and with all you have done it should be good to go.  I think you might get some flak from the purists about using Seal All, :idunno:, I use the "any port in a storm" theory, at least until I find a better way.  OK, specific sealing of the two bolts has solved (for now) the leak, hard to figure where the oil is coming through, unless it is some channel direct to one of the bolts that is now sealed.  I wonder about removing, cleaning and coating the head under the covers with the stuff used to seal the inside of the cases, that should block any defects in the casting if the heat doesn't affect the chemical.  You used RTV, Craig had a trick of installing the gasket to the pans, letting it sit overnight and then adding more RTV above the gasket inside the pan to compensate for the holes drilled too close to the radius of the bend from pan to flange.  I don't have enough experience with the old stuff, I put STD heads on after a machinist bored most of the original seats out on my mid fifties heads when I had the bike at an indie while I was driving around the country.  I may have put 6 k miles on the STD's with new chrome pans before the oil came out, frustrating.  That is all I can think of now, almost 4 am, brain has turned to mush, good luck!   

Offline fourthgear

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Re: Pan Cover leak
« Reply #2 on: May 29, 2016, 06:38:24 AM »
  It was just desperation to use Seal All , I had the front Head off , probably eight times ,lapping the Covers ( old covers & before complete motor rebuild ), I even set up a battery operated light to put inside the cover while on a lapping soon surface to see if any light came out around the Gasket Flange of the Cover , just to make sure it was true . ( its how I found that small crack at the back end of the cover )
   Before I installed the Rocker assemblies I used a Level around the Heads Gasket surface to make sure it was true & as said I used two different sets of the James Rubber coated Gaskets, James regular ( thicker ones ) & now the Cometic ones with New S&S Covers & still had the leak , so I had to go to extremes to try something & "Seal All " was it . I was not going to disassemble again if I didn't have to.

  Before I used the Seal All , I first removed one bolt at a time to see if any had oil on them , then replaced it before going to the next one , these two were the only ones in the area of the leak that had oil on them .

  Its bizarre & I seem to get the good ones . Time will tell if its sealed or not . Sealing the surfaces of the Heads with a coating is a good idea , but I think this leak is inside . There is an Oil Passage to the Rocker some what close , beginning to wonder if I have a hair line crack or something .

  I do know that the oil puddles up in that front exhaust Valve/Spring area & originally thought that there was pressure built up in the Cover & over coming the Gasket , but if the gasket has a good seal , I can't see that happening , especially since I went to great lengths to make sure it had good seating surfaces to seal properly .

Offline drifter

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Re: Pan Cover leak
« Reply #3 on: May 29, 2016, 12:52:33 PM »
I am curious too, I will go dig around in the barn for my old heads.  Maybe with them in hand I can visualize the options better.  Around here anything that you are not holding in your hand may walk away in the dark, if I am lucky they will still be there.  I need to do a visual inventory of what is stored there since I am at the age where I will not be needing any of it in the future, welcome to retirement.

Offline drifter

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Re: Pan Cover leak
« Reply #4 on: May 29, 2016, 06:11:52 PM »
Found them, and a box of photos I took in Vietnam that I thought were lost decades ago, I'm glad you got me to go look.  I can't see any obvious flaw in that area of the head, unless you count the seam where the sections of the mold left a vertical line on the outside.  I found the oil feed to the rockers but that is a distance from the leak area and the drain back oil return is in between.  The bolt hole in the pan that sits forward in that left front corner is the one that is very close in the radius of the bend and would be likely to cause a leak because of reduced sealing area.  I can't see anything else to facilitate a leak there except that bolt hole area unless you have a bodacious crack that only opens above a certain temp which you would see when you parked it with the oil flowing out.  Craig (from the Phoenix area) with that fine 70's style Pan chop describes how to reduce the chances of a leak there, somewhere in the past forums.  I can repeat the details of his fix if you want since I plan to do mine that way when I get that far.     

Offline fourthgear

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Re: Pan Cover leak
« Reply #5 on: May 30, 2016, 06:43:09 PM »
   Hard to say whats happening, far to many different gaskets & types with & with out sealer & new Covers for me to believe its just a gasket sealing issue , but you never know . I have to get some more miles on the Motor to see if it remains sealed. 

Offline drifter

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Re: Pan Cover leak
« Reply #6 on: May 30, 2016, 11:15:08 PM »
I mentioned in my first rely that I don't have much experience, I spend too much time reading several forums and technical information and manuals, I like the nuts and bolts and mysteries.  You put a lot of time and labor and thought into this problem so I don't think it is going to be an easy answer if you missed it with your skills.  That is why I found the old heads in case my memory was faulty.  Stopping the leak by using sealer on the two bolts focuses the leak directly on the bolts and the holes they occupy.  I hope they stay sealed, gives hope to the rest of us with that problem.

Offline fourthgear

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Re: Pan Cover leak
« Reply #7 on: June 06, 2016, 05:44:16 AM »
Still no leaks .