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Hot Rods flathead finned aluminum heads - chamfered washers

Discussion in 'The Hokey Ass Message Board' started by 31ACoupe, Oct 16, 2014.

  1. 31ACoupe
    Joined: Nov 14, 2005
    Posts: 1,416

    31ACoupe
    Member

    i can't figure out how to search the forum but quite a while back there was a thread on using chamfered washers and o rings on finned aluminum heads for the flathead v8. i can't find anything on it but i need some info like 1) is the chamfered side up or down? 2) is an o ring recommended and if so what size and fit? just around the stud? and 3) where can i find the chamfered washers? thanks in advance, i would appreciate any info out there and to make it easier my email is gw65atgwtcdotnet.
     
  2. lowsquire
    Joined: Feb 21, 2002
    Posts: 2,564

    lowsquire
    Member
    from Austin, TX

    I would think the chamfer faces down and the 'o'ring seals the stud to stop coolant seepage. If you seal the threads of the studs into the block correctly (I use GM thread sealant, comes in a can, sticky honey-like stuff)and use good condition original Ford studs (NOT new ones, they are usually the wrong class of thread fit, and CAUSE the leaks in the first place) you wont get the seeping in the first place.
    They can also weep past the head gasket of course, but properly prepared sufaces and good modern gaskets should stop that.
     
  3. gwhite likes this.
  4. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    If you are trying to stop a leak at the top of the head and studs, you've got a serious engine failure and are chasing it in the wrong direction!
    Stock studs set into extra tight block threads (I posted the 1930's thread class specs somewhere), a fit much tighter than that produced by a common tap or normal hardware. Bottom of unthreaded portion of stud nestled into a recess in the block. Stock, Ford assembled these by the million with no sealer and they stood up straight so heads were just slapped right on at assembly...no need or time for goo, no need to fight the studs to get the heads on.
    Now, MANY flathead blocks have had taps run through the stud holes to clean them, resulting in leaks, studs that have to be set up carefully to be straight, and of course weaker hold in the deck. We can't do much about the thousands with cut out threads but don't run a tap into those holes on any more blocks! Gun cleaning brushes ans solvents will do unless there is actual damage. Don't weaken any more engines!
    Good block...Nacewicz at site above can supply stockers, and many heads are made to use with stock ones changed out to all the longest size. I think he can make custom lengths.
    If your block threads have been wallowed out with a standard tap, they are a wobble fit like normal automotive hardware bolts and nuts, I think that's class 2 nowadays...need to look it up, but it ain't gonna stop water or hold studs vertical, especially with commercial studs not made for the recess.
    For these situations use your favorite goo (one good modern one is listed above) to stop the water...if water gets out at the bottom, trying to seal it at top is crazy. Tighten up studs to a very low torque.
    Now, before your goo dries, drop on gaskets' heads, and your washers and nuts, tighten enough to pull down against head, which will force studs to vertical...assuming heads are correctly faced. Let everything dry and harden, then you can remove the parts and go on with your work.
    Washers...the only special ones that might be needed are made to safety up or repair SBC aluminum heads. They are stepped and come with a stepped bit to cut the lower recess into heads. They would be a good thing if you have aluminum heads that have been wallowed out around the stud holes by someone who did not use good washers. Racers might well use these even on new heads to help bulletproof things, just as they install helicoils in any new aluminum or magnesium threads on thoroughly prepared racers.
     
    gwhite likes this.

  5. 31ACoupe
    Joined: Nov 14, 2005
    Posts: 1,416

    31ACoupe
    Member

    thanks guys for the info. bruce, i am installing finned alum heads (fentons) on my ab block in my 47. the heads are in real nice condition and i doubt they are wallowed out or damaged but i remember reading a few years ago that we should use chamfered washers and o rings when switching from stock heads to aftermarkets. also my studs seem to be just fine as i never had any leaks and have run the motor for several years. the chamfered washers and o rings sound right but i can't remember what the article said about installing them, whether the beveled side is up or down but someone on the hamb said bevel up and lowsquire thinks they should be down. i think the o ring should fit the stud just so but am not positive. you mention using washers but i don't know if you mean chamfered or regular steel and you don't suggest using o rings. i am just trying to get it right the first time instead of having to re-do the job. i sure appreciate your advice. thanks, george...
     
  6. jseery
    Joined: Sep 4, 2013
    Posts: 743

    jseery
    Member
    from Wichita KS

    Don't know anything about this o-ring setup, but what good would an o-ring do on top of a washer? Think about it. If you are attempting to seal something at the head wouldn't the o-ring have to be at that joint? An o-ring and a chamfered washer would provide a seal between the head and the stud, but know idea if this is a good idea, just commenting on the mechanics of the thing.
     
  7. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    If you have no problems with studs, and assuming head locations for nuts up top are square and clean, I would think you would be fine with good quality flat washers. SBC equipment here is a natural source, or stock one from Nacewicz. There should be no sealing issue up there, only issues are adequately spreading out the load on the aluminum and keeping everything parallel. Keep it simple, don't repair problems you don't have, etc.
     
  8. metlmunchr
    Joined: Jan 16, 2010
    Posts: 779

    metlmunchr
    Member

    I know less than nothing about flathead fords, but I do know a fair bit about o-rings and where they will and won't work. A standard rubber o-ring won't seal against a thread because it will cut before it can be crushed enough to fill the thread space. Tried that probably a dozen times over the years as a makeshift fix on various stuff, and it never has worked.

    Teflon o-rings would seal because teflon will cold flow under pressure and conform to the thread space. But the downside to that is that teflon won't recover its shape when the pressure is relieved, so if you wanted to remove the head you'd have to pick out the remnants of every o-ring before the head would slide up off the studs. Then when its time to replace the heads you'd need another hundred bucks worth of o-rings to cover both heads on a flathead.

    You'd be way ahead to do whatever is necessary to keep the coolant down below the studs where it belongs rather than trying to deal with it at the top of the head.
     
  9. 31ACoupe
    Joined: Nov 14, 2005
    Posts: 1,416

    31ACoupe
    Member

    thanks guys, i think i will do what bruce says and just go with steel washers and that should do the trick. good feedback as usual from the hambers. thanks....george
     
  10. HotRodMicky
    Joined: Oct 14, 2001
    Posts: 1,772

    HotRodMicky
    Member

    Where cna you buy taps then ,that have the close tolerance?
     
  11. try MSC
     
  12. 36tbird
    Joined: Feb 1, 2005
    Posts: 1,084

    36tbird
    Member

    I used these step washers, http://www.stefs.com/bandb/products/productpages/washerstep.htm. My thinking was that I wanted to keep the studs centered in the holes to hopefully reduce electrolysis for easier removal of the heads if need be. I haven't had to remove a head yet, so I don't have any data to support my theory. If you go with these, you need a special shouldered drill bit so don't overlook that.
     
  13. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    The taps made threads with closer fit and some interference, like modern class 3 or 4, but on an earlier specification...I think the modern grades are from the 1950s...the point is not to mess with the metal in there unless you have to repair damage, as with a heli coil or something. If threads have not been brutalized, some combination of the hot-tanking and brushes with solvent will do the job. If they have been tapped with a modern grade 2 (I think that is the grade of nearly all auto threads...did not remember to look it up) you simply have to patch surviving thread fit with sealant and improvised means of getting them 90 degrees to the deck.
     
  14. 36tbird
    Joined: Feb 1, 2005
    Posts: 1,084

    36tbird
    Member

    Received a PM asking me which heads I used the step washers on. Answer is both kinds, aluminum and stock cast iron. I am a fan of studs versus bolts and like I said, I wanted to keep the studs centered in the holes. There is a special drill bit you buy for the step washers that drill the diameter required for the step washer to sit down flush. Also, I've read before that to clean up the old threads in the blocks, you use an old stud, not a new tap. I discovered this tip too late so my studs are heavy on the Permatex in the block, with anti-seize on the shanks. I have had some water seepage but it stops after a while as things all mesh together with running on a fresh rebuild.
     
  15. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    Stef's as noted up there is the company I was thinking of but could not ID...the washers are for SBC, same stud size as flathead, and they sell the special stepped bit for the job.
    Most flathead blocks have been tapped to standard fit by now...blasted machinists think running a tap into a hole is ALWAYS a good thing. A standard stud or bolt is an excellent way of loosening crud without attacking metal. A prepared bolt can gobble up a lot of crud...hacksaw a slot or two over the threads, but run it through a standard die and wirebrush it so your slot does not try to become a cutting tool. And a set of gun brushes is a best friend for cleaning up elderly motors...brass and metal cleaning brushes and handles, readily available in plentiful sizes.
     
  16. Gene Boul
    Joined: Feb 9, 2006
    Posts: 805

    Gene Boul

    What he said! In general:
    Studs are better than bolts, Don't re-tap flathead bolt holes & Permatex ave sealer will prevent thread leaks!
     
  17. ARP has the chamfered washers, use #13 O-rings. For bolts, washer against the bolt head, chamfer towards the cyl. head, then install o-ring and thread sealant. Studs, it's o-ring, chamfer towards cyl heads then nut.
     
  18. 31ACoupe
    Joined: Nov 14, 2005
    Posts: 1,416

    31ACoupe
    Member

    thanks rb35, i sure wish i could find that tech thread on the chamfered washers on the why and stuff. my stock heads now on the motor do not leak anywhere but i want to put my fenton heads on cause i have the 2x2 fenton and fenton headers to dress it up. i do want to do the chamfered/o ring process and will let everyone know how it turns out.
     

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