Register now to get rid of these ads!

Ford spark plugs not seating

Discussion in 'The Hokey Ass Message Board' started by Johnny Angel, Jul 2, 2010.

  1. I need some advice Ford boys. I' m running a rebuild early 70's 302 with 1967 289 4V heads with Autolite 45 spark plugs. The problem is, since the compression is higher, I get blow by past a few plugs onto my headers and it fumigates the cab. Ford apparently doesn't have plugs with a compression ring (except flatheads plugs) like the early Chevy plugs did. Is there anyway I can get a proper seal without taking the heads off and re-reaming the tapered seat.???

    I thought maybe valve grinding compound on the plug threads might help, or would it act like locktight....don't want that....
  2. autobilly
    Joined: May 23, 2007
    Posts: 3,094


    I'm not a Guru and don't know these engines but your description is odd. Blowby into headers fumigates the cabin? Check that the plug holes are tapered seats and are clean, also that the threads are clean and match. If the holes require a "compression ring" seal, you'll have to find the rite plugs.
  3. smiffy6four
    Joined: Apr 12, 2010
    Posts: 333


    eeeeK! No valve grind compound on the plug threads! Chase the plug threads with the correct tap and get the correct plugs.
  4. The plugs holes are tapered and clean as the heads where just rebuilt. The plugs are new with matching tapers. The plugs are correct for that head but Ford does not make plugs with a compression ring like the early chevy plugs which would probably fix the problem. There is a chance the tapers are old and not a proper match for the plugs. This is only happening on 4 plugs. Hoping there is a quick fix....

  5. dave lewis
    Joined: Dec 12, 2006
    Posts: 1,364

    dave lewis

    OK, # 45 are the BIG plugs (18 mm) thread..
    Pretty common problem you are having.
    Find a wire wheel to fit your cordless drill, pull one plug at a time and clean the seat area with the wire wheel...Then blow out the residue with an air hose....
    Make sure you get them good and tight when you re-install them..
    And re- tighten them after the engine has been up to temp and cooled off ( next morning ?? )
    Good luck
  6. I think the correct Ford plug - Motorcraft - is a BF42 or resistor BRF42? I don't have my book handy so maybe someone can confirm. And I can't remember if they have seating rings or are tapered fit.

    Newer Autolites are NOT Ford but I think Allied Signal bought the name years ago - maybe early 70s? Ford's plugs are Motorcraft, have been for years.
  7. Thanks for nixing the valve grinding compound....The threads match up correctly but it seems to be in the taper...
  8. smiffy6four
    Joined: Apr 12, 2010
    Posts: 333


    The plug holes are tapered, or there is a taper at the outside of the hole?

    Are the plugs loose in the threads with the plug almost touching the taper? Perhaps the threads are buggered; could be it's time for helicoils?

    Try going to a different Ford dealer and look for the oldest guy in the parts dept. He might have the experience to point you at the right plugs.
  9. Thanks guys, I'll try wire wheeling the threads, although the engine has less than 100 miles on it and I'll check out those plugs....
  10. I hope the threads aren't buggered, but that is a possibility. I've only checked plugs with Carquest. I'll try a Ford dealer...

  11. Well guys I am the old Ford parts manager guy. . :) from the 70s and you 'forced' me to look 'em up. '65 to '72 289s, 302s & others - non resistors are BF42s, resistors BRF42. But I don't have any to look & see if they come with the rings.
  12. And a little anti seize on the threads is a good idea.
  13. That's a number I haven't heard of. I will definetly check it out. Thanks...
  14. I thought of that but wasn't sure if I would regret it when time to pull the plugs. It sure is worth a try if I find I am using the correct plug...
  15. You might check your local parts store, I get plugs & filters from my local Parts Plus store, they carry a near complete line of Motorcraft. The last set of BSF82s I got for my Yblock were around $3 each.
  16. smiffy6four
    Joined: Apr 12, 2010
    Posts: 333


    Why would you regret it at plug pulling time? The whole idea of the anti-seize is just that, to prevent the plugs from seizing. Not to mention keeping carbon from creeping around the threads and turning to fine abrasive when you turn the plugs out.

    I always use anti-seize, especially if an engine has aluminum heads(not that yours does of course)
    Last edited: Jul 2, 2010
  17. Thanks raceron1120. I hope I find a guy behind the counter that's as old as I am....
  18. Sorry guys, I mistook Hemideuce for meaning locktite. You just might have saved me with such a simple solution. Nice to know these little tricks...
  19. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,898

    from Quincy, IL

    I too have some background in Ford parts in the late 60's and was trying to recall the spark plug numbers and Racer1120's post jogged my memory. He is most certainly correct on the BF/BFR-42 number and they are definitely taper seat plugs (NO sealing rings). That in itself doesn't help much, unless you have incorrect plugs in the first place. If your plugs are correct, what you have there is, in my opinion, a very rare condition. Best wishes on finding a solution.

  20. dalesnyder
    Joined: Feb 6, 2008
    Posts: 427


    The old set of Snap-On spark plug thread chasers I have, have a spring loader cone shaped cutter on the end. When you run it in the hole it cleans the threads and the seat. Might want to see if someone near you has these..
    Taper seat plugs do not have sealing washers. Only the flat seat ones do.
    Are you sure the blowby is coming out the plug hole? Not the header or valve cover gasket?
    If the plugs were passing that much to fumigate the cab I would imagine they would be making a hell of a racket too.
  21. claymore
    Joined: Feb 21, 2009
    Posts: 896


    Yep as common problem but there is a tool offered by the usual tool guys made just for scrapping the seat area to get it clean. Then as others have said some anti seize on the threads and seat to prevent future problems. And if you have the room to get one in there torque the plugs to the proper spec.
  22. Truckedup
    Joined: Jul 25, 2006
    Posts: 3,980


    Next it'll start misfiring,you take a look to find a spark plug has unscrewed from the head with plug dangling ,wire still attached.:D
  23. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    Member Emeritus

    You bet your ass. Just one loose plug will make you fix it to get rid of the noise. I can't imagine what 8 leaky spark plugs would sound like.

    The spark plug must match the head that it is screwed into to seal.

    I personally think that you are barking up the wrong tree.

    Take a 3' piece of rubber fuel line. Hold one end to your ear and run the other end around the plug bases. If any are leaking you will hear it and find it. I bet you won't hear any problems. While you are at it run the hose over every gasket joint on the headers or manifolds.

    I had a customer swear that his new exhaust system was leaking because he could smell it in an OT hatchback. We could damn near kill the engine by plugging the tail pipe with rags. There were no leaks!! I had him open the hatch. The bottom of the hatch and the floor was riddled with huge rust holes. The fumes were coming in from the back after it left the exhaust.

    I had a 47 Chevy woody wagon. I tried to drive it with the tailgate window up. Even with all of the front windows down you would get a headache from the exhaust being sucked back into the cabin.

    The shape of your car and where the exhaust exits the vehicle can play a big part of exhaust fumes entering the cabin. Take a handful of rags and try to seal the end of the pipe. You will hear any leaks.

    I think you are presently on a wild goose chase blaming your spark plug seals.
  24. You might try a set of spark plug indexing washers on the seats. They aren't really designed to help seal, but they are made of copper and might do the trick.
  25. If you were lucky enough to pick a set of heads for your project that came from the rust belt the tapered seat area of the cylinder head could be damaged. If the tapered seat area is rusted or eroded you'll fight the sealing of the sparkplugs forever. Then if someone ran the engine with the sparkpugs loose for a very long time this will damage the tapered seat too. Good Luck >>>>.
  26. I know for a fact the fumes coming into the cab (the open windshield on my channeled A is 2 feet from my headers) are originating from my plugs on my right bank only (the wife's side). Three plug holes have a brown liquid seeping from them and when the engine is idling at a light, you can see the steam coming off the right header caused by a mist coming out of the plug holes with the plugs tight.

    I tried the fastest and cheapest tip first, putting anti-seize on the plug threads. I ran the car off and on all day and believe it or not, I never had a problem.

    I can only think as you say, the heads are old even though they have been rebuilt and there must be a bit of slop in the threads.

    I checked on the Motorcraft BF42 plugs and they are identical to the Autolite 45 I am using. There could be a slight difference in the threads if they are in fact a different manufacturer. I will definetly get the BF42's next time I change the plugs.

    Thanks to all for your great tips to such simple solution.....
  27. Autolite plugs are now coming from Mexico,,,,,nuff said?
  28. Good that you got the problem solved, and without a lot of effort or $$$.

    Yes, the plugs are same, just different maker. In my years in Ford parts I tried to stick with the OEMs plugs. Being a small town dealership, we got a lot of non-Fords in the service dept. I stocked Motorcraft for Ford, ACs for GMs and Champions for Mopars, and would use others only if requested by the customers. Nothing wrong with 'em but I'm just sayin'.

    If you do swap meets, you might find those BF42s. Remember those old Tune-up Kits in a can that Ford had back in the 70s? I sold tons of 'em. I'm sifting mental cobwebs here but I think the # TKF-1 had BF 42s in them along with points & condenser and TKF-17s had BRF 42s. I've seen them at swaps around here for $5. Check the back of the can, it says which plugs are included in the kit.
  29. RichFox
    Joined: Dec 3, 2006
    Posts: 10,004


    Brown liquid seeping from the spark plugs? As in water? From where? Water jacket? Where else? Is this bad? Yes.

Share This Page

Register now to get rid of these ads!


Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.