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Hey Oldtimers, I'm thinking about the Bon Ami trick

Discussion in 'The Hokey Ass Message Board' started by alchemy, May 24, 2011.

  1. carlos
    Joined: May 2, 2005
    Posts: 1,387

    carlos
    Member
    from ohio

    Dont do it If I done anything I would put a quart of reslone in it drive it around the block come back and change the oil and drive it.Give it Time
     
  2. xlr8
    Joined: Jun 26, 2006
    Posts: 700

    xlr8
    Member
    from Idaho

    It wasn't done to a Cat unless the rings didn't seat. It was not standard procedure and is considered a last resort. Cats use hardened sleeves and rings. I don't think it is a trick that is meant for a normal cast iron block, which is not to say that it won't work.
     
  3. Rickabilly
    Joined: Jul 17, 2011
    Posts: 22

    Rickabilly
    Member

    Hello all,
    I'm new here but have been building engines for twenty plus years as a professional, many things to say, but I'll start at CAT and the use of abrasive cleaners to bed things in, CAT uses high silicon (read very hard) cylinder liners, flathead fords are cast in soft grey iron, you couldn't find two more different materials when considering how abrasives might stick to the sides, soft iron will hold a lot more of the abrasive for much longer, and soft iron bores with soft iron rings will eventually wear in. If it's only been going for 800 miles and intermitantly at that you probably shouldn't worry.

    Get the car out, fill it with a good running in oil and put some miles on it, just go on a 500 mile hamburger run, that is; think of a town 250 miles away, drive there buy and eat the burger and drive home. check the oil regularly on the way.

    Most people treat a newly built engine too gently pootling around town and glazing it up. on a 500 mile trip you lose the inhibitions and let it work a bit, it'll do wonders for you and the car.
    Regards
    Rick
     
    mike in tucson likes this.
  4. 40fordtudor
    Joined: Jan 3, 2010
    Posts: 2,503

    40fordtudor
    Member

    That IS how it's done---works on Cummins as well.
     
    Truckdoctor Andy likes this.
  5. Rickabilly
    Joined: Jul 17, 2011
    Posts: 22

    Rickabilly
    Member

    Just to clarify, there is a big difference between "glazed" and "gummed" an engine that runs for few miles a year often gets gummed up and dose similar things to being glazed, the difference is; a good hard run will blow the gum out try that first then think about "deglazing" if that doesn't work.
    Rick
     
  6. RAY With
    Joined: Mar 15, 2009
    Posts: 3,132

    RAY With
    Member

    Back in the 60's I had an occasion to Bon Ami a pontiac engine that wouldn't seal. I used marvel mystery oil and a table spoon of bon Ami and rev the motor to 3000 and poured it through the carb. As I remember it was a quart of marvel and I had mixed it well and it did solve the problem and assisted in seating the rings. The motor would have had to come out so it was a gamble and it worked and all was happy.
     
  7. Although this wont help the O/P, maybe I, or someone should start a thread with a " proper engine break-in procedure " routine. Many folks either rebuilding thier own engine or installing a crate engine, might not really know how to break in a new engine while driving. Not saying this is what happened here, but there are many variables that could give issues with the end result of rings not sealing. I will say this, sadly for the O/P, a BIG RED flag went off when I read about rehoning 700 miles after the initial full rebuild, hope things get sorted out. TR
     
  8. There are stranger things than the Bon Ami trick also, even done by the factory's. In the 70's when I was attending Honda { motorcycles } private school, next to us was the BMW factory school. I became friends with one of the guys from BMW and we got talking engine design. We at Honda were looking and studying cylinder Cross hatch patterns under a microscope. He laughed and said with the cast iron cylinders- we just brake the glaze, soak the cylinders in water for a few hours and then leave them out at night to RUST!!. and yes, then they assembled the engines. Cast cylinders, cast rings and lots of RUST, taught by the BMW Factory in thier private school, TR
     
  9. spinout
    Joined: Jan 15, 2008
    Posts: 333

    spinout
    Member
    from Dallas, TX

    First time I heard of the Bon Ami trick, was from an aircraft mechanic friend. So they use it on aircraft too. Who wouda thunk?
     
  10. big creep
    Joined: Feb 5, 2008
    Posts: 2,945

    big creep
    Member

    H&H flatheads does!

     
  11. Hdonlybob
    Joined: Feb 1, 2005
    Posts: 4,115

    Hdonlybob
    Member

    Lots of very interesting info in this thread...
    Totally my opinion, but I think the differences stated here in the metals used for a Cat sleeve and a flat head are significant.
    I totally respect the old timer engine builders, and their tricks usually work well.
    I think you should run this engine for another 1500 miles or so to give it a chance to naturally break itself in first, before resorting to the other recommendations.
    Good luck, and keep us posted...
    Cheers,
     
  12. 34toddster
    Joined: Mar 28, 2006
    Posts: 1,482

    34toddster
    Member
    from Missouri

    What compression reading do you have in each hole?, although that really doesn't affect the oil ring too much maybe you have only one cylinder that is using all the oil, have a close inspection of the plugs, if all 8 are within spec drive the thing another 3000 miles before start dumping shit in a perfectly good engine. Good Luck
     
  13. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,250

    Ebbsspeed
    ALLIANCE MEMBER

    I've heard of the Bon Ami deal, and there is indisputable evidence that it works. For me, I'd rather pour oil into an engine than abrasives. Drive it a couple thousand miles and see if it gets better.
     
  14. alchemy
    Joined: Sep 27, 2002
    Posts: 20,405

    alchemy
    Member

    Since somebody brought this thread back, I'll give the latest details. I have not poured anything down the carb. The car now has 2,500 miles on the engine, with 1,800 since the rehone. It still drinks a quart of oil every 15 gallons of gas.
     
  15. terryble
    Joined: Sep 25, 2008
    Posts: 541

    terryble
    Member
    from canada

    I have done the Bon Ami trick a few times and it has worked, but I am more in tune to the drain the oil put in some cheap straight 30 and drive it like you stole it for a few hours. Vary your speed including a few wide open spurts and don't baby it, after a hundred or so miles change to the oil you are going to run and your oil consumption will be a thing of the past
     
  16. lippy
    Joined: Sep 27, 2006
    Posts: 6,825

    lippy
    Member
    from Ks

    I'm with Terry, I would change the oil, and run the shit out of it. Cyl pressure will help the rings to seal against the cyl walls. Are those two carbs working correctly, is it maybe rich and washing the cyls down and losing ring seal? Just thinking out loud. Valve guides and seals will cause a lot of oil burning and it's hard to see at a constant speed. When you wind it up and back it off is there smoke? If so I'd look at the seals and guides. Plugs should be showing this oil burning. I don't care for the Bon Ami deal, though it makes my fawcett look nice. :D Lippy (Don't run a flathead but I do have a flathead) and one in the shop also.
     
  17. I am a retired mechanic and I would not pour an abrasive into a known good engine. This engine needs to be driven. The oil consumption is not excessive on a engine with so few miles. I would on the other hand drizzle water into a running engine. Warm the engine up and dribble the water slowly into the carburetor throat while holding the RPM at 2500rpm or so. The steam produced will clean up any residue in the combustion chamber, including the cylinder walls. Check the spark plugs afterward to insure that they haven't been damaged.
    What worries me about using an abrasive is that you will never be assured that it is all out of the engine. I can't imagine the long term health of the engine would be improved by this last ditch effort.

    ~Alden
     
  18. boutlaw
    Joined: Apr 30, 2010
    Posts: 1,239

    boutlaw
    Member

    I won't recommend adding BonAmi or not, BUT, in the mid-60's, while in high school, working as a parts helper at a local Chevy dealer, the shop manager, told me that in 55 when the new 265 V8 chevy engined cars arrived at the dealership, most smoked and used oil, and that they were informed by GM to add BonAmi down the carb throat at around 2000 RPM, and according to this seasoned GM mech/shop foreman, it worked wonders for the new V8's. I never saw it done, but he had no reason to BS me. Totally different engine than a flathead, but ring seating was apparently an issue for GM in the mid 50's. I am also a aircraft mechanic (A&P) and I NEVER heard of anyone pouring BonAmi in an aircraft engine. Certainly not manufacturer or FAA approved. Opposed aircraft engines use updraft carbs, so it won;t pour in, but I guess it could be sucked up with the engine running or poured in an upper spark plug hole. Certainly not recommeded by Continental or Lycoming I'm betting. You can always pour in the BonAmi, I would try driving it some more to seat the rings. On aircraft engines, with chrome rings or cylinders, the breakin procedure was critical. If not done properly, the cylinder had to come off and be re-ringed or possibly replaced.

    Outlaw
     
  19. Mike, I really think the answer lies in the reason WHY it was "re-honed" at 700 miles. Why was this done? I'm really trying to help you and your Dad here, I suspect what ever happened with the first hone job, might not have been rectified with the second honing job, thank you, TR
     
  20. I don't know the particulars on the build regarding ring type, clearances, whether a torque plate was used, etc, but they did the re-hone because the engine never stopped consuming oil in those first 700 miles. Same issue as current. Don't remember if it was better, worse, or about the same, though.

    The car has seen all sorts of driving in those 2500 miles: in town, highway, drag strip (HAMB drags), gravel jammin', etc.

    To be honest, I don't think putting another 500-1000 miles on it will change much at this point.
     
  21. patman
    Joined: Apr 30, 2007
    Posts: 575

    patman
    Member

    Cylinder bores out-of-round maybe? Honing would not fix that.
     
  22. Thanks Mike for replying. Thats what I was anticipating you would say. Sorry you and your family are going through this. If I may suggest, stop for a bit and consider the correct options. If your going to take the engine apart again, you need someone who can accurately measure each piston. Not just one. Then hopefully this same person can accurately measure the cylinder bores for size, taper, and flare in the center of the bores. Now determine if these pistons are still usable, if not you will need to rebore and hone or hone to the next size over. If forged pistons are available for your particular engine, {they are expensive}, a good machinist can probably touch-up hone the bores enough for the forged pistons to run just fine. Either way, I would highly absolutely recommend a new set of rings. Make sure to set the end gaps correctly before using them, and they are made of the correct material for the type of finish you have on the cylinders. The machinist must know what type of ring you are using so he can match the stones to give the correct finish for the ring material. You also need the correct finish and the correct X-hatch on the cylinders for the rings to seal. Finally, is clean, clean, and clean again before you assemble. Also have someone who know how to check the valves and guides properly while your apart. Now is the time to make sure you are not running real rich, so you wont wash down the cylinders when you freshen the engine this time. Check your ignition timing and advance now before you tear it down again so when the engine is fresh you don't hurt it. I'm not trying to build you a race engine, just one so this will be the last time you rebuild this one and you and your family can enjoy many, many miles, TR
     
  23. Johnny Switchblade
    Joined: Sep 27, 2010
    Posts: 48

    Johnny Switchblade
    Member
    from Upstate NY

    I haven't seen this mentioned. May be too many miles already but, varying the rpm and decel help to break in rings.
    Vary the Load for Initial Break-In
    For the first 200 miles, drive the vehicle with varying speeds and loads on the engine. Occasional full throttle runs from a rolling start (2,000 rpm or so) to 4,500 will help seat components such as piston rings, but the engine should be cooled after doing this. Also, it is wise to check rocker and valve clearance after 150-2oo miles to insure adjusters are tight and lash is proper. Re-check again at about 500 miles.

    Break-In Plan
    Although it is not necessary, the following procedure will help speed up the break-in process:

    • Make five or six medium-throttle accelerations to about 4,500 rpm before letting off in gear and coasting back down to 20 miles-per-hour.
    • Run a couple hard throttle accelerations up to about 5,000 rpm and once again coast back down to 20 miles-per-hour.
    • Let the engine cool, change the oil and filter, and check the coolant level.
    • Drive the next 500 miles normally, keeping the engine below 5,000 rpm and minimizing operation at idle.
     
  24. alchemy
    Joined: Sep 27, 2002
    Posts: 20,405

    alchemy
    Member

    Wow Johnny, blast from the past.

    I never poured any foreign stuff down this engine, and it has about 6,000 miles on it now. Still uses as much oil as it ever did. I've been on short trips across town, quick blasts down the highway, and long treks to other states. Nothing has made these rings seat any better.
     
  25. slowmotion
    Joined: Nov 21, 2011
    Posts: 3,330

    slowmotion
    Member

    Well, at this point, maybe the BonAmi trick might be worth a shot Alchemy. Been 6 yrs, 6000mi.
    Good read btw.
     
  26. 28dreyer
    Joined: Jan 23, 2008
    Posts: 1,166

    28dreyer
    Member
    from Minnesota

    Yes and well beyond Lycoming and Continental as it was done during WWII on the Wright R1820 radials on B-17 bombers that I am specifically aware of and probably many other as well.
     
  27. Yes, , but it was used by the guys on used car lots to reduce the smokers. I remember as a cheap trick when they didn't want to do a teardown.
    If the valve seals are new, as you suggest, then one trick I have used, is to get the engine warmed up, then spray about 1/2 can of engine cleaner while keeping the engine running. When the can is near empty, spray as rapidly as possible so that the engine will stall. Just leave the engine overnight and you should see an improvement. All this does, is clean the oil off the cylinders and allow the rings to reseat, which is a problem associated with chrome rings.
    Another trick, is run the engine under a high load for long enough to seat the rings. It doesn't have to be at a high RPM. I have had aircraft engines in excellent condition, where the consumption has increased, and by running the engine for about 20 minutes or more at high load, with the propellers in coarse pitch, is enough to solve the problem. This has worked for me several times.
     
  28. I had a '64 Ford that was horrible with oil. A can of Alemite CD2 and 5 quarts of Valvoline 60 weight blower oil cut the smoke back a ton. I had a tired Chevy panel truck with a 6 in it, drive 10 miles to the beach and back, add 3 quarts. So bad I'd use the waste oil from work strained through a shop rag.
     
  29. paleot
    Joined: Aug 29, 2011
    Posts: 232

    paleot
    Member
    from louisiana

    I read through your posts and I don't see mention of engine operating temperature, I have overhauled so many I have lost count. If your engine is not coming up to recommended op temps it will be hard to seat rings. I did a 273 in a Barracuda had to put cardboard in front of the radiator to heat it up enough to make them seat.
     
  30. seb fontana
    Joined: Sep 1, 2005
    Posts: 8,442

    seb fontana
    Member
    from ct

    I would put in 10-40 Amalie Imperial oil and run it...
     

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