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Technical One cylinder dull knock under load

Discussion in 'The Hokey Ass Message Board' started by Fabulous50's, Mar 24, 2021.

  1. blowby
    Joined: Dec 27, 2012
    Posts: 7,737

    blowby
    Member
    from Nicasio Ca

    Doesn't sound like a rod knock to me, usually quieter under load. Did you try and wiggle the rod around to see if the pin or piston are loose?
     
  2. TA DAD
    Joined: Mar 2, 2014
    Posts: 423

    TA DAD
    Member
    from NC

    How could you trust anyone's work who would allow all that spray paint inside the motor.
     
  3. Fabulous50's
    Joined: Nov 18, 2017
    Posts: 322

    Fabulous50's
    Member
    from Maine

    My thoughts exactly. And every Rod is in the wrong bore the Caps are all matched with rods but the numbers are all off it just seems they put whatever in haphazardly. This was actually done at a Ford dealer in 1988. The previous owner was an accountant not mechanical at all and had the dealer do everything where he worked
     
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  4. Fabulous50's
    Joined: Nov 18, 2017
    Posts: 322

    Fabulous50's
    Member
    from Maine

    Yes I removed every cap and checked wrist pin tightness and feel they all felt perfect. I know the type bearing is not the source of knock. The knock is very slight oh, it is definitely only in one cylinder. And is something in this bottom end.
     
  5. Torana68
    Joined: Jan 28, 2008
    Posts: 1,258

    Torana68
    Member
    from Australia

    Im a bit confused, your still looking for the noise? there it is right there in your photo below.




    [​IMG]
     
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  6. RidgeRunner
    Joined: Feb 9, 2007
    Posts: 906

    RidgeRunner
    Member
    from Western MA

    Do you remember if one rod nut might have been a bit looser than the other when you pulled that rod cap?

    Ed
     
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  7. Fabulous50's
    Joined: Nov 18, 2017
    Posts: 322

    Fabulous50's
    Member
    from Maine

    No all rod nuts were tight. Spec is 50 ft.lbs. I'm going to measure the big end of the rod to see if it's out of round.

    I'm aware, I'm just looking to figure out what caused it. I'm going to replace all the bearings, just dont want this to happen again.

    I've never seen a bearing wear just in one spot that didnt have a burr or some debris behind it in that spot.
     
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  8. 1971BB427
    Joined: Mar 6, 2010
    Posts: 6,899

    1971BB427
    Member
    from Oregon

    Be sure to check the journal in several directions to make sure it's not machined out of round. Just checking one direction wont reveal a out of round journal.
     
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  9. Yes,,,,very possible the journal was not 100% right to start with .
    It is a new crank,,,,possibly machined a little off,,,or out of round ?
    Check the rod journal as well,,,,,,maybe a high spot on the area of rod,,,,holding the bearing out somewhat.
    Or just a defective bearing that had a high spot .
    I would mic the thickness of the bearing shell in that area .

    Tommy
     
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  10. 73RR
    Joined: Jan 29, 2007
    Posts: 6,577

    73RR
    Member

    ...that ain't a good sign......
     
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  11. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,318

    Dan Timberlake
    Member

    Have you Plastigaged rod #6 yet ?

    I'd expect to find something very funky indeed. To the extent getting that rod out for detailedbig end inspection at a minimum.
     
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  12. Fabulous50's
    Joined: Nov 18, 2017
    Posts: 322

    Fabulous50's
    Member
    from Maine

    No, it was so tight there was no side to side movement. It just was squashed onto the crank journal. I'm borrowing a micrometer, bore scope, and bore micrometer this weekend to have a looksee.
     
  13. TA DAD
    Joined: Mar 2, 2014
    Posts: 423

    TA DAD
    Member
    from NC

    So that rod had no side clearance ?
     
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  14. jaracer
    Joined: Oct 4, 2008
    Posts: 1,099

    jaracer
    Member

    Most rod knocks are on a float. They typically don't knock under load. However, I worked at a dealership and we sold a used C10 with a 350 to a kid. He brought it back and said there was a noise in the engine. The owner's son, Paul, called me out to listen to it. It was a knocking noise under acceleration and you could hear it when the engine was revved up. Paul thought it was carbon on a piston, I thought it was deeper in the engine. Paul proceeded to spray a lot of water in the carburetor and then took it out on the highway to blow the carbon out.

    About 15 minutes later Paul walked in the showroom where we were eating lunch. His brother, Phil, asked it he figured out what the noise was. Paul said it was number 2 rod. Phil said how in the world can you tell it is number 2 rod just by driving it? Paul said easy, now I can read the number on it.
     
  15. lippy
    Joined: Sep 27, 2006
    Posts: 5,550

    lippy
    Member
    from Ks

    Looks like the rods big ends weren't re-sized last time. Lippy
     
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  16. RodStRace
    Joined: Dec 7, 2007
    Posts: 2,607

    RodStRace
    Member

    Yeah, a crank journal out of round would wear all around the bearing.
    Think about one fan blade longer than the rest. It will wear on the shroud all the way around.
    The rod is not round or there was trash behind the bearing at the wear point.
    There is no way I'd slap another bearing in and run it.
    I'd have that whole engine down and check everything since the work is questionable (paint inside bottom end, rods out of order, messed up bearing).
     
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  17. Kevin Ardinger
    Joined: Aug 31, 2019
    Posts: 338

    Kevin Ardinger

    That’s the way ones I’ve seen wear before. The crank is probably rough, first layer of bearing material goes away and that spot is probably where the most load is when the piston is fired downward. I assume that is the upper bearing. A lot of trash has been through the other half.


    Sent from my iPhone using H.A.M.B.
     
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  18. jimmy six
    Joined: Mar 21, 2006
    Posts: 9,442

    jimmy six
    Member

    No one painted the bottom of the engine. The timing chain cover was off and it only effected the front side of the first main and I would guess it’s over spray from long ago.
    If you have the heads off it’s pretty easy to make all the repairs to the rods and install them correctly. Remember a Ford is 1-2-3-4 front to back on the passenger side and 5-6-7-8 front to back on the drivers. The most forward one in # 5 and it’s on the same throw as #1.

    With all the rod/piston combo out you can check the crank for out-of-round easier and there is a tolerance. All it takes is time and a good gasket set from “Best Gaskets” good luck.
     
    Last edited: Mar 26, 2021
  19. Joe Travers
    Joined: Mar 21, 2021
    Posts: 330

    Joe Travers
    Member
    from Louisiana

    I bought a 289 car from a 'so-called friend' many years ago and found the same thing after I pulled the engine. Sorry to hear this :( I was led to believe the high-mileage engine had never been touched. Someone very inexperienced had torn it down and *cough**cough* re-built it. Good short blocks were available back then, so I bought one, brought the heads to the machine shop and put it back together. Always a crap shoot brother. Happens to the best of us. :(

    Joe
     
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  20. Ford dealer rebuild. Possibly flat rate shop and they had an "apprentice" who was paid by the hour at a very low rate do the rebuild. Journeymen mechanics who receive a flat rate for repairs set by the manufacturer were too experienced and valuable to spare on an employee rebuild. Several years ago a reputable local shop hired a new machinist to bore blocks and regrind crankshafts. Some customers came into the parts counter complaining the .010 over bearings they bought had some .030 and .020 sizes in to make a complete set. The difference was traced back to the "new hire machinist" who could not grind two bearing surfaces identical on the same crankshaft. Engine bores were found to be the same with some blocks receiving .010 to .040 bores and no two alike. These were all makes of engines not just one brand so he was let go. The shop never did recover and went out of business. what had been an established local business was destroyed within a week by a "machinist" who knew nothing about what he was doing.
     
  21. Torana68
    Joined: Jan 28, 2008
    Posts: 1,258

    Torana68
    Member
    from Australia

    Post Up a photo of the back of that bearing shell where the damage is. Get everything measured before you put it back together.
     
  22. Fabulous50's
    Joined: Nov 18, 2017
    Posts: 322

    Fabulous50's
    Member
    from Maine

    Back of bearing where damage is. 16168529193705768950331327227766.jpg

    16168530274201462893073733712234.jpg

    Bearing measured 0.793 at wear point, and 0.810 where no wear is showing.
     
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  23. lippy
    Joined: Sep 27, 2006
    Posts: 5,550

    lippy
    Member
    from Ks

  24. Fabulous50's
    Joined: Nov 18, 2017
    Posts: 322

    Fabulous50's
    Member
    from Maine

    I'm pulling the engine...... as much as I dont want to. Measured the rod big end in 4 places and found a total out of round to be 0.0083 tolerance is 0.0002 which of course corresponds with the wear point on the bearing. 16168627079715239537048336328009.jpg

    And of course this rod is in backwards...then other 7 are correct. Also found there are 2 number 6 rods and no number 5. So when the reground crank was installed there must have been a used rod installed in place of # 5 which presumably spun. Someone should have taken the time to measure the big ends of the rods. But this was done in 1989, and it was driven until 2001.
     
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  25. 73RR
    Joined: Jan 29, 2007
    Posts: 6,577

    73RR
    Member

    It is actually quite amazing that it made 10K miles...Ford tough...
     
  26. If it was 8 thou out of round then I would say it’s amazing it stayed together as well.


    Sent from my iPhone using H.A.M.B.
     
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  27. Fabulous50's
    Joined: Nov 18, 2017
    Posts: 322

    Fabulous50's
    Member
    from Maine

    I can't figure out what caused it... the rod doesnt show any signs of ever having had a spun bearing. It is within spec of not having been resized. This is a stock 250 horsepower engine with an Autolite 2100 2 barrel.

    I used a borescope and checked that all pistons were in correctly and they all are. Just this rod is the problem child it seems.
     
  28. jimmy six
    Joined: Mar 21, 2006
    Posts: 9,442

    jimmy six
    Member

    Not having them in the correct direction, there should be some witness scoring on the edge of the bearing on the counter weight side unless a 352 is different than most engines. All is weird.
     
    54 ford coupe likes this.
  29. Joe Travers
    Joined: Mar 21, 2021
    Posts: 330

    Joe Travers
    Member
    from Louisiana

    Some of the original rods may have been replaced with donors due to stress cracking. Considering the bearing wear, I highly doubt it but it's a possibility. Swapping rods would require special attention that obviously was shown by the builder. The old FE rods will crack below the wrist pin with age. If you're pulling the engine, consider having the rods Magnafluxed to check for cracks that aren't obvious. Yes, it's only 250 hp but it's old. No telling what the rods have been through at their age.

    Joe
     
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  30. 19Eddy30
    Joined: Mar 27, 2011
    Posts: 1,276

    19Eddy30
    Member
    from VA

    in pics . Does not look to been Hammering the bearing ( if so not that long ) as we can see tight at that spot .
    Not related to the crank Journal or your rod,Problem
    I was chasing down a weird sound,
    I would hear this Weird knock ,not like a rod bearing , & a slight click hollow sound about every 45 sec to 2mints depending on the RPMs, chase this sound for about a month, sometime it would sound deep on the bottom end and sometimes not , I could tell it was on DS #5 or 7 cylinders, come to find out it was #7 (chevy) the Exhaust Guide bad (bronze guide) , as the valve was rotating , the sound was the valve centering its self up to Valve seat when closing .
     
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