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  •  » Rod bearings

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    8/19/2022 12:21 PM  #1

    Mark Hone
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    From: Ontario Canada
    Registered: 4/08/2013
    Posts: 37

    Rod bearings

    I have to convinced myself that I should replace the rod bearings (/66 289). I am unable to remove the engine but can raise the car a foot or so. Is it possible to replace the rod bearings and maybe the main caps while in the car. As far as I know the crank is original. I have some mechanical skill so if it’s possible I could do it (he said just before,,,). I would just be going back to original sizing. Thanks. Mark

     

    8/19/2022 1:14 PM  #2

    Bullet Bob
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    Re: Rod bearings

    I have been able to drop the pan by dropping the idler arm and letting the center link fall as low as it will.  Or maybe I had to knock loose a tie rod end.  Been a while.  But, why do you think it needs new rod bearings?  If it's knocking due to rod bearing failure it is likely going to need more than just a new set of bearings....like crank grind, main bearings, timing set....pretty much a complete rebuild.  Just sayin'.

    Last edited by Bullet Bob (8/19/2022 1:18 PM)

    "you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
     

    8/19/2022 1:49 PM  #3

    Mark Hone
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    From: Ontario Canada
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    Re: Rod bearings

    No rapping I can hear. A little low oil pressure (by gauge in dash, gets lower under acceleration, goes up (marginally) under deceleration, seems like a (fairly) easy job, will give me an idea of bottom end condition, peace of mind unless I f@&# it up, inexpensive. See, I told you I have convinced myself with reservations.

       •Thread Starter
     

    8/19/2022 2:56 PM  #4

    Bullet Bob
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    Re: Rod bearings

    Oil pressure drop under acceleration normally is an indication of worn main bearings.  Have you run a compression check or leak down test?  You might put a mechanical OP gauge on it and see exactly what the pressure is doing, just so you know.  You may be right on the cusp of an engine job.  Might be better to save you time and $$ and do it once....right.
    I normally advise to find a core (5.0 roller in this case) and do a slow, careful rebuild as you can afford it.  Then weekend the engine swap.  That way you don't have to lay down big $$ all at once and you have minimum down time on the car.

    BB1
     

    "you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
     

    8/19/2022 3:48 PM  #5

    Bolted to Floor
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    Re: Rod bearings

    I’m not familiar with an oil pressure drop on acceleration.  Everything I’ve owned whether is was worn out or in descent shape may have a low pressure at oil pressure at idle but would increase as the RPMs increased.

    I’d start with a good oil pressure gauge.

    John  -- 67 Mustang Coupe 390 5 speed
     

    8/19/2022 4:19 PM  #6

    MS
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    From: Canyon Lake, Texas
    Registered: 1/24/2013
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    Re: Rod bearings

    Stick a high volume oil pump on it and let it be until you final a roller 5.0 to build and replace it.  I guarantee you, the WYAIT MONSTER will grab you by the balls and you will lay on your back, replace 7 bearings, then the eighth one will be bad and you will wind up yanking the engine anyway.

    Yes, you could change them, but it is difficult to plastigage laying on your back. Not worth the effort. If you want to do it, just pull the engine.  It is just a bunch of bolts…

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    8/19/2022 7:28 PM  #7

    6sally6
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    From: Surfside Beach,SC
    Registered: 4/02/2013
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    Re: Rod bearings

    +...you're gonna need more than "lifting it a couple feet"!
    Don't sweat the oil light coming on at idle and such (wish I would take my OWN advice!
    FoMoCo small blocks have a terrific oiling system and do NOT need high oil pressure to function well (like a Shivel-lay)!
    I would put thicker oil in it.....STP....idle it up a tad... and/or all the above before I would climb under mine and wrestle with all that's involved to drop the pan....much less start pulling two piece bearings! Mine is so clean underneath from doing other things I wouldn't hardly get greasy and I still wouldn't do it!
    At the MOST you should drop the pan and replace the oil pump with a hi pressure pump!
    (That will be messy enough for someone with  "some" mechanical ability)
    6sally6

    Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
     

    8/19/2022 8:56 PM  #8

    rpm
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    Re: Rod bearings

    Notwithstanding why you want to change your rod bearings, yes it can be done. I removed all of my bearings before dropping the crank to get it repaired with the motor still in the 69.

    Bob. 69 Mach 1, 393W, SMOD Toploader, Armstrong  steering, factory AC.
     

    8/19/2022 11:33 PM  #9

    Mark Hone
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    From: Ontario Canada
    Registered: 4/08/2013
    Posts: 37

    Re: Rod bearings

    Thanks all. I will start with a real oil pressure gauge and see what’s what. Mark

       •Thread Starter
     

    8/20/2022 11:10 AM  #10

    BobE
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    From: White Plains, NY
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    Re: Rod bearings

    How many miles are on this engine?
    Check Amazon, you can get an inexpensive 60 or 100# gauge, 2” diameter, back mounted with ¼” NPT thread.  Remove the installed sender, and install the gauge.
    Original OEM specs for oil pressure is 35-55psi. 

    65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
     

    8/20/2022 7:49 PM  #11

    Mark Hone
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    From: Ontario Canada
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    Re: Rod bearings

    Thanks BobE. I did just that. A cheap 60# gauge for $9.00. 53,000 miles on the clock. 153,000 or 253,000 don’t know but I suspect 153,000

       •Thread Starter
     

    8/20/2022 7:54 PM  #12

    Bullet Bob
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    Re: Rod bearings

    It's dun!

    "you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
     

    8/21/2022 6:09 AM  #13

    TKOPerformance
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    Re: Rod bearings

    You have to understand that we now live in a world where electronic fuel injection has made fueling so precise, and engines have gone to rollerized valvetrains, so its not considered uncommon for gas engines to go 300k miles or more.  These old carbureted engines were only really designed to go 100k.  They just wear out faster.

    My advice would be to verify the oil pressure.  If you have decent pressure I'd leave it alone.  If you don't I'd do a compression test, because my guess is that if the bearings are worn out, so are the rings, etc.  In which case its time to pull the engine and rebuild it, or build something else to swap in.  IME throwing new parts at a worn out engine is a quick way to waste money and chase your tail.  This is one of those situations where can you swap bearings with the engine in the car?  Sure, the the real question is should you?  I'd swap bearings in a relatively fresh engine due to the need to make a repair from something that went wrong, but I wouldn't do it in an old worn out engine to try and get a few more miles out of it.  Just my $0.02
     

     

    8/21/2022 9:34 AM  #14

    BobE
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    Re: Rod bearings

    I agree w/TKO regarding an entire rebuild, rather than just changing bearings.  If the oil pressure is a little low, add some STP as other posts have suggested, and keep on driving until you really need to do a rebuild.
     
    TKO – regarding modern vehicles, I totally agree, my 2010 Murano daily driver has 168k miles, I change the oil every 6k, it doesn’t burn any oil, I can maintain 80-85MPH on the highway.  I did have the transmission replaced (under warranty) at 117k miles, otherwise it’s still going strong and without the rust issues of years ago.

    65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
     

    8/21/2022 9:47 AM  #15

    Raymond_B
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    Re: Rod bearings

    Like BB said *main* bearings would affect oil pressure. Does oil pressure change any between hot and cold?

    Also oil pressure dropping on accel and coming back up (if that reading is to be trusted) would probably indicate low oil or the oil pump pickup is clogged/loose vs rod bearings. The oil moves away from the oil pump pickup in a front sump pan.

     

    8/21/2022 3:53 PM  #16

    TKOPerformance
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    Re: Rod bearings

    BobE wrote:

    I agree w/TKO regarding an entire rebuild, rather than just changing bearings.  If the oil pressure is a little low, add some STP as other posts have suggested, and keep on driving until you really need to do a rebuild.
     
    TKO – regarding modern vehicles, I totally agree, my 2010 Murano daily driver has 168k miles, I change the oil every 6k, it doesn’t burn any oil, I can maintain 80-85MPH on the highway.  I did have the transmission replaced (under warranty) at 117k miles, otherwise it’s still going strong and without the rust issues of years ago.

    Yep, 284k on my daily driver F250.  Granted its a Diesel, but it also makes literally twice the power it did when it left Ford.  I bought my FJ Cruiser with just under 100k on it.  I consider that barely broken in.  With the 10k a year my wife will put on it the kids will be in college before its got 250k.  My WRX is still going strong with 218k on it too.  Change the oil and filters regularly and replace stuff that wears out.  Use OEM or equivalent parts.  Do that with most vehicles now and they should go 300k or more. 

     

    8/22/2022 7:10 AM  #17

    BobE
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    Re: Rod bearings

    TKOPerformance wrote:

    BobE wrote:

    I agree w/TKO regarding an entire rebuild, rather than just changing bearings.  If the oil pressure is a little low, add some STP as other posts have suggested, and keep on driving until you really need to do a rebuild.
     
    TKO – regarding modern vehicles, I totally agree, my 2010 Murano daily driver has 168k miles, I change the oil every 6k, it doesn’t burn any oil, I can maintain 80-85MPH on the highway.  I did have the transmission replaced (under warranty) at 117k miles, otherwise it’s still going strong and without the rust issues of years ago.

    Yep, 284k on my daily driver F250.  Granted its a Diesel, but it also makes literally twice the power it did when it left Ford.  I bought my FJ Cruiser with just under 100k on it.  I consider that barely broken in.  With the 10k a year my wife will put on it the kids will be in college before its got 250k.  My WRX is still going strong with 218k on it too.  Change the oil and filters regularly and replace stuff that wears out.  Use OEM or equivalent parts.  Do that with most vehicles now and they should go 300k or more. 

    I should have added that I did have to repalce the front suspension bushings a few months ago, I would consider this normal wear.
    I'm curious, your FJ Cruiser, is (was) there any frame rot?  A few fiends that had them had frame rot that Toyota didn't cover like they did for the pickup trucks. 

    65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
     

    8/22/2022 6:23 PM  #18

    TKOPerformance
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    Re: Rod bearings

    BobE wrote:

    TKOPerformance wrote:

    BobE wrote:

    I agree w/TKO regarding an entire rebuild, rather than just changing bearings.  If the oil pressure is a little low, add some STP as other posts have suggested, and keep on driving until you really need to do a rebuild.
     
    TKO – regarding modern vehicles, I totally agree, my 2010 Murano daily driver has 168k miles, I change the oil every 6k, it doesn’t burn any oil, I can maintain 80-85MPH on the highway.  I did have the transmission replaced (under warranty) at 117k miles, otherwise it’s still going strong and without the rust issues of years ago.

    Yep, 284k on my daily driver F250.  Granted its a Diesel, but it also makes literally twice the power it did when it left Ford.  I bought my FJ Cruiser with just under 100k on it.  I consider that barely broken in.  With the 10k a year my wife will put on it the kids will be in college before its got 250k.  My WRX is still going strong with 218k on it too.  Change the oil and filters regularly and replace stuff that wears out.  Use OEM or equivalent parts.  Do that with most vehicles now and they should go 300k or more. 

    I should have added that I did have to repalce the front suspension bushings a few months ago, I would consider this normal wear.
    I'm curious, your FJ Cruiser, is (was) there any frame rot?  A few fiends that had them had frame rot that Toyota didn't cover like they did for the pickup trucks. 

    No, and its the reason I was willing to pay what I did for it.  Its an '07 that everyone assumes is a new vehicle due to the condition. 
     

     

     

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