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Help Needed to Replace Rod Bearings on 454

 
Hauler308
I love my Chevy Chevette!
Posts: 1
Joined: 06/08
Posted: 06/08/08 01:43 PM

Earlier I posted a request for some info about my 1986 Chevy Silverado C30 1 ton dually with a Big Block 454 that was overheating like a son of a *** when I towed my 13000lb 5th wheel trailer. From Bad to more Worse I got a Knock in my number 7 cylinder, (3er back drivers side) pulled the plug wire and of cause the knock went away. I then pulled the oil pan and the number 7 and number 3 rod caps and of cause the number 7 insert bearings showed signs of heat cracks an quite possibly were spinning or at least had the tabs that lock them in place worn off. The number 3 insert bearings looked good but showed signs of wear at their sides. I would suspect that the other 6 sets are probably worn too, but not knocking yet. The journal that I exposed that held the 7 & 3 rods looks pretty dam good. It has some slight signs of wear such as minor lines but nothing that appears to have been abused to long.

MY SITUTATION IS… I am not in a position to pull the motor and have the crank turned or replace the motor, so I have decided to replace the rod bearing inserts and try to get the truck home to Arizona from California as soon as my business trip is over.(a 700 mile ride done in to short days) NO MORE TOWING OF CAUSE. Blush

 MY QUESTION IS…. 1) Do you think that replacing the bad insert bearings might buy me a Good bit of time, if not fix it for a few thousand miles. (My wife Loves this Truck) 2) Do you think I should go 10 thousandths or so over size in the bad cylinder to compensate for ware or leave it stock. 3) And last do you think I should go ahead and change them All while its open thicken back up to stock and to be sure another one doesn’t crap out on me next week.  

Any help would be appreciated. I can also send some photos.


P.S  I measured 2” + 170 thousands across the journal. Would any one know if that’s close to normal Spec.  I’ve never done a rod job before and don’t know if I need to measure the rod as well and if some of the numbers like 0022 or 0025 are referring to actual bearing thickness.


Thanks………..  

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zach133
I love my Chevy Chevette!
Posts: 13
Joined: 06/08
Posted: 06/09/08 11:29 PM

i'm no expert, but id say your best bet would be to replace them all now, id take the old bearings and go to autozone or something and talk to them about it. then get home with it and look further into it.  

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waynep712
I have an SS396 tatoo
Posts: 358
Joined: 12/07
Posted: 06/11/08 08:12 PM

examine the crank if you have not already fixed. it...   if it is damaged... you really need to swap out the crank...   they can be welded and reground... (its not a race car)

if the rod bearings have spun in their bore .. they will spin again...  there is only a few thousands of crush that holds them in place...

rods will have to be changed...

decades ago i tryed this on MY pontiac motor...  it made it 5 blocks before it started squeeking and locked up.....   and i changed all the bearings.. i just did not turn the crank...  or the spun rods..    i am not saying that it wont work...   it might..  

a used motor is cheeper than a tow in from the road...  

years ago... mechanics and rodders when they spun a rod bearing used some boot leather.. or a section of leather belt...    it worked for a long time...   others have blocked off the oil passage and ran it with that rod pushed up the bore...   with a 454  the stroke may be too long...

i know this is not a a lot of help... but good luck anyway...  

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