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Discussion Starter · #1 ·
What will happen if the order of the pistons and connecting rods are mixed up and put back into an engine in any order after overhaul? In that instead of them staying in the order in which they came out, they are mixed up. Block was honed at machine shop, and a 289 by the way. Pistons were never unconnected from the connecting rods, and they are still stock, noting but being cleaned were done to them. Will this cause vibration to happen in the motor making it "self destruct" over time?
 

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Look on the connecting rod & cap for identification numbers. They should be there unless its a virgin rebuild
 

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I wouldn't think this would be a problem as long as you put the pistons in the correct way, dots pointing to the front of the block. The rods are chamfered on one side and that side of the rod needs to face toward the outside of the crank journal
 

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Piston pins are offset if you switch sides you change your piston to deck height, ( some pistons will sit higher then others ).
 

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Nothing will happen unless the pistons are really crappy and the block was honed to match each one - not a normal situation. Swapping piston/rod assys around to correct deck variations is pretty common. What must not change is the rod and cap relation - mix the rods and caps and you've got trouble.
 

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On 2006-04-04 03:52, Freddie wrote:
Piston pins are offset if you switch sides you change your piston to deck height, ( some pistons will sit higher then others ).
Thats assuming the person installing them didn't notice the offset pin location in the piston and installed the piston/rod assy backwards. It's entirely possible to install the 1-2-3-4 rods/pistons on the 5-6-7-8 side and vice-versa without affecting the deck height.
 

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Discussion Starter · #8 ·
What must not change is the rod and cap relation - mix the rods and caps and you've got trouble.
Are there numbers one the connecting rods that will match the cap to match them back up? Machine shop really messed me up taking my tags off the piston/connecting rods and then taking the caps and throwing them and the piston/connecting rods all in a box together, ill know not to use them anylonger.
 

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On 2006-04-04 11:52, ckelly wrote:
Nothing will happen unless the pistons are really crappy and the block was honed to match each one -
Reminds me of a 351w I bought once. Had 7 dished pistons all standard bore...one flat top .030". I still have that block, in fact, it's in the Maverick I think
 

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Sounds like your on a severe budget. However, id have to recommend
that if you dont know what caps go with which ,you need to start over and have the rods resized. If you dont you could spin a rod bearing in an instant from the mis-matched parting line on the cap-rod match.
Id have the assembly rebalanced if you were going with new pistons, but you might be ok with the stock pistons for a "Getting by rebuild" if you dont rev it past 4500 or try to get more performance out of it because of the imbalance factor.
Good luck
 

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Typically, there are numbers on OEM rods. Look for them on the side of the rod caps. Yes, do not use a shop like that again. Connecting ros and caps are to be treated as matched components. Good shops will mark the caps and rods with a punch if there is any doubt on what goes where. If you replaced the bolts and did not have the big ends resized, it would be time to do it now.
 
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