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-   -   What is involved in rebuilding rods? (http://www.hotrodders.com/forum/what-involved-rebuilding-rods-190605.html)

Silver Surfer 01-11-2011 11:15 PM

What is involved in rebuilding rods?
 
The title says it all, how do you rebuild them? What is involved here?

timothale 01-11-2011 11:55 PM

connecting rods?
 
connecting rod bottom ends can stretch and distort at high loads and rpm's. If there is too much crankshaft end play the surface can be rounded instead of flat in that direction. the rebuild process is to machine the flat connecting surface, then bolt the pieces together and torque. that then makes the hole a modified oval, then machine the hole round to the correct size. the piston end on some rods have a bushing that can be replaced then machined to size, , also the rod can be twisted, and requires straightening, this machine work can shorten the center to center length which cannot be corrected. removing material can effect balance so that is the next step in a performance engine.

BOBCRMAN@aol.com 01-12-2011 06:33 AM

All the above. Plus I magnaflux and shot peen them. No use rebuilding a cracked rod.

matts37chev 01-12-2011 08:06 AM

ive found, that often by the time you pay to have all that done, unless you have some really special con. rods, its not much more to just go buy new ones

bullheimer 01-17-2011 04:42 PM

Quote:

Originally Posted by matts37chev
ive found, that often by the time you pay to have all that done, unless you have some really special con. rods, its not much more to just go buy new ones


what he said

do you mean "re-sizing" them for say, ARP bolts?. i have discovered that rather than using arp bolt$ and paying more big bucks to re-size the rods (required), that it is waaaaaay better to just buy new stock rod bolts, and use them, then you dont have to resize the rods. you would be , i think, better off buying cheap new rods than going the arp route, right BobCRman?????? hey dude!!! :welcome:

BOBCRMAN@aol.com 01-17-2011 04:59 PM

Sorry, but ANYTIME you disturb rod bolts, such as installing new stock ones or aftermkt. You are pressing a different shape into the bolt hole. Re-sizing is required. Most used rods are going to be out of round anyways..

Silver Surfer 01-18-2011 03:13 PM

So if they machine metal off the rod to restore a flat surface and make the lower rod journal round...doesn't that make an already used rod even weaker?

Good point about throwing the engine balance off...sounds like buying new rods is the way to go!

Silver Surfer 01-18-2011 03:16 PM

Quote:

Originally Posted by bullheimer
what he said
do you mean "re-sizing" them for say, ARP bolts?

Wow I had no idea you had to resize for ARP's!

1971BB427 01-19-2011 09:05 AM

Quote:

Originally Posted by Silver Surfer
So if they machine metal off the rod to restore a flat surface and make the lower rod journal round...doesn't that make an already used rod even weaker?

Good point about throwing the engine balance off...sounds like buying new rods is the way to go!

There are tolerances that need to be held. They don't take enough off a rod when they resize it to weaken it. If it needs more than a set amount they just toss them. Having rods checked and resized is pretty minimal cost compared to new rods. The shop that did the machine work on my 427 charged me $8 per rod to check and resize them.

matts37chev 01-19-2011 09:17 AM

Quote:

Originally Posted by 1971BB427
There are tolerances that need to be held. They don't take enough off a rod when they resize it to weaken it. If it needs more than a set amount they just toss them. Having rods checked and resized is pretty minimal cost compared to new rods. The shop that did the machine work on my 427 charged me $8 per rod to check and resize them.

pressed pin?
because my math includes hanging pistons.
so if you buy new rods, you can get floating pin and assemble them yourself :thumbup:

i would rather spend my money on new upgraded parts, then pay someone else to do a bunch of labor on older stressed out stuff (but this only applies to, original low perf., parts) :thumbup:

1971BB427 01-19-2011 07:42 PM

Yes, my 427 has pressed pins. I guess they're good enough for me, as it dynos at around 465hp, and it's been 10 yrs. of fun since I rebuilt it. I suppose it may go any day now. :)

bullheimer 01-21-2011 11:52 AM

Quote:

Originally Posted by BOBCRMAN@aol.com
Sorry, but ANYTIME you disturb rod bolts, such as installing new stock ones or aftermkt. You are pressing a different shape into the bolt hole. Re-sizing is required. Most used rods are going to be out of round anyways..


not like i need to verify anything you have to say bob, but my machinist said the same thing as you. in jim hands book he said you wouldnt have to. but regardless, you need to check them and most of the time, as i understand it now, you will have to resize them anyway, even with a stock bolt.


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