do 340 rods wear out?

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abodylurker

abodylurker

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On the piston end. I would like to put 340 full floating rods in my 360 and found a set for sale but I got to wondering if the piston end usually is ok or do they usually need rebushed or reamed for a bigger pin. And I wondered if all 340 rods were full floaters? Thanks in advance of a response.
 
Most rod failures are due to the bolts. Get new bolts and have them installed and the rod reconditioned. They can also bush the piston wrist pin bore also if needed. After 5 tightening cycles, you are stretching the bolts to where they may get weaker.
 
Think twice. Sometimes, new rods are cheaper. This is also a HP level dependent item. For the price, often you can get new rods that are stronger and cheaper than rebuilding old ones.
 
Pricewise ,if they need to be rebushed, would it be as cheap to just have my 360 rods bushed?
 
Reworking old OEM rods is never worth the money. Lets look at some ballpark figures.

Press old pistons off .........$5 each
Glass bead/Cleaning .........$30
Magnuflux ......................$5 each
Resize big end..................$18 each
Convert small end to bushing....$80
ARP bolts.........................$70
Bushings..........................$32
total...........................$440 ballpark depending on shop

New SCAT I beams .......$330

Less money for a lighter, stronger, more accurate piece.
 
skrews said:
Reworking old OEM rods is never worth the money. Lets look at some ballpark figures.


total...........................$400 ballpark depending on shop

New SCAT I beams .......$330

Less money for a lighter, stronger, more accurate piece.
Click to expand...

xs2
 
The new rods do not have oil squirt holes. I like squirt holes.
 
krazykuda said:
The new rods do not have oil squirt holes. I like squirt holes.
Click to expand...

I agree. i like the idea of having the extra oil lubing the wrist pins and cooling the pistons. I wish the new rods came with oil squirt holes.

I just paid $150 to have my 340 rods resized on the big end, and install new bushings. Plus I bought new arp wave locks at $80. If I had to do it again I think I would just buy a set of scat rods.
 
ALL 340 rods were bushed. I've seen one or two factory bushed 360 engines. A lot of early 318s and 273s were bushed. My 331 Hemi has factory bushed rods. In general, the factory rods are great pieces. It's always good to know their history though. If they were used in a stock or mild engine and didn't see extreme RPM, they will be fine. But, everything has a service life. I would invest having them cleaned and magnafluxed at the very least. If they pass a mag test, have them rebuilt with good rod bolts and spin the hell out of them.
 
The Scat I Beams are stronger and lighter then factory rods. Less weight means quicker revs and less stress on the rotating assembly.

You don't need the oil holes in the rods even for a street driven car.

Like stated above by the time you get the factory rods reconditioned you could have bought the stronger/lighter Scat I beam rods.
 
krazykuda said:
The new rods do not have oil squirt holes. I like squirt holes.
Click to expand...

I have Scat I-beams in my stroker, no oil squirt holes...I talked to my machinist before I built my motor because I was alarmed that these holes were missing, he informed me that over the years they discovered that they aren't needed. So I went ahead and built my motor...now 5 years later, with TONS of abuse, mid 10's in the 1/4, driven on the street weekly, no problems whatsoever. The Scat I-beams are a great rod for the price.
 
Generally Speaking,

* 1968 thru 1973 > '340' Connecting Rods.... #2899496

* Full-Floating Piston Pin
* Weight............ 758 Grams

In most cases, 'stock' Street Performance 340 Engine Connecting Rods do not develop a
problem in the Piston Pin 'bushing'.

For Performance tolerances, a Machine Shop with a Sunnen "LBB-1810" Power-Stroke
Rod Reconditioning Machine is the 'best choice'.

Machine Shops are charging around $150 to $175 to recondition {hone} '340 Rods'.

With the 'ARP' High Performance Series {#144-6001} Connecting Rod Bolts, that adds
in another $75.
 
Scat I-beams are about 595 grams.......WAY lighter than stock, and WAY stronger (4340 steel).
 
the stock 340 rods are bad ***. many races/championships have been won with those.

only reason i would suggest upgrade is if you are trying to fine tune the bob weights / lightening crank etc where you want to run 9000 rpm or something. then with that kind of sponsored budget money i would get billet rods from callies to go with a billet crankshaft lol
 
Personally, if it's anything up to medium duty - the seasoned factory rods are fine. Like Skrews said, the price can be more money but for me it ends up almost a wash so if the plan doesn't mandate them (meaning power level, rpm, etc) then I'll use factory rods and ARP bolts. I've heard of guys running the pins as floating without bushings. Personally never tried it, and I don't think I'd do it that way - but I've heard of running them with no issues noted.
on the oil holes - no - not needed. Assuming you have the right wall finish for the rings you have, all you're doing is making life harder for them to clear the oil off the walls. Wall finish, piston design, ring materials and design, and understanding of oil control have come a long way in 60 years.
 
skrews said:
Reworking old OEM rods is never worth the money. Lets look at some ballpark figures.

Press old pistons off .........$5 each
Glass bead/Cleaning .........$30
Magnuflux ......................$5 each
Resize big end..................$18 each
Convert small end to bushing....$80
ARP bolts.........................$70
Bushings..........................$32
total...........................$440 ballpark depending on shop

New SCAT I beams .......$330

Less money for a lighter, stronger, more accurate piece.[/QUO

Thanks! This is exactly what I needed. And to everybody. Nobody talks smallbock like this forum!:prayer:
Click to expand...
 
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