Shotpeening rods

[The1]

Are they truly a necessity? The reason I'm asking this is because I really can't find no one that does them locally so I'm just looking like :shrug: for the time being. I'm just trying to do a basic rebuild because I'm not looking for 500 hp, just a reliable 375-400.

 

[IJ.]

It stress relieves the surface of the rod if done correctly
(most times it isn't)

 

[The1]

I always wondered its purpose. Even though it's basic, I still want a quality build. It sucks being poor.lol

 

[IJ.]

It's the finishing touch on well prepped rods and shouldn't be too expensive.

 

[The1]

But finding someone that does them is my biggest dilemma.

 

[IJ.]

Nah the big trick is finding someone that knows how to do it correctly

 

[The1]

Nah the big trick is finding someone that knows how to do it correctly

I'll send them your way... :icon_bigg

 

[IJ.]

I have a couple of shops here that can do it but shipping's gonna kill

 

[DL.]

IJ, maybe for everyones benefit, could you explain the proper way of shotpeening rods? I'm not sure I could explain the correct way, or how to find a shop that does it right.

 

[IJ.]

Has to be xx size shot

xx angle and xx pressure.

Sorry I can't be more specific but it's not just a case of blasting away at em like most shops do.

Add to this any grinding/sanding/polishing of the beams needs to be done lengthwise and not across them and it's one of those jobs I leave to the guys that are equipped to do it. (not to mention new bolts resizing, end balancing and small end bushing)

Once added up AM rods don't look quite so expensive

 

[Yeahdoug]

As someone who works with parts that depend highly on different levels of shot peening (valve springs) I'll tell you this. It's more beneficial then you think.

Shot peening doesn't stress relieve. It induces benificial compressive residual stress into the part. By having this compressive residual stress, it is harder for cracks to form and propagate. Increasing the parts fatigue life.

I'd suggest a condition cut wire steel shot around .3 mm- .35mm. This will give you decent depth. but still give you a nice surface finish. You could double peen with a smaller shot too, but it will be hard to find someone with access to shot smaller than that.

I've done a lot of R&D with all different kinds of shot material and sizes for our springs.

 

[IJ.]

^ And this is why I wasn't specific it's an exact science as Doug has pointed out (sorry for my gumby explanation but I figured "stress relief" was about as techie as anyone would care about)

 

[jetjock]

What yeahdoug said. If that's hard to visualize just look at the bottom of any aerosol can, a perfect example of compressive residual stress.

 

[Yeahdoug]

^ And this is why I wasn't specific it's an exact science as Doug has pointed out (sorry for my gumby explanation but I figured "stress relief" was about as techie as anyone would care about)

no problem

 

[Rennat]

for the amount it would have cost me to shot peen, put in arp bolts, resize everything, and all of that stuff... buying a set of forged eagle rods was easier, and i know they hold almost twice what stock can...

eagles - 450shipped to my door
OEM - probably cost 300+ (damn inline 6.....)

 

[The1]

But that goes along the question that I asked in the tech forum. Is it really good to put forged rods on OEM pistons?

 

[Doward]

You know the rods won't be the weak point

 

[Rennat]

is it ok? i dont even see why you would ask... thats like saying is it ok to put a 3'' downpipe in a stock turbo... OF COURSE ITS OK!!!!!

theres not some special law that says "those who buy forged rods MUST buy forged pistons"... if you just want some good rods, eagle are good for the price.

my probe pistons cost me like 350... rods cost me 450... i didnt see the point of running stock internals when i could upgrade for such a small price.

 

[IJ.]

Stock pistons can run much tighter tolerences and make for a quiet motor, forged give you a little more leeway in case of detonation.

 

[Rennat]

Stock pistons can run much tighter tolerences and make for a quiet motor, forged give you a little more leeway in case of detonation.

which is exactly why i got the probe pistons. i want that little "buffer" zone in case my motor is happy on first start up.