Shotpeening advice

[joey]

Hey guys,
I'm looking to shotpeen some 2t rods i have for a hybrid application. My dads a metallurgist (spelling?) and can get it done for free, so although the stock 2t should work fine for my application from what i understand, im sorta just interested to see how it turns out for future reference. My question is should on the inside where the pin and the bearings go be protected in the shotpeening process? If so how and with what?
Any advice appreciated.
Thanks, Joe

[BigWorm]

Yep all the machined surfaces need to be protected, when I had mine done we used some thick black tape, very similar to electrical tape but thicker, that was specifically for masking things to be shot peened.
Whover is doing it should be able to supply you with something suitable.

[white ls]

dont get the 3m whit crap we had it for work and walnut shell took it off and destroyed the machined edge

[SuperDave]

As said above, I can't imagine it's good for clearances having them peened. Make sure you do it with the bolts removed as under the bolt head/nut is the area that needs it most.

[skiddz]

pehaps a used bearing shell may be an ideafor the big end? for the small end just stick a bit of wooden dowel, so its a tight fit.

[KARNAGE]

thats what i used for mine i had some old shitty bearings we put in and i had a peice of dowel that i hit in to the small end. it worked very well and it was quick to as i didnt have to worry bout taping things up.

[joey]

Thanks for the replys guys.
Hmmm will have to get my dad to ask the guy who does it to see if he has any of that tape stuff bigworm. An old bearing and dowel seems to be the most logical way i guess, dont have any but ill see if i can hunt around for any. If i do use the old bearings i'd have to keep the bolts in there to secure the bearing, or is SuperDave right in saying they should be removed as they are the parts that cope with the most stress?
Cheers, Joe

[jeffro ra28]

Id just like to add that you should only shotpeen the rods if you are polishing the beams.
Shotpeening unpolished rods is a waste of time. You should also not polish rods if you are not going to shotpeen.

So i hope you are going to polish the beams, and then get them shotpeened

[jeffro ra28]

Could you super glue the bearings in place? with bolts removed?

[joey]

Thanks for that jeffro, wasnt aware that they should be polished first. Did a little bit of research so will whip out the die grinder and give it a go.
Another question, do the rods need to be resized after the shotpeening process? Some people are saying that it warps the rod

[jeffro ra28]

Joey, Your best bet for polishing rods is with a linishing belt. Start with course grit belts to removed bulk of hard casting surface, move onto finer grit after hard casing is removed and shape the beam, then finally polish with scotch bright belt. Ideally you want the beams of the rod to be reflective :d.

[30psi 4agte]

Joey: jeffro is totally correct. You must linish before shot peening and only linish if you intend to shot peen.

Now shot peening actually induceses stress back into the rod as the peening process changes the rods surface structure. This is not ideal. If you are serious about the engine you should have the rods sonicly relieved after the process.
What this is ...... is a bed that the rods bed that the rods are attached to and then vibrated at high frequency to relieve the rod of any stress caused by the peening process.
I understand you are getting the peening done for free and cost could be a concern so this mabe not for you.
Not everybody does this and it is not prob gonna do much in a 2t unless you plan on some serious revs with it but in a full on build where the engine is to see some real loads then id highly suggest it if you have had the rods etc peened.

P.S yes re-sizing will be needed.

[joey]

Finally got myself a die grinder and all neccesary tools, so gonna have a go at it today. One more question.... is a polishing compund needed or can i just use the white buffing flap wheel straight after removing the casting marks? Just wanna make sure i get everything right.
Thanks for all the help so far guys.
joey

[af300e]

Isn't he going to need to weigh the rods as he linishes them in order they maintain some kind weight tolerance? And, what sort of tolerance would be required?

Saliba engines (Clayton?) quoted me $275 to race prep (linish and shot-peen) 4 rods. They do excellent work. Maybe it's worth going pro on this one?

[KARNAGE]

yes you will need some kind of cutting or polishing compound its easy to find the stuff normally the white blocks are polishing compound and the darker blocks are for cutting back small abbrassions and scratches