Speed Pro H405 (4 valve relief, low compression) pistons & pressed pin con rods

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greymouser7

greymouser7

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If you give the machinist these pistons, and stock rods- he tells you the pistons are NOT for full floating wrist pins (supposed to be pressed fit), can't he fix or adjust for that himself? better solution? thanks
 
Probably cost more to machine them for wrist pin clips, than to select a piston designed for them. No problem with pressed pins though, for lots of applications
 
Let me get this straight........you give him STOCK rods, out of what? If foggy memory serves me right, your pistons are for a 360, all 360's used pressed pins, no problem there......is the issue that you wish to convert to full floating piston/pin combination?.......or did you give him a set of bushed rods from another engine that ran a full floating piston/pin assembly??

If you want to rum floaters with out cutting grooves for pin locks, use buttons made from Nylon etc, old school but it still works
 
Mmmmm.... can't use buttons on those since they are flat sided pistons around the pin boss, not round sided.

As said, grooves for pin locks would have to be machined into these pistons for full floating. And as also said... 360 rods are set up for pressed pins... so what's up with the rods? Or is something not being communicated with the machinist?
 
Why are you wanting floating pins? Pressed pins are fine. As mentioned, those pistons are not made for floating pins. They will have to machine a groove into each side of each pin bore for the locks to install into. Pretty expensive when pressed pins will work just fine.
 
I bought 24 TRW remanufactured stock rods and gave 8 to the machinist. I guess they were bushed for floating wrist pins? I thought stock rods would work with 405 pistons because stock was press fit except for some 340's and older stuff that was full floating.
 
I would check and make sure what you gave the machinist. Do you have a link to the rods you bought?
 
RustyRatRod said:
I would check and make sure what you gave the machinist. Do you have a link to the rods you bought?
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eBay :( , I thought the machinist could 'machine' or re bush the rods for press fit.
remember when you (rightfully) chastised me for getting into these problems for being TOO CHEAP? I bought those rods long ago (before the advice, $50 total). So we reap what we sew and it sure is hot in this handbasket!
 
greymouser7 said:
eBay :( , I thought the machinist could 'machine' or re bush the rods for press fit.
remember when you (rightfully) chastised me for getting into these problems for being TOO CHEAP? I bought those rods long ago (before the advice, $50 total). So we reap what we sew and it sure is hot in this handbasket!
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Can you post a picture of one of the rods?
 
greymouser7 said:
Yes. The bushing on the small end were not correct (not centered all the way through?) , and there was some minor problem with the large end as well.
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Did you get those bushed 273/318 rods from The Saturn Group?
 
greymouser7 said:
Maybe, I really don't remember. They were on Ebay from some older guy with a few different Mopar parts for sale-don't remember his name. I wanna say they 318 rods.
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If they are 318 bushed rods, then they are the early small rods for the 273 and early 318. They were all bushed. They are not nearly as beefy as the late 318,340 and 360 rods.
 
Have the shop check the center-to-center distance on those reman rods. I was offered a batch of 8 and measured them to have a total center-to-center length variation of .019" !!! I declined the purchase LOL

I would not worry over the lighter rods for that use for their strength. But know that they will change the bobweight by about 50 grams versus the heavier rods.
 
greymouser7 said:
If you give the machinist these pistons, and stock rods- he tells you the pistons are NOT for full floating wrist pins (supposed to be pressed fit), can't he fix or adjust for that himself? better solution? thanks
Click to expand...
I just had this done. Not the same slug though. The pistons are the KB-399 (IIRC) for a 340. The pins were stiff in the piston. The machinist agreed. To hone all 8 pistons for the pin was a whopping $48.
 
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