dish pistons factory rods
 

I currently have my 455 in the machine shop for a rebuild. I bought Keith Black 15cc dished pistons and had the factory rods reconditioned. The shop called today and said they can not use the factory rods because the pin end is to small. Does anyone know where I could get a rod that will work with these dished pistons. Tried Kauffman and Butler today no one is available. Brian

I have never found the pin end too narrow just too wide for some pistons?When we did my 421 with stock rods the machine shop just had to narrow the pin end a little.We found the piston was designed for aftermarket or 455 SD rods which are more narrow than cast rods.Tom

It wouldn’t take a rocket scientist to mill the insides of the piston bosses a little for rod clearance. Some body in KC area can do this...
Biggest problem might be time for you shop doing build.

Which KB's did you get?
Are they press fit or floating?

A shop that can resize/recondition rods should be able to open up the little end if the pins too big. If the pin is big enough, rod length lost from resizeing the big end can be gained back opening the little end.

Clay

I got the forged 15cc dish I think press fit but not sure. He said machining the small end of the rod might affect the integrity . The bad thing about it he already resized the factory rods with Arp bolts. So it looks like that was a waste,I guess I will check with Butler in the morning and see what they think.

I think the dish might affect fit as well.

They can be pressed or floating, the rod determines which. Stock rod would require a pressed fit.

If you buy new rods, as I have done many times, I recommend RPM H-beams. They're $400 shipped. They're much lighter & stronger than cast rods. They are available for press-pins or bushed, for floating pins.

http://www.racingpartsmaximum.com/sa...elhbeam-2.html

Cliff has posted here several times that he has used several brands of Chinese H-beams, and they were all good.

Curious, what was the total cost to have your rods resized, including the ARP bolts ? If you don't know, PLEASE ask the shop & post that info. There are guys here, on a regular basis, who are trying to make the decision of what rods to use. When the 5140 rods were barely over $200, it was a no-brainer. Those rods were apparently discontinued. Similar 5140 Eagle brand rods are nearly $400. So knowing a CURRENT cost for having stock rods resized should help guys make an informed decision about rod choice.

https://www.jegs.com/i/Eagle/356/SIR...QaApCeEALw_wcB

PS: Paul Carter did a 400 engine last year, that used cast Olds 455 pistons. The owner said that Paul had to remove some material from the cast rods, because the small end was slightly too big for the Olds pistons. He said he didn't know the cost of the extra rod work, because it was just all included in the machine shop cost. Told me to ask Paul about the details. I sent a PM to Paul several days ago. No reply. I reckin he's busy building engines. Have noticed that he seldom posts here anymore. May be tired of giving out free info. OR may just be too busy.

There is a nice set of H beam forged on Ebay right now they look like really good quality $329.00 set. But I would hate to buy and they wouldn't fit.

Tried to look some up and all I saw was .981" pin size.....

That would be less than one thousand of an inch from factory press fit. And would have no affect on integrity.

If your stock rods need bushed for floating pins.....Don't know what to say about that. Other than we used to do it years ago without problems.

Clay

"...Tried to look some up and all I saw was .981" pin size..."


Sometimes Pontiac pins are listed as .980, & sometimes at .981. Has been posted here many times that, the ACTUAL size of pins vary between brands.

Not likely that a shop would shrink back from honing a pin hole by .001. Guessing that many have been honed to use .984 Mopar pins & even .990 BBC pins.

Check out this pic & compare the small end of the cast vs a 5140 rod. Although the shape of the small end is different, I'm assuming the pin hole is the same size in both rods. So, if the hole in the cast rods is too small, seems logical that the hole in the 5140 rods is also too small. Since Pontiac pins are listed at .980, in most cases, it would make no sense at all for somebody to make a Pontiac rod with a .981 hole. That would make it unusable for pistons with .980 press pins.

Can't imagine a shop that would not enlarge a pin hole by .001. It has been posted here, many times, that most pins need to be fitted in the pistons & rods. It seems to be a very common part of the engine building process.

I just got an email from Butler saying there 5140 forged is press fit and should work just fine. I guess I will go with a set of those. Thanks Brian

Could be a blessing in disguise 50 year old rods could be a little risky!!.

Here's a pic of those Eagle 5140 rods.

They're cheaper from Jegs. But I understand that lots of guys are willing to pay more to support shops who do mostly Pontiac engines.

https://www.jegs.com/i/Eagle/356/SIR...MaAiKLEALw_wcB

Again, the H-beam rods weigh only 760g, vs the 870g weight of the 5140 rods. This will make your rotating assembly lighter. And the H-beams are said to be much stronger.

Thanks for the good info!!

You shouldn’t have much trouble selling your rebuilt cast rods, they’re not the most ideal rod type but still plenty good for a mild to stock engine. I’ve seen many sets sell in the classifieds over the years, someone will want them.

Won all my bracket racing cash and trophies with a cast rod 455 running in the 12s for over a decade, the rods weren’t even rebuilt. :)

I'm not sure what you have going on. We've never ran into an issue using the factory rods on a KB piston but you can narrow up the small end of the factory rod quite a bit before there is any need for worry.

Paul,Racetec did mine and the opening was too narrow to use a stock cast rod.That was with a 428 custom piston.Tom

The common SP forged Pontiac pistons show to have .980 pins.

https://www.summitracing.com/parts/s...w/make/pontiac

SRP pistons show .980 pins.

https://www.summitracing.com/parts/s...w/make/pontiac

D.S.S. pistons have .980 pins.

https://www.summitracing.com/parts/d...w/make/pontiac

Auto Tec pistons show .980 pins, except of course for the stroker pistons which use BBC .990 pins.

https://shanonsengineering.com/produ...at-top-pistons

Don't know why KB/Icon shows .981 pins.

Yeah, at first I thought he meant the rod was too big for the piston. But, after I went back & read post #1, it says "...can not use the factory rods because the pin end is to small..."

Don't say the pin end is too BIG, but too small.

Don't think a piston is said to have a "pin end" . A ROD does have a pin end.

So, maybe this needs to be cleared up.

Is the pin hole too small ? OR, is the outside of the pin end of the rod too big ? :confused: