Rod Bolts

[Squirt-Truck]

If someone will send me samples of each, I will get the chemistry and mechanical properties of each, then we will have something to compare with.

 

[FMJ]

"We don't know"

Gotta love that customer service. . . . .

 

[TehTDK]

I don't have much to add other than Westy sent the specs to ARP and their quote to make some was WAY out of line, like $120 per bolt. Finding some of those bigger-badder bolts sounds like the way to go.

I rather recall it was 25$ pr bolt, for an order of 2000 or so bolts. And with 12 bolts pr engine it wouldn't take a lot of people to get to those magic 2000

 

[bill2444]

My " new" replacement motor has the "good" 12 point bolts in it. I noticed the difference right away between them and my old engine. They are more desigined like high performance style rod bolts.
Now though, Were mine new at the time of the motors rebuild or resused? And add to that I removed one set to inspect the rod bearing for wear. I think new rod bolts would be good measure before the motor goes in. Any more leads on new "good" replacement bolts.

 

[gimpyrobb]

I rather recall it was 25$ pr bolt, for an order of 2000 or so bolts. And with 12 bolts pr engine it wouldn't take a lot of people to get to those magic 2000

I didn't know you talked to Westy about it, my bad.

 

[sandcobra164]

Mine's a "New" in the 90's motor. I've run her hard, extended cruising on the governor, quite a few heavy loads. I believe there is logic on the 12 point rod bolts as mine has not slung apart. She does have an oil leak from the head gasket that I will fix but it's so slight, I never have to add oil to the motor and most folks tell me not to worry about it. The passenger side of the block was dry until I started towing 20,000 plus pounds and turned up the fuel to get over hills.

 

[FMJ]

All the quotes I've gotten are between 30 and 36 dollars PER bolt. . . . .
And they are all listed as surplus items, and for that price the companies that specialize in NSN parts can hang onto them forever. . . .

 

[JasonS]

Gotta love that customer service. . . . .

I called HyCapacity which is an ag parts distributor to ask about their "HC40-1091706" rod bolt. It is the correct rod bolt for the Hercules 478. They purchase it directly from Hercules. HyCapacity was helpful and tried to contact Hercules regarding the specs but couldn't get a response from Hercules. I can order it through a number of local ag places or Advanced Auto Parts. If you do a search on line, there are other places as well (~$16 each). I will try to contact Hercules and determine if this is the later, 12 point head bolt and if they have any insight on the inordinate number of rod bolt failures.

 

[Sumner]

I was just thinking about this the other night. Has anyone tried sourcing a stud to replace the bolt, and then just use a nut instead. I imagine it would be a lot easier to find a stud that will do the job rather than these hard to find and very expensive bolts?

 

[MikeON]

I'll also offer to get a chemical analysis and hardness profile done on bolts if someone will send them. Just PM me if interested.
Mike

 

[swbradley1]

I was just thinking about this the other night. Has anyone tried sourcing a stud to replace the bolt, and then just use a nut instead. I imagine it would be a lot easier to find a stud that will do the job rather than these hard to find and very expensive bolts?

Why? A stud won't work for a rod bolt.

 

[Sumner]

Why not? Many engines use studs on the connecting rods rather than bolts. What would prevent a person from using a stud and nut in this application?

 

[swbradley1]

I'm intrigued. I have never seen a rod stud setup. Head studs yes, rods no. How do they go in? What holds them in the rod? If it's just a flat spot to keep it from turning that makes it a bolt. If it goes all the way through doesn't that make it a bolt as well?

Now if the rod was solid and you pressed or screwed the stud in then it would be...a stud.

A Google search for rod studs only shows more bolts. I'm just asking as I would like to know.

 

[Heath_h49008]

GM uses studs on the rods in the 383 stroker kits.

They don't seem to have issues.

Edit:

If you try studs, remember the torque values will be different for different thread pitches and lubes!

 

[swbradley1]

Do you have a picture? I have seen cap screw type bolts and something that looked different but it was not a stud. How would a stud even work with an existing style LDT rod?

 

[porkysplace]

Do you have a picture? I have seen cap screw type bolts and something that looked different but it was not a stud. How would a stud even work with an existing style LDT rod?

The rod would have to be designed for studs . To tap out the existing hole for a oversized stud , would weaken the rod and cap .

 

[Sumner]

Most gas engines used a bolt that passed through the rod, and was held from turning by a shoulder on the head of the bolt. I have worked on an engine (can't for the life of me remember what it was though, but it would have been something old school) that had studs that screwed into the rod.

One issue I can think of though is that it may be difficult to install a piston/rod into the engine with the studs sticking off the rod due to the fact that the rod cap does not sit perpendicular to the rod. You might have to put the rod in place on the crank, then thread the stud into the rod and place the cap over it.

In pretty much any application a stud will have much more clamping force than a bolt. A proper length stud would just thread into the existing threads in the rod just like the bolts that are being used now. I haven't had a rod from a multifuel in my hands, just throwing ideas out there and seeing if they would work.

 

[Heath_h49008]

It would depend on the profile of the bottom of the rod's threaded hole, because the stud "bottoms out" when it is installed.

Why do you think it would need to be tapped out to a larger size? If the stud can bottom on a uniform seat, the existing threads should be fine I would think. As long as there was enough space available for an appropriate nut, it would seem to be plausible.

.

 

[Sumner]

Something along the lines of this

 

[Heath_h49008]

I'm not seeing a huge reason why a stud couldn't be used.

But...

Unless studs in the appropriate size and strength are commonly available for some other application, we are back to the expense of a "custom" fastener(s).