Who Made this Rod?

[frnkeore]

I found a couple of 7/16 x 14 bolts. The ones in the rods would be 7/16 x 20 but, I couldn't find a matching pair of those. One grade 8 and the other SHCS, both the same length.

Regarding head bearing area, the G8 is .580, while the SHCS is .640 or 10% more bearing area. The head thickness for the G8 is .290 and the SHCS is only .187 at the bottom of the hex drive area. OA height is .437 so, that won't be as strong. The corner radii, under the head, looks about the same but, less than 1/64 on both. The socket is 3/8" and the corners of the socket are .429 so, the socket, itself won't add much to the head strength above the root of the thread.

[WConley]

A high performance fastener, like a 12-point, will in general have more bearing area than a socket head cap screw.  The hardware store six-point Grade 8 you're comparing to isn't suitable for a critical application.

I don't care about showing people that I'm right.  All I care about is keeping people reading this forum from getting bad information.  In mechanical engineering practice, you will not see socket head cap screws used in critical, high performance joints.  They are inferior to the external Torx or 12-points that are in all of the specialty / racing / military / aerospace applications.  Those are what you want.

[mike7570]

Frank, you should replace those bolts if you use the rods.  Allen head capscrews are known for fracturing at the bottom of the hex; in fact they are illegal via NHRA rules for attaching a transmission bellhousing to an engine.  I doubt that this is ever checked, but the rule is there for a reason...

And if you buy a new SFI Quicktime bellhousing it comes with cap screws.
You would think it would come with proper bolts being expensive and SFI certified.

My SFI certified Quicktime FE-C4 bellhousing came with cap screws (just about the only fastener that will fit) I tried to use grade 8 hexbolts but there is not enough clearance for the bolt heads. NHRA list them as illegal for certain certified bellhousing for manual transmissions, for Automatic transmissions the bellhousing bolts are not mentioned. It's probably because a flywheel/clutch explosion creates much more stress on the bellhousing.

[Tunnelwedge]

My SFI certified Quicktime FE-C4 bellhousing came with cap screws (just about the only fastener that will fit) I tried to use grade 8 hexbolts but there is not enough clearance for the bolt heads. NHRA list them as illegal for certain certified bellhousing for manual transmissions, for Automatic transmissions the bellhousing bolts are not mentioned. It's probably because a flywheel/clutch explosion creates much more stress on the bellhousing.

I'm working on a Lakewood that needs bolts.
I have these steel ARP 7/16x14x1.5 with a small shoulder. I need to trim them for length.
That's what I used on the Quicktime.
You can also get some flange head bolts from Holley. They should come in the box with the Quicktime.

https://www.holley.com/products/fasteners_and_hardware/transmission_and_drivetrain/transmission_bolts/parts/RM-172

[Heo]

 

All good points.

Wait? What, what.....what just happened here?
Did Frank just agree with Bill and Brent?
Where am I? What has happened to this place? 


I get the serrated cap concept, but don't like the idea on a steel rod. Just like the 'cracked caps' they use on today's engines, they are a one and done deal. For an aluminum rod, they make good sense.

 

[Tunnelwedge]

They are in Mickey's HEMI Galaxie.

https://www.youtube.com/watch?v=xtY7OMT49CE

[Rory428]

Oh Noooo's !

I installed the cast aluminum oil pan on my FE with socket head cap screws!

Now the pan is gonna fall off at the most inopportune time!

             

I certainly hope that you are not comparing the stress of 20 bolts holding a 10 pound oil pan to the block, to the stresses of 2 connecting rod bolts pulling down a piston at high RPM, and keeping the rod anchored  to a reciprocating crankshaft, right?

[MeanGene]

I have a new old stock set of Mickey Thompson aluminum FE rods from 1965 and they use Allen heads like that.

I had a NOS set like that in the box that I found at Turlock, and sold to someone- same ones?

[galaxiex]

Oh Noooo's !

I installed the cast aluminum oil pan on my FE with socket head cap screws!

Now the pan is gonna fall off at the most inopportune time!

             

I certainly hope that you are not comparing the stress of 20 bolts holding a 10 pound oil pan to the block, to the stresses of 2 connecting rod bolts pulling down a piston at high RPM, and keeping the rod anchored  to a reciprocating crankshaft, right?

It was posted as a joke.....     

[Stangman]

I have an old Mickey Thompson aluminum rod from our 389 Pontiac and it had the serrations that why I said that was a MT rod. The aluminum rod didn’t have those bolts though.

[frnkeore]

I passed on them so, I can't add anything more.

[Joe-JDC]

Wise move.  Headache avoided.   Joe-JDC