Bushing six pack rods for 1.094 pins

[polyjohn]

Some very good points there Guys.
A number matching 1971 GTX is what I have and it will stay 'as is'.

If I am going to run into the 10's with my 512ci engine then its going to be a stripped out race-car then?
Where is the cut-off between a number matching street-stripper and a drag car?

The MMA-UK say its 21.01 in their book but have insisted on cages at 13.99 as well.
Safety is the first precaution of the MMA and self harming on the drag strip is frowned upon indeed.

Happy new Year to all who have contributed to my thread.
Its sad some prefer Chinese rods over factory six-pack, but hey, thats progress ( I suppose)?
Its a shame that ARP wasted their time making 3/8 rod bolts for many years, as no one rates them.

 

[polyjohn]

Talking of rods and bolts and all things 426 engine.
How's about a hemi rod, good or bad?

(The six-pack rod is almost identical to the hemi rod except for the bolts.)
So Weslake Engineering got Mother Mopar to make some hemi/440 length rods in 1969.

The front rod is outta my 426 hemi.(6.860)
The rod on the piston is outta the Weslake 426 Nascar engine. (6.768)

Back then they didn't have any options and they still ran over 200mph with them.
The weirdest thing is they are factory press fit how bizarre indeed.
I guess the six-pack rod had not been invented in 1969, so they made a special hemi 440/426 rod!?

 

[padam]

There are a lot of DNF’s for mopars in those old NASCAR programs.

 

[33 IMP]

Talking of rods and bolts and all things 426 engine.
How's about a hemi rod, good or bad?

(The six-pack rod is almost identical to the hemi rod except for the bolts.)
So Weslake Engineering got Mother Mopar to make some hemi/440 length rods in 1969.

The front rod is outta my 426 hemi.(6.860)
The rod on the piston is outta the Weslake 426 Nascar engine. (6.768)

Back then they didn't have any options and they still ran over 200mph with them.
The weirdest thing is they are factory press fit how bizarre indeed.
I guess the six-pack rod had not been invented in 1969!?

View attachment 1780540

You are correct. The 69 Sixpack motors used LY rods. Not till 1970 did the Sixpack engines get Sixpack rods.
And .100 longer rod is hardly the same except for bolts.
And I'm pretty sure the Nascar engines used Carillo rods even way back then......

 

[polyjohn]

Both rods in the picture are Hemi rods!

The front one is a longer hemi rod.
The one attached to the piston is also a Hemi rod, special made at 440/426 length for Weslake Engineering in 1969.

Both have factory 7/16 rod bolts and are the same apart from one is .100 shorter for a wedge engine.

I guess you are saying ''they is all 50+ years old and are scrap''...
Best I get some Molnars and put this thread to bed for 2024...

 

[Curiousyellow71]

We run Ly rods in a couple cars yet. Years ago we had a 70 six pack engine that spun a bearing, but the HD Rod held together and it lived to fight another day.

We raced Ly rods with the 2295 Trw/federal mogul pistons for years. Those pistons had a special tapered wrist pin that may have helped the longevity w its pressed fit pins. At one time we checked the tach recall and it had seen 8300 rpm. In the mid 10s we we were going out the traps over 7k. The rods held in there till a cylinder wall gave up. When that happened it broke a rod bolt. I am not sure if it would have mattered what Rods were in it at that point. We have had a couple sets of rods Bushed over the years. The machine shop usually measures the needed specs and orders them. They typically are not specific to a engine, they are just bushings and are less then half price of what you would typically spend. If this were my car I would likely keep the six pack Rods in it as well. They are pretty stout. Yes, there lots of rods available that are better, buy I get what the op is trying to do.

 

[RemCharger]

We run Ly rods in a couple cars yet. Had a 70 six pack engine that spun a bearing, but the HD Rod held together. We ran Ly rods with the heavy 2295 Trw/federal mogul pistons for years. Those pistons had a special tapered wrist pin that may have helped the longevity w its pressed fit pistons. At one time we checked the tach recall and it had seen 8300 rpm. In the mid 10s we we were going out the traps over 7k. The rods held in there till a cylinder wall gave up. When that happened it broke a rod bolt. I am not sure of it would have mattered what Rods were in it at that point. We have had a couple sets of rods Bushed over the years. The machine shop usually measures the needed specs and orderd them. They typically are not specific to a engine, they are just bushings and are less then half price of what you would typically spend. If this were my car I would likely keep the six pack Rods in it as well. They are pretty stout. Yes, there lots of rods available that are better, buy I get what the op is trying to do.

On the motor that the cylinder was toast, were the pins bushed?

 

[Curiousyellow71]

On the motor that the cylinder was toast, were the pins bushed?

Nope...press fit.
It had wrist pins in it that were factory machined to be stronger. Guessing that may have helped? Dunno.

That block got 2 sleeves and is still going. I wouldn't push a LY rod or a six pack rod as hard as we did back then. LOL

 

[RemCharger]

Nope...press fit.
It had wrist pins in it that were factory machined to be stronger. Guessing that may have helped? Dunno.

That block got 2 sleeves and is still going. I wouldn't push a LY rod or a six pack Rods as hard as we did back then. LOL

Just asking because the only time I broke a rod was from the pin going out into the cylinder, and locking it up in the groove and taking out the adjacent rod. So not a rod failure, but pin failure creating a rod failure

 

[Moparfever65]

Only time I threw a rod was street racing my 69 Cougar, 351W, stock rods. Don't know what RPM, but I didn't want to lose. Found the rod nut stripped and the cap broke, crank came around and pushed the rod through the pan. ARP bolts ever since.

 

[Gunner1]

Seems like most, if not all, aftermarket rods are Chinese. All i-beam aftermarket rods I've seen are 5140 Chinese. Why 5140 i don't know. Apparently cheaper than 4340. I've read were 5140 is used a lot in ship building. For what I do 5140 is good enough or maybe better than factory steel. Keep in mind that back in that era cast rods were still being used by some manufacturers. I think i- beam versus h- beam might be a good discussion.

If I remember correctly all of Scat’s H Beams are 4340. The owner would periodically take a sample rod and crank and cut them up. He would send the pieces to a lab for a metallurgy report.

 

[polyjohn]

I suppose I am 'living in the past' with my GTX and its numbers matching engine.
I know the sixpack set up was a fine example of Mopar engineering (at that time).

Never broke a rod in forty years of drag racing.
Used everything from LY to BME aluminium.

We use what parts we want too and until it breaks we just carry on regardless.
Happy New Year to one and All.