Mopar 383 Connecting Rods

[Rich Biebel]

I did most every rod in a small shop for over 10 years.

All brands and from street rebuilds to race engines of all kinds.

Sunnen manual LBB machine with the gauge.

Did big ends, small ends, bushed rods, offset bushed and reduced pin sizes using bushings we made or bought.

Stock rods used in race engines were generally out of round once run....

Usually a good amount....

We used SPS bolts back then and picked the best looking cores we could find.....Did not matter once it was run....out of round...

Mag, shotpeen, resize, bush pin end....generally

Very difficult to hone big ends or even pin ends and hold them true and without a taper one way or the other....

I would chuck the mandrels up in a lathe and true up the brass guide shoes often and dress the stones....constantly...

I used the gauge to check the rod and as described held it flat and carefully pulled it away from the back reading the size. A very tedious process......honing to size and keeping them as straight as possible....

I always honed rods and let them sit and they change size as the honing process heats them up.....let 'em cool and touch 'em up....

A buddy had a shop with a similar machine but with a power stroker and I don't know if that helped as I think it did pairs of rods at one time...

Honing anything was a time consuming process if you were trying to do as good as possible....

I marvel at the Youtube videos of Block hones that do a V8 without an operator constantly running the machine and checking the bore sizes....

Honing a race block and doing a real good job was the shop owners specialty along with head work.....Any block he honed made better power than previously usually....



I also rebuilt Mack connecting rods a lot......new bushings mostly....big ends were usually pretty good even after a half million miles ! Engines in UPS trucks....

[Paul Precht]

Originally Posted by Rich Biebel

I did most every rod in a small shop for over 10 years.

All brands and from street rebuilds to race engines of all kinds.

Sunnen manual LBB machine with the gauge.

Did big ends, small ends, bushed rods, offset bushed and reduced pin sizes using bushings we made or bought.

Stock rods used in race engines were generally out of round once run....

Usually a good amount....

We used SPS bolts back then and picked the best looking cores we could find.....Did not matter once it was run....out of round...

Mag, shotpeen, resize, bush pin end....generally

Very difficult to hone big ends or even pin ends and hold them true and without a taper one way or the other....

I would chuck the mandrels up in a lathe and true up the brass guide shoes often and dress the stones....constantly...

I used the gauge to check the rod and as described held it flat and carefully pulled it away from the back reading the size. A very tedious process......honing to size and keeping them as straight as possible....

I always honed rods and let them sit and they change size as the honing process heats them up.....let 'em cool and touch 'em up....

A buddy had a shop with a similar machine but with a power stroker and I don't know if that helped as I think it did pairs of rods at one time...

Honing anything was a time consuming process if you were trying to do as good as possible....

I marvel at the Youtube videos of Block hones that do a V8 without an operator constantly running the machine and checking the bore sizes....

Honing a race block and doing a real good job was the shop owners specialty along with head work.....Any block he honed made better power than previously usually....



I also rebuilt Mack connecting rods a lot......new bushings mostly....big ends were usually pretty good even after a half million miles ! Engines in UPS trucks....

I have a nice LBB-1499 with the AG, not sure when they were made but I'm thinking 60s. I did hundreds of rods on an old bench top Sunnen in a shop I used to work at, not sure what model it was. It's an art that definitely takes time and talent to master.

[Larry Hill]

''It's an art that definitely takes time and talent to master.'' How true!

[Tom Broome]

Originally Posted by Larry Hill

''It's an art that definitely takes time and talent to master.'' How true!

Kinda' like block honing.

[Larry Hill]

Any size target honing is the artform, "damn I honed to much wont fix it".

[Rich Biebel]

Ya can’t put metal back so ya gotta sneak up on it !

[HP HUNTER]

Originally Posted by Rich Biebel

I did most every rod in a small shop for over 10 years.

All brands and from street rebuilds to race engines of all kinds.

Sunnen manual LBB machine with the gauge.

Did big ends, small ends, bushed rods, offset bushed and reduced pin sizes using bushings we made or bought.

Stock rods used in race engines were generally out of round once run....

Usually a good amount....

We used SPS bolts back then and picked the best looking cores we could find.....Did not matter once it was run....out of round...

Mag, shotpeen, resize, bush pin end....generally

Very difficult to hone big ends or even pin ends and hold them true and without a taper one way or the other....

I would chuck the mandrels up in a lathe and true up the brass guide shoes often and dress the stones....constantly...

I used the gauge to check the rod and as described held it flat and carefully pulled it away from the back reading the size. A very tedious process......honing to size and keeping them as straight as possible....

I always honed rods and let them sit and they change size as the honing process heats them up.....let 'em cool and touch 'em up....

A buddy had a shop with a similar machine but with a power stroker and I don't know if that helped as I think it did pairs of rods at one time...

Honing anything was a time consuming process if you were trying to do as good as possible....

I marvel at the Youtube videos of Block hones that do a V8 without an operator constantly running the machine and checking the bore sizes....

Honing a race block and doing a real good job was the shop owners specialty along with head work.....Any block he honed made better power than previously usually....



I also rebuilt Mack connecting rods a lot......new bushings mostly....big ends were usually pretty good even after a half million miles ! Engines in UPS trucks....

You have two rods your honing..........theres .0025 to hone to size on both rods, one rod has .0005 taper the other has .0007 taper. How do you set these two rods up on the already trued mandrel?

[Larry Hill]

Does the cap grinder cut the cap 90* to the bore? At .0006 taper per inch, it would taper .0072 per foot. That's a lot.

It might take truing the mandrel a few times to get rod to size using a slightly lower stone pressure.

If accepted size is 2.5000 to 2.5005 is any size on or between good or is there a taper tolerance " Tapper not to exceed .........."

[HP HUNTER]

[QUOTE=Larry Hill;602288]Does the cap grinder cut the cap 90* to the bore? At .0006 taper per inch, it would taper .0072 per foot. That's a lot.

It might take truing the mandrel a few times to get rod to size using a slightly lower stone pressure.

If accepted size is 2.5000 to 2.5005 is any size on or between good or is there a taper tolerance " Tapper not to exceed .........."[/QUOT


The cap cutter would be dialed in @ 90 degrees, setup with the horse shoe.

How would the rods be put on (position) the mandrel at the start of the honing?

Chevrolet BBC rods from the factory sometimes the mating surface is not 90 degrees to the sides, which will cause taper when the mating surfaces are cut.

[Tom Broome]

Chevrolet BBC rods from the factory sometimes the mating surface is not 90 degrees to the sides, which will cause taper when the mating surfaces are cut.

I agree many rods, not just BBC, don't have the housing bore and sides perpendicular to the parting line. My personal opinion is that we often find rods (especially OEM) that also don't have the sides parallel to each other. If that is the case then one side will be closer to "square" than the other.

We understand that we will hone, more or less, perpendicular to the rod sides. The cap cutter should cut the parting line perpendicular to the sides. Therefore we need to prepare the sides, to the best of our ability, before we cut the parting surfaces. Then we need to check the parting surfaces before we cut them. How did we remove the pressed in bolts? Did we twist the forks doing that? Are there burrs or dings anywhere?

Only then do we begin to cut the parting surfaces. Production "guys" will touch off on one rod,or cap, dial in the amount they want to remove, and make their cuts.

I prefer to touch off every rod and cap, every time, and observe the cut surface to see if it's cutting "flat". If not, I turn the part around to square off the other side and touch it again. I pick the best side and cut the amount I prefer.
Then we get to prep our newly machined surfaces. Reinstall the press in rod bolts, again trying not to twist the forks. Reinstall the cap(s), torque the bolts using a procedure we can repeat on final assembly. And make sure the sides are flat so that the rods don't "rock" as we hold the pair on the hone.
After that, it's up to the hone operator to do his job. The prep work is "just machining", the honing is where the "touch" comes into play.

All in all, it's not easy, or cheap, to do the job right.
Then if we want to have "fun" let's do some rods that the need to be "saved". You know....the blue ones.