BBC Rods with .927" Piston Pins

[gt350hr]

   Are you begining to see why the rods were $320? Look how much additional work ($$$ too) you are spending to use an inexpensive set of rods.  Does a street engine warrant all of this? You should be using 4032 alloy for a street engine instead of 2618. Gas ports are not needed on a street engine. Window mill and spin boss leave the piston heavier than a standard .125 thick skirt mill. Contact reduction is not necessary. I hope you have someone that can make your spacers/washers for your piston guided application. Be SURE the rod is located correctly so the oil hole in the crank is not exposed. Accumulator groove an double pin oiling are beneficial.
    Randy

[1967 XR7 GT]

   Are you begining to see why the rods were $320? Look how much additional work ($$$ too) you are spending to use an inexpensive set of rods.  Does a street engine warrant all of this? You should be using 4032 alloy for a street engine instead of 2618. Gas ports are not needed on a street engine. Window mill and spin boss leave the piston heavier than a standard .125 thick skirt mill. Contact reduction is not necessary. I hope you have someone that can make your spacers/washers for your piston guided application. Be SURE the rod is located correctly so the oil hole in the crank is not exposed. Accumulator groove an double pin oiling are beneficial.
    Randy

The rods were made in 2008 and just sat on the shelf and was probably why they were put in the clearance section, and I was going Custom Rods & Custom Pistons to begin with, But now with the rod & crank change, I've saved money, the pistons were the same price regardless.

I spoke to JE today, they make spacers for rod guided pistons on their current configurations, but because of the .927" pin and the small end of the rod only being .900" wide, they'll design them without spacers, so the rods will be clearanced between the pin bosses.

A street engine with Blairs Pro Ports, small cam .600" Lift  260 x 270@ .050" , for me to play with.

[gt350hr]

  That usually means a Forged Side Relief ( FSR) design piston and they are tricky at best to run in a street application. Good that they are willing to help you out.

[1967 XR7 GT]

  That usually means a Forged Side Relief ( FSR) design piston and they are tricky at best to run in a street application. Good that they are willing to help you out.

I have run Nascar pistons in my 914 for years. My 1st set were a new set of Nascar BME pistons I ran @ .010" cylinder clearance, the pistons came partially finished, I had to have valve reliefs cut & a pin fit, tore it down after 6 months, the piston skirts look like they did when I assembled the motor.

After that I was running one race take outs, some have even came with rings that I ran, The JE's I dropped the cyl clearance to .008"

Pic's of the pistons are used set of SB2 take outs, JE 4.1535"-105.5mm dia for a 105.7mm-4.1615" bore with 2.250", .866"-22mm pins, with about a 1.200" pin height and will be ran with  .008"-0.2032mm clearance, giving a 105.702mm bore, and are gas ported. Rings were used that came with the pistons and are .043" top 1.5mm 2nd and 3mm oil.
I checked the end gap on the rings, Top was .019" and 2nd was .025", the cyl's I will have light hone done and run the rings as they are.

These were ran air cooled, one set I ran a year in a daily driver 30,000 miles, I pulled the motor to take the straight cuts out, they were driving me up the wall, the pistons were beautiful.  So the FSR's in a more stable water cooled motor, I don't see an issue.

The piston guided rod, is my 1st time, a few of my motors I was going to try it out, but never had a crank or rods cut to try it, so now I am.

[gt350hr]

   Water cooling brings on the challenges with an FSR.

[1967 XR7 GT]

   Water cooling brings on the challenges with an FSR.

Can you elaborate on your statement, what challenges are you talking about ?   

[gt350hr]

     An air cooled cylinder expands more than a water cooled cylinder . While you have had good results with the air cooled combination , using the FSR in an iron , water cooled block will require different clearances for sure to prevent scuffing. Using a cast iron head adds to the scuffing potential.
     Randy

[1967 XR7 GT]

     An air cooled cylinder expands more than a water cooled cylinder . While you have had good results with the air cooled combination , using the FSR in an iron , water cooled block will require different clearances for sure to prevent scuffing. Using a cast iron head adds to the scuffing potential.
     Randy

The FSR pistons are not new, they been out for a bit, and I will have to ask JE about the scuffing & clearance issue's and will have to see what is recommended for clearance.

So I will be running around a 1.6" C/H, so I will have  little more skirt area than the norm, more than like what a stroker and a 6.7" rod or longer would require in a C/H.

      "Using a cast iron head adds to the scuffing potential."   

But for the record, my heads are Edelbrock Pro Ports.   But I am curious as to how a cast iron head could add to piston scuffing ? I know of a debate as to if an aluminum head deters detonation compared to a cast iron head, some say yes others say no, but for a cast iron head causing piston scuffing is new to me.

[gt350hr]

  Richard ,
        I have dealt with forged side relief pistons since they became the ''craze" in Nascar engines and unless I told you that there would be no way of you knowing I had. Because of that I will assume I have more experience with them than you do. Parts I engineered won many "TV" races including Michael Waltrip's first Daytona 500 win. That and a few bucks will still buy me a cup of coffee so I have that going for me. LOL
     The "strut" area of an FSR piston is very rigid and is the area where scuffing is most prevalent . It is unusual to see them scuff in the center of the skirt. In the ''early days" of FSR technology , I think every manufacturer scuffed them until methods were developed to reduce it. Innovative cam turns and barrel shapes have come along way .  The reason I say a cast iron head can add to the scuffing is likely two fold. One would be the fact that an iron head is more rigid limiting "some" amount of flex versus an aluminum head. Second would be the iron head's heat retention over the aluminum head , leaving more heat for the piston to absorb.  You have an aluminum head had should be fine.
    1.600 is actually fairly long for an FSR design. FSRs like 1.300 or less. (Well IMHO anyway)
         My opinions are from hands on development , not debates or magazine articles.
             Randy