TheSamba.com :: View topic - What's the best Connecting Rod for the money, 6500 rpm

Sun Feb 17, 2013 5:52 am

The old rule of thumb is I beams handle stretch (high rpms) better and H beams compression (turbo or detonation) but in this range it is rarely the rod itself that fails. A famous hillclimb here has the "bent carillo" trophy, if you buy one of the better rods such as the scat or CB maybe it won't hurt so much when it is time to replace them? I think the clearancing problems with a stock rod rules them out.

190HP + nitrous - this is obviously a drag engine, which spends most of it's life producing maximum power, I think you should count on breaking whatever you use.

Sun Feb 17, 2013 6:12 am

I've got DRD Chevy journal 5.4 H beam's in my 2110 bus motor, well chuffed with them. Cheap compared to Scat & CB plus they are beautifully made!

Sun Feb 17, 2013 9:40 am

Quokka42 wrote: The old rule of thumb is I beams handle stretch (high rpms) better and H beams compression (turbo or detonation)

You have it backwards. I-beams are better at handling compressive loads, like high torque and turbocharged engines. H-beams get used in high RPM engines because of their light weight vs the other type, and no other reason. The third type, forged aluminum rods, only get used in drag engines where they will be changed at regular intervals. They are subject to fatigue failure, which explains why you don't see them in long haul street engines.

Sun Feb 17, 2013 11:20 am

Who knows what part is made in america and china now days. Im happy with my Scat rods and they have spun up to 8300 rpms np. I have used unitechs, scat i beams, and many sets of stock rebuilt rods. For I beams I would use Scat hands down. But thats just me. I will always build it more stout for myself. If you want a cheap, though decent h beam, you can opt for a set of Empi's. I have picked up sets of H beams as cheap as 140.00 and I beams as cheap as 80.00. I have used only 1 set of Empi H beams to date, but they spec-ed out fine. Keep an eye out.

Sun Feb 17, 2013 11:39 am

4340 wrote: Hotrodvw wrote:
Yup, I run 5.5" 311B rods with 3/8" ARP bolts....had it to 7K on a 78mm Berg crank. No worries! :lol:

I think you meant 5.394” and not 5.5” the stock rod is 137mm long. :wink:

They measure 5.5" center to center, on the nut.

Sun Feb 17, 2013 11:48 am

Tell me HotRod what engine did you get VW 311B rods out of that are 5.500" in length.
The longest ones I ever seen out of factory engine are like 4340 says, 137mm or 5.394"

Sun Feb 17, 2013 1:00 pm

mild steel connecting rods can be cut apart and welded back to gether to make them shorter or longer. Of course, it isn't real common :wink:

Sun Feb 17, 2013 3:41 pm

Quokka42 wrote:
190HP + nitrous - this is obviously a drag engine, which spends most of it's life producing maximum power, I think you should count on breaking whatever you use.

Nope it is a street car. I built it for my wife. It has a fully auto trans from a type 3. I'm running 3.67 r&p and 26.2 rear tires. The use of the converter has helped make the car quite civilized. My wife has told me to put it back together and leave it alone. I pulled it down today thinking I had melted pistons. As it turns out, I only melthed the plugs. The pistons and cylinders are showing considerable wear, so its time for new ones.

I just ordered new pistons cylinders rings pins and SCAT RODS Thanks for all the help.

Sun Feb 17, 2013 5:05 pm

jsturtlebuggy wrote: Tell me HotRod what engine did you get VW 311B rods out of that are 5.500" in length.
The longest ones I ever seen out of factory engine are like 4340 says, 137mm or 5.394"

Came out of a motor I bought, built in Portland, Or. Berg crank and flywheel, I beleive the rods weere re-worked by Rimco. You can question it all day long, but the fact is, they are 5.5" eye to eye...I measured them myself.
Why would I fib about the length of my rod?? :lol:

Sun Feb 17, 2013 5:29 pm

Hotrodvw wrote: jsturtlebuggy wrote: Tell me HotRod what engine did you get VW 311B rods out of that are 5.500" in length.
The longest ones I ever seen out of factory engine are like 4340 says, 137mm or 5.394"

Came out of a motor I bought, built in Portland, Or. Berg crank and flywheel, I beleive the rods weere re-worked by Rimco. You can question it all day long, but the fact is, they are 5.5" eye to eye...I measured them myself.
Why would I fib about the length of my rod?? :lol:
if you are happy with 5.5 inches......far be it from us to question you.... :P

Sun Feb 17, 2013 5:32 pm

58Dub wrote: Hotrodvw wrote: jsturtlebuggy wrote: Tell me HotRod what engine did you get VW 311B rods out of that are 5.500" in length.
The longest ones I ever seen out of factory engine are like 4340 says, 137mm or 5.394"

Came out of a motor I bought, built in Portland, Or. Berg crank and flywheel, I beleive the rods weere re-worked by Rimco. You can question it all day long, but the fact is, they are 5.5" eye to eye...I measured them myself.
Why would I fib about the length of my rod?? :lol:
if you are happy with 5.5 inches......far be it from us to question you.... :P

Somebody somewhere is jealous...........I just know it in my heart. :lol:

Sun Feb 17, 2013 6:04 pm

neil68 wrote: My CB H-beam rods run to 7900 rpm's without any issues.
X2 and then some.
2 liter autocross engine (multiple track race) using Cb rods w. ARP2000 bolts. Rev limit 8500 rpm. No problems for 4 seasons. Engine is retired as of end of the 2012 season.

For 6500 rpm max, stock or Unitech rods are fine.

T