How strong are the stock connecting rods?
- Thread starter CDX_NSX
- Start date
I have one of the free ones that woodwork gave us. I went out and hit it with a baseball bat, ran over it with my Duramax Truck, and dropped it on the concrete driveway from my third story. It still looks pretty good. I say they are tough:biggrin:
What SC are you using to get 500HP? Is that rwhp?
It's custom, and yup, that's what is being estimated at this point at the wheels. It's an estimate right now because there hasn't been another similar setup. Starting point was 400 rwhp at 6 lbs. Boost will be doubled with the rebuild, and all else is guesstimation.
CDX_NSX said:
Very optomistic number, keep us posted....................
Armando
CDX_NSX said:
Is it a rotrex blower?
They are Titanium... I don't believe they make stronger ones...CDX_NSX said:
Of course they make stronger ones, you can't compare just the metal you have to compare the process with which it was made. Titanium was used because of its lightness and strength. i.e a similar cast connecting rod made of steel would be heavier which would increase reciprocating mass, which is never a good thing and it wouldn't of been as strong. However comparing a cast titanium rod to a quality forged I or H beam steel rod, the forged steel rod will be stronger, yes it will weigh more but it will fare better in a boosted application, i.e. less likely to throw a rod. I'd take the forged steel rod for boosted applications. If you are tearing your motor apart I would consider changing your rods to forged H or I beam design.
Graeme, you should ask for an Adamantium application.
it is nearly indestructable.
heres a link for more info.
http://www.marveldirectory.com/misc/adamantium.htm
it is nearly indestructable.
heres a link for more info.
http://www.marveldirectory.com/misc/adamantium.htm
Thanks for the input, guys.
Erick, as I understand it, the molecular structure of Adamantium can be severely compromised by Spiderman's pee. Not knowing if it this is caused by the mutation of Spiderman's genes, I'd rather not risk the chance of a spider crawling into my engine during an oil change and melting the rods.
Erick, as I understand it, the molecular structure of Adamantium can be severely compromised by Spiderman's pee. Not knowing if it this is caused by the mutation of Spiderman's genes, I'd rather not risk the chance of a spider crawling into my engine during an oil change and melting the rods.
How strong are the OEM rods? I dunno, but here's what happened to mine @ 500...
Not strong enough, I guess.
Not strong enough, I guess.
:biggrin: yet also :frown: KGP
Tore my motor down for a rebuild, found an original titanium rod fractured through the cap area
Fracture ran from the outside of the rod bolt bore to the bearing surface of the cap.
The motor did not lunch but I don't believe it one more 8k rev left:smile:
Perfect timing for the tear down.:biggrin: New rods will be forged alloy steel; slightly heaver but much stronger
I have the rod intact if anyone would care to see this break. It appears the break did allow the rod to grow in length slightly at high rpm, you can see where the exhaust valves slightly coined against the valve relief area on top of the piston.
Bob
Fracture ran from the outside of the rod bolt bore to the bearing surface of the cap. The motor did not lunch but I don't believe it one more 8k rev left:smile: Perfect timing for the tear down.:biggrin: New rods will be forged alloy steel; slightly heaver but much stronger
I have the rod intact if anyone would care to see this break. It appears the break did allow the rod to grow in length slightly at high rpm, you can see where the exhaust valves slightly coined against the valve relief area on top of the piston.
Bob
Wow. I shook my head as I read that. Hope you bought a lottery ticket on the way home, Bob. Any clues on what caused it or where exactly it started? Toward the top-side or bottom?
clr1024 said:
I do realise the different processes. However, I have never seen any information which states the NSX titanium connecting rods are cast, or in fact that they are forged.
A forged Titanium rod will be stronger than a forged steel rod.
I had assumed that when the NSX was developed back in the late 80's Titanium connecting rods were only used in racing applications. In addition, the cost of Titanium meant that the difference between forged or cast processes would have been minimal.
Therefore, I had assumed that the NSX used forged Titanium connecting rods.
Secondly, as to are they strong enough... Well I still have the original connecting rods in my engine which has been putting out 550bhp reliably for over 12 years now...
Daedalus said:
I have the rod in front of me as I write this: the crack runs from the inside shoulder of the seat for the rod bolt nut upward at approximately a 30 degree angle to vertical center line of the rod. It appears that total failure was prevented by the washer and nut assemble retaining [holding down] the broken part of the cap after the crack occurred.
I have no idea what caused this to occur
There is damage; given that the bearing "slightly" spun. The crank is serviceable and will be cleaned up by grinding and not used in the SC engine. Lucky I have a spare
Bob
AU_NSX said:
I agree it is likely that the Titanium rod are forged but I would not make the assumption based upon racing use. The pistons used in the NSX are cast and are one of the week points when boosting the motor. I know that forged pistons were around long before the NSX was developed given we were using them in the mid seventies. For racing use a forged piston would have been used given its superiority to the cast ones.
I disagree that a forged Titanium rod is stronger than than a forged alloy steel rod given thier differences in tensile strengths.
A forged Titanium rod is stronger for rods of equal weight; you can build an alloy forged steel rod that is slightly heavier than a titanium but also appreciably tougher/stronger.
The builders I have spoken with do not recommend using the stock Titanium rods in a bored, stroked and SCed engine. They do recommend the use of forged alloy steel rods.
Bob
Bob Kenney said:
Yes, the pistons are cast and definetly a weak point! The stock pistons didn't last long after boosting the engine. That is why I now have cermaic topped forged pistons, but still the stock Titanium con-rods... This set-up has proven to be very reliable.
the ring-lands are usually the first to go on a cast piston, followed by the head lifting (head gasket). The rods will go if a major detonation occurs, or a spun bearing.
Bottom line, I would upgrade EVERYTHING. I found this out the hard way ONCE.
OEM Honda stuff is great, BUT I still doubt that they are as good as perfectly balanced aftermarket stuff. Not only that, but if boosting alot, I would drop the comp ratio with the pistons as well, so you can sleep at night when boosting @ 8k+ all day.
Don't forget some good head bolts (ARP) and an upgraded gasket.
Bottom line, I would upgrade EVERYTHING. I found this out the hard way ONCE.
OEM Honda stuff is great, BUT I still doubt that they are as good as perfectly balanced aftermarket stuff. Not only that, but if boosting alot, I would drop the comp ratio with the pistons as well, so you can sleep at night when boosting @ 8k+ all day.
Don't forget some good head bolts (ARP) and an upgraded gasket.
RP-Motorsports said:
I am with you on this:biggrin: :wink:
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