Ebay china rods for L16. Any good ?

[datsun 160J SSS]

Hello anyone buy and use the china made race rods off ebay ? from the photos they look good . but who knows first hand ?

[Ratwagon1600]

Hmmmmmmm.

 

I havent used them but I will apply my standard mathematical equatiom for stuff like this.

 

Chinese+Egay+high revving engine internal = polished turd

[G-Duax]

Eagle rods are Chinese....

Brian (brat) Crower rods are Chinese.

Scat rods are Chinese.

 

So what's your point ratwagon ?

Because they are on eBay ?

I get better quality parts off eBay than I do from the bait & switch kings that go by the name 'rock auto'.

 

Datsun 160j sss,  just what do you consider high rpm ?

I put Maxspeeding rods in my 3mm over bore L18, and will be turning it 8500.

I had eagle rods in my long stroke Toyota 7M, and was turning it 9k.

 

The Maxspeeding rods are much lighter than the stock rods, which lessens the stress on them, and the crank.

And they came with ARP bolts.

 

Would I use them in an all-out, 10,000 rpm engine?

Probably not, but the amount of stress when going from 8500 to 10k is almost double.

[Ratwagon1600]

 

So what's your point ratwagon?.

 

Simple.

 

OP is talking about (unamed manufacturer) "race rods", implying they are going to be used in a high performance engine working at peak RPM.

 

In 25+ years of building rally/race engines and competing in rally and hill climb events, I have always used stock rods albeit crack tested, balanced, peened, closed and honed and running my engines at a peak rev range of approximately 7500 rpm without a failure.

 

My experience in recent years (and that of some acquaintances) with chinese turbo's, intercoolers and radiators bought off Ebay hasnt been good, wth issues such as poor welding, bad machining/tolerances and general overall poor finish quality hence my polished turd comment.

 

Try and get warranty on something you purchase from China!

[G-Duax]

The machine work on my maxspeeding rods was precise, and the weight matching between the set of 4 was closer than the Eagle rods.

I see worse quality control from people like PPG in Australia, with high failure rates in their gear sets.

Which brings up the thought of how much stuff coming from Australia is actually Chinese?

 

I've been fighting the Chinese parts invasion for about 15 years, but some of the manufactures over there are getting their shit together.

 

Personally, I would never buy a Chinese turbo, intercooler, radiator, clutch, or electronic, but that is mostly due to the fact that they are being contracted to make the shit as cheap as possible.

[datzenmike]

Red line, this is for sustained high RPM without failure, on stock factory rods under perfect conditions. This is the metallurgical limit  the rod and it's bolts can resist the acceleration/deceleration G forces when traveling at 4,000 ft per min. without stretching or failure.

 

L16......... 8,250 rpm. The rod is traveling through 73.7mm (2.9") 16,500 times a minute or 275 times a second

 

L18......... 7,800 rpm. The rod is traveling through 78mm (3") 15,600 times a minute or 260 times a second

 

L20B....... 7,100 rpm. The rod is traveling through 86mm (3.38) 14,200 times a minute or  236 times a second.

 

 

 

 

 

 

"Captain! 105% on the reactor is possible .......... but not recommended!!"

 

"Go to 105%"

[DanielC]

I have heard L-16 con rods came in at least two versions, one with 8 MM bolts, and one with 9MM rod bolts.  If you have the 9 MM bolt variety, I would have then inspected, get new ARP rod bolts, and have a machine shop resize the big end.

 

Remember, L-16, and L-24 uses the same rods. 

 

My gut feeling is Nissan OEM 45 year old con rods, the ones with 9 MM bolts would be the way to go.

[Crashtd420]

Are you talking these....

I got these off eBay from cx racing I believe and i am so far very happy... they are hbeam and require a floating pin piston... they also have larger arp bolts... quality and tolerances were actually really high...

my machine shop that bored my engine did hone the small end to fit my new piston pin it was smooth but they didn't like the finish.. and they torqued the bolts for stretch and honed the big end once torqued for

[Tom1200]

Just out of of curiousty how are the stock L16 rods? On the A series engines A12 & A15 engine I'm using completely clock rods with standard bolts and revving the motors to 8500rpms in the A12 an 8000 in the A15. I even use the standard Nissan bolts. Of course the motors power outputs are only about 75-85% of a national engine. Again just curious on the standard L rods.

[Ratwagon1600]

Red line, this is for sustained high RPM without failure, on stock factory rods under perfect conditions. This is the metallurgical limit  the rod and it's bolts can resist the acceleration/deceleration G forces when traveling at 4,000 ft per min. without stretching or failure. L16......... 8,250 rpm. The rod is traveling through 73.7mm (2.9") 16,500 times a minute or 275 times a second L18......... 7,800 rpm. The rod is traveling through 78mm (3") 15,600 times a minute or 260 times a second L20B....... 7,100 rpm. The rod is traveling through 86mm (3.38) 14,200 times a minute or  236 times a second."

Source?

[datzenmike]

Have no idea where I got that from. It was a rule of thumb sort of rough rule to follow. As long as the 4,000 ft/min is not exceeded then stock steel rods will survive. (it may very well be very conservative??) I believe 4,000 feet per min was the upper average piston speed limit. Naturally the piston is accelerating and decelerating most of the time. Going up and down through about 3" 260 times a second means a lot of Gs.

 

The end of the crank throw with the rod on it for an L16 is 73.7mm from the center line. If the rod end is traveling 4,000 ft/min in a circle or 8,200 RPM the centrifugal outward force is over 2,000 G's. A pound of rod weighs a ton.

 

Half the stroke (1.5") the rod and piston is either speeding up or slowing down so you would have to decelerate from 4000 ft/min (roughly 45 MPH) to zero in 1.5" or in 1/520th second. The on line calculator says just over 1,000 G's linear. The rod is following a circle so the deceleration starts off slowly increases then reduces to zero at TDC. So probably much higher.

 

 

 

Do you have a formula or rule of thumb you feel comfortable with for red line limit?

[G-Duax]

Red line, this is for sustained high RPM without failure, on stock factory rods under perfect conditions. This is the metallurgical limit  the rod and it's bolts can resist the acceleration/deceleration G forces when traveling at 4,000 ft per min. without stretching or failure.

 

L16......... 8,250 rpm. The rod is traveling through 73.7mm (2.9") 16,500 times a minute or 275 times a second

 

L18......... 7,800 rpm. The rod is traveling through 78mm (3") 15,600 times a minute or 260 times a second

 

 

But when going to aftermarket rods, these numbers go up, way up due to better design, materials, and lighter weight.

 

The Kamari built L6 engines (using their rods) turn over 12k through the lights on a drag track, and 10k on a road course.

 

Of course, you can't use stock pistons & pins if you are trying to get all the benefits of a aftermarket rod.......

[Ratwagon1600]

 Do you have a formula or rule of thumb you feel comfortable with for red line limit?

Anecdotal. Old school mechanic who taught me how to build engines circa 1986.

 

He helped me build my first rally engine which survived 7500 rpm abuse.

 

It was a formula which I havent changed much in 30 years.

[DISLEXICDIME]

What will the engine be used for ? I ran stock balanced and shot peened l18 rods with upgraded bolts on my old street engine. It regularly saw 8000 rpm . would see 9000 rpm on hard runs.

[datzenmike]

But when going to aftermarket rods, these numbers go up, way up due to better design, materials, and lighter weight.

 

 

Oh absolutely! Lighter and stronger helps.

 

 

 

What will the engine be used for ? I ran stock balanced and shot peened l18 rods with upgraded bolts on my old street engine. It regularly saw 8000 rpm . would see 9000 rpm on hard runs.

 

 

A stock head cam and carb is running out of breath by 5 - 5.5K. Yes it will rev higher.... with a brick on the gas. But basically the stock rods will be more than enough. To get to 7-8K while making any worthwhile power will require some major head work. There's an old saying...."Power comes from the head, strength from the block.   

[scooter]

My lz23 uses a z22 crank and l20b rods with arp bolts and it takes 7500 rpm and a 75 shot of nitrous. The stock rods are strong.

[DanielC]

Oddly enough, the greatest stress on the connecting rod is not under pressure from the firing stoke.  It is at the end of the exhaust stroke, and beginning of the intake stroke.

Due to the geometry of the angles between the crank pin, angle of the con rod to the crankpin, the piston is halfway done the cylinder about 75 degrees before, and after TDC.  The piston is also travelling at maximum speed at that point.

Lets take Mike's 4,000 feet per second, for example.  75 degrees BTDC, the piston is travelling 4,000 FPS, up.  At TDC, the piston is stopped.  75 degrees ATDC, the piston is again going 4,000 FPS, the other way.  From 75 degrees BTDC, on the exhaust stroke, the con rod is pulling on the piston, all the way to somewhere near the end of the intake stroke.

 

For reference, the SR-71 was said to fly around mach 3.  That is about 3,000 FPS.

[datzenmike]

That was 4,000 ft/ min about 45 mph Daniel. Imagine the crankshaft rolling down the highway at 45 MPH.

 

Maximum piston speed is at the point the crank throw and the rod are at right angles to each other. This is greatly affected by the rod length. Longer rods have the maximum speed farther from TDC point. Pistons and rod ends are moving slower through the TDC position than a shorter rod, lessening the acceleration/deceleration G forces on them and one of the reasons long rods are called 'rev happy'. A long rod engine can tolerate high revs better but otherwise performs about the same other than the strange things that happen in the combustion chamber from a slower moving piston that dwells at TDC longer.

[Stoffregen Motorsports]

What will the engine be used for ? I ran stock balanced and shot peened l18 rods with upgraded bolts on my old street engine. It regularly saw 8000 rpm . would see 9000 rpm on hard runs.

This is the most pertinent argument I've heard so far. If it's an actual race engine, then spend the money and get name brand rods. If it's a street car with some mods, go for big bolt L16 rods (or L24 rods). If it's being turbo'd or something crazy, then you'd better spend the money on good rods.

 

Stock, big bolt L16 rods have been used in many GT4 racing engines, but they have to be polished, shot peened, balanced, etc. Usually a back up motor would have stock rods, but the real race motor gets Carrillos or equivalent.

[banzai510(hainz)]

I thought stock L16 rods are strong as Chev LS1 rods(article I read about 20years ago they did a test). Just the weak point is the rods bolts and most people get them swapped out for the 3/8 ARP bolts

[G-Duax]

ARP even made bolts for the smaller 8mm bolt rods.

Anyone want a set ?

Had them stashed away for a rainy day, but I have no more L16s laying around.

[banzai510(hainz)]

Eagle ,Crower,Scat

wow I did nto know those were all chinese made

[datsun 160J SSS]

Well that's a lot of good information guys , I am going to buy a set of the CRX rods . I will say, I have the china radiators in 2 of my cars and, I looked them over and all the welds looked good only thing I did not like was no drain petcock so I added one . The cooling was way more sufficient then stock no leaks.

[Crashtd420]

Crx?

Or did you mean curating?

Make sure you buy the set that has the bolts, some don't come with them....

[Crashtd420]

Damn auto correct even got me... curating???

Cxracing.