Why you dont cheap out on rods on a rebuild.
 

So I was tearing down the spare 2001 motor I have in my shed today... (got it from fmowry who purchased the car from Robbi Laurenson who ran a haltech and water injection and maybe around 250 rwhp if I recall all that correctly) and pulling out the pistons to send across the pond and found this:

http://gallery.y8s.com/d/21910-1/DSC_0704.JPG

http://gallery.y8s.com/d/21914-1/DSC_0705.JPG

http://gallery.y8s.com/d/21917-1/DSC_0706.JPG


Yes that's right folks! FOUR BENT RODS. Not sure if this matters, but 1 and 4 were bent in the plane of the rod and 2 and 3 were bent out of plane.

I think the motor had less than 650,000 miles on it at this point. frank can pipe up on that though. Everything else looks great. No serious wear on any parts or surfaces.

go figure.

go get rods for your build for $300.

bmw:
http://amsteam.net/files/2/ams_20_rods_03.jpg

yeap...aside from the block, our little motors are shit in comparison to just about any other 4-cylinder.

I wouldnt say any other 4-cylinder, but most any modern 4-cylinder, yes...

B18C5 FTMFW!

my buddy is parting his out right now. u need rods or pistons?

Would a motor run seemingly normally with rods like that ???

I bet neither owner of the car had any clue that there was something wrong. There's really no way to know that the rods look like that until you tear it down.

a bent rod that's only marginally shorter will hardly show up on a compression test...

Daaaamn, they did that with 250 hp?

Gulp.

i dont think its a matter of whp, isn't det. what kills rods?

I can't agree with that. I think the 1.6L is one of the best motors ever made. And so did few magazines for a while.

I buy nothing but 90-93 to turbo. Bone stock motors, as old as they are. I never work on them. They Run great and hold up well to boost. psi for psi, I would tear up the honda's.

Yea the new motors are startig to carry more power. But will they have the legacy that these have had. I doubt it.

For the dated technology on these motors, they still hold their own. And if clean, N/A and under 190,000 miles are usually still very dependable.

torque pushes down on the pistons, too much and they squish the rods.

that's just it, the pistons look pristine

http://gallery.y8s.com/d/21929-1/DSC_0713.JPG

There's no broken lands or pitting or any obvious signs of repeat offending detonation. plus as I mentioned, there was a water injection system hooked up.

I think the rods were just designed for no boost.

with the rods bent did it F up the cyl walls?

Bent two (killed one) of the four stock rods in my stock engine last year (as some of you may remember). Everyone was quick to blame detonation, but I do not think that is what did it. I think it was 16 psi with a GT2560 on a cold morning :giggle:

Too much power = too much cylinder pressure = too much compression load on the stock rods = Euler column bucking (a.k.a. bent rods).

225 < Too much power < 300 WHP (based on anecdotal evidence, assuming stock redline).

Look at the positive side, it was a DIY variable-compression engine!

Differential compression surely :D

The award for the best 4 banger has to go to the mighty 4G63..hands down..

Best 4-banger?

http://image.turbomagazine.com/f/854...bochargers.jpg

Billet block, 55 psi, 4,000hp. I win.

Norwood Racing's 4,000 hp Max-4 Integra - Tech Review - Turbo Magazine

yeah this is all the more reason for me to put in my mtuned rods that ive had for th epast 2 yrs almost and nvr installed.

More the reason I have completely decided against any boost on my stock rods. My $1000 and 3 month long rebuild was completely useless because I cheaped on the rods. Go me!

Threads like this are convincing me that overall stress killed my stock rod as well. No one could figure out a definite cause and just trying to start the car one day caused it to bend enough to contact the cylinder wall. It bent on both planes.

Attachment 202995
Attachment 202996

What confuses the hell out of me is that there are all these people with bent rods, and yet there are 10 times more people running the same kind of power/boost on stock rods for 10's of thousands of miles with no problems.
Did mazda pick-n-choose which cars got shitty rods and which ones got good ones or what? LOL

This reminds me of something I read somewhere about R package and SE vehicles got the engines that Mazda deemed the best. I guess the ones that made the most power or were balanced the closest. Is this true? Forget where I saw this.

I do not believe that. But if someone shows any proof I'll be happy to retract my statement.

I thought our motors were pretty bad ass, and that the 4g63 was shit. I guess Im wrong :dunno:

I don't believe it either, but I just recall reading it and this topic made it come to the front of my mind. Thought maybe someone else would have some proof for or against this.

In order for that to be the case, Mazda would have to run every single engine on a dyno. Lamborghini can afford this luxury. Pretty sure that the first time a BP / B6 gets fired up is after it's had a car installed on it.

You guys are going to get everyone all paranoid. After 10 months of my noob ass trying to figure out how to tune my rods looked perfect. Turn up the boost!

Thats kind of what I figured. I wish I could remember where it was I read it. Seems like it was someone quite reputable. Guess they shouldn't be so reputable in that case.

Fuck it, our motors are cheap. More boost ftw.

http://image.turbomagazine.com/f/854...car+piston.jpg

Nice article, very interesting read. Thanks for the link.

this car had no problems either! as i said above, you dont know until teardown if there's an issue.

and part of the "pick n choose" is the higher compression cars.

What bugs me now is that I'm probably driving my own car around with rods that look like that. eek.

As long as they don't bend too much or break I guess the car would be acting normal though, right?

I've been arguing with my dad about this whole "bent rods" issue. He REFUSES TO BELIEVE that you could bend a rod and the engine would still be driving and not knocking or blowing up. This is really helping my argument.

For all four to bend like that and not break you'd have to be right at the threshold of what those rods can take...AND not see any detonation. Since detonation usual finds the weak link (weakest rod of set) and causes catastrophic failure, and det is often more prevalent in one cylinder more than others.

It appears that the motor saw just a little too much power, the rods bent and work hardened...becoming "stronger" (although more brittle) and the motor was happy...if not running as designed for a while. Kind of a steady state failure that allowed the motor to keep running.

If anything this points strongly towards EXCELLENT engine management and det prevention...and suggests a real upper limit on torque capacity for stock rods.

y8s: Did either of previous owners ever dyno it? Any idea on peak torque?

When I was a teenagers and in the first year of college I worked in a VW shop in a warehouse next to Norwood's place. The shit that rolls out of his shop is on another level. We always saw shit in there like Bugattis, Ferraris, Callaways, you name...wild shit.

But if you notice all the people with stock motors and lots of boost are the 1.6 evey time you hear of someone bending a rod it's in a 1.8 or at least the majority

He mentioned planning to go to the dyno in various threads but never posted up results

Well then now you have the reduced compression ratio you've always wanted!

yea this seems kinda crazy. m-tuned guy road around on 360whp for like 8 months no issues and this one bends up rods at 250? looks like im not putting a stock motor back in my car.

if you believe these lies, then sure. lol

On the subject of R package and SE cars having better internals it's quite feasable they picked the rods cranks blocks etc. that were closest to the blueprint and used them

Let's end this retardation right now. The origins of this myth go back to a magazine test of an R back in 94 or 95. The R ran .1 sec quicker 0-60 than the M of the same year. M.net morons then take that to mean that the R car must have a hotter mill.

Let's examine that a little. The stripper (read: base) R-pack with stiffer suspension runs a little quicker to 60 than a fully optioned up pig with crap suspension. Hmm.

You can thank our friend Don on m.net for coming up with this, as well as other gems such as shocks don't effect ride quality.

I would not be surprised if the manufacturer's test car they send out to the magazines were more carefully assembled than standard production models, but Mazda doesn't have the resources to expand that to production cars. This is not Mercedes AMG here.
The only car I'd believe might have a chance of having a tighter than standard motor would be the Club Spec cars, and even then I doubt it.

^^^ I agree with your assessment; I was about to write something similar.

I believe it. Clearly this guy is capable of some very serious builds. I am really impressed with that motor. Built from scratch, and designed specifically for drag racing.

wow this thread reminds me of how easily i bent my rod thsi summer. 200 rwhp and uneven compression across the cylinders is all it took for me.

Another reason not to believe the R-Package crap, my car is an R-Package and did that. Just saying.

not that i have much weight here... but i agree, another naaay. A robot drops that motor in. I believe there are some that are better than others... but its luck of the draw

I think its def power, not det... a yay.

Maybe the reduced rod length lowered the compression ratio... therefore reducing cylinder pressure... lowering the forces the rod sees.

I know some "old school" engine builders that have seen it all... Im going to ask them if they have seen motors run strong like that.

Not heard the rumour until this thread just know that it wouldnt be hard to do from a manufacturing point of view cost effective is another story.
Totally agree with test cars fully blueprinted engines/ higher boost leaves the press raving