Why you dont cheap out on rods on a rebuild. - Miata Turbo Forum - Boost cars, acquire cats.

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Old 10-24-2009, 02:59 PM   #1
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Default 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:








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.
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Old 10-24-2009, 03:04 PM   #2
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bmw:
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Old 10-24-2009, 03:04 PM   #3
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yeap...aside from the block, our little motors are **** in comparison to just about any other 4-cylinder.
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Old 10-24-2009, 05:11 PM   #4
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Quote:
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yeap...aside from the block, our little motors are **** 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!
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Old 10-24-2009, 05:17 PM   #5
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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?
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Old 10-24-2009, 05:24 PM   #6
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Would a motor run seemingly normally with rods like that ???
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Old 10-24-2009, 06:28 PM   #7
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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...
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Old 10-24-2009, 06:40 PM   #8
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Daaaamn, they did that with 250 hp?

Gulp.
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Old 10-24-2009, 06:43 PM   #9
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i dont think its a matter of whp, isn't det. what kills rods?
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Old 10-24-2009, 06:44 PM   #10
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yeap...aside from the block, our little motors are **** in comparison to just about any other 4-cylinder.
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.
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Old 10-24-2009, 06:44 PM   #11
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i dont think its a matter of whp, isn't det. what kills rods?
torque pushes down on the pistons, too much and they squish the rods.
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Old 10-24-2009, 07:07 PM   #12
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Quote:
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i dont think its a matter of whp, isn't det. what kills rods?
that's just it, the pistons look pristine



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.
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Old 10-24-2009, 07:15 PM   #13
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with the rods bent did it F up the cyl walls?
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Old 10-24-2009, 07:16 PM   #14
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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

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).
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Old 10-24-2009, 07:17 PM   #15
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Look at the positive side, it was a DIY variable-compression engine!
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Old 10-24-2009, 08:45 PM   #16
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Look at the positive side, it was a DIY variable-compression engine!
Differential compression surely
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Old 10-25-2009, 01:11 AM   #17
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The award for the best 4 banger has to go to the mighty 4G63..hands down..
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Old 10-25-2009, 01:18 AM   #18
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Best 4-banger?



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

Norwood Racing's 4,000 hp Max-4 Integra - Tech Review - Turbo Magazine
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Old 10-25-2009, 01:32 AM   #19
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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.
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Old 10-25-2009, 01:58 AM   #20
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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!
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