Why you dont cheap out on rods on a rebuild. - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 10-25-2009, 02:01 AM   #21
Elite Member
iTrader: (33)
 
RotorNutFD3S's Avatar
 
Join Date: Jan 2007
Location: Newnan, GA
Posts: 2,539
Total Cats: 29
Default

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.

Name:  DSC01787.jpg
Views: 2
Size:  69.9 KB
Name:  DSC01790.jpg
Views: 2
Size:  64.2 KB
RotorNutFD3S is offline   Reply With Quote
Old 10-25-2009, 02:33 AM   #22
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,186
Total Cats: 2,582
Default

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
18psi is offline   Reply With Quote
Old 10-25-2009, 02:39 AM   #23
Elite Member
iTrader: (1)
 
NA6C-Guy's Avatar
 
Join Date: Feb 2008
Location: Birmingham Alabama
Posts: 8,038
Total Cats: 43
Default

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.
NA6C-Guy is offline   Reply With Quote
Old 10-25-2009, 02:46 AM   #24
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,186
Total Cats: 2,582
Default

I do not believe that. But if someone shows any proof I'll be happy to retract my statement.
18psi is offline   Reply With Quote
Old 10-25-2009, 02:52 AM   #25
Elite Member
iTrader: (9)
 
Join Date: Sep 2008
Location: Bloomfield, Michigan
Posts: 5,682
Total Cats: 10
Default

I thought our motors were pretty bad ***, and that the 4g63 was ****. I guess Im wrong
buffon01 is offline   Reply With Quote
Old 10-25-2009, 02:58 AM   #26
Elite Member
iTrader: (1)
 
NA6C-Guy's Avatar
 
Join Date: Feb 2008
Location: Birmingham Alabama
Posts: 8,038
Total Cats: 43
Default

Quote:
Originally Posted by 18psi View Post
I do not believe that. But if someone shows any proof I'll be happy to retract my statement.
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.
NA6C-Guy is offline   Reply With Quote
Old 10-25-2009, 03:53 AM   #27
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,318
Total Cats: 1,916
Default

Quote:
Originally Posted by NA6C-Guy View Post
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.
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.

Last edited by Joe Perez; 10-25-2009 at 09:15 PM. Reason: B6, not B8... Thinking Honda today...
Joe Perez is offline   Reply With Quote
Old 10-25-2009, 04:00 AM   #28
Elite Member
iTrader: (17)
 
Join Date: Aug 2007
Location: Fort Myers, FL
Posts: 2,791
Total Cats: 130
Default

You guys are going to get everyone all paranoid. After 10 months of my noob *** trying to figure out how to tune my rods looked perfect. Turn up the boost!
pdexta is offline   Reply With Quote
Old 10-25-2009, 04:09 AM   #29
Elite Member
iTrader: (1)
 
NA6C-Guy's Avatar
 
Join Date: Feb 2008
Location: Birmingham Alabama
Posts: 8,038
Total Cats: 43
Default

Quote:
Originally Posted by Joe Perez View Post
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 / B8 gets fired up is after it's had a car installed on it.
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.
NA6C-Guy is offline   Reply With Quote
Old 10-25-2009, 04:53 AM   #30
Elite Member
iTrader: (13)
 
Join Date: Dec 2006
Location: Taos, New mexico
Posts: 5,702
Total Cats: 237
Default

**** it, our motors are cheap. More boost ftw.
Fireindc is offline   Reply With Quote
Old 10-25-2009, 10:25 AM   #31
Elite Member
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default



Nice article, very interesting read. Thanks for the link.
ZX-Tex is offline   Reply With Quote
Old 10-25-2009, 11:05 AM   #32
y8s
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Quote:
Originally Posted by 18psi View Post
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 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.
y8s is offline   Reply With Quote
Old 10-25-2009, 11:15 AM   #33
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,186
Total Cats: 2,582
Default

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.
18psi is offline   Reply With Quote
Old 10-25-2009, 11:23 AM   #34
meatbag
iTrader: (50)
 
gospeed81's Avatar
 
Join Date: Nov 2008
Location: Houston, TX
Posts: 7,357
Total Cats: 26
Default

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?
gospeed81 is offline   Reply With Quote
Old 10-25-2009, 11:24 AM   #35
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by ZX-Tex View Post


Nice article, very interesting read. Thanks for the link.
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 **** that rolls out of his shop is on another level. We always saw **** in there like Bugattis, Ferraris, Callaways, you name...wild ****.
hustler is offline   Reply With Quote
Old 10-25-2009, 12:13 PM   #36
Senior Member
iTrader: (3)
 
Join Date: Jul 2005
Location: Connect-I-Cut
Posts: 1,431
Total Cats: 0
Default

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
miataspeed2005 is offline   Reply With Quote
Old 10-25-2009, 12:41 PM   #37
y8s
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Quote:
Originally Posted by Robbi Laurenson @ m.net
I must be around 225 rwhp at 9 psi, and probably 240+ at 10 psi. That's on an FMII BBB, turbo midpipe and single exhaust with the MoTeC M4 running full sequential, tuned on a WB02 to 0.85 lambda. Timing is FM map from Ken for an '01.

This is probably a low estimate since others are making better power with the same gear. I am adjusting for no dyno tuning.

So far no knock registered on the J&S with water injection. Still going after 12k boosted.
He mentioned planning to go to the dyno in various threads but never posted up results
y8s is offline   Reply With Quote
Old 10-25-2009, 02:13 PM   #38
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Quote:
Originally Posted by y8s View Post
What bugs me now is that I'm probably driving my own car around with rods that look like that. eek.
Well then now you have the reduced compression ratio you've always wanted!
JasonC SBB is offline   Reply With Quote
Old 10-25-2009, 02:33 PM   #39
Junior Member
iTrader: (1)
 
Join Date: Oct 2008
Location: Palm Harbor FL
Posts: 332
Total Cats: 4
Default

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.
1slowna is offline   Reply With Quote
Old 10-25-2009, 02:38 PM   #40
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by 1slowna View Post
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
hustler is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 58 Yesterday 10:04 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
Odd Steering issue interestedofold Suspension, Brakes, Drivetrain 5 09-29-2015 02:42 PM
Bp/b6 Scat H beam rods Dparks7 Miata parts for sale/trade 1 09-28-2015 10:49 AM


Tags
2001, broken, rods

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:09 PM.