fail - 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 01-29-2010, 12:10 PM   #1
Newb
Thread Starter
 
Join Date: Feb 2007
Location: melbourne, FL
Posts: 13
Total Cats: 0
Default fail

my list of engine failures for others to learn from

high mileage + poor luck + boost + oil pump = fail

building motors on the beach + rod cap on backwords + "help" from a friend = spun bearings and devoured crank journals.... fail

crank "kit" = fail ...I don't care what your "book" says the miata does not have a cast, half counter-weighted crank

eagle rods don't like supertech wrist pins.... Don't force them, then take them to your machinist and shrug your shoulders your machinist will hone the rod a tiny amount and you will put it all together then find out in a few weeks that your rods are bent by a few thousandths because you will hear loud clanking from "localized, diametrically, worn bearings. see pic below.... fail

on a side note is it just me or do these pistons have a little too much build up for 3k miles
Attached Thumbnails
fail-img_0069.jpg   fail-img_0177.jpg   fail-img_0175.jpg  
The Punisher is offline   Reply With Quote
Old 01-29-2010, 12:22 PM   #2
Newb
 
Join Date: Nov 2009
Posts: 25
Total Cats: 0
Default

Quote:
Originally Posted by The Punisher View Post
eagle rods don't like supertech wrist pins.... Don't force them, then take them to your machinist and shrug your shoulders your machinist will hone the rod a tiny amount and you will put it all together then find out in a few weeks that your rods are bent by a few thousandths because you will hear loud clanking from "localized, diametrically, worn bearings. see pic below.... fail
This is one of the reasons I'm debating in my head whether it's worth it to do rods or not. It's not so much the $300, but the install adds another point of potential failure. It's a typical don't fix it if it ain't broken kinda thing.
crazygambit is offline   Reply With Quote
Old 01-29-2010, 12:30 PM   #3
meatbag
iTrader: (50)
 
gospeed81's Avatar
 
Join Date: Nov 2008
Location: Houston, TX
Posts: 7,357
Total Cats: 26
Default

Don't post this **** up as I get ready to assemble my motor in the gayrage...


I know it's worth it to pay someone to check pin fit...but how exactly did that kill your big end bearings?

Was the hone not straight?
gospeed81 is offline   Reply With Quote
Old 01-29-2010, 12:35 PM   #4
Elite Member
iTrader: (9)
 
Join Date: Sep 2008
Location: Livonia, Michigan
Posts: 5,684
Total Cats: 10
Default

Holy **** man, thats some FML material.
buffon01 is offline   Reply With Quote
Old 01-29-2010, 12:37 PM   #5
Elite Member
iTrader: (10)
 
Join Date: Oct 2008
Location: Seattle, Wa
Posts: 1,780
Total Cats: 30
Default

Guys guys guys. Don't sweat putting together a bottom end.
1. Before you disassemble anything, use a sharpie/scribe to mark orientation on the pistons/rods/crank journals if they aren't already marked.
2. Have a machinist check the important bits like rod ends.
3. Liberally use plastigauge and a good set of calipers/feelers. If you aren't sure, check it twice.
4. If everything checks out...Profit. Just be thorough with the torque wrench.
Jeff_Ciesielski is offline   Reply With Quote
Old 01-29-2010, 01:02 PM   #6
Newb
Thread Starter
 
Join Date: Feb 2007
Location: melbourne, FL
Posts: 13
Total Cats: 0
Default

oh yeah and i forgot to mention that your water temperature gauge wont tell you that something put a hole the size of a golf ball in the bottom of your radiator while traveling 80mph down the interstate.... well fast enough to keep your head gasket from going kaboom anyway... yeah deff FML stuff since I am yet to use my boost controller see more than 6psi(aside from boost creep)

well I dont know if it was a crooked hone or me trying to force the the pins in or a mixture of both but either way it causes the big end to sit crooked on the crank journal and wear out opposite edges of the bearings and the need for new rod(s). I'm going with the M-tuned set this time they have more clearance for the wrist pin .788" instead of eagles .787" and they are cheaper and weigh about 65 grams less per rod... epmiata.com says that eagle claims 900hp capability but I'm willing to bet my engine that I'll never need more than the 600hp m-tuned claims.

don't be discouraged from DIY there is no better way to learn(I pulled and disassembled my engine without an engine hoist or air tools in about 6 hours and that was taking my time) and no better feeling than saying "I built it" but I would say at least take month or 2 to read read read and go and talk to your machine shops and "professional" engine builders (I have literally spent hours doing this and even some of them have learned stuff from debating answers to questions I asked)
The Punisher is offline   Reply With Quote
Old 01-29-2010, 01:43 PM   #7
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,689
Total Cats: 1,562
Default

I am most amazed by that crankshaft comparison. Did you ever find out what the "half weighted" crank was really originally designed for?
sixshooter is online now   Reply With Quote
Old 01-29-2010, 01:48 PM   #8
Elite Member
iTrader: (5)
 
m2cupcar's Avatar
 
Join Date: Jan 2005
Location: Atlanta
Posts: 7,244
Total Cats: 291
Default

IF you're going to assemble you're own engine, then approach it as if you were going to operate on yourself.
m2cupcar is offline   Reply With Quote
Old 01-29-2010, 04:52 PM   #9
Junior Member
iTrader: (1)
 
Join Date: Apr 2008
Location: Bristol
Posts: 442
Total Cats: 0
Default

Quote:
Originally Posted by m2cupcar View Post
IF you're going to assemble you're own engine, then approach it as if you were going to operate on yourself.
Wasted on nitrous and gin?
Duckie_uk is offline   Reply With Quote
Old 01-29-2010, 05:02 PM   #10
Elite Member
 
Join Date: Dec 2008
Location: Colorado
Posts: 1,669
Total Cats: 36
Default

^Or with a rusty pocket knife on a boat in the South Pacific while listening to B.O.C.?
Sparetire is offline   Reply With Quote
Old 01-29-2010, 05:28 PM   #11
Elite Member
iTrader: (1)
 
Join Date: Jun 2007
Location: VA, Germany, Afghanistan
Posts: 2,967
Total Cats: 3
Default

Quote:
Originally Posted by Sparetire View Post
^Or with a rusty pocket knife you just stole from the loser of a monkey knife fight on a boat in the South Pacific while listening to B.O.C.?
Word.
KPLAFIN is offline   Reply With Quote
Old 01-29-2010, 05:36 PM   #12
Elite Member
iTrader: (13)
 
Join Date: Nov 2006
Location: Tigard, Oregon
Posts: 3,908
Total Cats: 0
Default

Quote:
Originally Posted by The Punisher View Post

on a side note is it just me or do these pistons have a little too much build up for 3k miles

Those look just like the 80K mile pistons in the motor I'm currently tearing down. Damn that's a lot of crap on them for 3k!


Really curious about the rod honing and the problems there. It's been discussed recently that pretty much all the rods need to be honed to fit the pins. Wonder who's mistake made it eat the bearing and what to look out for.
cueball1 is offline   Reply With Quote
Old 01-29-2010, 05:43 PM   #13
Junior Member
 
Join Date: Jan 2008
Location: Sparta, NJ
Posts: 96
Total Cats: 0
Default

Quote:
Originally Posted by The Punisher View Post

eagle rods don't like supertech wrist pins.... Don't force them, then take them to your machinist and shrug your shoulders your machinist will hone the rod a tiny amount and you will put it all together then find out in a few weeks that your rods are bent by a few thousandths because you will hear loud clanking from "localized, diametrically, worn bearings. see pic below.... fail
This is why you are supposed to measure wrist pin clearances for ANY build.
avante43 is offline   Reply With Quote
Old 01-29-2010, 10:09 PM   #14
Newb
Thread Starter
 
Join Date: Feb 2007
Location: melbourne, FL
Posts: 13
Total Cats: 0
Default

I believe the crank is from a 91-93 protege... It fits but it's not what I ordered... I may use it someday for an all motor build with some ITBs and an electric supercharger for the extra cool kid effect...

Although idk if it was just honed wrong or whatever. I was talking to an engine builder and he told me to always lay the rods on a piece of glass to make sure they are perfectly straight... If they aren't find some new ones
The Punisher is offline   Reply With Quote
Old 01-29-2010, 10:30 PM   #15
Elite Member
iTrader: (8)
 
Join Date: Jun 2009
Location: Albany, NY
Posts: 1,523
Total Cats: 4
Default

Quote:
Originally Posted by avante43 View Post
This is why you are supposed to measure wrist pin clearances for ANY build.
The fsm for the B6 says 0.0004-0.0011 clearance between small end and pin, I would assume the same for BP (check, though). Guys smarter than me can chime in, but even with this little amount of clearance, there should be no appreciable bind or tightness when inserting the pin in the rod. This is going to sound like a broken record to some guys, but my local NAPA only charges $60 to fit the set, and they will turn them around within 24 hrs. You should be able to measure them in your home shop well enough.
webby459 is offline   Reply With Quote
Old 02-01-2010, 04:56 PM   #16
Senior Member
iTrader: (16)
 
Join Date: Jul 2009
Location: salem ark
Posts: 563
Total Cats: -1
Default

i wish i had a picture of my dsm eagle crank one day i pressed the clutch in it shudderd like a sonabitch. first thought flywheel bolts backed out "the stroker motors" tend to do this. i pulled the tranny the crank was snapped in two she made it like that 4 miles home. it is now a paper weight at a buddies performance shop
browning is offline   Reply With Quote
Old 02-01-2010, 05:23 PM   #17
Guest
iTrader: (6)
 
Join Date: Sep 2007
Location: Vaughan, On, Canada
Posts: 1,092
Total Cats: 0
Default

Quote:
Originally Posted by m2cupcar View Post
IF you're going to assemble you're own engine, then approach it as if you were going to operate on yourself.
Yup.. Very very clean area..

Always check your clearances and NEVER force anything. If the Piston Wrist Pin is tight is will take only a few $$s from a machinist to make it fit proper.
M-Tuned is offline   Reply With Quote
Old 02-01-2010, 05:29 PM   #18
Guest
iTrader: (6)
 
Join Date: Sep 2007
Location: Vaughan, On, Canada
Posts: 1,092
Total Cats: 0
Default

Quote:
Originally Posted by The Punisher View Post
I'm going with the M-tuned set this time they have more clearance for the wrist pin .788" instead of eagles .787" and they are cheaper and weigh about 65 grams less per rod... epmiata.com says that eagle claims 900hp capability but I'm willing to bet my engine that I'll never need more than the 600hp m-tuned claims.
We could claim 900hp but there has never been a Miata who has made 900hp. We have had our rod used in a 600hp with our ARP 2000 Bolts.

I used to own a 500hp Miata. It was nuts! 4th Gear Burnouts on the Highway when I got on the loud pedal!! 900hp would be retarded = CRASH!
M-Tuned is offline   Reply With Quote
Old 02-01-2010, 08:21 PM   #19
Elite Member
iTrader: (17)
 
Join Date: Apr 2009
Location: Atlanta, GA
Posts: 2,831
Total Cats: 0
Default

Quote:
Originally Posted by [email protected] View Post
We could claim 900hp but there has never been a Miata who has made 900hp. We have had our rod used in a 600hp with our ARP 2000 Bolts.

I used to own a 500hp Miata. It was nuts! 4th Gear Burnouts on the Highway when I got on the loud pedal!! 900hp would be retarded = CRASH!
"900 HP Miata" im gonna be the one to do it!
WonTon is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
91 1.6l turbo complete part out. Tony the Tiger Miata parts for sale/trade 63 12-29-2016 03:23 AM
Prepping my '95 for track asmasm Build Threads 82 05-26-2016 05:37 PM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM
MS3 Basic Connection Issues EErockMiata MEGAsquirt 6 09-24-2015 10:49 AM
91 Celica manual trans, is this fucked? Onyxyth Insert BS here 1 09-19-2015 08:27 PM


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 07:05 AM.