crank pulley wobbling - how do i fix this? - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 02-14-2012, 08:54 PM   #1
Senior Member
Thread Starter
iTrader: (8)
 
Join Date: Sep 2010
Location: misery
Posts: 1,130
Total Cats: 9
Default crank pulley wobbling - how do i fix this?

i'll post a video when i get home, but i'll try to describe this as best as i can.

when putting the pulley onto the crank, it wobbles back and forth. the hole on the pulley is slightly larger than the crank. the notch lines up, but there's too much play...

the piece on the pulley that has the hole...is that the boss? or hub boss?
can that be replaced without replacing the whole pulley?

thanks in advance. when i get home, i'll post a video for further clarification.
phillyb is offline   Reply With Quote
Old 02-14-2012, 09:46 PM   #2
Senior Member
 
Join Date: Aug 2010
Location: Arl. Texas
Posts: 937
Total Cats: 23
Default

Buy a used pullie. There pretty cheep.

Did you have the crank machined? Was this the reason the pullie is off of the motor in the first place? Why, why is it too big?
Miater is offline   Reply With Quote
Old 02-14-2012, 09:54 PM   #3
Senior Member
Thread Starter
iTrader: (8)
 
Join Date: Sep 2010
Location: misery
Posts: 1,130
Total Cats: 9
Default

this is a used pulley i got from a member here about 2 weeks ago.
it's out cause the engine is being rebuilt.
phillyb is offline   Reply With Quote
Old 02-14-2012, 10:46 PM   #4
Senior Member
Thread Starter
iTrader: (8)
 
Join Date: Sep 2010
Location: misery
Posts: 1,130
Total Cats: 9
Default

here's the video. it's a 99 engine

phillyb is offline   Reply With Quote
Old 02-14-2012, 10:56 PM   #5
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 13,776
Total Cats: 1,106
Default

Which pulley? The front one with the 2 belts or the one that the timing belt goes on?

Just watched the video, have you tightened the main bolt down to 120ft/lbs and then installed the 4 10mm bolts on the big pulley?
shuiend is offline   Reply With Quote
Old 02-14-2012, 11:00 PM   #6
Senior Member
Thread Starter
iTrader: (8)
 
Join Date: Sep 2010
Location: misery
Posts: 1,130
Total Cats: 9
Default

crank pulley...the one with two pulleys. you can kind of see it in the video

this guy





Attached Thumbnails
crank pulley wobbling - how do i fix this?-0419d5bd.jpg   crank pulley wobbling - how do i fix this?-1e73167c.jpg   crank pulley wobbling - how do i fix this?-ee940a2c.jpg  
phillyb is offline   Reply With Quote
Old 02-14-2012, 11:21 PM   #7
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 13,776
Total Cats: 1,106
Default

I think you need to tighten down the big bolt to 120ft/lbs and then see if it moves.
shuiend is offline   Reply With Quote
Old 02-15-2012, 05:30 AM   #8
Elite Member
iTrader: (2)
 
Mobius's Avatar
 
Join Date: May 2008
Location: Portland, Oregon
Posts: 3,178
Total Cats: 267
Default

There's a plate that goes behind this pulley.

a) is it there?
b) is it oriented correctly? It has a front and a back. The center is slightly humped, the hump should go towards the front of the car, away from the engine.
Mobius is offline   Reply With Quote
Old 02-15-2012, 06:51 AM   #9
Elite Member
iTrader: (6)
 
blaen99's Avatar
 
Join Date: Sep 2010
Location: Seattle, WA
Posts: 4,112
Total Cats: 27
Default

Quote:
Originally Posted by Mobius View Post
There's a plate that goes behind this pulley.

a) is it there?
b) is it oriented correctly? It has a front and a back. The center is slightly humped, the hump should go towards the front of the car, away from the engine.
Any chance of pictures of said plate?
blaen99 is offline   Reply With Quote
Old 02-15-2012, 08:59 AM   #10
Senior Member
Thread Starter
iTrader: (8)
 
Join Date: Sep 2010
Location: misery
Posts: 1,130
Total Cats: 9
Default

Quote:
Originally Posted by Mobius View Post
There's a plate that goes behind this pulley.

a) is it there?
b) is it oriented correctly? It has a front and a back. The center is slightly humped, the hump should go towards the front of the car, away from the engine.


a) silver piece is the plate, no?
phillyb is offline   Reply With Quote
Old 02-15-2012, 09:27 AM   #11
AFM Crusader
iTrader: (18)
 
olderguy's Avatar
 
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,438
Total Cats: 84
Default

Plate was on later NA's and NB's for crank sensor. Looks like OP has one of the early ones since the TB cog has made an impression. I would tighten everything up and see if it runs true on the car.
olderguy is offline   Reply With Quote
Old 02-15-2012, 12:19 PM   #12
Junior Member
iTrader: (1)
 
Join Date: Apr 2007
Location: Toronto, Canada
Posts: 455
Total Cats: 18
Default

I had a '00 engine with the #4 bearing fault. Mazda warranty replaced the engine and it never ran properly. Diagnosis eventually tracked the problem to a wobbling pulley (crank trigger miss) caused by A BENT CRANKSHAFT. Mazda replaced that engine too. Any chance you have a bent crank here?
BarbyCar is offline   Reply With Quote
Old 02-15-2012, 12:22 PM   #13
Senior Member
Thread Starter
iTrader: (8)
 
Join Date: Sep 2010
Location: misery
Posts: 1,130
Total Cats: 9
Default

doubt it...it's been measured and made sure that it's in spec during this build.
phillyb is offline   Reply With Quote
Old 02-15-2012, 03:42 PM   #14
Elite Member
iTrader: (2)
 
Mobius's Avatar
 
Join Date: May 2008
Location: Portland, Oregon
Posts: 3,178
Total Cats: 267
Default

I have a pdf copy of the 99-00 service manual; here's a page showing the plate.

My engine is a bit different since it's a 2001, and my pulley looks different, no keyway in mine. However my page in the 2001 manual looks similar to this, so I'm assuming the plate is similar. My plate is ~1/8" thick, and has the same diameter as the accessory crank pulley. It is not attached to the pulley in any way, it is a separate piece which gets sandwiched underneath the accessory pulley. The inner area with the 4 bolt holes is the part that is humped.

Attached Thumbnails
crank pulley wobbling - how do i fix this?-1999-2000workshopmanualp201.jpg  
Mobius is offline   Reply With Quote
Old 02-15-2012, 03:51 PM   #15
Senior Member
Thread Starter
iTrader: (8)
 
Join Date: Sep 2010
Location: misery
Posts: 1,130
Total Cats: 9
Default

that plate is there.
i took off the four bolts that bolt together the plate and the pulley boss from the pulley itself...the boss is shot (i think and hope). i just ordered a new one and it should be tight. i'll keep everyone posted, but i don't think i'll need to loctite anything. and i'm fairly certain the crank doesn't need to be replaced.
thanks for your help.
phillyb is offline   Reply With Quote
Old 02-15-2012, 04:01 PM   #16
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,366
Total Cats: 1,327
Default

Scary. Try swapping the backing plate with another one - I doubt the crank wore down.

Take a picture of the keyway on the crank too.
Savington is offline   Reply With Quote
Old 02-15-2012, 04:46 PM   #17
Senior Member
Thread Starter
iTrader: (8)
 
Join Date: Sep 2010
Location: misery
Posts: 1,130
Total Cats: 9
Default

i'll try to get a picture tomorrow, though i was just over there. the key is fine. the crank is fine.
phillyb is offline   Reply With Quote
Old 02-16-2012, 01:05 AM   #18
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Quote:
Originally Posted by BarbyCar View Post
I had a '00 engine with the #4 bearing fault. Mazda warranty replaced the engine and it never ran properly. Diagnosis eventually tracked the problem to a wobbling pulley (crank trigger miss) caused by A BENT CRANKSHAFT. Mazda replaced that engine too. Any chance you have a bent crank here?
I really doubt the crankshaft was bent.

The crank is pretty much the strongest thing in the whole miata.
Faeflora is offline   Reply With Quote
Old 02-17-2012, 07:42 PM   #19
Junior Member
 
Join Date: Jan 2012
Location: Magnolia,TX
Posts: 87
Total Cats: -1
Default

Crank nose shouldn't be bent.
If the key way is fine to still be able to index the boss and crank together, it should be fine.

The assembly on yours from front to back should be..

21 mm bolt>>large accessory pulley>>boss pulley>>lower timing cog>>crankshaft.

(correct me if I am wrong)

You DID inspect the keyway inside the boss and on the nose of the crank correct?
Moffitt is offline   Reply With Quote
Old 02-17-2012, 08:43 PM   #20
Senior Member
Thread Starter
iTrader: (8)
 
Join Date: Sep 2010
Location: misery
Posts: 1,130
Total Cats: 9
Default

yeah, crank is fine.
keyway is fine.
hoping it's the pulley boss.

when we unbolted the four bolts that hold the pulley to the boss, flipped the boss over and there was considerably less play on the nose of the crank. obviously you can't bolt it on like that and expect it to work. we just did this to test the theory that the boss was not to spec...and it was not.
phillyb 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 12-13-2017 10:04 PM
Need help - Stock Balancer and Fastforward overlay pulleys Frank_and_Beans Supercharger Discussion 13 09-12-2016 09:17 PM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM
Missing/knock at idle, can someone point me in the right direction? Mikel MEGAsquirt 4 09-28-2015 05:46 PM
Got bad Crank Angle Sensor and Random Misfire codes, but runs fine. Greasyman General Miata Chat 2 09-28-2015 11:44 AM


Thread Tools

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 06:20 AM.