Timing belt walking off gears - 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 09-01-2009, 11:18 PM   #1
Senior Member
Thread Starter
iTrader: (7)
 
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,371
Total Cats: -1
Default Timing belt walking off gears

So, I just got my engine put together and i've driven it about 15 miles now. When I popped the hood to check everything out, the timing belt was almost off of the pulleys. It has worn a slot in my timing covers. Does anyone have any ideas what might be causing this?
wes65 is offline   Reply With Quote
Old 09-01-2009, 11:53 PM   #2
Elite Member
 
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,322
Total Cats: 12
Default

The tensioner could be loose.
dustinb is offline   Reply With Quote
Old 09-02-2009, 12:06 AM   #3
Elite Member
iTrader: (1)
 
NA6C-Guy's Avatar
 
Join Date: Feb 2008
Location: Birmingham Alabama
Posts: 8,038
Total Cats: 43
Default

Well thats not good at all. For sure check the tension and make sure its still tight. Otherwise, I don't know what would cause the belt to walk.
NA6C-Guy is offline   Reply With Quote
Old 09-02-2009, 12:16 AM   #4
Elite Member
 
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,322
Total Cats: 12
Default

I suppose a misaligned crank sprocket wobbling could cause it to come off too, but unlikely that's it.
dustinb is offline   Reply With Quote
Old 09-02-2009, 12:21 AM   #5
Senior Member
Thread Starter
iTrader: (7)
 
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,371
Total Cats: -1
Default

I will check the tension. Any tips on exactly how to check it? I mean, it feels about right. I did reuse my old tensioner spring (about 80k miles old) but I put a little bit more pressure on it when I torqued the tensioner bolt so that it would be good and tight. It doesn't sing like I have heard overtightened belts do.
wes65 is offline   Reply With Quote
Old 09-02-2009, 12:26 AM   #6
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,147
Total Cats: 6
Default

Any chance you bent one of he cam gears when removing the belt? Maybe prying a gear off a cam for some crazy reason? Any misalignment of the gears themselves relative to one another or an untrue gear could cause walking.
The belt it self could also be to blame do to some material irregularity causing it to apply pressure on one side more than other or maybe when it was cut there was some type of failure.
I assume there are no obvious signs of irregular wear on the belt giving you any idea of where the pressure causing it to walk is coming from?

If you look straight down at the belt you should be able to see a gear wobble as the belt walks as well.
cjernigan is offline   Reply With Quote
Old 09-02-2009, 12:29 AM   #7
Senior Member
Thread Starter
iTrader: (7)
 
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,371
Total Cats: -1
Default

Well, this is a head I bought on craigslist, so let's hope they're not bent. The cam gears do not wobble. I'm not sure about the crank pulley but it's an ATI super damper. I will take a look at it in the morning. There is also a fuel leak that I need to fix before running the motor again.
wes65 is offline   Reply With Quote
Old 09-02-2009, 12:36 AM   #8
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,107
Total Cats: 518
Default

DO NOT put extra tension on the tension pulley, it says that right in the manual. The spring is all the tension it needs. While you're redoing your timing belt, double check everything it rides on is flat and turns true.
curly is offline   Reply With Quote
Old 09-02-2009, 12:39 AM   #9
Senior Member
Thread Starter
iTrader: (7)
 
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,371
Total Cats: -1
Default

Quote:
Originally Posted by curly View Post
DO NOT put extra tension on the tension pulley, it says that right in the manual. The spring is all the tension it needs. While you're redoing your timing belt, double check everything it rides on is flat and turns true.
I will go back and loosen the tensioner and re-torque it. The reason that I put extra tension on it was because I figured the spring was worn out.
wes65 is offline   Reply With Quote
Old 09-02-2009, 12:44 AM   #10
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 wes65 View Post
Well, this is a head I bought on craigslist, so let's hope they're not bent. The cam gears do not wobble. I'm not sure about the crank pulley but it's an ATI super damper. I will take a look at it in the morning. There is also a fuel leak that I need to fix before running the motor again.
Maybe they didn't drop the head on the cam gears and bend them. For sure look them over closely.
NA6C-Guy is offline   Reply With Quote
Old 09-02-2009, 01:52 AM   #11
:(
iTrader: (7)
 
Join Date: Jul 2006
Location: nowhere
Posts: 8,281
Total Cats: 2
Default

damn im stumped wes
magnamx-5 is offline   Reply With Quote
Old 09-02-2009, 01:55 AM   #12
Senior Member
Thread Starter
iTrader: (7)
 
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,371
Total Cats: -1
Default

Quote:
Originally Posted by magnamx-5 View Post
damn im stumped wes
Haha that's not what I like to hear. It's all good. Tomorrow, I will check to make sure the gears are true, make sure the crank pulley is straight, re-torque the tensioner and idler and check them with a straight edge.
wes65 is offline   Reply With Quote
Old 09-02-2009, 02:01 AM   #13
:(
iTrader: (7)
 
Join Date: Jul 2006
Location: nowhere
Posts: 8,281
Total Cats: 2
Default

is it cuase you didnt wanna get rolled by goverment cheese at hardinsburg?
Good that site is growing on me, i sure hope fly gets some damn money to buy my trans am between you and me i have my doubts. :(
magnamx-5 is offline   Reply With Quote
Old 09-02-2009, 02:03 AM   #14
Senior Member
Thread Starter
iTrader: (7)
 
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,371
Total Cats: -1
Default

Quote:
Originally Posted by magnamx-5 View Post
is it cuase you didnt wanna get rolled by goverment cheese at hardinsburg?
Good that site is growing on me, i sure hope fly gets some damn money to buy my trans am between you and me i have my doubts. :(
Haha, I don't get the whole "government cheese" thing. Yeah, deals like that rarely work out.
wes65 is offline   Reply With Quote
Old 09-02-2009, 02:05 AM   #15
Elite Member
iTrader: (6)
 
Join Date: Sep 2007
Location: CA
Posts: 1,990
Total Cats: 9
Default

In my Integra, my timing belt too would walk. I notice that one of the gears towards the edge was damaged (flat spotted). I replaced that.

Not sure if Miatas have this, but there were 2 plates near the crank that would sandwich and re-align the belt. The belt would go slightly off near the cam gears, but get re-aligned w/ the plates at the crank. I had them installed backwards.

I'd probably check the tension first.
kenzo42 is offline   Reply With Quote
Old 09-02-2009, 08:38 AM   #16
Junior Member
iTrader: (4)
 
Join Date: Oct 2006
Location: Alberta Canada
Posts: 228
Total Cats: 5
Default

I have seen incorrect tension on the belt do this on some engines. Follow the belt tension procedure to the letter, I bet that will do it. Why not get a new spring to ease your mind on that part as well.

Ron
Alta_Racer is offline   Reply With Quote
Old 09-02-2009, 08:43 AM   #17
Junior Member
 
Join Date: Mar 2008
Location: Charleston, S.C.
Posts: 159
Total Cats: 0
Default

Sounds like you haven't followed the manual properly. There is a specific set of steps to do to tension the belt properly. I'd suggest following them and see what happens then. Of course there is always the possibility that the belt will continue to track now since it was adjusted that way to start with.
04 Miata is offline   Reply With Quote
Old 09-02-2009, 08:45 AM   #18
AFM Crusader
iTrader: (18)
 
olderguy's Avatar
 
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,438
Total Cats: 84
Default

If you replaced the water pump, make sure that it is flat against the block and that there is no dirt under the base of the idler or tensioner pulleys.
olderguy is offline   Reply With Quote
Old 09-03-2009, 12:49 AM   #19
Senior Member
Thread Starter
iTrader: (7)
 
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,371
Total Cats: -1
Default

I pulled the idler and tensioner off and put them back on. I checked the cam gears with a straight edge, they were fine. The crank pulley doesn't wobble. I took some videos and pictures.



Name:  IMG00333-20090902-2304.jpg
Views: 26
Size:  186.7 KB
Name:  IMG00334-20090902-2305.jpg
Views: 19
Size:  174.0 KB
Name:  IMG00339-20090902-2305.jpg
Views: 23
Size:  167.7 KB
Name:  IMG00343-20090902-2308.jpg
Views: 19
Size:  83.2 KB
wes65 is offline   Reply With Quote
Old 09-03-2009, 01:02 AM   #20
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,107
Total Cats: 518
Default

A. Use your camera's flower button.
B. I have no idea what your problem is.
C. Your poor starter and battery.

The 2nd video is really confusing. It walks towards the right immediately, than slowly walks left. Do you have access to a mag base and indicator? I'd check flatness of both pulleys and all 3 sprockets. Not 30 minutes ago I finished installing my own timing belt. After a minor hiccup with one of the cam sprockets being on incorrectly (smoke out the air filter), it started up immediately and didn't budge. I double checked cause I had this thread in the back of my head the whole time.
curly is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 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 06:02 PM.