Notices
924/931/944/951/968 Forum Porsche 924, 924S, 931, 944, 944S, 944S2, 951, and 968 discussion, how-to guides, and technical help. (1976-1995)
Sponsored by:
Sponsored by:

Broken KEVLAR timing belt.

Thread Tools
 
Search this Thread
 
Old 07-08-2013, 10:23 AM
  #31  
Van
Rennlist Member
 
Van's Avatar
 
Join Date: Oct 2002
Location: Hyde Park, NY
Posts: 12,008
Received 93 Likes on 63 Posts
Default

Originally Posted by Yummybud924
hmm. I was thinking about those nuts coming loose when I did my belts and pump a week ago. is it a good idea to loctite those bolts?
Yes, I now use blue thread locker on those nuts.
Old 07-08-2013, 10:43 AM
  #32  
F40LM
Rennlist Member
Thread Starter
 
F40LM's Avatar
 
Join Date: Feb 2009
Location: Mississippi
Posts: 1,294
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Van
Yes, I now use blue thread locker on those nuts.
Good idea Van, will add thread locker to mine before I button it all up.
Old 07-08-2013, 04:57 PM
  #33  
F40LM
Rennlist Member
Thread Starter
 
F40LM's Avatar
 
Join Date: Feb 2009
Location: Mississippi
Posts: 1,294
Likes: 0
Received 0 Likes on 0 Posts
Default

Well gave her a try. No joy. Tunes over ok but not catching, even backfired on me. Never did that before.

Decided to catch up on my online course while a wait for anyone to offer ideas.

Was thinking out of time but I know that's correct. Double checked the coil and plug connections as well.

Took off fuel rail cap and it seemed to be under pressure when removed.
Old 07-08-2013, 06:15 PM
  #34  
Van
Rennlist Member
 
Van's Avatar
 
Join Date: Oct 2002
Location: Hyde Park, NY
Posts: 12,008
Received 93 Likes on 63 Posts
Default

Sounds like out of time... Do a thorough double-check. Remember that the camshaft only goes around once for every two revolutions of the crankshaft.

Make sure your rotor is screwed on at the right place (at TDC it should be pointing to the lower right - which is the #1 plug).
Old 07-08-2013, 06:29 PM
  #35  
F40LM
Rennlist Member
Thread Starter
 
F40LM's Avatar
 
Join Date: Feb 2009
Location: Mississippi
Posts: 1,294
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Van
Sounds like out of time... Do a thorough double-check. Remember that the camshaft only goes around once for every two revolutions of the crankshaft.

Make sure your rotor is screwed on at the right place (at TDC it should be pointing to the lower right - which is the #1 plug).
Thanks Van. I lined up TDC with the lower fly wheel notch, then double checked it with the OT line at the top, and the cam gear line was at the correct position as well.

Will check it all again. Then check the rotor.
Old 07-08-2013, 07:40 PM
  #36  
F40LM
Rennlist Member
Thread Starter
 
F40LM's Avatar
 
Join Date: Feb 2009
Location: Mississippi
Posts: 1,294
Likes: 0
Received 0 Likes on 0 Posts
Default

Double checked TDC. Double checked rotor ponting to number 1 wire, lower right.

Swapped in another rotor just to see.

All the same story.

Opinions welcome.
Old 07-08-2013, 07:42 PM
  #37  
divil
Three Wheelin'
 
divil's Avatar
 
Join Date: Feb 2011
Location: Indianapolis, IN
Posts: 1,716
Received 27 Likes on 26 Posts
Default

Double check speed/ref sensor connections?
Old 07-08-2013, 07:51 PM
  #38  
AKCJ
Instructor
 
AKCJ's Avatar
 
Join Date: Sep 2004
Location: Fairbanks, Alaska
Posts: 144
Received 0 Likes on 0 Posts
Default

TDC on compression stroke?
Also, check the plug at the AFM.
Old 07-08-2013, 08:20 PM
  #39  
Van
Rennlist Member
 
Van's Avatar
 
Join Date: Oct 2002
Location: Hyde Park, NY
Posts: 12,008
Received 93 Likes on 63 Posts
Default

If you turn the engine over by hand with a wrench, does it feel like it has normal compression? And or, when it's cranking, does it sound like the compression is causing the right amount of resistance?

Not only does the spark timing have to be about in the right place, but the fuel/air charge needs to be compressed the right amount... I'm wondering if the valve stems are a bit too long one one of your sets of valves... and they're being held open a tiny amount.

(I suppose you could also do a compression test).

You do have the plug wire firing order going in a clockwise direction on the distributor?
Coil wire fully plugged in?
Injector plugs fully connected?
Manifold gaskets are fresh?
Old 07-08-2013, 09:57 PM
  #40  
F40LM
Rennlist Member
Thread Starter
 
F40LM's Avatar
 
Join Date: Feb 2009
Location: Mississippi
Posts: 1,294
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Van
If you turn the engine over by hand with a wrench, does it feel like it has normal compression? And or, when it's cranking, does it sound like the compression is causing the right amount of resistance?

Not only does the spark timing have to be about in the right place, but the fuel/air charge needs to be compressed the right amount... I'm wondering if the valve stems are a bit too long one one of your sets of valves... and they're being held open a tiny amount.

(I suppose you could also do a compression test).

You do have the plug wire firing order going in a clockwise direction on the distributor?
Coil wire fully plugged in?
Injector plugs fully connected?
Manifold gaskets are fresh?
Yes engine has correct amount of resistance when turned by hand. Yes sounds right turning over.

Not ready to think about valves stems being wrong, but will look into it.

Coil firing in correct order clockwise.

Need to double check connections etc tomorrow. Coil wire in good checked it three times.

Will check out a compression tester from Autozone.

Heading to Fort Knox this weekend, was hoping to take the 944. Not looking to promising right now.
Old 07-08-2013, 11:00 PM
  #41  
Van
Rennlist Member
 
Van's Avatar
 
Join Date: Oct 2002
Location: Hyde Park, NY
Posts: 12,008
Received 93 Likes on 63 Posts
Default

Could there be some kind of major vacuum leak? Like the idle stabilizer... or the ports in the side of the J boot?
Old 07-09-2013, 12:14 AM
  #42  
16valver
Racer
 
16valver's Avatar
 
Join Date: Jan 2013
Location: Portland OR
Posts: 320
Likes: 0
Received 1 Like on 1 Post
Default

When I got done with my T-belt replace, we went to start it and got the same deal, turning over but wouldn't catch. Turned out the AFM wasn't plugged in. Doubt thats you're issue but its usually something stupid when you've been super thorough about all the complex stuff and its late at night etc... Good luck!!
Old 07-09-2013, 12:26 AM
  #43  
Travis - sflraver
Site Sponsor
Lifetime Rennlist
Member
 
Travis - sflraver's Avatar
 
Join Date: Aug 2002
Location: A great big building in the woods, FL.
Posts: 6,527
Likes: 0
Received 4 Likes on 3 Posts
Default

Did you happen to check to make sure the cam key didn't sheer.
Old 07-09-2013, 10:21 AM
  #44  
Van
Rennlist Member
 
Van's Avatar
 
Join Date: Oct 2002
Location: Hyde Park, NY
Posts: 12,008
Received 93 Likes on 63 Posts
Default

Originally Posted by Travis - sflraver
Did you happen to check to make sure the cam key didn't sheer.
You know... could that have been the cause of the bent valves and subsequent timing belt failure?
Old 07-09-2013, 11:59 AM
  #45  
F40LM
Rennlist Member
Thread Starter
 
F40LM's Avatar
 
Join Date: Feb 2009
Location: Mississippi
Posts: 1,294
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Travis - sflraver
Did you happen to check to make sure the cam key didn't sheer.
When I removed the cam tower I turned the cam with the cam gear over and over checking for damage and making sure no foreign body was in there.

I use the offset key suggested with the NA-tune.


Quick Reply: Broken KEVLAR timing belt.



All times are GMT -3. The time now is 11:56 PM.