C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Timing won't stay set. Distributor moving?

Thread Tools
 
Search this Thread
 
Old 09-16-2007, 12:19 PM
  #1  
rrubel
Burning Brakes
Support Corvetteforum!
Thread Starter
 
rrubel's Avatar
 
Member Since: Jan 2002
Location: Glen Burnie MD
Posts: 993
Received 3 Likes on 2 Posts

Default Timing won't stay set. Distributor moving?

I've been checking my timing every couple months and I'm noticing that it keeps reverting to 0* advance. Not sure what's going on, but it's the third time this has happened over the past year.

- I'm making sure to check it with the timing wire disconnected.
- The engine is at normal operating temps (coolant/oil both over 150).
- The timing marks on the balancer are NOT slipping - I have a ~2 year old FluiDamper which is all one piece so the marks can't move.
- I have a non-stock distributor (Davis Unified Ignition)

Near as I can tell, the distributor is turning a little, but it always stops at the same place. I'm tightening the hold-down bolt as much as I can, but I'm afraid of breaking it so I'm not *REALLY* hanging on it. Also, it's not easy to figure the torque spec when tightening because of its location and the fact that I need to use an offset wrench to reach it.

This time, I marked the distributor and the plenum to see if it actually is moving; if that is the problem, anyone have suggestions on how to convince it to stay put?

Thanks.
[RICHR]
rrubel is offline  
Old 09-16-2007, 12:29 PM
  #2  
Muffin
Race Director
Support Corvetteforum!
 
Muffin's Avatar
 
Member Since: Jun 1999
Location: Merritt Ils Fl
Posts: 14,924
Likes: 0
Received 9 Likes on 7 Posts

Default

I have never seen a distributor that was bolted down slip. Are you sure you don't have something very funky going on between your cam gear and distributor gear? I ran a bronze distributor gear for a short time. Couldn't keep the beast in time. Pulled the distributor,bronze gear was almost gone, worn so bad.
Muffin is offline  
Old 09-16-2007, 12:34 PM
  #3  
Pete K
Race Director
 
Pete K's Avatar
 
Member Since: Feb 2004
Posts: 12,515
Likes: 0
Received 15 Likes on 15 Posts
Default

Replace the bolt with a stud, and smear a little valve grinding compound on the bottom of the clamp, where it contacts the distributor.
Pete K is offline  
Old 09-16-2007, 01:31 PM
  #4  
rrubel
Burning Brakes
Support Corvetteforum!
Thread Starter
 
rrubel's Avatar
 
Member Since: Jan 2002
Location: Glen Burnie MD
Posts: 993
Received 3 Likes on 2 Posts

Default

Hm. I honestly don't remember what material the distributor gear is made form. The cam has whatever Lingenfelter provides; I'd hope it's not bronze since they make high-performance/high stress items...

Pete, nice thought on the stud. I'll have to try that.

Car runs SOO much better when it's in time :/ .

[RICHR]
rrubel is offline  
Old 09-18-2007, 12:47 AM
  #5  
Dads90
Burning Brakes
 
Dads90's Avatar
 
Member Since: Oct 2004
Location: Pearland Texas
Posts: 898
Likes: 0
Received 1 Like on 1 Post
Default

I have a stupid question. Have you ever removed the distributor hold down bolt ? After a manifold gasket replacement I put the hold down clamp on upside down and the distrb. would not stay tight and would slip. Once I fliped the clamp I added a washer and it doesn't slip anymore. Just a thought.
Dads90 is offline  
The following users liked this post:
kenmohr (11-25-2019)
Old 09-18-2007, 05:27 PM
  #6  
rrubel
Burning Brakes
Support Corvetteforum!
Thread Starter
 
rrubel's Avatar
 
Member Since: Jan 2002
Location: Glen Burnie MD
Posts: 993
Received 3 Likes on 2 Posts

Default

Interesting thought; it's not a stock distributor and I *thought* I put the hold-down on right. I'll look at it again.
Thanks.
[RICHR]
rrubel is offline  
Old 09-18-2007, 07:02 PM
  #7  
SunCr
Le Mans Master
 
SunCr's Avatar
 
Member Since: Dec 2000
Location: San Diego, Ca
Posts: 7,839
Likes: 0
Received 19 Likes on 17 Posts

Default

Sounds like the Balancer - Find TDC and see if the mark is still in alignment.
SunCr is offline  
Old 09-18-2007, 11:15 PM
  #8  
rrubel
Burning Brakes
Support Corvetteforum!
Thread Starter
 
rrubel's Avatar
 
Member Since: Jan 2002
Location: Glen Burnie MD
Posts: 993
Received 3 Likes on 2 Posts

Default

No offense, but I stated initially that the timing marks can't move - the balancer is a single piece Fluidamper, not the GM rubber-mounted ring. Also, the car WAS out of timing. It runs a heck of a lot better now.
[RICHR]
rrubel is offline  
Old 09-19-2007, 01:25 AM
  #9  
John A. Marker
Le Mans Master
 
John A. Marker's Avatar
 
Member Since: Mar 2004
Location: Dublin CA
Posts: 5,107
Received 167 Likes on 148 Posts

Default

There is another possability....your distributor hold down bolt may be bottomed out. That happend to me and I'll be damned if I wanted to pull the bolt out and cut it off and fight to get it back in. Instead, I cut out a small section in a lock washer, backed out the bolt a little and slipped the washer around the bolt between the head and the distributor hold down piece. This gave me the additional clearance to tighten the bolt without bottoming out. The distributor does not move any more.
John A. Marker is offline  
Old 11-25-2019, 04:40 AM
  #10  
Chippos
2nd Gear
 
Chippos's Avatar
 
Member Since: Nov 2019
Location: 6530 Trask Terrace Alexandria, VA 22315
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default packing and moving companies near me

Originally Posted by rrubel
I've been checking my timing every couple months and I'm noticing that it keeps reverting to 0* advance. Not sure what's going on, but it's the third time this has happened over the past year.
- I'm making sure to check it with the timing wire disconnected.
- The engine is at normal operating temps (coolant/oil both over 150).
- The timing marks on the balancer are NOT slipping - I have a ~2 year old FluiDamper which is all one piece so the marks can't move.
- I have a non-stock distributor (Davis Unified Ignition)
Packing and moving companies near me url g&j moving.
Near as I can tell, the distributor is turning a little, but it always stops at the same place. I'm tightening the hold-down bolt as much as I can, but I'm afraid of breaking it so I'm not *REALLY* hanging on it. Also, it's not easy to figure the torque spec when tightening because of its location and the fact that I need to use an offset wrench to reach it.

This time, I marked the distributor and the plenum to see if it actually is moving; if that is the problem, anyone have suggestions on how to convince it to stay put?

Thanks.
[RICHR]

how did you solve your question?
Chippos is offline  
Old 11-25-2019, 05:52 AM
  #11  
rrubel
Burning Brakes
Support Corvetteforum!
Thread Starter
 
rrubel's Avatar
 
Member Since: Jan 2002
Location: Glen Burnie MD
Posts: 993
Received 3 Likes on 2 Posts

Default

I'm sorry; this was 12 years ago and I just don't recall now.
[RICHR]
rrubel is offline  
Old 11-25-2019, 11:32 AM
  #12  
TommyFox
Melting Slicks
 
TommyFox's Avatar
 
Member Since: Jun 2011
Location: Leland , North Carolina
Posts: 2,104
Received 304 Likes on 211 Posts

Default

Originally Posted by rrubel
I'm sorry; this was 12 years ago and I just don't recall now.
[RICHR]
Lol
TommyFox is offline  
Old 11-25-2019, 11:56 AM
  #13  
KyleF
Drifting
 
KyleF's Avatar
 
Member Since: Jun 2018
Location: Michigan
Posts: 1,661
Received 225 Likes on 173 Posts
Default

Originally Posted by Chippos
how did you solve your question?
12 year old thread... It could quite possibly have been the bolt bottoming out?

Something I didn't see in this thread that should be mentioned (if someone is searching these issues), is shimming the distributor shaft for end play. They sell kits for it, and basically if its loose the distributor gear can walk up and down the cam gear affecting the timing slightly.


KyleF is offline  

Get notified of new replies

To Timing won't stay set. Distributor moving?




Quick Reply: Timing won't stay set. Distributor moving?



All times are GMT -4. The time now is 10:04 AM.