Buick When starting new posts, please specify YEAR, MAKE, MODEL, ENGINE type, and whatever modifications you have made.

Compression test readings '93 BRMW

Thread Tools
 
Search this Thread
 
Old 06-09-2012, 04:33 PM
  #1  
Junior Member
Thread Starter
 
zamboni920's Avatar
 
Join Date: Apr 2012
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
zamboni920 is on a distinguished road
Default Compression test readings '93 BRMW

Rough running, surging at idle when cold. All sensors replaced, throttlebody rebuilt, new intake manifold gasket, new distibutor incl. ignition module.
Pulled all sparkplugs, kept in order of cylinders they came out of. All looks normal (greyish/tan).
Did compression test today. Wide open throttle, all plugs removed.
7 compression strokes each.
#1 , #2 , #4 , #6 , #8 -----all reads 180
#3 -----reads 215
#5 , #7 ----reads 175
Why is #3 so high? Do I need to pull the head (left side) ? carbon build up? Can anything fix it without removing head?
Have not done a leakdown test as I am not sure it will tell me much about high comp in one cylinder.
when I bought the car a few years ago, I found the exhaust lifter rod MISSING in #3 . I replaced and it seemed fine for a long time. I recently checked adjustments on all valves, and at the same time checked for, and replaced all rods with even a slight bend. #3 exhaust was one of them.
Could carbon build up possibly hit the valve?
Old 06-09-2012, 07:03 PM
  #2  
Retired Senior Admin

Expert Gearhead
 
Danthurs's Avatar
 
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Likes: 0
Received 28 Likes on 24 Posts
Danthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to all
Default

Seems like your exhaust valve may not be opening all the way. I see a history of valve problems on #3. I'll bet the valve is bent.
Old 06-09-2012, 07:17 PM
  #3  
Junior Member
Thread Starter
 
zamboni920's Avatar
 
Join Date: Apr 2012
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
zamboni920 is on a distinguished road
Default

Danthurs......If the valve indeed is bent, it would have to be on rocker arm side of head? With high reading on this cylinder, I would assume it does close fine. Is it possible to determine this without removing head?
You mentioned noticing a history regarding cyl #3 .....could you explain/detail?
Old 06-09-2012, 08:12 PM
  #4  
Retired Senior Admin

Expert Gearhead
 
Danthurs's Avatar
 
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Likes: 0
Received 28 Likes on 24 Posts
Danthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to all
Default

I found the exhaust lifter rod MISSING in #3 . I replaced and it seemed fine for a long time. I recently checked adjustments on all valves, and at the same time checked for, and replaced all rods with even a slight bend. #3 exhaust was one of them.
I would look real close at the rocker. To check the valve you would need to remove the head and pull the valve out.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
wf2tm51
1992-1999
12
03-29-2006 06:26 PM
Daron97SSE
1992-1999
6
11-22-2005 02:17 PM
marksssei
1992-1999
18
03-23-2005 02:14 PM
Drifter420
1992-1999
2
08-22-2004 01:04 AM
SSEimatt93
1992-1999
0
02-20-2004 01:36 AM



Quick Reply: Compression test readings '93 BRMW



All times are GMT -4. The time now is 06:14 AM.