1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Found an old pic - is this bad?

Thread Tools
 
Search this Thread
 
Old Apr 11, 2008 | 10:56 PM
  #1  
Crit's Avatar
Thread Starter
No distributor? No thanks
Tenured Member 15 Years
iTrader: (6)
 
Joined: Oct 2003
Posts: 3,438
Likes: 6
From: Outskirts of Road Atlanta
Found an old pic - is this bad?

What does this EKG tell you?

Reply
Old Apr 11, 2008 | 10:59 PM
  #2  
djessence's Avatar
djessence
 
Joined: Aug 2007
Posts: 2,063
Likes: 0
From: Alberta, Canada
Well is says that the atrial valves on your heart are not being sufficiently stimulated by the required nodes.

Or it could mean you've got one good seal, 1 mediocre seal and 1 bad seal on your front rotor. Or at least thats how i would interpret it?
Reply
Old Apr 11, 2008 | 11:37 PM
  #3  
djessence's Avatar
djessence
 
Joined: Aug 2007
Posts: 2,063
Likes: 0
From: Alberta, Canada
and actually looking at it, isnt the compression overall (ignoring the huge differences in the front) fairly low, the peak being like 80?
Reply
Old Apr 12, 2008 | 03:05 AM
  #4  
MattG's Avatar
MattG FTW!!!!!
Tenured Member 15 Years
iTrader: (2)
 
Joined: Feb 2005
Posts: 2,733
Likes: 1
From: South Windsor, CT
Did you just have that done?

Its the engine pulses,

You front rotor is Shot, see the peak every three blips, that means that one rotor facing is haveing some what of a good compression, where the other faces are not.

The Rear is fine, 3 equal pulses, thats how they should look.

-Matt
Reply
Old Apr 12, 2008 | 09:58 AM
  #5  
Stevan's Avatar
Rotary Enthusiast
Tenured Member 15 Years
iTrader: (17)
 
Joined: Sep 2003
Posts: 1,041
Likes: 1
From: Jax, FL.
One apex seal is sticking or worn out.
Not sure IIRC, 80 psi is medium / low.
Reply
Old Apr 12, 2008 | 11:42 AM
  #6  
Jeff20B's Avatar
Lapping = Fapping
Tenured Member 15 Years
iTrader: (13)
 
Joined: Aug 2001
Posts: 15,725
Likes: 91
From: Near Seattle
Stevan is correct. One less than ideal apex seal.

If it showed only one low peak, it would indicate a bad side seal.
Reply
Old Apr 12, 2008 | 07:50 PM
  #7  
Crit's Avatar
Thread Starter
No distributor? No thanks
Tenured Member 15 Years
iTrader: (6)
 
Joined: Oct 2003
Posts: 3,438
Likes: 6
From: Outskirts of Road Atlanta
Yeah, I know. I found that scan of an old 4-port I had that ran fine, but overheated often. It ended up going cheap with a good GSL, but I didn't realize just how bad it was until I had that compression test done. As far as the 80 psi, I'm not a big believer in that number. If a tester has long or large-ID tubing, it'll always show low compression. Anything that's too large to fit between the engine and fender will show lower numbers.
Reply
Old Apr 13, 2008 | 10:13 AM
  #8  
hanman's Avatar
Rotary Freak
Tenured Member 20 Years
 
Joined: May 2001
Posts: 1,779
Likes: 0
From: Peoria, IL
Anybody know where i can get rolls of that paper?
Reply
Old Apr 13, 2008 | 10:16 AM
  #9  
ray green's Avatar
Gone
iTrader: (14)
 
Joined: Jul 2002
Posts: 11,442
Likes: 210
Or the compression tester in the Atlanta area? Crit I may be having a problem with the White One.
Reply
Old Apr 13, 2008 | 01:48 PM
  #10  
Crit's Avatar
Thread Starter
No distributor? No thanks
Tenured Member 15 Years
iTrader: (6)
 
Joined: Oct 2003
Posts: 3,438
Likes: 6
From: Outskirts of Road Atlanta
Yeah, Dave Girod did that at a Varsity meet soon after my engine swap. I've got a manual compression tester if you want to borrow it, Ray. Girod's tester is the old, original Mazda tester and I have no idea where he got the paper.
Reply
Old Apr 13, 2008 | 03:52 PM
  #11  
ray green's Avatar
Gone
iTrader: (14)
 
Joined: Jul 2002
Posts: 11,442
Likes: 210
But wouldn't a manual tester record only the highest compression of the three rotor faces? It wouldn't detect a problem in a rotor if just one seal went bad, as seems to be the case in your EKG.

But if two seals are bad, a manual tester would pick it up, right? Without two good seals you can't get good compression, so that rotor would read low.

But if an engine starts running badly over a period of 100-200 miles, until it's hard to keep running and won't keep an idle, it's probably just one seal going bad, not two, right?

So it sounds like I need one of those fancy EKG machines. For a car located 55 miles out of Atlanta. That doesn't run. Any rental units out there?
Reply
Old Apr 13, 2008 | 07:00 PM
  #12  
Crit's Avatar
Thread Starter
No distributor? No thanks
Tenured Member 15 Years
iTrader: (6)
 
Joined: Oct 2003
Posts: 3,438
Likes: 6
From: Outskirts of Road Atlanta
No, no such thing as a rental, and new testers are digital and VERY expensive. I made a tester that doesn't have a peak-hold or bleed, so you're just measuring the chamber pressure with nothing fancy. I can show you how to use it, but it's a pretty good home-made tool.
Reply
Old Apr 13, 2008 | 08:02 PM
  #13  
ray green's Avatar
Gone
iTrader: (14)
 
Joined: Jul 2002
Posts: 11,442
Likes: 210
I think I'm going to need it, the sea foam didn't work. So it reads out chamber pressure continuously - while the engine is cranking, you just look at the dial? Sounds perfect.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Queppa
New Member RX-7 Technical
11
Nov 18, 2024 03:47 AM
Th0m4s
Build Threads
25
Feb 26, 2019 02:04 AM
Marty RE
New Member RX-7 Technical
0
Aug 17, 2015 09:36 AM




All times are GMT -5. The time now is 12:11 AM.