2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Compression test numbers: Thoughts?

Thread Tools
 
Search this Thread
 
Old 04-05-14, 08:39 PM
  #1  
Rotary Freak

Thread Starter
iTrader: (3)
 
funkjaw's Avatar
 
Join Date: Jul 2008
Location: San Jose, CA (NorCal/S.F. Bay Area)
Posts: 2,515
Received 4 Likes on 3 Posts
Compression test numbers: Thoughts?

Rebuilt engine, 450 miles on it when this was done.
S5 TII irons, with 0.002" step wear
Very low mileage FD housings
Low mileage FD rotors
New OEM 2 piece Apex seals
Side seals were all @0.0025"

Stock ports.

#1


#2


Vacuum at cold idle ~750 is about 14. Vacuum at warm idle ~1050 is about 17.

Any input on if these are ok/not ok numbers for the amount of miles on the rebuild at the testing RPM?

Thanks!
Old 04-05-14, 09:28 PM
  #2  
Rotary Freak

iTrader: (16)
 
PvillKnight7's Avatar
 
Join Date: May 2002
Location: Maryland
Posts: 2,597
Likes: 0
Received 2 Likes on 2 Posts
640 kPa = 92.8 psi
650 kPa = 94.3 psi
680 kPa = 98.6 psi

620 kPa = 89.9 psi
650 kPa = 94.3 psi
640 kPa = 92.8 psi


8.7 psi variance

The difference between the highest and lowest reading is low (good) but the numbers are low and the vacuum at idle is low for stock ports. Was there any flaking on the edges of the housings? If it starts fast hot/cold I wouldn't worry about it. What numbers are expected for a new engine read with that type of tester?
Old 04-06-14, 12:13 AM
  #3  
Retired Moderator, RIP

iTrader: (142)
 
misterstyx69's Avatar
 
Join Date: Sep 2005
Location: Smiths Falls.(near Ottawa!.Mapquest IT!)
Posts: 25,581
Likes: 0
Received 131 Likes on 114 Posts
.. you got better Numbers than Billy Dee Williams..(and that engine can't dance!)

at 450 miles that isn't bad.
I've seen numbers lower than that on engines in cars at meets..
Old 04-07-14, 10:15 PM
  #4  
Rotary Freak

Thread Starter
iTrader: (3)
 
funkjaw's Avatar
 
Join Date: Jul 2008
Location: San Jose, CA (NorCal/S.F. Bay Area)
Posts: 2,515
Received 4 Likes on 3 Posts
Good info thanks peeps.

Yeah I agree the vacuum is low, and it doesn't start up right away. I have starter issues right now, and I also have tune issues, as it's very rich on start up. Need to go through the microtech settings and see if I can get a better startup. I'll also triple check for any kind of vacuum leaks to see if I can bring the idle vacuum up higher.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Jeff20B
1st Generation Specific (1979-1985)
73
09-16-18 07:16 PM
ZacMan
Build Threads
4
09-19-15 09:20 PM
mulcryant
2nd Generation Specific (1986-1992)
10
09-09-15 05:24 PM
SCinfidel
3rd Generation Specific (1993-2002)
4
09-08-15 05:36 PM
ZaqAtaq
New Member RX-7 Technical
2
09-05-15 08:57 PM



Quick Reply: Compression test numbers: Thoughts?



All times are GMT -5. The time now is 06:13 AM.