1.8 compression results help - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 06-20-2016, 08:15 PM   #1
Newb
Thread Starter
 
Join Date: Jun 2016
Posts: 30
Total Cats: -11
Default 1.8 compression results help

So i did a dry test on a supercharged motor, the spark plugs were pretty drenched with oil and the results came out

-170
-150
-165
-160

valve cover seems to be leaking. Since its a car im interested in buying, i dont have a compressor to do a leak down test and didnt think to do a wet test while i was at it. But considering the variation with cylinder 2, is this a NO GO?
markooo89 is offline   Reply With Quote
Old 06-20-2016, 08:16 PM   #2
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

not no go, but definitely not healthy
18psi is offline   Reply With Quote
Old 06-20-2016, 08:19 PM   #3
Ich verstehe nur Bahnhof
iTrader: (3)
 
psyber_0ptix's Avatar
 
Join Date: Mar 2012
Location: Northern VA
Posts: 3,701
Total Cats: 319
Default

What are your plans with the car? Are you going to build on top of what the previous owner has done or are you prepared to have a motor waiting for you when this one goes?

12.5% difference; I'd like to see under 10, but it could be super worse. #2 is a bit dodgy, might be able to just break it down and hone/re-ring the cylinders and be fine
psyber_0ptix is offline   Reply With Quote
Old 06-20-2016, 08:21 PM   #4
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

rule #1: no BP get's re-built with stock rods and re-used rings
18psi is offline   Reply With Quote
Old 06-20-2016, 09:10 PM   #5
Newb
Thread Starter
 
Join Date: Jun 2016
Posts: 30
Total Cats: -11
Default

Quote:
Originally Posted by psyber_0ptix View Post
What are your plans with the car? Are you going to build on top of what the previous owner has done or are you prepared to have a motor waiting for you when this one goes?

12.5% difference; I'd like to see under 10, but it could be super worse. #2 is a bit dodgy, might be able to just break it down and hone/re-ring the cylinders and be fine
id like to keep it as is and have some fun with it for a bit but if the motor dies i wouldn't mind paying to have it rebuilt with better internals. Just don't wanna drive it home then run into issues very soon.
That oil on the spark plugs could easily be the valve cover gasket right? Not sure if that compression result is very bad or not

Last edited by markooo89; 06-21-2016 at 02:37 AM.
markooo89 is offline   Reply With Quote
Old 06-20-2016, 11:36 PM   #6
Junior Member
iTrader: (1)
 
Join Date: Sep 2009
Location: Colorado
Posts: 166
Total Cats: 5
Default

Quote:
Originally Posted by markooo89 View Post
id like to keep it as is and have some fun with it for a bit but if the motor blowd i wouldnt mind paying to have it rebuilt with better internals. Just dont wanna drive it home then blow it 2 hours later loll
that oil on the spark plugs could easily be the valve cover gasket right?
hard to rebuild with a rod sticking out the side, something to think about.
GraemeD is offline   Reply With Quote
Old 06-21-2016, 10:56 AM   #7
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 13,775
Total Cats: 1,106
Default

Oil on the spark plugs could very easily be a VC gasket. I have seen that many times before. Compression numbers a a bit wide spread then I would like to see, but I have seen far worse on running cars.
shuiend is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1994 Cylinder Head + Valve cover- Disassembled, in need of resurfacing petrolmed Miata parts for sale/trade 5 08-31-2016 02:04 PM
7.8k fair for m62 supercharged M-edition miata? markooo89 General Miata Chat 12 06-22-2016 11:44 PM
Pretty sure my car is possessed... .one lane General Miata Chat 3 06-13-2016 08:39 PM
E-Supercharger emilio700 General Miata Chat 31 06-05-2016 11:06 PM
Supercharger Miata - Log Files Andre94R MEGAsquirt 7 06-01-2016 01:16 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 10:02 PM.