12a compression reading
#1
Junior Member
Thread Starter
Join Date: Oct 2004
Location: Orlando, Florida
Posts: 36
Likes: 0
Received 0 Likes
on
0 Posts
12a compression reading
I recently bought my 84 GSL and did a compression check on the engine about 3-4 weeks ago. The motor was completely cold. I used a "boinger" compression tester with a check valve in the base.
The compression reading maxed out at about 95 psi on both rotors. When I pulled the gauge off I could feel three even pulses per rotor. The engine has roughly 140K miles and is totally stock (as far as I can tell).
This morning I was doing some other stuff, such as cleaning up my rat's nest removal, and decided to do a hot compression check. I had driven the car to normal operating temps about 5 minutes beforehand.
The reading never got higher than 80-ish psi. Still have even pulses on both rotors, though.
My questions are: Is this a cause for concern? Should the reading go back up to 95 psi on a cold motor, or should I expect bad things? Could some ATF help bring up the compresson?
Any ideas, suggestions, comments, etc. are welcome.
The compression reading maxed out at about 95 psi on both rotors. When I pulled the gauge off I could feel three even pulses per rotor. The engine has roughly 140K miles and is totally stock (as far as I can tell).
This morning I was doing some other stuff, such as cleaning up my rat's nest removal, and decided to do a hot compression check. I had driven the car to normal operating temps about 5 minutes beforehand.
The reading never got higher than 80-ish psi. Still have even pulses on both rotors, though.
My questions are: Is this a cause for concern? Should the reading go back up to 95 psi on a cold motor, or should I expect bad things? Could some ATF help bring up the compresson?
Any ideas, suggestions, comments, etc. are welcome.
#2
rotary sensei
iTrader: (5)
Join Date: Mar 2001
Location: Virginia
Posts: 2,312
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Farleytron
I recently bought my 84 GSL and did a compression check on the engine about 3-4 weeks ago. The motor was completely cold. I used a "boinger" compression tester with a check valve in the base.
The compression reading maxed out at about 95 psi on both rotors. When I pulled the gauge off I could feel three even pulses per rotor. The engine has roughly 140K miles and is totally stock (as far as I can tell).
This morning I was doing some other stuff, such as cleaning up my rat's nest removal, and decided to do a hot compression check. I had driven the car to normal operating temps about 5 minutes beforehand.
The reading never got higher than 80-ish psi. Still have even pulses on both rotors, though.
My questions are: Is this a cause for concern? Should the reading go back up to 95 psi on a cold motor, or should I expect bad things? Could some ATF help bring up the compresson?
Any ideas, suggestions, comments, etc. are welcome.
The compression reading maxed out at about 95 psi on both rotors. When I pulled the gauge off I could feel three even pulses per rotor. The engine has roughly 140K miles and is totally stock (as far as I can tell).
This morning I was doing some other stuff, such as cleaning up my rat's nest removal, and decided to do a hot compression check. I had driven the car to normal operating temps about 5 minutes beforehand.
The reading never got higher than 80-ish psi. Still have even pulses on both rotors, though.
My questions are: Is this a cause for concern? Should the reading go back up to 95 psi on a cold motor, or should I expect bad things? Could some ATF help bring up the compresson?
Any ideas, suggestions, comments, etc. are welcome.
#3
Racingbeat dealer
Join Date: Dec 2002
Location: Uden (AFB Volkel), The Netherlands
Posts: 787
Likes: 0
Received 1 Like
on
1 Post
Originally Posted by Farleytron
I recently bought my 84 GSL and did a compression check on the engine about 3-4 weeks ago. The motor was completely cold. I used a "boinger" compression tester with a check valve in the base.
The compression reading maxed out at about 95 psi on both rotors. When I pulled the gauge off I could feel three even pulses per rotor. The engine has roughly 140K miles and is totally stock (as far as I can tell).
This morning I was doing some other stuff, such as cleaning up my rat's nest removal, and decided to do a hot compression check. I had driven the car to normal operating temps about 5 minutes beforehand.
The reading never got higher than 80-ish psi. Still have even pulses on both rotors, though.
My questions are: Is this a cause for concern? Should the reading go back up to 95 psi on a cold motor, or should I expect bad things? Could some ATF help bring up the compresson?
Any ideas, suggestions, comments, etc. are welcome.
The compression reading maxed out at about 95 psi on both rotors. When I pulled the gauge off I could feel three even pulses per rotor. The engine has roughly 140K miles and is totally stock (as far as I can tell).
This morning I was doing some other stuff, such as cleaning up my rat's nest removal, and decided to do a hot compression check. I had driven the car to normal operating temps about 5 minutes beforehand.
The reading never got higher than 80-ish psi. Still have even pulses on both rotors, though.
My questions are: Is this a cause for concern? Should the reading go back up to 95 psi on a cold motor, or should I expect bad things? Could some ATF help bring up the compresson?
Any ideas, suggestions, comments, etc. are welcome.
Second: try to get a decent (digital) compression test done if you want to get accurate numbers (digital even recalculate to 250 Rpm Mazda specs)
Compression numbers are not holy, if the car starts fine in cold an hot condition, you're fine. I've got people driving with 5 Bar for years now, only if you want to do some mods for more power you should be carefull..... It's just a sign that the engine has milage on it, it's not a garantee your seals won't break.
The lower the compression, the more you need to prep yourself for a rebuild, but there's no ETA given on it
#4
Junior Member
Thread Starter
Join Date: Oct 2004
Location: Orlando, Florida
Posts: 36
Likes: 0
Received 0 Likes
on
0 Posts
Thanks.
I doubt I will waste the time or money to get a digital test done. I don't plan on modding the motor whatsoever, other than the rat's nest removal, air pump and catalyst deletion.
The car starts "fine". It doesn't fire up vigorously, but rather starts in a slow "putt-putt" fashion to a normal idle. My most annoying problem right now is a rather prominent misfire at idle. The plug wires looks a bit old and may need replacing. I am thinking about fashioning a direct fire setup that seems to be so popular with the DIY'ers around here.
I was just concerned the engine may not be long for this world.
If I were to sell this engine to someone, with transmission, how much do you think it would be worth?
I doubt I will waste the time or money to get a digital test done. I don't plan on modding the motor whatsoever, other than the rat's nest removal, air pump and catalyst deletion.
The car starts "fine". It doesn't fire up vigorously, but rather starts in a slow "putt-putt" fashion to a normal idle. My most annoying problem right now is a rather prominent misfire at idle. The plug wires looks a bit old and may need replacing. I am thinking about fashioning a direct fire setup that seems to be so popular with the DIY'ers around here.
I was just concerned the engine may not be long for this world.
If I were to sell this engine to someone, with transmission, how much do you think it would be worth?
Thread
Thread Starter
Forum
Replies
Last Post
mulcryant
2nd Generation Specific (1986-1992)
10
09-09-15 05:24 PM
ZaqAtaq
New Member RX-7 Technical
2
09-05-15 08:57 PM