Just Had a qiuck ? about the compression of our cars. What is the compression range for a 95 max.

 

compression what?

 

i think it was 145-182psi. +/- that what the tech told me at my dealer. i may be off cause i have a horrible memory.

 

You were pretty close...
I have a 95 Service Manual; it lists a ‘standard’ and ‘minimum’ but no max. Minimum =142psi and standard =185psi, with a difference limit between cylinders of 14psi (all measurements are at 300rpm).
Hope this helps.

 

Nissan FSM are great for finding the compression ratio as well as the specification for compression tests.

 

hahahah i got my last numbers reversed.

 

Quick note:

Compression tests should be done on a warm engine.

 

Guys, thanks for all your help. Hope the compression test turns out ok.

 

Is there a maximum ever listed? Would high compression be a bad thing, assuming everything is stock? I understand the problems that can arise from raising it, but if a stock max was to post a number of say 200, would that be a bad thing?

 

The first test I ever did was on a cold engine. Those numbers were scary!

 

Anything over 185psi on a stock max is not good. High mileage and lots of carbon buildup. Again, do it on a warm engine. I read this somewhere here on the org, so mayby try looking for those letters-----------> s e a r c h on the upper left of the screen.

 

I meant upper right

 

do a dry test and a wet test for the best reading

 

where exactly can i get a compression test done, and how much does it cost?

 

You're better off getting a good compression gauge for $40 or so and DIY. All you do is warm up the engine, take out all the sparkplugs and screw the gauge into each sparkplug hole. Crank the engine and wait until you see the gauge stop moving. Read the scale, release the pressure in the line and move on to the next cylinder.

You should also disable the fuel and ignition systems during the test.

 

crank the engine for 4 strokes no more then that.

 

So my compression test was:

Front: 190 190 190
Rear: 210 210 210

So my engine is foobared?

IanS

 

Is there a reason for this, I've never seen that before

 

all my techers at school said that anythign after 4 strokes gives you a incorrect reading. And that the first stroke you should get about 3/4th of your total reading with only 10 to 15% difference between the highest and lowest total numbers. I honestly never heard of this do it only when the engine is hot thing. I know when the engine is hot it will compress. I was told to do it whenever , with a first dry test and if the readings are bad do a wet test. It the wet test proves to be good then you have a blown gasket, bad rings whatever.

 

Huh, never noticed whether or not the first stroke was 3/4 of the total reading or not. Interesting.

When I did it on the engine cold (on another car) I got 3 cylinders coming back at 120. They should have been 145-154. When I re-read the service manual, I noticed it said to do the check with the engine warm. On the re-test, everything looked great. I'd assume that it has to do with having all the different metals in the engine at the correct operating temperature so all the clearances will be as designed. Maybe someone else can elaborate?