Thread: Change the headgasket on the QR25DE. (Altima Sentra)

Originally Posted by SilverBullet

If i was at TDC I could move the chain up so that the marks that are on the chain not the ones I made but they ones on the chain and bring then up to mate them with the marks on the cams and I should be good to go right?

I'm just trying to figure out if there was a way to do it if the markings on the chain were not there, or on the cams.

Just draw your own markings. Get top dead center, then get some paint and make a line going from the chain down onto the sprocket.

im trying to get to TDC but my Exhaust cam sprocket isnt turning? Why is this?

I started up the car and everything ran superb. I checked my compression and across all 4 cylinders I got 200.

Is this normal? How come compression went up?

When I did the compression I forgot to mash the gas pedal down. <-- could this affect numbers?

Now I've been wondering on how to do the compression test.

I had an old timer tell me to pull all 4 plugs when I do it.

Put the tester into cylinder 1, bump the starter a few times, take the reading and repeat for the next 3.

I'm curious as to how others do it.

Originally Posted by willms81

Now I've been wondering on how to do the compression test.

I had an old timer tell me to pull all 4 plugs when I do it.

Put the tester into cylinder 1, bump the starter a few times, take the reading and repeat for the next 3.

I'm curious as to how others do it.

thats how i do it. you dont want to only pull the one out cuz you dont want the car to start on you haha. this reminds me i need to do a compression test myself.

Make sure you pull the fuel pump fuse too .

Originally Posted by frozenbarb

Make sure you pull the fuel pump fuse too .

I was just going to depressurize the fuel system with Cipher, but that works too.

Or simply disconnect fuel.pump connector. Or fuse

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Originally Posted by frozenbarb

When I did the compression I forgot to mash the gas pedal down. <-- could this affect numbers?

The reason you need to do this is so that oil can flow into the motor, with it close it will talk longer to build compression, it takes me about 10 cranks to build full compuression at 160psi, I have a little lower compression pistions so my readings will be lower than yours. And your compression might go up after replacing the HG as you could have had a leak but 200 is a good number across the board i believe.

170-180 psi is a good number for stock. if you have the 07+ pistons then it should be 205-215 psi. if your boosted with say 8:1 pistons then it should be about 155-165 psi

Can you guys recommend a compression tester or are they universal to all engines?

It's a universal kit. One with a stainless steel braided hose is what I would recommend.