Compression? Whats that?

[TrueSlide]

Could someone explain what compression is to my motor? Well Iam having the most horrible luck when it comes to my 240. The last time I did a compression it read:

120, 130, 105, 130

Well since then I purchased a different head that was rebuilt. I put it on and did 3 compression tests today and here is how the results layed out:

cylinder 1: 150 then 145 then 150cylinder 2: 170 then 170 then 160cylinder 3: 170 then 100 then 110cylinder 4: 110 then 120 then 110

Now could someone explain to me wtf is going on?!?!?! Iam lost complelety. It also seems to me that the car is not getting oil as when i was cranking it and then pulled my valve cover, no sign of oil coming to the top at all?!?!?!

Any help if greatly appreciated.

[Infamous]

was the headgasket installed properly?

[Structure240sx]

did u torque down the head in the right sequence?

[[Zero-S]]

TS please tell me you're coming to the BBQ. And btw, I am just as in the dark on the compression as you are.

[TrueSlide]

I torqued the head down in the right sequence, new gasket, new bolts. Maybe the rings?

Talking I was told maybe my rings have not set in, could that be true? Also the same person told me to try and start it and if it starts well I forget, but they also said my rings could be broke

BTW, I will try my damnest to goto the BBQ. When is it so I can request off. Also if my car isnt running, you guys dont mind if I come in a camaro, do you?

[[Zero-S]]

25th @ 4PM. Fredricksburg. I know its in the meets section...lemme find it.

[[Zero-S]]

http://www.nissaninfiniticlub....25449

[S13Ka24e]

I torqued the head down in the right sequence, new gasket, new bolts. Maybe the rings?

Talking I was told maybe my rings have not set in, could that be true? Also the same person told me to try and start it and if it starts well I forget, but they also said my rings could be broke

BTW, I will try my damnest to goto the BBQ. When is it so I can request off. Also if my car isnt running, you guys dont mind if I come in a camaro, do you?

There is a easy test to tell if it is your rings,

1. Add one capful (1-2 tablespoons) of oil to the cylinder with low compression.

2. Let it sit for a minute to allow the oil to flow down and coat the sides of the cylinder and piston. If there are any gaps in the rings, the oil will seal them for the next few minutes.

3. Crank the engine for 4 revs, remembering to floor the throttle.

4. If the reading improved significantly (more than 30 psi), your rings are probably worn.

As far as your test have gone, i'm not suprises with 1,2,4. But i don't know why 3 went for 170 to 110. I'm not too suprised that the reading changed, many factors affect the test. It looks the 3,4 are bad, and 1 looks like it is going.

S13ka24e

[TrueSlide]

The thing is though, they are brand new rings! Everything is pretty much brand new except for my rods.

[S13Ka24e]

Did you let the engine "break in" after you replaced everything? (I.E. not reving the engine up)

[TrueSlide]

it hasnt even started

[S13Ka24e]

oh, well i don't know then, hopefully someone else will. Good luck.

[TrueSlide]

Oh ya, I also really havent tried to start it, the plugs I have = very dead. Iam gonna buy new plugs tomarrow. And then try and start it.

[stickgoat]

Dammit, this is not a very motivating thread.

I'm in the process of removing the head from my S14 to replace the valves and am paranoid that something is going to go wrong again when I put it all back together...

[TrueSlide]

Its okay stickgoat, just becareful. Your only replacing valves, I replaced everything. Its not my top end causing problems, it my bottom end. Good luck.

[89240sx]

Let us know what happens when you try to start it with the new plugs.

[TrueSlide]

Tried to start it and it goes over and pops hard, like it wants to start, but nothing.

There is a local mechanic who is kickass with nissans, Iam just probley gonna take it to him and bite the bill :-/

[89240sx]

too bad you are not local .... i could come by and see if i could help out ..

hopefully you wont have too high of a bill to bite

[red240ne]

Damn True, you've worked so hard!!!! I feel bad for ya man. I think your only objective right now would be just to get the fukker started up! Then maybe let everything settle in a bit and do a compression test to see how everyone in the neighborhood's doin.