I found the low compression issue on my car! (I think)

[silviaz]

Hi so on my silvia s15 I noticed the rocker arm snapped on cylinder 2 which had 125 PSI, others had 135-138, 145, and 145, and weird thing is I didn't notice this when taking the valve cover off. Only when I tried to put it back on and noticed a piece stuck in the right top corner (no idea how it got there) and also I noticed my timing belt has no guide is this ok? Here is picture of broken rocker arm, and surprisingly the head isn't damaged.

What do you think?

[Kinkstaah]

Rockers snap fairly frequently on SR20's that have had a beating. There's a few designs for better rocker arms that are less prone to doing this. That said when I've seen SR20's that have had broken rockers, they have basically 0 compression in the cylinder thats affected and effectively are driving around on 3cyl.

If your car was driving around mostly okay, and only concerned about the comp results then this is likely to be something that broke in the past.. got replaced, and the bit was never removed ?

If you were driving around on 3cyl, chasing the misfire and found a broken rocker then yes that will cause it....

[silviaz]

12 hours ago, Kinkstaah said:

Rockers snap fairly frequently on SR20's that have had a beating. There's a few designs for better rocker arms that are less prone to doing this. That said when I've seen SR20's that have had broken rockers, they have basically 0 compression in the cylinder thats affected and effectively are driving around on 3cyl.

If your car was driving around mostly okay, and only concerned about the comp results then this is likely to be something that broke in the past.. got replaced, and the bit was never removed ?

If you were driving around on 3cyl, chasing the misfire and found a broken rocker then yes that will cause it....

Thanks. I noticed my rocker arm has a certain number. Do I need to find that replacement or I can buy any rocker arm? Are they all the same size?