No compression s40 2.4

Garly24 · Post by **Garly24** » 13 Mar 2014, 18:13

Hi new to this .... Hope you can assist I have a 2005 s40 2.4 non turbo that overheated I removed the cylinder head and found cylinder 2 piston had melted a bit I had it replaced along with all the rings and crank shells.on the other 4 cylinders. I also had the valves checked and reseated. And now when I rebuilt it there is low compression across all 5 cylinders it reads 25-30 psi.. Do I now have to reset the tappets or am I missing something... Again hope someone can assist I've put a lot of money into this

difflock54 · Post by **difflock54** » 15 Mar 2014, 21:39

Might be down to what is called 'lawnmower syndrome' ???
See the attached link below.
If it is that a simple small squirt of oil into each cylinder usually fixes it.

https://www.matthewsvolvosite.com/forums ... =1&t=18175

Post by **jimmy57** » 15 Mar 2014, 22:08

How were cams timed when re-assembled? Did you use the cam locking tool?
If the valves or valve seats were ground then the valve clearance changes and the clearance is checked and tappets changed as needed to get the correct clearance.

Garly24 · Post by **Garly24** » 17 Mar 2014, 17:49

Thanks for reply yes I did use cam locking tool and pin for crank gona try the tappets

Garly24 · Post by **Garly24** » 21 Mar 2014, 17:27

Is this lawn more syndrome a myth or worth a shot

difflock54 · Post by **difflock54** » 23 Mar 2014, 17:10

Read some of these posts that are within this very forums database.
No personal experience with this problem but it might have a bearing on your situation.

https://www.matthewsvolvosite.com/search ... &sa=Search

Post by **jose456891** » 01 Apr 2014, 21:25

Check timing

Else, you might have incorrectly machined or installed the head gasket.

Did you send the head to a machine shop, in what conditions were the valves?

Post by **jose456891** » 01 Apr 2014, 21:26

Garly24 wrote:Is this lawn more syndrome a myth or worth a shot

Its not that common, but I heard that its not rare. I say that its not worth a shot.

difflock54 · Post by **difflock54** » 01 Apr 2014, 22:05

For a few minutes removing the plugs and a teaspoon of oil in each pot, what have you got to lose?
It can only be timing out of sync otherwise and if engine turns over freely without resistance or knocking the valves shouldn't be contacting the pistons and bending.

The OP however has not confirmed whether the head was checked for warping when the valves were reseated or if it was all done by an experienced / qualified machine shop engineer ???