S54 Compression test

offyourmarks · Post by **offyourmarks** » Wed 16 Nov, 2011 08:18

Guys further to my last post concerning certain issues cropping up with the S54 in the E46 M3, I thought I would stop myself wondering and carry out a compression test on my M3 and check for the signs of HGF

Its reasonably straightforward and takes around an hour maybe little more.

My readings were pleasing showing very healthy compression values and closely balanced across all 6 cylinders.

The important thing is to have an accurate gauge as the ebay ones for £20 are rubbish. I used a calibrated 'Snap-on' item

If anyone wants more info then let me know.

If there is anyone in the NW area that wants it done then I would be happy to either talk them through it or book it in with me and I will complete it for a £30.00 charge

Many thanks

Matt

Desiro · Post by **Desiro** » Wed 16 Nov, 2011 14:15

Hi Mat
It would be nice to know the procedure for doing the test and what readings you got.

I did my S50 recently and had a few psi difference on cylinder 2, but I am not sure I followed the corect procedure when carrying out the test.

offyourmarks · Post by **offyourmarks** » Wed 16 Nov, 2011 15:08

Bentley manual allows ~5% iirc between cylinders so based on 180psi that's obviously 9psi. It's usually between 5 & 6 cylinders where hgf occurs. I took some pics so I'll write up when I get a min.