TD42 high compression

[robbo_]

G day all so after converting my GQ TB42 to Td42 iv decided it's time for a turbo kit. So as precaution and to Se were the engine is at thought I'd do a compression test. As u all know nissan service manual states standard 427 psi minimum 356psi So my results are
(1) 490 (2) 485 (3) 500 (4) 500 (5) 490 (6) 495. The engine has approx 500,000 ks on it reco head bout 15,000ks old dosnt use any oil between services and has been serviced religiously. My concern is why is it so much higher than standard and is it still safe to turbo
An yes I did the compression test correctly with a quality gauge any feed back greatly appreciated cheers

[AB]

Can Carbon build up over time cause higher compression?

[Ben-e-boy]

The only thing I can think of is that a thinner head gasket was used when the head was off

[BigRAWesty]

The only thing I can think of is that a thinner head gasket was used when the head was off

Yea didn't the black tops use a thicker gasket to de comp the engine?? Or is that an after market option?

[kevin07]

they do machine them as well

[Ben-e-boy]

Yea didn't the black tops use a thicker gasket to de comp the engine?? Or is that an after market option?

No every td has the same 22.7:1 compession

[robbo_]

The cylinder head was re surfaced. I'm unsure on the thickness of the head gasket used I didn't realize there were different sizes, I would be stoked with the results if I was leaving it N/A but is the compression to high to run 10-12 psi of boost got my heart set on a turboglide system
Any feedback appreciate

[nissannewby]

It will be fine. Put the turbo on.

[Cuppa]

It will be fine. Put the turbo on.

robbo ..... in case you are not aware, nissannewby is a man to listen to on such matters.

[robbo_]

Yeah sweet just saw he's a diesel fitter good enough for me thanx guys