J13 CYLINDER COMPRESSION

[ONELOWDATS]

i have a 520 with a j13 engine. ive looked through all my repair manuals and there is no spec on what the compressions suposed to be. if any one of u guys out there know please help and let me know. thank you and i hope u guys can give me some answers. thanx again.

[MicroMachinery]

As a general rule, you want them within 10%(from highest reading to lowest) of each other(i.e. 10% of 180 = 18. 188, 175, 179, 184 would be acceptable readings ). If they have a wider range of variance, it's definitely not ideal, but if all 4 are fairly close to the same, you're ok. On a newer(lower mileage) motor used in a regular, passenger vehicle(such as a 520 pickup), 160-180psi should be a normal reading. But remember, it's not so much the higher number that's important, as it is that you have 4 readings that are numerically close to one another.

[ONELOWDATS]

thank u

[Datsun fan]

According to Datsun1200 club the normal reading is 150 psi , service limit is 110 psi .

Before comp test, First be sure the oil is in good condition and change it if necessary, adjust valve clearance .

Good luck