1998 XP compression test

[lvnspeed]

1998 XP compression test What should it be?

[Johnnylaw]

Re: 1998 XP compression test

~140 to 150 psi, both cylinders should be within 5% of each other

[lvnspeed]

Re: 1998 XP compression test

Thanks if they are below that then time for a rebuild?

[Johnnylaw]

Re: 1998 XP compression test

Not necessarily. Use a known accurate guage and post it here. If it is running good and they are in the 130 range I'd keep on riding

[lvnspeed]

Re: 1998 XP compression test

I am going to check tonight and post the resluts. I have a Snap-on compression guage.

[Bill O'Neal2]

Re: 1998 XP compression test

Most new 951 engines blow between 130-135 psi at sea level with a fully charged battery.

[lvnspeed]

Re: 1998 XP compression test

I found they are at 125 on #1 and 128 on #2 so I think I am ok

[Sarge 707]

Re: 1998 XP compression test

Bill- Why do the 98 951,s read 150-155? Did SD De Tune the newer 951,s? Also is it common for the PTO Reading to be a couple pounds higher than the MAG?

[Bill O'Neal2]

Re: 1998 XP compression test

Sarge,
All 947 engines read about the same, there is no differences between the 1998 and 1999 motor. Everyone I ever tested here at 700 ft above sea level pump about 135-140 psi on my newest and my older Snap-On compression tester guages if the motor is in new condition.

If I see one that pumps 150, I start checking my guages, or looking for a milled head.