Does my engine need a rebuild?

[Anonymous-0]

When I mow with the finish mower or the bush hog, oil pressure drops to zero after about 15 minutes of use. Winter time when I plow, its fine. I also found large amounts of oil looking gunk in the radiator however no coolant in the oil. I just ran a compression test 60 psi across all 4 cylinders. Any ideas whats causing my problem or is the motor shot?

 

[LP GAS ONLY]

use streight 30w. oil in the summer!
forget the 10w30 and so on.

 

[Danny in CO]

Gary,

60 psi is low. Minimum recommened is 90 psi. You really need to do a dry and then wet compression test to help tell whether rings or valves are bad. Make sure throttle is wide open when you do the tests.

My guess is since you have low compression, you probably have worn bearings which is causing your low oil pressure when hot. As a band-aid, try straight 30 or 40 weight oil in hot weather.

Danny

 

[TheOldHokie]

(quoted from post at 13:24:12 06/24/09) When I mow with the finish mower or the bush hog, oil pressure drops to zero after about 15 minutes of use. Winter time when I plow, its fine. I also found large amounts of oil looking gunk in the radiator however no coolant in the oil. I just ran a compression test 60 psi across all 4 cylinders. Any ideas whats causing my problem or is the motor shot?

Sounds like it's worn and weak.

Low (non-existant) oil pressure is a strong indicator of worn bearings and/or oil pump

Low compression is a strong indication of worn rings/cylindres and/or valves.

In combination I'd say they are strong indicators of a motor on it's last legs.

So if it were me I'd be planning an overhaul in the "near" future at a time convenient to me and my need for the tractor's services.

TOH

 

[Anonymous-0]

I did a wet too and it only brought it up 70 psi. I've got straight 30 in it with Lucas oil additive.

 

[Anonymous-0]

I've been running it like this for a long time. You can hear when its running the valves aren't seating properly. Sad thing was when I bought it, it supposedly had a rebuilt engine...so much for that.

 

[TheOldHokie]

(quoted from post at 14:39:25 06/24/09) I've been running it like this for a long time. You can hear when its running the valves aren't seating properly. Sad thing was when I bought it, it supposedly had a rebuilt engine...so much for that.

Quite frankly everytime I see a tractor advertised and the seller says "recently rebuilt motor" I cringe. Too many tractors and too many novice engine builders for that to mean anything positive in my book. In fact I'd rather hear "it runs strong, has good oil pressure, and I've never touched it in the 10+ years I've owned it".

TOH

 

[Ultradog MN]

[i:654c4848f0]Quite frankly everytime I see a tractor advertised and the seller says "recently rebuilt motor" I cringe. Too many tractors and too many novice engine builders for that to mean anything positive in my book. In fact I'd rather hear "it runs strong, has good oil pressure, and I've never touched it in the 10+ years I've owned it".[/i:654c4848f0]

Well said TOH.
My theory is that many of these rebuilds we see on these boards are really the same engines getting rebuilt over and over and over...

 

[Danny in CO]

You might pull the head and check the valves for ones that might be burned. It could also be that the valves are not adjusted correctly and not completely closing.

Good luck with what you find,
Danny

 

[Anonymous-0]

Would valves not seating cause oil pressure problems?

 

[Anonymous-0]

YES!

 

[Danny in CO]

Sorry,no. I headed off on a tangent. CRS I guess!

Danny