Bolt torques for Farm Pro 2420

[bigcountry1009]

I'm gonna have to replace the head gasket on my Farm Pro 2420 with the Jinma TY290 motor. I can't find any bolt torques for when I put the motor back together. Can any body help me out? Thanks ahead of time.

[timwil]

give Jerry at AFFORDABLE tractor a call and i am sure he can help you

[Ranch_Hand_Supp]

I have in my notes 95-105 foot pounds for head bolts.

I can't remember where I got the spec and don't know if it is a correct spec ??.



Ronald
Ranch Hand Supply

[Harrygoodwrench]

I believe Ron is correct on the torque. Here is a link to Johns Jinma that I believe will help.


JMretorque

[GuglioLS]

Here is a chart to help you decide:



Larry

[greg_g]

Here is a link to Johns Jinma that I believe will help. JMretorque

Head bolt torque numbers differ significantly between my 4 cyl YangDong (TS354C) and my 3 cylinder FeiDong (KM454). As such, I would find it surprising if the YT290 and Y385 shared a common spec. I know 95-105 is wrong for the Y385, an error that would ordinarily justify independent verfication for the TY290. But since Ron had previously posted 95-105, I think that's probably the correct set of numbers.

Note paragraph (5) though. I personally do not agree with the " do no loosen first " advice.

//greg//

[Dave_Lilly]

Head bolt torque numbers differ significantly between my 4 cyl YangDong (TS354C) and my 3 cylinder FeiDong (KM454). As such, I would find it surprising if the YT290 and Y385 shared a common spec. I know 95-105 is wrong for the Y385, an error that would ordinarily justify independent verfication for the TY290. But since Ron had previously posted 95-105, I think that's probably the correct set of numbers.

Note paragraph (5) though. I personally do not agree with the " do no loosen first " advice.

//greg//

Why do you not agree with the "do not loosen first" advice?
The JMretorque page at Johns Jinma seems pretty straight forward.

[greg_g]

Two reasons Dave;
1. First one's common sense. A good mechanic doesn't assume the last guy knew what he's doing. He checks for over-torque as well as under-torque. Let's say you've set your torque wrench to click at 105 ft-lbs. You don't loosen the head bolt, you just assume the bolt's ok when the wrench clicks. So what if that bolt's actually torqued to something above 105#. You'll never know.
2. Second one's science. When headbolts are tightened, the force of applied torque on elastic threads serves to "clamp" the male and female parts. Without a secondary locking device (Nylok nut, lock washer, etc) this "clamping" is all that holds properly torqued fittings together. Over time, engine heating/cooling cycles, moisture, vibration, can render the clamping force to become greater than the torque spec. To verify/reset torque, you must first overcome the clamping force. That means backing off on the existing force that hold the bolt in place, then resetting it to the specified torque spec

Loosen, retighten, set.

//greg//

[Dave_Lilly]

Two reasons Dave;
1. First one's common sense. A good mechanic doesn't assume the last guy knew what he's doing. He checks for over-torque as well as under-torque. Let's say you've set your torque wrench to click at 105 ft-lbs. You don't loosen the head bolt, you just assume the bolt's ok when the wrench clicks. So what if that bolt's actually torqued to something above 105#. You'll never know.
2. Second one's science. When headbolts are tightened, the force of applied torque on elastic threads serves to "clamp" the male and female parts. Without a secondary locking device (Nylok nut, lock washer, etc) this "clamping" is all that holds properly torqued fittings together. Over time, engine heating/cooling cycles, moisture, vibration, can render the clamping force to become greater than the torque spec. To verify/reset torque, you must first overcome the clamping force. That means backing off on the existing force that hold the bolt in place, then resetting it to the specified torque spec

Loosen, retighten, set.

//greg//

bigcountry1009's original post asked about head bolt torque specs after he replaced his head gasket, so whatever any previous mechanic did is irrevelant since he has his head bolts out of his engine.
The JM retorque page is also irrevelent because it describes the procedure for re-torqueing the head bolts as a 50 hour maintenance procedure.
As far as your "science" goes, loosening the head bolts before re-torqueing them on a 50 hr maintenance program goes directly against the procedure in the JM retorque procedure for this tractor.
If you are suggesting that any one who decides to retorque their head bolts without any need to, loosening the head bolts before retorqueing them can cause a host of problems, not the least would be a warped head.