head bolt retorque

[Amez]

Does anyone know if a 50 hour headbolt retorque is required on a 2007 Jinma or do they have multi layer steel gaskets (or torque to yield headbolts)? The manual says nothing about it.

[rrboomer]

Hello ! I would check the head gasket that came in your parts kit. The one on the tractor and the one in the kit should have come from the same bunch.This was is not 100% sure but a good start. Good luck ! joe

[RonMar]

Regardless of the gasket material, I don't think confirming/re-torqueing will hurt anything. Then you at least know the status of the head bolts/studs... When I did mine, I found and removed quite a bit of machineing debris in the head when I removed the rocker assembly to accomplish the retorque.

[YukonKing]

Yes,

And yes, Hope the attachement works. It took me abbout and hour to complete. I did mine at 73hrs. Set clicker torque wrench to 105ft/lbs. Nothing budged. So at least it was torqued properly at the factory.

YukonKing





JMretorque

[greg_g]

Set clicker torque wrench to 105ft/lbs. Nothing budged. So at least it was torqued properly at the factory.

Not necessarily true. What if one or more of them was torqued to something in excess of the factory spec? Or maybe undertorqued - but rusted in place? Without loosening them before resetting torque, you'll never know.

I know Mike Stuart's document says it's not necessary to loosen first - I simply have a different opinion.

//greg//

[Bob Rooks]

Not necessarily true. What if one or more of them was torqued to something in excess of the factory spec? Or maybe undertorqued - but rusted in place? Without loosening them before resetting torque, you'll never know.
I know Mike Stuart's document says it's not necessary to loosen first - I simply have a different opinion.
//greg//

I'm on Greg's side. You'll never know what you had unless you undo it. This is what Caterpillar used to recommend.
In some cases it is impressed upon to see what the "break-loose" torque is/was, wherein you use a dial torque wrench set to zero then take the "break-loose" value for reference. Although this practice is reserved for multi-million dollar engines where you must have a BS just to change filters, it won't hurt a thing.

[YukonKing]

Mmmm,

Fair enough, but the recommendation is to not loosen. Even though they may have been over torqued at least it wasn't leaking up till now. (aint broke don't fix it). But I would think you are risking things moving. In my opinion if your breaking them loose you should be replacing the gasket. Plus when they were initially torque beeing brand new, assembled with lots of oil, now after many heating and cooling cycles with the oil drying out a bit they could actually require more torque to break them than when they were put in? An extreme example is any old hardware on most vehicle, say 10 years old... it usually takes more to break them than when they were new? I realize that 50hours bathed in oil is not the extreme but maybe? Anyhow i'm sure either way I will get many more hours out of my little Y385 diesel.....I hope.

So what is the correct way...........? Heck if I know.

YukonKing

Either way I am very impressed with these Engines/Tractors up till now.

[Ranch_Hand_Supp]

Hey YukonKing,
I am not on Greg's side but, I recommend breaking the head bolts loose for a retorque and have done so for many years. It has been a general practice in my field. I would never oil the threads unless you have a wet thread spec.


As of yet these engines do not have torque to yeild head bolts.

Ronald
Ranch Hand Supply

[YukonKing]

hey,

no worries, the more opinions, ideas and information the better. the only reason I offer my opinion is because I bought a tractor. if i haden't I wouldn't be on here.

but the question remains should he retorque? I think yes.

P.S. Its spring here I have 8 inches of mud around the house i'm building and living in.

peace

[Bob Rooks]

If you want to do it the correct way, remove each bolt one at a time (in sequence), clean and oil the threads (most torque values assume clean oiled threads and head seat) and then re-torque to 2/3 of the final value. When you have completed that, then torque to the final value (in sequence).
It seems kinda anal retentive for these engines, but you asked.


Head torque trivia
On the RND Sulzer engines, the "head studs (about 4-1/2" dia.)" go all the way down through the crank bearing caps (approx 22 feet); the nuts are spun on hand tight and then "pinged" with a slugging wrench. All that while under 12 tons of hydraulic jack tension. Six at once.

Fuel injection trivia:
The RND is a two-stroke diesel engine. Every time the injector "pops", there goes ~85 gallons of HFO.

Enough; back to tractors.