I am the owner of a 2011 Jinma 284 that I bought new in Dec of 2012. In reading most of the posts about the head the general consensus is that you should re-torque the head bolts after 100 hours. I posed that question to the dealer I purchased my tractor from and they said its not necessary. Any thoughts on this revelation?
To re-torque or not?
- Thread starter skinny49
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Bob Rooks
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Ask the dealer why it's unnecessary. Does the dealer know more than the factory's design engineers? What are the dealers credentials?
Stick with the factory recommendations. Who is the dealer?
Stick with the factory recommendations. Who is the dealer?
Affordable
Advertiser, Platinum Member
I have seen a lot of head gasket failures over the years, I would recommend the re-torque at a 100 hours, the operation manual for the engine manuf. also states that. Why would you question the manual and all the comments about this subject you have seen or read.
Tommy
Affordable Tractor Sales
"Your Jinma Parts Superstore"
Home of compact Jinma, Foton, and Koyker Tractors and Parts, Wood Chippers, Backhoes - Affordable Tractor Sales Company
Tommy
Affordable Tractor Sales
"Your Jinma Parts Superstore"
Home of compact Jinma, Foton, and Koyker Tractors and Parts, Wood Chippers, Backhoes - Affordable Tractor Sales Company
So,you are telling me that every new Jinma you sell,is brought back into the shop at 100 hours,and you retorque the head ?
greg_g
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100 hours must be new in recent years. Prevailing wisdom regarding all four of my new Chinese tractors between 1999 and 2006 spec'd a retorque as part of the 50 hour break-in service. And since the valve train has to be removed anyway, a valve lash adjust was recommended as part of the reassembly. That "not necessary" statement alone would have me looking for somebody else to service the tractor.
//greg/
//greg/
Rich Waugh
Platinum Member
Absolutely re-torque the head and set the valve lash (which should have been done at 50 hours). Any dealer that told me it was unnecessary would be a dealer that would never again see my tractor. Tommy at Affordable and Ron at RanchHand Supply are two of the most knowledgeable Jinma dealers in the country and both of them recommend it. I'd follow their recommendation over that of just about anyone else. I certainly did with my tractor and have never been sorry.
I doubt that every tractor Tommy ever sold has come back to him for the head re-torque, as a large percentage of Chinese tractor owners prefer to do their own service. However, I can tell you that Tommy sets up every tractor he sells before it leaves his premises - assembly, clutch adjusted, valves adjusted, all fasteners checked, etc. Many dealers only assemble them and hope for the best, which results in problems with out-of-adjustment clutches, valves, etc. These tractors do not come from the factory with everything to spec. If you neglect any opportunity to do the proper service and maintenance as per the manual, you can pretty much expect problems not much further down the road unless you're very lucky.
I doubt that every tractor Tommy ever sold has come back to him for the head re-torque, as a large percentage of Chinese tractor owners prefer to do their own service. However, I can tell you that Tommy sets up every tractor he sells before it leaves his premises - assembly, clutch adjusted, valves adjusted, all fasteners checked, etc. Many dealers only assemble them and hope for the best, which results in problems with out-of-adjustment clutches, valves, etc. These tractors do not come from the factory with everything to spec. If you neglect any opportunity to do the proper service and maintenance as per the manual, you can pretty much expect problems not much further down the road unless you're very lucky.
Affordable
Advertiser, Platinum Member
Thanks Rich, we can only recommend the owners do it,Rich is correct most Chinese tractor owners do there own work and most will do the re-torque the head.It only takes about 2 hours to do the job so its not a big deal, that will save future headaches down the road.We have to go over all the bolts on a Chinese tractor during assembly, you would be surprised at how many are loose.
Tommy
Affordable Tractor Sales
"Your Jinma Parts Suprestore"
Home of compact Jinma, Foton, and Koyker Tractors and Parts, Wood Chippers, Backhoes - Affordable Tractor Sales Company
Tommy
Affordable Tractor Sales
"Your Jinma Parts Suprestore"
Home of compact Jinma, Foton, and Koyker Tractors and Parts, Wood Chippers, Backhoes - Affordable Tractor Sales Company
Rich Waugh
Platinum Member
Happy to recommend that folks take your advice, Tommy. You and Ron have both given me a lot of helpful advice and guidance with my Jinma 304 and never have either of you been wrong. I will believe either of you guys over what the factory manual says, since I know you deal with these tractors every day and have for years now. Since I bought a crate tractor (the only affordable option here in the Caribbean), your assistance has made my ownership a pleasure rather than a pain.
Thanks again!
Thanks again!
quicksandfarmer
Veteran Member
To definitively answer the question you would have to look at hundreds or thousands of engines and compare the gasket failure rate for those that were re-torqued against those that weren't. Failing that, I will say that these engines seem to have a propensity to blow head gaskets. It's entirely possible that the re-torquing does nothing, and the factory knows that, but they also know that most people don't do it anyway, so they only recommend it so they can blame you for the gasket failure when you don't do it. Or maybe re-torquing is the solution to head gasket longevity. Who knows.
I will offer my experience though. I did not re-torque my head bolts at the 50-hour mark, which is what was recommended for my tractor when it was new. At around 400 hours I had to replace the head gasket. Once bitten, I followed the installation procedure to the letter: I torqued it to the specifed torque, ran the engine until it was warm, let it cool off, and then re-torqued. After another 50 hours I re-torqued it again. When I put the valve train back on the valves were so tight I had to loosen the adjustment bolts substantially to get any gap, at first I thought I must have it misaligned it was that tight. So in the second re-torquing the head moved significantly closer to the block, which means that the gasket compressed significantly during those 50 hours. Will this gasket last longer? Since I use my tractor about 100 hours a year, it will be a while before I can tell with any certainty.
Some people recommend marking the head bolts with a pencil to see if they move in retorquing. They have a 1.5mm pitch, so each full rotation is 1.5mm, you can estimate how much the head moved by the fraction of a rotation the bolts tightened. I'm not sure what the practical use of that knowledge is but it does let you know if the re-torquing is doing anything.
I will offer my experience though. I did not re-torque my head bolts at the 50-hour mark, which is what was recommended for my tractor when it was new. At around 400 hours I had to replace the head gasket. Once bitten, I followed the installation procedure to the letter: I torqued it to the specifed torque, ran the engine until it was warm, let it cool off, and then re-torqued. After another 50 hours I re-torqued it again. When I put the valve train back on the valves were so tight I had to loosen the adjustment bolts substantially to get any gap, at first I thought I must have it misaligned it was that tight. So in the second re-torquing the head moved significantly closer to the block, which means that the gasket compressed significantly during those 50 hours. Will this gasket last longer? Since I use my tractor about 100 hours a year, it will be a while before I can tell with any certainty.
Some people recommend marking the head bolts with a pencil to see if they move in retorquing. They have a 1.5mm pitch, so each full rotation is 1.5mm, you can estimate how much the head moved by the fraction of a rotation the bolts tightened. I'm not sure what the practical use of that knowledge is but it does let you know if the re-torquing is doing anything.
Rich Waugh
Platinum Member
Diesel engines are much higher compression that gasoline engines and thus the head gaskets re subject to higher pressures. Proper torque becomes more important as a result. Proper torque also affects valve lash, as you noted, which is a significant factor in engine performance. I can't think of a good reason not to re-torque them as recommended.