Torque for Rocker Arm Assembly Bolts?

JINMA224XR · Dec 16, 2005

And then like Chip says, you've got to do the math to compensate for the torque offset 

Hey Greg,

Very Good Advice, and I thank you.

I guess now the question is: What is the Crow's Foot Formula when using a Torque Wrench?

Sir Isaac Newton, are you reading this?

Thanks to everyone here for the great advice.

Chip, did you meet your goal for this year on # of Chinese Tractors Sold? Next year, we're looking for at least Twice as many To Roll Through your Establishment. /forums/images/graemlins/smile.gif

Thanks Again &
Have a nice day,
Joe /forums/images/graemlins/cool.gif

greg_g · Dec 16, 2005

( I guess now the question is: What is the Crow's Foot Formula when using a Torque Wrench? )

Click HERE Joe. Merry Christmas

//greg//

bluechip · Dec 16, 2005

Inspite of the interuption in supply from China when the factory reorganized, we had a very good year and have high hopes for another in 2006!

Too all my friends and customers here on TBN I wish a very merry Christmas! and all the best in 2006!

Ranch_Hand_Supp · Dec 16, 2005

Description: **for attachment**
Special crowfoot wrench design provides the strength necessary for removal/installation. 12-point, 7/8" wrench size. 1/2" drive. Nickel/chrome finish.

quote,
Minor point Ronald, but if it's boxed - it's technically not a crows foot anymore. I'm curious though, where have you seen such an extension anyway?

//greg//

greg, can't get to technically with ya...no reason to....cause I am not a technically kind of guy. I don't really think I can tell you excatly where I have seen them...sorry !. I did have a couple styles in my tool box if I dig deep enough.

This type of boxed end crows foot I guess is a specialty tool. I have used/needed it for head bolts only and it has been a long time ago.... Sorry, you feel that it was a minor point..... It is just hard to do the math with a lot of flex.

On these tractors it's pretty easy to just pull the rockers and torque the head ...the valves have to be adjusted any way.

I have tried to attach a picture of one style boxed end crows foot, I think.?

Ronald
Ranch Hand Supply

gunslinger101 · Dec 17, 2005

The full box end type crows foot and the line wrench type crows foot and the standard crows foot can be bought from Sears or snap-on, Mac tools and such.They are all called by the crows foot name reguardless of style.
If one takes in the account of the small change in torgue reading from using a crows foot( non extended) then take it a step more and count the change of using a extension, 2 inch , 3 inch, what ever,not to include a standard to deepwall socket(it does make a difference) and when all done you can qualify yourself as a high performance mechanic. TO bad the factory uses a multi head air impact driver that torques within 20% of spec. Makes all this trival effort to compensate torque senseless. Not to mention the average Joe doesn't even own a calibrated torque wrench. Sort of like peeing in a bucket with a hole in it Huh.I will leave that one for greater minds on here to figure out.
By the way blame the guy who named it a crows foot, since it doesn't look like a crows foot, but then again who knows, some back woods places might have 2 toed crows or round foot crows.

Ronald:
Thanks for posting the picture, atleast one other person knows what a crows foot is.

Merry Christmas

greg_g · Dec 17, 2005

( Description: **for attachment** Special crowfoot wrench design provides the strength necessary for removal/installation. 12-point, 7/8" wrench size. 1/2" drive. Nickel/chrome finish. have to be adjusted any way....I have tried to attach a picture of one style boxed end crows foot, I think.?)

Thank you Ronald. Answers without attitude always carry more weight with me. I've called that a box extension in the past, as opposed to a crow's foot extension or flared crows foot extension. It's obviously the best choice of the three for the head bolt. But once " crows foot " was tossed on the table, I wanted to make sure Joe didn't race out and buy the cheapie U-shaped version. Along with your clarification, maybe we both saved Joe from buying the wrong thing.

//greg//

JINMA224XR · Dec 18, 2005

Thanks to all, for the great help.

I was able to finish, the Retorque and Valve Lash adjustment on my 224 Saturday.

It was a great day to be in the garage, and working on the tractor. It was cold and raining outside all day. I turned the heaters and the radio(Blues Compliments of New Orleans) on, and got to it.

All went well, except for chasing down some washers and screws, that I dropped and trying to find them. I found all except one screw, that is somewhere. /forums/images/graemlins/smile.gif

I didn't have time to get the closed in Crow's Foot type offset for the torque wrench, but It sure would have come in handy. There were only 2 head bolts that needed that type of tool. I didn't have it, so I remove the Rocker Arm Assembly and did it that way.

The Rocker Arm Mounting bolts cracked loose at about 15ft lbs. My torque wrench isn't the best in the world and i didn't trust it too much at those values, so I handtightened the mounting bolts without the torque wrench.

On my Jinma 224, Y380T engine. I checked the headbolts up to 120 ft lbs, only #5 moved about 1/2 a hair, all the others stayed put. Adjusted the Intakes to 35mm and the Exhaust to 40mm.

Thanks again &
Have a Merry Christmas,
Joe /forums/images/graemlins/cool.gif

schmalts · Dec 18, 2005

For those who are doing a head bolt re-torque job, i would recommend loosening the head bolts one full turn and then retorque them. To just put a torque wrench on them and expect them to turn a bit is not going to happen much unless the joint has loosened up a lot. Reason is this, kind of hard to explain in detail and i wont try but.. When a bolt sits for a while the contact patch between the underside of the bolt head where it meets the actual head takes a kind of fretted set. you can also get a bit of this happen with the threads as well. Ever notice how some bolts SNAP loudly when you break them loose?
As an prototype engine builder by trade i do a lot of end of test engine inspections. One of the things the engineers ask for a lot is the "break away and return to mark"
value of head bolts. I mark a paint line across the bolt head to the head (or whatever part it is on) and using a digital torque meter measure the break away, when the bolt snaps loose, and then the return to paint mark value. In almost 95% af all cases the break away WILL BE HIGHER that the return to mark because of the set that the bolt takes. When a steel bolt is used in aluminum this is even more of a concern.
So please, if you are going to do the work of doing this head retorque consider loosening the bolt one full turn and then retorqing it. Just for giggles put a paint pen mark on the head bolts and you will find doing it the way i recommend will usually show that the bolt has in fact turned past the original position. If the factory lubes the bolt threads and underside of the bolt head when installing the bolt should be removed completely and relubed. Friction of a dry bolt will also give undesireable effects in many cases and a bolt sometimes is not close to its maximum clamp load if done dry when the factory value was with lube. These things i am describing is why many heads are no longer torqued to a spec, but instead are turned to a light torqe spec before friction really kicks in, and then are turned a certain amount of degrees to final setting.
Hope this helps

JINMA224XR · Dec 21, 2005

So please, if you are going to do the work of doing this head retorque consider loosening the bolt one full turn and then retorqing it. 

Hey schmalts,

Oh My!

The instructions, that I was going by, said not to loosen the headbolts.

So since I have allready just completed removing the Valve Cover, Rocker Arm Assembly and checking the Headbolt Torque at 120 ft lbs, Do I have to dissasemble everything and do it all over again?

Merry Christmas,
Joe /forums/images/graemlins/cool.gif

schmalts · Dec 21, 2005

Its your call. Doing a head gasket replacement isnt the toughest job in the world so maybe you might wait and see what happpens. If you do decide to do it again, put a paint pen mark on the bolt head and head and let us know the results of where the bolt ended up VS the way you did it. My guess is it will be different. Loosen the bolts and retorque one at a time before doing the next bolt so there is no worry of the gasket surface losing grip.
When i do mine i am going remove the bolt and lube the threads and underside of the bolt heads to get the best clamp load that the bolt can give. That is the proper way to do this maintnance. Be aware that the valve lash can close up a little too, so recheck the lash. Sorry to make you think about this but it really isnt a big job doing this, and the second time will go fast now that you know what to expect /forums/images/graemlins/grin.gif

camman12 · Dec 21, 2005

You may consider draining the coolant below the level of the head. Loosen all head bolts in reverse steps and sequence.
Then tighten them back with the proper bolt squence in three steps 49N.m +- 10 N.m , 88 N.m and finally to 130 N.m or 150 N.m or what ever torque is correct for your style head.
camman12

JINMA224XR · Dec 21, 2005

You may consider draining the coolant below the level of the head. 

Hey Cammann12,

What is the purpose of draining the coolant? What happens if you don't drain the coolant and tighten the headbolts?

Merry Christmas,
Joe /forums/images/graemlins/cool.gif

tat2z1969 · Dec 22, 2005

If you don't drain the coolant and just tighten the head bolts nothing happens, if you loosen the head bolts first like suggested on here and don't drain the coolant the coolant can migrate between the head and gasket or block and gasket or both, more problems.
Joe you did it right, don't let it get turned into a cluster *****

schmalts · Dec 22, 2005

You dont need to drain the coolant. if you loosen only one bolt and retighten it you will not get any gasket problems, nor will the coolant get past the gasket. Besides, at room temps there is no coolant pressure anyway besides the little that gravity poses. Usually the head needs to be pryed off the gasket surface even with all the bolts loose. Trust me, if you didnt loosen the bolts first, you pretty much did nothing. The fact that none of the bolts moved pretty much prooves it. Read any service manual of an engine that recommends this head torque and you will find they all instruct to loosen the bolt first to break the set up that makes the bolt stick. Bolts stick to the point that the torque required to break the set is sometimes higher than the torque spec of the head bolt itself. Therfore you can have a bolt that is actually below the torque setting but never moves because you didnt snap it out of its set.

JINMA224XR · Dec 23, 2005

Joe you did it right, 

Thanks Jim & Schmalts,

I had to leave for about 24 hours and when I got home late last night, I didn't make it to the bed and just fell assleep on the floor. /forums/images/graemlins/smile.gif I have been really concerned, about whether I did the procedure correctly. I mean trying to maintain a machine, that is not broken to begin with and then making a mistake that leads to damage can be really heartbreaking. But So Far So Good, Thank God and all you guys here on the Forums.

I want to thank all you guys that have helped me so much with my tractor maintenance.

This last project was really in a learning curve for this do it yourselfer. And using all of the advice and instructions given online, made the project go much easier.

For us Chinese Tractor Owners, we all have a common bond and that is our Chinese Tractors. Sure we have differing opinions sometimes and sometimes, we think that our way is much better. I think that it is a good thing for us to thrash these issues out in the open to see if the socalled, "Bucket Will Hold Water", so to speak.

This can be accomplished without becoming combative, so to speak. Skirmishes will happen from time to time, even though we are very good friends here. But we just have to agree to disagree and then go back to the Huddle and get ready for the next Play, to get us all to that socalled, "Goal Line", without bobbleing the ball.

It is Christmas Time and Time for Love and Peace among us here. Although, while you all are opening your presents, I will be out in the garage as usual. This time, taking out the Hydraulic Pump Screen and doing the cleaning procedure.

I think that I will go out today and try to find some Good High Rubber Content Gasket making material, for the fitting on the hydraulic reservoir.

Also everybody, please be extra careful on the highways, as there is a lot of wrecks and casualties, this time of year. I passed 2 on I-10 Wednesday night and they were pulling them out the windows.

Have a Safe Very Merry Christmas,
Joe /forums/images/graemlins/cool.gif

schmalts · Dec 24, 2005

If there is one thing to be said about these chinese tractors, it is you will learn to work on them a little because of the lack of maunals and a large dealer network. Most repairs are easier done by yourself than it is to load one up and haul it someplace to get fixed. Stop worrying, the head gasket retorque is suggested, not mandated /forums/images/graemlins/wink.gif

camman12 · Dec 24, 2005

Joe,
I am sorry if I created any unnecessary concern or stress. Sounds as if 99 times out of 100 not a problem to loosen and then retorque single head bolts.
You must have been (or should have been) a little league coach ! /forums/images/graemlins/laugh.gif
enuf said /forums/images/graemlins/grin.gif
camman12

JINMA224XR · Dec 24, 2005

I am sorry if I created any unnecessary concern or stress. Sounds as if 99 times out of 100 not a problem to loosen and then retorque single head bolts.
I have seen in automotive heads where coolant has found its way between the gasket and head from what appears to be from loosening and retightening head bolts one at a time. With no where for the liquid to go, it eventually found its way out between the cylinders. Heated liquid expands 600 times its original volume when it turns to a gas. 

Hey camman12,

I appreciate any and all helpful advice on my Jinma 224 tractor. I want to thank you Fellows for helping me with my little 224. And I mean that from the bottom of my heart.

I personally think, that it is a very good thing for us to express our experience, opinions and views on Tractor Maintenance in the attempt to help each other, with Our Chinese Tractors, and to help ensure that they will last as long as absolutely possible with as few mechanical problems as possible.

My first Chinese Tractor(1990, Shinniu/24hp/2 cylinder), developed a head gasket leak. The cause of which, I am not exactly sure. In replaceing the head gasket, I discovered that the Gaskets were of an old type design, which is not a hard type gasket, that we use here in America now( I understand that we did about 50 years ago). The extra Head Gasket that came in the parts box, appears to be a much better quality grade of HeadGasket and is a hard type Gasket, but going on the Suggested Maintenance Schedule and others suggesting that the headbolts, need to be checked at the 50 hour mark, I wanted to take every precaution possible to help prevent any problems with the head gasket. I have 131 hours on my little 224 now.

It appears that what I did in the headbolt tightening procedure, did not harm anything, at least, I sure hope not.

And I am sure glad that I checked the valve lash before taking off the rocker arm assembly though. As I had been told that the Valve lash specs in the operations manual were changed to a much higher value. Book says: Intake cold 20 to 25 mm, and exhaust cold 25 to 30mm. The new values that have been circulating is intake cold 35, and exhaust cold 40mm.

I am glad that the valves were in the general new setting range, as my little engine has been really running very well, Quiet(Very Little Knocking Noise),Very Little Smokeing, Cranks easily, revs smooth and fast and pulls good, so I don't have any complaints out of the little Y380T/20hp/3 cylinder engine.

When I checked the valve lash prior to dissasembly, the intakes were in the 35 range, but some were tighter and some were looser. And the Exhausts were in the 40mm range, with some being tighter and some being looser. /forums/images/graemlins/smile.gif

I plan on rechecking the valve lash in another 100 hours(Book recommends every 100 hours), to see how the settings have changeded, and to estimate how often that they really do need to be checked and/or adjusted.

Thanks Again & Tell Santa to Stop by my house tonight,
Merry Christmas,
Joe /forums/images/graemlins/cool.gif