View Single Post
Old 04-12-2012, 01:13 PM   #9
Mr. Cob OP
Howling "Mad", Adventurer
Mr. Cob's Avatar
Joined: Aug 2001
Location: Granite Falls, Washington State, USA
Oddometer: 9,509
Howdy All,

After leaving from Organ Pipe Park, I drove to Uralista "cpres" home in Hespria California, Craig and Jennie hosted me when I did the circumnavigation of the USA the summer of 2008 on the Ural. Craig was kind enough to let me park my truck-trailer in his front yard for the time that I spent at his home, THANKS Craig.

When I arrived at Craig's home he was in the process of installing new push rods in his Retro, one of them had failed so we replaced all of them and did some detail work in the process. This is the push rod that failed.

On the older Ural's, built prior to 2010, the nuts used to secure the rocker arm supports -heads to the engine were not finished flat on the top or bottom. This rough edge would dig into the rocker arm supports causing metal displacement between the nut and the rocker arm support. The rough surface of the nut made it impossible to get accurate torque readings when tightening the nuts and in my opinion was a major cause of many cylinder head studs threads being pulled from the crankcase.

Starting in 2010 ALL the new engines came equipped with "flange nuts", these nuts can be bought from a Ural dealer and installed on ALL older engines, I highly recommend doing this. If you don't want to replace the old nuts you can do what I have helped Craig do to his engine as he wanted to RIDE and not wait for parts.

This what the surface of the old style nuts looks like, this rough surface is what prevents proper torque readings and is what galls when it is tightened against the rocker arm supports.

This is the damage done to the mating surface between the nut and the rocker arm supports.

This is a "THEORY" that I have, I have no official information to collaborate this, I think the nuts were made this way so that when they were tightened they kinda locked into position, remember the Ural was first built as a military vehicle, worked on in very nasty conditions by folks who had only minimal training to keep them going, I doubt that the field mechanic had a torque wrench in his tool box he would have been lucky to have a full set of tools that comes with the rig. Using the old style nut once it was tightened down the changes of it backing off were pretty slim, the trick was DON'T over tighten the nut.

As we didn't have the new flange nuts and we wanted to RIDE we did what I have done to my older Ural's years ago before I got the new style nuts, using common sense and regular tools we "re-machined" the old parts.

Step one, using a good sharp hand file, CAREFULLY dress the burrs from the surfaces of the rocker arm supports that have been gouged but the old nuts. You DON'T have to remove the deep gouge, just the burrs so that you have a FLAT mating surface. Here Craig is doing the file work.

This is what you want to end up with when your done filing, a FLAT surface, do this to both ends of both rocker arm supports on both sets of heads.

Step two, using the SIDE of the grinding wheel on a common electrically powered bench grinder, CAREFULLY dress the mating surface on one side of the nut to remove all the nasty bits ending up with a FLAT surface, like this.

Both of these steps must be done slowly and carefully, you don't have to remove a lot of metal and you must be extremely careful NOT to file or grind an angle onto the mating surfaces, TAKE YOUR TIME, its easy to do, just don't rush it. Once you have flat mating surfaces on the nuts and the rocker arm supports you need to make a trip to the local hardware store, when there pick up some proper size FLAT washers, these washers will be installed in-between the nuts and the rocker arm supports.

You don't need hardened washers, there really is no stress being put on these washers they are used only to provide a "full" contact FLAT mating surface between the nuts and the rocker arm supports. In this case we used hardened washers as the store didn't have any grade 5 regular washers of the proper size.

This shows the rocker arm support in place.

Here the washer has been installed.

This is what the assembly looks like after ALL the nuts have been torqued in the proper sequence to the proper reading, NEVER, NEVER, EVER, torque a Ural cylinder head nut to more then 36-38 pounds MAXIMUM. As you can see in this photo the threaded stud does not protrude past the top surface of the nut, when using hardened washers ( hardened washers are usually a bit thicker then regular grade 5 washers ) this is NORMAL and there is plenty of thread engagement between the nut and the stud to safely do its job.

This is a procedure that I would highly recommend everyone who has an older Ural doing the next time they set valves, rework the stock parts as we have done here, or better yet BUY the new flange nuts and have them on hand before you do your next valve adjustment. REMEMBER if you buy the new flange nuts you will still have to hand file a FLAT burr free surface on the rocker arm supports BEFORE installing the flange nuts.

All the head work done, Craig changes all the fluids in preparation for the afternoons ride.

I loaded the Boys into my sidecar, Jennie jumped into the hack of "her" rig and we had a short ride around the area, it was a good day of wrenching and riding. Stay tuned for "sidecar alignment 101".

Part of the agreement between myself and IMWA is that as I travel and attend Ural gatherings, I am on the lookout for things that aren't right on the rigs and when ever possible I'll do all I can to help the owner get his rig in to proper trim-tune or suggest what he needs to do in order to eliminate what ever problem they may be having. I also carry a good assortment of spare parts so in many cases I have the part on hand to fix something that isn't right. I don't work for Ural, I work with them, its the best job I have never had.
Dave, aka "Mr. Cob"

My photos, Join Smugmug, use this coupon ( )

Mr. Cob screwed with this post 04-12-2012 at 01:23 PM
Mr. Cob is offline   Reply With Quote