|
|
|
|
|
|
|
|
|
|
|
|
|||||
| Busted in BC | Short Cuts | ||||
|
|
|||||
By: George Reiswig - 7/2002
 |
| Amidst Mack dump trucks, semi tractors, and other big rigs, Grog the Mog looks small for a change. Cleanup in Bay #1! |
Unimogs are designed to be relatively easy to service in the field. Yet the manual has three ominous words at the beginning of nearly every section dealing with engine repairs and service: Lift the cab.
Grog 's cab is a four-door cab, which makes the prospect of tilting the cab forward on it's pivoting front mount even more daunting than a single cab would be... worse yet, we've made a number of changes that make it more difficult still. First, the two 45-gallon fuel tanks that Northwest Metal Products produced for us are mounted to the cab subframe, not the vehicle frame. There are also new wires and so forth that make the task more difficult.
Gee, if you could do it, the engine and everything would be right there, out in the open, ready to be worked on. Alas... it is not to be.
It would seem, also, that many of the things that the manual lists as requiring cab-tilting can be done, but only through serious contortions lubricated by swearing. Yesterday, I got virtually everything removed from the cylinder head: fuel lines, coolant lines and manifold, exhaust manifold. Then came the clincher.
 |
| One of two holes made in the body tub (just underneath the wiper, top of picture) to allow extraction of the pushrods without tilting the cab. |
| FISH STORY CAPTION: You shoulda SEEN the size of that mosquito that attacked our rig! |
The OM-352 is a pushrod engine. The pushrods are bloody long in this thing (apologies to any British readers for my inexcusable language). All but three lifted right out. The problem trio, however, interfered with the cab long before they could be pulled out of the head. It looked like I had finally run into a situation where tilting the cab could no longer be avoided.
What's that you say? If only the cab had holes in the right places? Exactly! Out came the drill bits, and two holes (one small, one large) later, the pushrods were coming out. I'll get a cork to plug it up later, I guess.
 |
| Ken Schultz patiently reassures me that this type of fracture in the cylinder head is not unheard of, and that engines often run for a long time without a problem despite such fissures. Nevertheless, we performed a pressure test to make certain that the coolant was not leaking out through hairline fractures. |
Today, we magnafluxed the head. More bad news, at first glance. Between each injector and the nearest exhaust port, and on some cylinders radiating a quarter of an inch away from the injector in other directions, tiny fractures glowed an evil green in the ultraviolet light. What to do?
The general consensus seems to be that these types of fractures are not that uncommon, and that the head would probably be just fine if we bolted it back up. A vacuum test revealed that the valves were not seating well at all, so that work would have to be done. When we pulled out the valves, we magnafluxed again to see if the fractures continued below the level of the bottom of the valve seats. They did not. Well, that's one piece of good news.
Ken Schultz even says that he has seen some manufacturers cause a fracture in a known high-stress area like this, since they know that it will likely happen anyway and they want it to happen in a controlled way. I would feel better if the fractures hadn't appeared, but the prospect of spending several extra days and spending a thousand dollars or so to get another head shipped to us makes the decision (to hope for the best with what we have) a bit easier.
| Related Links |
|
North by Northwest Expedition: - Introduction - Sponsor List - Reviews - Photo Galleries Before Departure Shakedown Cruise Lower British Columbia More Lower British Columbia Busted in BC BC with Coast Mountain Crawlers Upper British Columbia Almost Alaska |
| Please support 4x4Wire by visiting our featured sponsors | ||||||
|
||||||
|
| 4X4Wire Portal | About 4x4Wire | Search 4x4Wire | TrailTalk Forums | Advertiser's Guide | |
