Pat 12 gets a nose job

[Phil Waterman]

Hi Bob

Got a kick out of your two steps forward one back, on a good day it is three steps forward and only one back.

Well this morning - Another Lesson Remembered- when things don't seem to fit call it a day go have a cool one and start over again in the morning. Which fortunately is what I did yesterday when the inner fender panels didn't want to fit.

When I started fresh this morning they fitted with only having to remove one part. Which was much better than what I thought would have to be done yesterday.

As to how do I manage to assemble these trucks working alone, you know how the Pat 11&12 are some times referred to as Monkey Faced. Like every one I assumed this reference was to the appearance, wrong it is a reference to who assembled the trucks I am now convinced that they were assembled by monkeys with extremely long arms who could also hold wrenches with their feet. Though I've not taken my shoes off to hold a wrench but come close. Actually a really fast impact wrench will often let you push a bolt through a hole then instal the washer lock washer and nut, if you put the impact socket on the nut you can spin the nut tight before the bolt has a chance to turn allowing one sided tightening.

Well the truck is nearly all reassembled which is good because we have some real hot weather forecast for next week 30C or 86F which will give me a chance to see if after all this work I've actually cured the over heating problem.

Ian yes you are in for a lot of fun and just as Bob says lots and lots of pictures. Don't know how many times I've gone back to the pictures I or other people have taken of their trucks to get a part positioned correctly.

One other thing Ian if you whether or not you plan to reuse the bolts have lots of small containers which you can label right front fender etc and throw all the bolts into the correct bucket. Will help in figuring out what bolts and what size and length to get as well. I buy all grade 8 bolts in 50-100 count bulk from an industrial supplier much cheaper than the hardware store or auto-parts store.

Cheers Phil

Cheers Phil

[Ian Johns]

Thanks guys

[Phil Waterman]

Hi All

Well the nose job and engine swap worked, the truck can now breath and it doesn't seem to overheat. Took the truck for an extended drive today ambient air temp 29C or 84F and the truck never got much over 190F which is a far cry from boiling into the recovery tank which it did before.

Also now that the clutch completely disengages the truck shifts like a dream. The clutch problem was caused by a clutch disk that actually was sticky to the touch.

Cheers Phil

[Bob Carriere]

Hi Phil

Any idea how the sticky stuff came from??

Leak somewhere.....?

What temp setting are you using for the thermostat...... we are using the GM 1959 manual recommended 160 on ours and fear it may be too cold.

We are about ready to fire up Grant's rebuilt 261 in the next few days.

Bob C

[Phil Waterman]

Hi Bob

Not sure of the source of the sticky stuff, this is the second time that I have run in to it. Both times it has developed on clutches that had worked fine but were out of the truck for some reason then when reassembled the clutches did release correctly and sometimes I would have to start the engine with the truck in gear, brake on and clutch peddle pushed all the way in. Only cure seemed to be to pull the clutch out again and replace or really clean it.

Only thing I can suspect is that I had degreased or cleaned the clutch plate while it was out but not gotten it really clean. Then the first time the plate was warmed up the oil or grease came to the surface. But what confuses me is that when I overhauled the HUP I had this problem when I reassembled. Had to pulled the clutch again, really cleaned it, flywheel and pressure plate. Second time cleaned it I know I used brake cleaner and then a water based degrease and rinsed the whole thing with very hot water 160F and it worked fine since then.

Now as to the thermostat what I wanted was a 140F but they are no longer available so went with a 160F drilled a 1/8th hole in the thermostat to be sure that there would be flow to get the hot water up into the thermostat housing. Without a heater connected to the thermostat housing and the water pump as on all current cars there can be a real lag in getting the thermostat to open. On my 261 I actually put a small bypass tube to be sure of flow.

As to worrying about not getting the engine warm enough don't think it will be a problem. The dog house is tight enough that my 261 with no manifold heat riser starts and runs fine even below "0"F do put the radiator muff on to drive in real cold weather but that is more for the driver.

My IR gun readings of the oil pan tell me that drives of hour even in cold weather the oil is getting up to 180F. The remote oil filters on 261 do not get that warm though. Suppose in arctic conditions there might be a problem with water collecting and freezing in the oil filters.

Cheers Phil

[Phil Waterman]

Hi All

My Pat 12 was missing the left inner panel that gives access to generator from under the left front fender and I need some photographs so I can fabricate a new one.

W Pat 12 Nose Change Details 032.jpg

The truck is running great and the engine overheating problem seems to be solved. Now I'm working on the Driver Over Heating problem and trying to understand the cooling of the engine compartment. We have all seen pictures of Pat 11s & 12s operating in the desert without hood or upper side panels, but I'm coming to believe that this may actually make cab over heating worse not better. My logic for this is that with out all the panels in place the air from the fan is allowed to escape without blowing past the engine in the dog house and pushing the heat out and back under the cab.

Here are some photos of the Cab all repainted.

W Pat 12 Nose Change Details 025.jpg W Pat 12 Nose Change Details 026.jpg W Pat 12 Nose Change Details 033.jpg

W Pat 12 Nose Change Details 034.jpg

I spent an afternoon driving the truck around the back roads of town with the air temp in the mid 80sF/30C and the engine did NOT overheat either driving up long grades in 3rd gear or running along flat ground in 4th. I have fabricated new door hooks so that I can drive with the doors open to scoop air into the cab which helps with the driver over heating.

Hope somebody has a photo of the inner panel in their collection. I've searched through all the photos that Bob sent me a couple years ago and have not found a picture yet.

Cheers Phil

[Grant Bowker]

If I understand the problem correctly and the hole above the tyre in the first photo is filled by the panel you need to find/make, Bob does have the panel to be able to photograph and measure it. His best panel is already in the truck so not all sides are easily seen/photgraphed but the second or third best should supply views that can't be gotten of the best panel. As always on cab 11/12 it is a wrestle to get the panel in place. If you are fabricating a new one, you can put the holes in place to match your arch bar and fasteners so it should all fit "perfectly". You may also end up loosening or removing the headlight support bracket for installation clearance.