Monday, November 23, 2009

Radiator mounting planned

I was fortunate to get a couple of hours on Sunday with limited distraction, so I rolled under the bus between showers and I believe i have a plan for mounting the radiator under the bus. I ran out to Lowes, got a bunch of hardware, and started what I believe to be the final run on the brackets before installing this beast. Most of today's post will deal with that. I have no further news about Tom or Marianne. My wife will be traveling to visit with them in a few weeks, so she'll dig up what's really going on when she's there.

One of my lingering concerns about mounting a radidator under the bus is that it will be subjected to road debris abuse. Beyond just simple plastic bags, and gravel, there can be large obstacles in the road. I've seen mattresses, sheet rock, lumber, a ladder, etc, all in the last year on the Oregon highways. Add to that the ice and snow that we got last winter, where my Jetta was getting high-centered by the mid-road snow pack, and I think the concerns are justifiable. I have looked at many designs by different people, and they seem to fall into 2 categories: avoidance and strength.

The under-mount radiator designs that follow this pattern are purposely placed as flat as possible, and as close to the floor of the bus as possible. These achieve some degree of safety because the debris can't really get to them. The downside of this design is that the air can't get there naturally either so any cooling is done exclusively by fans. This puts considerable pressure on the system working correctly, leaving little margin for error for a failed fan. Some kind of fan monitoring should be used to indicate when the fans are on / off at the dashboard so the driver can know when the fan(s) has failed.

The under-mount radiator designs that follow this pattern are angled to catch the air, and have a cage of sorts around the radiator. This cage deflects debris from getting to the radiator, in theory. I would think that there is the possibility of high-centering or having the entire thing ripped off by passing debris, if the debris is something like a tree stump or some other non-movable object. These do have the benefit of naturally grabbing some air on its way by, so they can operate with some success if a fan(s) fails.

This is the pattern that I'm going to try. It is a take on the strength pattern, but allows for travel within the mounting so that the radiator mount can partially absorb, and partially avoid debris. This pattern should allow for natural air passage and the use of fans like the "strength" pattern, but with the ability to move up and down if a tree stump or other immovable object is traversed.

First, I made the bracket relatively simply - it is just a simple "c" wrapping each of the 4 mount points on the radiator. These "c" wrappers then tied into one of 3 brackets - one for the front and 1 for each of the 2 rear. The front is a basic square tube the should assist in the strength of the front bracket while partially obstructing the temperature sensor from direct contact by flying debris. I covered this in previous postings.

To these brackets, I have attached eye-hooks. These eye hooks will connect, through chain, to eye-hooks that are connected to the cross-members under the belly of the bus (the point at the cross-member will be re-enforced with some extra steel). This chain will add the flexibility to move. To prevent the radiator from bouncing up into the floor of the bus, I will add a rubber travel-stop (think snubber from the front end). I will be able to vary the depth of the angle of the front end by adding or removing chain links. I have selected chain and single-links that can handle up to 450 pounds. Anything less seemed too thin and anything more seemed excessive.

Across the front bracket, I will attach a larger round pipe (like a 16" stretch of fencepost). This will serve as a bumper that will absorb the initial contact with the immovable object and cause the front lip to bounce up - at least that's the theory. Behind the post, I'll put in a security screen style grid to prevent larger rocks from getting past and into the radiator area.

Last, surrounding the floating radiator, I will put a small cowling / shroud. This will help guide the air to the radiator and keep the rad-heated air from recirculating when at a dead stop. This shroud won't be more than a half-dozen inches tall. If it were much taller, it would prevent the movement that the chain is allowing. If I can figure out a clever way, I'll curve the shroud so it rounds off at the top. This would allow the shroud to be taller. Regardless, it needs to be removable so I can get to the chain for maintenance.

That's it for today. I was able to get started on the eye-hooks, but I ran out of bolt-nuts, and daylight. I need to stop at the hardward store for lock washers and nuts. I doubt I'll have much more time before Thanksgiving to work on Hapy. I may not get any time on him for another week, actually, so, I won't post until after the holiday. Happy Thanksgiving, and thanks for reading.

top - the rear brackets with the eye-hooks attached. The long eye-hooks will go into the thick cross member in front of the transaxle
bottom - the front bracket with the long eye-hooks attached. These will be connected via a chain to one of the shorter cross members (which will be re-enforced / backed with some steel at the mount point)


Tom Foolry said...

That's a sweet 'bus' you've got there! I keep hearing people talk about washers and lock washers, and I wasn't sure if there was a difference between them, or if they are the same thing. Can you help me with this?

PdxPaulie said...

a simple washer is just a flat ring. A lock washer is that same simple ring, but it has been cut and bent so the cut ends don't line up. When the nut is torqued down onto the washer, the ends align, and the force of that re-twist helps hold the nut on.

Anonymous said...

Hello. And Bye.