Evening. In the process of building a 28 RPU with no hood or fenders and cannot decide on whether to run the upper radiator to firewall bars. I see a lot of rods without them but wonder the best way to support the radiator if I don't. Thank you in advance for any ideas!
I supported mine even with hood most of the time. There are a lot of people on here that have issues with this. Do a search
The upper support bars are absolutely necessary with stock lower rad mounts...as in it's not designed to self support without the upper support bars So I would think you have to fab rigid upright supports or a frame from the base of the rad and that's doable but obviously you would want it streamlined and not in your face. Personally I think that is part of what makes a Hotrod a Hotrod...its kinda cool to see them...but of course that's me...but one bit of advice If you run upper support rods...try to keep them straight with No bends as bends weaken the triangulation and allow the shell to shake side to side.
The radiator hoses will probably hold the radiator. If not, the fan should keep it from leaning back too far.
Without rods it will eventually suffer from fatigue and break. Mighty as well be flapping in the breeze at speed and be bouncing around whilst being driven without being being supported at the top.
One other option is to attach the radiator support bars to the front of the engine. There's still some vibration (and eventually fatigue failure), but it has been done successfully. Here's Bobby Hilton's channeled coupe for example:
I once saw a set up where 5/16 heim ends were used on the ends of the support rods and wonder if that was enough to absorb some of the vibration. A while back there was a thread posted about the firewall mounts tearing off due to it being too rigid.
No radiator rods and your asking for trouble, mounting the radiator correctly you will need the rubber pads along with the springs to allow the radiator to flex to prevent stress cracking or breaking the mounting tabs. HRP
Good choice really. In the traditional vain that end of the mechanical structure really was largely left alone...No speed advantages to ditching them and as said that standing brick gets a lot of pressure from the frontal air assault... Now in the wild sixties show type Rods perhaps that might have been determined to be an encumbrance on the eyes looking at all that gleaming engine and firewall... And nowadays billoty street rods might deem them a nuisance...but in the envelope of 1965 and older that is no concern of ours...
How close is your fan from the radiator? I would thing that enough wind resistance at 70 mph would push the radiator back a bit. With out the rods I think you're asking for trouble.
You really want something to keep your radiator from flopping forward and aft. Some guys run without the factory style supports but run a little bit of a brace diagonally from the rad to the chassis.
Much as I really admire Bobby Hiltons work I really do not think that those radiator supports going direct to the block are his best idea ,unless the engine is solid mounted. The power he and Ross build into these vintage engine will surely be rock n rolling.