Radiator

[pspeaks]

I may be posting this in the wrong place, if so, sorry!  I've decided I would like more ground clearance for my radiator than my 1965 Mustang 6 cylinder radiator can give me.  Speedway has an aluminum cross-flow 22" radiator (917-348-22) but the distance between the frame rails is 19".  If I cut the area indicated by the X'ed area in the picture below, will it weaken the car too much; has anyone done this?  I also have a 15" Turbo-Swirl Fan (910-159-15) which by my measurements will just barely fit in the room I have.  Any advice before I do anymore cutting will be greatly appreciated.

Thanks,

Paul

[DiDueColpi]

I doubt that it would compromise any of the vehicles structure.
I think the only real function of that area is to provide support for the bumper.
So hack away but box it in just to be safe.
Cheers
Fred

[BlownMGB-V8]

Many people have made this cutout, just be aware that if you bump anything the radiator becomes a primary sacrificial element, sandwiched within a shear at each side, and it won't take much of a bump to destroy it. Plus, with that support gone the front end sheet metal will have to absorb any impact  that would normally be absorbed by that strut.

I would suggest that you extend the cut forward so that it gets rid of the shearing structure, and then add a stiffening beam outside of the existing box. 1/16" wall 2 x 2" square tubing works pretty well here, welded to the side wall of the existing box section and the ends can be tapered or boxed off as needed. If you must keep the shelf it would be a good idea to make sure that  you have a full width cross brace tied into the reinforcements. The closer it is to the radiator the more it will shroud it and the greater the risk of radiator damage, but much will depend on what you choose to do with the existing box structure.

Jim

[Moderator]

This article might give you some ideas for how to box it in, reinforce it, etc.:
http://www.britishracecar.com/JamesBowler-MG-MGBGTV8.htm

[burner1]

Many people build custom radiators to spec; width height, type of flow, drain, ports, cap location, etc. I ordered mine locally which was built through PRC.

[mgbreis]

I did exactly what you're thinking of doing Paul. Here's a couple pics. I reinforced the area with plate on the outside of the chassis rail, but I'm sure if there is ever a front end collision it will collapse. Speaking of strength, I've still had this car on a rotator where those chassis rails support the weight of the shell, and I didn't have any issues once this mod was finished.

[flitner]

Here is a couple of shots, one while in mock up and the next while upside down for undercoat, I made 2 plates per side and sandwiched 2" box tube as the support. Then a shot of the radiator in it, hope you can make it out.

[BlownMGB-V8]

I'm sure you've already seen the way the MG-Roadmaster was done right? That is undoubtedly the biggest radiator that has ever been put in an MGB and it fits in very nicely.

Jim

[pspeaks]

Thanks everybody, that helps a lot.  I ordered my new radiator yesterday and I'm feeling a little better so as soon as I get it and my headers I'm ready to get back to work on the GT.  Does anybody know the size and wall thickness of the radiator hoop used for the lower radiator mount on James Bowler's 69 GT race car? I ordered the same radiator and this is exactly what I plan to do.  Thanks again

Paul

[BlownMGB-V8]

Not sure, but on the Roadmaster we used 1/16" wall for the down tubes and 1/8" wall (1 x 2 rectangular) for the cross tube under the radiator. That is stiff enough to resist dings, but considering the box section is right at 1/32" thick it's best not to just connect 1/8" directly to it unless it is plated and gusseted. With a round tube .093" wall or even .087" would be fine and plenty strong enough, as well as being light weight. Then carefully plan your transition to the box section and you may be able to get away without the gussets and plates. The trick is to spread out the joint so that the combined cross section of the sheet metal it connects to is as much or more than a cross section of the tube itself. There's a little more to it than that but with that basic guide and a generous fudge factor you'll do fine. Some techniques are an angled mating line, passing through two or more planes of the thinner material, and going into a corner of the monocoque with the tube.

Jim

[pspeaks]

Thanks Jim, at the hot rod shop where we built T-Buckets, we also had an industrial and commercial real estate sign shop with a pile of different size and thickness scrap rectangular tubing that might be easier than round tubing and for me a lot less expensive.  Also while I'm thinking about it, I've never used an aluminum radiator before.  The Manufacture recommends a cap of 32 lbs or less, what would you guys with aluminum radiator experience recommend?

Paul

[rficalora]

I used rectangular tube on mine.  Hard to describe, but to make the bends I cut the inner section & sides and then rolled it over some pipe to make a nice curve.  Then closed it up.

[flitner]

I've got an 18 lb cap at the thermostat housing filler neck and a 28 lb on the radiator, before I had just the 28 lb cap on the smaller radiator and it never needed a catch can, and it would get up to 220* in traffic.

[pspeaks]

Thanks guys, I think I've got a handle on what I need to do now.  Friends like you are great!!

Paul

[ex-tyke]

The Manufacture recommends a cap of 32 lbs or less..

Wow!....that would show up system leaks in a hurry and that cap pressure would allow coolant temps of 300F before boiling.
 Personally, I would use the lowest possible pressure cap that puts less stress on the coolant system and still allows reasonable operating conditions (coolant temps kept below 210-220F, recovery bottle filling but not expelling coolant)......for our LBC's, somewhere in the 10-16lb range.

[pspeaks]

That was my concern too Graham, which is why I asked.  Mayby it was a misprint!

Paul