Antique and Collectible guy needs help!

[jerry w]

Ok Guys,

I am looking at my lower radiator mount for an Antique and Collectible frame. According to the manuel, it should bolt to the inside of the front bumper mounts. When I set the lower radiator mount between the bumper mounts I have a 1/2 inch gap on each side. So there is a 1/2 insh space between the bumper mount and the radiator mount.

1. Do I flex the mount to fill the space?
2. fill the space with.....?
3. Did I get the wrong size or defective radiator mount?


Appreciate the time of all who answer.

Jerry

[PNJSNAK]

Jerry: Heh, I had the same issue, Joe said to flex it and it would be okay. So, I did and it is fine. I know some of the other A & C guys did not like the Radiator mount and made their own. Check out John Polings car, he made a bracket of his own design.
Jim

[jerry w]

Jim,

Thanks for the reply, I will look at John's pics and tinker around to figure something out.

[gman]

Jerry, I got the torch out and put some bends in the side pieces. Pics in my gallery. Gman

[Roscoe]

I used either aluminum or phenolic material to space it out. Don't remember which but it doesn't matter. Worked out fine.

Roscoe

[mj_duell]

I had the same problem. I also wanted my radiator to lean back as per the originals. I filled the side-to-side space with pieces of aluminum (same idea as Roscoe) and that seemed to work well.



--Mike

[jerry w]

Mike, Roscoe, Gman, Thanks for the reply! Confidence level back up to operating levels again.

Regards,

Jerry

[Roscoe]

Jerry,
I also made some support brackets for the sides of the radiator out of strips of aluminum stock. These were riveted to the sides of the radiator and then bolted to the 'v' pieces that the quickjacks bolt onto. Made for a sturdy mounting of the radiator. I also placed a piece of rubber on the bottom mount so that the radiator would not be sitting metal to metal.
Roscoe

[jerry w]

Roscoe,

really like that idea, I am going to scrounge up some aluminum tomorrow!

Jer

[John Poling]

Jerry,

GEEESH! It always takes me so long to reply. As Jim mentioned above, I designed my own radiator mount system. I too had the same issue you are having and do not believe you should flex anything to fit so that was my original reason for the rework. The other thing was that I wanted my radiator to be easily removable and utilizing the A&C design, it is not. What I did was to cut apart the original bottom piece they supplied and used only the side pieces welding these to the bumper frame extensions at about a 3 degree forward rake. Then I designed and fab'd a cradle to fit the bottom of my radiator that would extend from side to side to bolt directly to the welded in brackets from the A&C unit I also hand carved lower radiator rubber bushings for the insulators. Doing this allows for you to lift the car, remove 4 bolts on the cradle and two bolts on the top mount and lower the radiator module out the bottom. For the top mounts, I simply threw the parts supplied by A&C in my recycle bin and fab'd simple aluminum plates and had them welded to the front of the radiator tanks and the fab'd another set of "L" brackets that bolt into the horizontal lip in the radiator opening right in front of the radiator, the bracket welded to the radiator then bolts to the one that is attached to the lip in the grill opening area.

Also, keep in mind what you intend to use the car for. I leaned my radiator forward due to forces that could be put on the radiator causing the radiator to create a lift on the front of the car. If the radiator is slanted back, it will cause a lift on the front end at higher speeds, if the radiator is leaned forward it causes a downforce on the front. This theory is based on the direction that the radiator directs airflow. Like I stated above, mine is raked about 3 or so degrees forward and therefore airflow through the radiator will have little effect on high speed steering(Theoretically). Doing this also will help air flow through the radiator easier helping keep your cool, we all know that these things can be difficult to keep cool and every little thing can help.

In mounting my radiator the way I did, I had to do some mods to my radiator, like shortening the nipple for the lower radiator hose connection to clear my steering rack and also I removed the upper radiator cap and had it welded close since I wouldn't be able to access it with the radiator in the car. Also, due to my cradle design I had the drain cock installed in the side of the tank in place of the typical front or rear of the tank.

Any questions? Let me know.

John

[mj_duell]

Hi John,
I just got done reading your post and I must relate an opposite opinion on one piece of information. First let me say I am glad we can all come here and pass on our ideas and I will not claim myself an aerodynamics scholar, however........ After building two road racing corvettes, both with factory angled back radiators, it became apparent why this is a good idea compared to other angles. If you look at the intake designs of Ferrari, lotus, etc. you find that radiators are leaned backward to take advantage of aerodynamic curling. The same type of curling you find that causes lift on an airplane wing. This curling turns under when hitting the radiator making intake through the radiator less efficient. Leaning the radiator backward corrects this flow through the radiator and allows better cooling. The amount of forced air at high speed through the radiator is not enough to cause lift. Most is lost to the vacuum created at the back of the vehicle, which sucks air down the transmission tunnel; hence the Ferrari 355 belly pan with tunnel exists to the rear. Lastly, excess air that is not forced through the radiator is expelled over it (or under it in the case of a radiator leaned forward) like an airplane wing. Meaning, leaning a radiator forward may actually cause lift, leaning back may cause down force. My last argument is that if you were to attach a chin spoiler to your cobra which way would it lean to create down force? This of course is just my opinion. You have been a great help to me in the past. Thanks for the banter.



--Mike

[John Poling]

Mike,

I based my theory off of what I learned directly from an SAI representative that I met back in '98 in Auburn at the fall auction. He stated that at high speeds it was noted that the Cobra's were having problems with the front ends getting light and having a tendency of a floating feeling. He stated that what their research showed was that the radiator angle was causing a lifting effect on the front end. His words not mine.

Now as far as the other cars you mentioned, they benefit from far superior aerodynamics of the overall body than does the Cobra. I'm pretty sure the the typical Cobra has a bunch of "Dirty" air underneath the more modern cars dont have.

I by no means am defending my position as I don't know the correct answer as I also am not an aeronautics Engineer, just relaying what I was told by Don R. from SAI.

I can see your point though and believe it also has merit, keep in mind though that problems experienced by a "lifting" effect on the front end are only going to be experienced at extreme high speeds, not at speeds that the average responsible person that owns a Cobra attain. I'm thinking that the lifting effect probably doesn't start overcoming gravity until well into triple digit speeds.



John

[mj_duell]

Hi John,

Now as far as the other cars you mentioned, they benefit from far superior aerodynamics of the overall body than does the Cobra

Hmmmm.... Good point. Maybe I have been working with too many wind tunnel bodies. As round as the Cobra is, I guess it was not a modern day computer generated wind machine. Damn "Dirty" air! I am still wondering however, why it is that the backward angle (as per the original) would cause a lift effect. Remember these cars did run on some of Europes fastest courses and I believe Shelby would have tried to remove any high speed instability. However, that may not be the case and they just never found the problem. So does SAI leave the radiators rake (backward) the way it is on the "new" cars to match the original? It would be interesting to get one of our Cobras into a wind tunnel. Perhaps lift may occur from the front end design allowing air under the car. I was going to build a chin spoiler at one time and scrapped the idea. I may try to build one this winter for fun.

average responsible person that owns a Cobra

Does this mean I can't go WOT at Watkins Glen?

Thanks again John,



--Mike

[John Poling]

Originally posted by mj_duell





Does this mean I can't go WOT at Watkins Glen?

Thanks again John,



--Mike

No, what I meant by the "responsible person" thing was directed at the individuals who drive their cars on the road. Watkins Glen, although I've not been there, is a track and that is being a responsible person. As far as what Don R. from SAI was telling me, the problems appeared around the 140 mph area. Now I don't know about you but I don't think I'll be going that fast in an open top car any time soon.

What are the speeds you can see at WG?

To answer your question as t owhy the rearward leaning radiator would cause a "lifting" effect, again, the way it was explained to me, the air comes straight into the front and is directed by the tubes of the radiator. If the radiator is tilted rearward, the back of the radiator will be pointing towards the ground which directs the airflow through the radiator down towards the ground and the radiator to have an lifting effect. If the radiator is tilted forward, the front of the radiator is pointed to the ground which directs airflow up into the engine compartment and therefore causing a downforce on the radiator pushing the front end down


Again, this is just a theory and only a wind tunnel test could prove this true or false, but to me it does make sense.

John
John

[mj_duell]

Hey John,
Watkins should be good for about 140 on the long straight. Braking might get interesting. Don't know if I have the marbles to try such a stunt, but you never know. I haven't run the Cobra there yet, but took a pass in a 94 Vette at 138 mph. With no roof I believe it would be far to turbulant, but with the right set of tires and a good alignment I think an A&C would do well. I've seen 100 mph (For about five seconds) in the Cobra already, and it was not that bad. The car was actually very stable. I plan on getting over to the Glen with the Cobra next year. I have put a lot of money into safety equipment so I hope it will be allowed to run. I'll let you know.



--Mike

[John Poling]

Mike,

I've inched mine up to 105 about a month ago and could probably hit 125 or so with my current gearing. at 105, it wasn't too bad, but I still have a slight front end vibration that makes me a little uncomfortable. I am trying to track down someone who can turn my tires to true them up.

BTW, have we hijacked a thread here?

If so, I apologize, hopefully Jerry's question got answered for him. If not Jerry, please ask more questions.

John

[mj_duell]

Oh....sorry Jerry. We did get off topic.



--Mike

[jerry w]

Mike & John,

thanks to both of you for your time in responding. Yes, not onlydid you guys answer my question, but provided some very interesting reading not only for me, but a whole bunch of other guys. Check the thread data at how many people viewed this topic! Back out to the garage, I've got work to do!

Jer

[Roscoe]

John,
When you have the wheels balanced make sure they do it inside and out.
Roscoe

[John Poling]

Roscoe,

Yeah, that's the way they're done now and I'm sure they'll need to be rebalanced if they're cut. I still need to find someone who can cut them.

Thank you.

John