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Basque1
03-30-2013, 12:08 PM
Hello folks:
Happy Easter to all,
I am having some 2nd thoughts on how my sidepipes are attached to the underframe of my car, it is a simple angle iron that bolts to the sidepipe and to the undercarriage. No rubber isolation to damper the vibration etc. While this have been working so far, I am concerned about the negative effect that torque might have on the pipes and the headers if there is no flexing. Any one has any ideas that include the rubber isolation which you might be willing to share? Pictures please.
Tks
Lou, II

GianM
03-30-2013, 12:28 PM
Hi Lou, good to hear from you again!

How did the roll bar wind deflector project go????

I'll take a few photos of my side pipe mounts when I get a chance and post them.

Basque1
03-30-2013, 01:52 PM
Hi Gian:
all is great, the wind deflector is looking great, I will install it soon, the cut out of the lexan is perfect . We have a place that you can take the template and they cut it to your specs.I have mine done in 1/2" smoke lexan. I just have to attache it .I had a blown header gasket and needed to replace it, to do that had to remove the side pipes. Now that they are off I would like to modify the rear hanger bracket to something more civilized.The weather is still cold so I am still wrapping some winter projects so that as soon as spring settles in it will be done. How is the weather down under?
Stay well
Lou
PS
Are you in Facebook? If so look up the New York State Cobra Club

Redmt
03-30-2013, 05:26 PM
The mounts on Ron's coupe are much the same. They were made out of old alternator brackets welded to the original pipe mounting points. They had kind of a funky shock absorber bushing mounted in between . Needless to say they were both broken. My fix is going to be to move the bracket on the car about 1/2 -3/4 " ahead and use a phenolic bushing with a hole the same size as the mounting bolt. I'll then make some new mounts with a slotted hole in them and bolt them together less than screaming tight. I haven't seen any better ideas,,, so far. I'd sure be interested though as my idea may not be that great either .

nomad
03-30-2013, 08:26 PM
This Topic reminds me of a funny story.

I have a dear friend that is a Marine Engineer with the Corporation that I work for. About 3 years ago he built a Factory Five Cobra.

It took him 1 year. He built the entire car by himself, INCLUDING a small block Ford Stroker, and the paint. He is very much a

detail kind of guy. He threw EVERY fastener that came with the Kit into the garbage can first off, and replaced everything

with Aircraft Grade bits.

A chap that Dobebob and I know, came over to see the finished Product a few months after it's completion.

I was there.................

My friend opens the doors of his Shop, removes the car cover, and there is this gleaming little monster!

The visitor (who owns a Factory Five) displayed no emotion whatsoever. He walked once around the car and asked "have you ever broken a

sidepipe bracket"?

That was it.

That was the sum total of his first encounter with this work of engineering and art.

I was aghast..................

My friend was speechless for a second.

Then he replied "no".

The visitor retorted "you will".

End of conversation.

After the visitor left, my friend said "can you believe that guy"???????

I said "no".

So here's the point of my little reenactment.

My friend then said " of course I've broken one, but I wasn't going to tell HIM that"!!!!!!!!

I just howled.

I was laughing so hard there were tears running down my leg.

I must apologize to our loyal readers, it was one of those "you had to be there moments", that I just had to share.

Basque1
03-31-2013, 03:43 AM
=))I had one of those. Has nothing to do with the bracket but here it goes. I was installing a pair of shorty headers on my Ford Bronco with a friend who is a retired Auto Tech teacher. After we disconnected the "Y" pipe I suggested to cover the pipes with rag, he said nah no problem nothing is going to go in there.Famous last words, he is tightening the last bolt on the header the socket slips off the ratchet and bingo in the "y" pipe hole goes ---perfect hoop! well to this day I have a nice rattling noise for we never disconnected the pipe off the cat to remove the darn socket. To this day I remind him to cover funky holes.=))
Like Nomad said you had to be there

Morris
03-31-2013, 07:45 AM
Basque1

Look at post #45 under KMP259 and you will see how we have a c-channel (blue dykem) facing down and a c-channel facing up with some springs holding them together......this allows movement in both directions up & down.....and we use a cup or half round piece of tubbing holding the exhaust pipe to the inner c-channel......

Morris.

Basque1
03-31-2013, 10:04 AM
Morris
I am having a bit difficulty visualizing this picture, the left side of the C channel is welded to the body correct and the other part to the sidepipe? that's clever, now you have springs on top and the bottom?
Lou

Basque1
03-31-2013, 10:19 AM
I also thought about using a polyurethane bushing between the pipe bracket and the angle bracket on the car to establish some cushioning.
Lou

Redmt
03-31-2013, 10:52 AM
I wasn't thinking of cushioning as much as a twist factor for the torque of the motor. I don't like the idea of hanging that much weight on the header flanges themselves or on the collector flanges. The whole design I don't believe was intended for long term use. Remember that these cars were designed for comparatively short life spans.

AC Bill
03-31-2013, 11:08 AM
There has been some issues with the FFR side pipes cracking, right near the tab that is welded on to them, for the side pipe brace to attach to. It seems the torque that you mention, was causing stress at this point, and eventually the pipe itself failed next to the bracket weld, as the metal is rather thin. You need to allow for some flexing.

To prevent this, some builders did not use any side supports whatsoever, finding that the 4 into 4 headers were strong enough to support the pipes. Some even tested the strength, by standing on the side pipes, and jumping up and down...
The other work-around, was to attach the side brace using only a standard exhaust pipe rubber hanger cushion, rather than mounting the brace firmly to the frame. Not sure how much support was gained by this, but it does allow for the needed flexibility, to prevent the cracking issue.
Another method was to use only one bolt only, on the side pipe tab, where it mounts to the side brace, using a ny-lock nut. The ny-lock was left slightly loose. This would allow a pivot point for the side pipe when the engine was torqued, which using two bolts would not. Now this tab and style of bracket, may be exclusive to the FFR system, so it may not apply to other replica makes, but the idea of how to do it, could perhaps still be incorporated.
Another thing that also was occurring to cause cracking issues was when the bracket was contacting the frame at all, during the engine torquing, it would restrict the needed movement of the pipes, thereby causing stress on them. You had to make sure there was enough clearance between the frame and the bracket to allow for full movement.
Some builders used solid engine mounts, which would not allow any movement from torque. This apparently prevented the stress issues on the pipes, but I question the stress using solid mounts, on the frame itself??

One builders support method.

http://www.ffcars.com/forums/attachments/factory-five-roadsters/33762d1340920430-fatigue-cracking-failure-side-pipe-mount-100_0981.jpg

Basque1
03-31-2013, 02:52 PM
There has been some issues with the FFR side pipes cracking, right near the tab that is welded on to them, for the side pipe brace to attach to. It seems the torque that you mention, was causing stress at this point, and eventually the pipe itself failed next to the bracket weld, as the metal is rather thin. You need to allow for some flexing.

To prevent this, some builders did not use any side supports whatsoever, finding that the 4 into 4 headers were strong enough to support the pipes. Some even tested the strength, by standing on the side pipes, and jumping up and down...
The other work-around, was to attach the side brace using only a standard exhaust pipe rubber hanger cushion, rather than mounting the brace firmly to the frame. Not sure how much support was gained by this, but it does allow for the needed flexibility, to prevent the cracking issue.
Another method was to use only one bolt only, on the side pipe tab, where it mounts to the side brace, using a ny-lock nut. The ny-lock was left slightly loose. This would allow a pivot point for the side pipe when the engine was torqued, which using two bolts would not. Now this tab and style of bracket, may be exclusive to the FFR system, so it may not apply to other replica makes, but the idea of how to do it, could perhaps still be incorporated.
Another thing that also was occurring to cause cracking issues was when the bracket was contacting the frame at all, during the engine torquing, it would restrict the needed movement of the pipes, thereby causing stress on them. You had to make sure there was enough clearance between the frame and the bracket to allow for full movement.
Some builders used solid engine mounts, which would not allow any movement from torque. This apparently prevented the stress issues on the pipes, but I question the stress using solid mounts, on the frame itself??

One builders support method.

http://www.ffcars.com/forums/attachments/factory-five-roadsters/33762d1340920430-fatigue-cracking-failure-side-pipe-mount-100_0981.jpg

Ac Bill:
Thanks for the detailed explanation that is pretty thorough and well thought out, I am glad that at the end you mention the one bolt issue, that is what I have now one bolt to the pipe tab. What I am going to do is put the neoprene bushing in between the bolt and the nut much as a space to take the torque of the engine. I will tell you this, my car is not gunned ever and it is never raced or dragged it is more s show and cruise car (my racing reckless days are over) 1 roll over with a TR-6 and stopping with a jersey bumper barrier @ 65mph sideways on a 67 Volvo GT is more than enough for me. I will keep you all posted of my results.
Happy Easter to all
Lou

Morris
04-01-2013, 11:47 AM
Basque1

Not sure if this will help out..... on KMP259 we had to compensate for any off track adventures.....and that usually happens when you are pushing the car.... so we built the rear exhaust hangers so they could flex in all directions and I'm proud to say they survived a few off track adventures..... and they worked as they should by flexing ....
Here's some photo's to explain a bit better what we did.... hope it helps out....

http://talk.cobraregistry.com/attachment.php?attachmentid=7767&d=1364844655

Here's a better photo of the bracket .... it will flex up and down and twist within the two c-channels in a rotational motion


http://talk.cobraregistry.com/attachment.php?attachmentid=7769&d=1364844663

Morris
04-01-2013, 11:51 AM
This is what we want in the end .... a half tube saddle to clamp the exhaust pipe or muffler to ....


http://talk.cobraregistry.com/attachment.php?attachmentid=7768&d=1364844657

And here are the Clamps we hold the muffler to the collector and then t-bolt clamps to hold the rear of the exhaust system up. yet be able to flex in anyway....

http://talk.cobraregistry.com/attachment.php?attachmentid=7772&d=1364844841

Morris
04-01-2013, 11:54 AM
Here we weld the Pclamp to the exhaust collector

http://talk.cobraregistry.com/attachment.php?attachmentid=7773&d=1364844842

And do the same thing to the muffler side of the Clamp, you can also see the muffler is all SS

http://talk.cobraregistry.com/attachment.php?attachmentid=7775&d=1364844846

Morris
04-01-2013, 11:58 AM
Just so you see the Coast Fabrication muffler is almost straight thru (on left).... where as the other muffler chokes the motor down significantly....

http://talk.cobraregistry.com/attachment.php?attachmentid=7771&d=1364844834

The Coast Fab mufflers are on the left.....

http://talk.cobraregistry.com/attachment.php?attachmentid=7774&d=1364844844

Morris
04-01-2013, 12:04 PM
This is what we want .....and exhaust system that is easy to remove and is strong enough to take the occasional off track adventure and also work with the motor as it torques up and down thru it's power curve....

With the exhaust banded to the saddle it's very strong and the strain is not on the pipe or weld on the pipe.... it's on the bracket and the bracket is twice as strong as a mufffler or exhaust pipe as it all made out of 4130 steel ....

Hope this helps others

http://talk.cobraregistry.com/attachment.php?attachmentid=7777&d=1364844974

James Stern
04-01-2013, 01:05 PM
Morris, You never cease to amaze me. The thought/engineering in your car is extraordinary.9::-

Jim

nomad
04-01-2013, 02:40 PM
Morris, You never cease to amaze me. The thought/engineering in your car is extraordinary.9::-

Jim

My thoughts exactly!

Morris
04-01-2013, 04:08 PM
==)I'm glad you guy's enjoy it......

Basque1
04-01-2013, 05:04 PM
Aha that' s much better tks
Lou
Basque1

Not sure if this will help out..... on KMP259 we had to compensate for any off track adventures.....and that usually happens when you are pushing the car.... so we built the rear exhaust hangers so they could flex in all directions and I'm proud to say they survived a few off track adventures..... and they worked as they should by flexing ....
Here's some photo's to explain a bit better what we did.... hope it helps out....

http://talk.cobraregistry.com/attachment.php?attachmentid=7767&d=1364844655

Here's a better photo of the bracket .... it will flex up and down and twist within the two c-channels in a rotational motion


http://talk.cobraregistry.com/attachment.php?attachmentid=7769&d=1364844663

AC Bill
04-02-2013, 09:19 AM
So Morris, those bolts are left with the extra shank exposed, to allow for up and down movement, and the side pipe just rests in a U cup, rather than actually being fastened to the brace?
First I have seen using that set up.. quite ingenious.

DobeBob
04-04-2013, 06:54 PM
My thoughts exactly!

I had a thought too.....but I forgot what it was.....oh well........