Rear Suspension Reinforcement Options

[Gint]

troublemaker...

Actually the lift rails are too narrow to allow a motor drop. I may find some way to modify it, dunno yet.

As for motivation, well, I guess I could use some. But that's not the *only* rust I have to repair. You need to come over and have a good look to fully understand.

[brant]

crap I nuked my response...

Mike,
I'd like to come see it
maybe next weekend..
worse case senario.. you could always pull the motor and then roll it onto the lift.. utilize the lift to get that chassis up and weld while standing on 2 feet instead of your back..

You'll do as good of a work as others.. just because of your attention to detail.

its doable..
I'd like to see it some time...

brant

[Jeroen]

Hey Ginter,

Musta missed your earlier posts on your rust issues
Have you got any pics to post?

Personally, I think the area between the rear susp.pickups and the firewall is the most complex of the 914. There are places where 4 or 5 different pieces of sheetmetal overlap

Did you also see the pic on the bottom of my "body" page.
You'll see there is a reinforcement on the inside of the frame-rails
If you just start cutting out sheetmetal there without good caution, you may do more damage than good (you might cut into the reinforcements).

I'd suggest you (carefully) grind away as much rust as you can
Use Ospo (or likewise product) to treat the surrounding surface and Por15 or what ever anything you can reach while you're in there
Clean the surrouding surface of the part you need to weld and spray on layer of zinc-primer (the weld-through kind)
Also do this with the backside of the sheetmetal patch before you weld it.
I'd suggest you weld a patch over the damaged area instead of in it.
May not be as clean, but if you nicely grind your welds after you're done it would be hard to notice.
If the covered area is a bit bigger, you could drill some holes in the sheetmetal patch so you can do some spotwelds closer to the center of the patch.

Just take some time to do it right.
Don't be too eager to fire up your weldingmachine.
Look, poke around, sit back, think and look again before you decide on anything definate...

Cheers,

Jeroen

[Brad Roberts]

I just get tired of seeing people install shit on their cars...and they dont really know why. I personally dont want anything on my car that doesnt help in some form or fashion...and if you can prove that it helps.. I'm all for it and will shut up. Ask my wife about the plates that hang on our walls here at the house.. LOSE THEM. I cant eat off of them... worthless.

My favorite write up is the stress analysis tests done by true to god stress testing engineers for General Dynamics. They tested the 914 control arm with and without that stiff kit installed (on the arm)..It took the guy almost 6 months to complete all the testing and metalurgy tests. In a nutshell.. he said that the side we weld the kit is not the week side. The side with the exposed pivot arm is what tweaked first in side load testing. They could not get it to twist without completely breaking. Again.. Porsche slapping a band-aid on a problem.

I wish I could find the test. I sold the guy a 914 that him and his son built.

B

[mskala]

Likin' this thread. Content is very good, too. I don't plan on having these problems (IMG:style_emoticons/default/smile.gif) but want to know what not to do and where to look every year under the belly. Right now I've got very minimal rust problems on the former jackposts which will be repaired by spring.
Mark S.
'70 914-6

[Gint]

Jeroen,

I didn't ever post about my rust issue. I had been talking to Brant on the phone Thursday night trying to describe my rusty area on the right long. I took the opportunity to use your pic to describe the area to him. I'll get some pics this weekend. Believe me, I'm in no rush to start melting metal on an original /6. It would probably be a different story if it were a rusty beater 4 cylinder car. I'm kinda afraid of that welder at the moment.

Did you mean this pic?
I saw it. I need to print it and take it out to the car with me to get a better orientation.

I'll start a new thread tomorrow with pics.

(IMG:http://www.berloth.nl/914/pics/r_long07.jpg)

[kdfoust]

...SNIP... My favorite write up is the stress analysis tests done by true to god stress testing engineers for General Dynamics. They tested the 914 control arm with and without that stiff kit installed (on the arm)..It took the guy almost 6 months to complete all the testing and metalurgy tests. In a nutshell.. he said that the side we weld the kit is not the week side. The side with the exposed pivot arm is what tweaked first in side load testing. They could not get it to twist without completely breaking.
...SNIP...
B

That's the kind of info I'm looking for! I had this gut feeling that the tailing arm reinforcement plates were a bogus 'improvement." Scratch that one off the list... (IMG:style_emoticons/default/tongue.gif)

Kevin

[Jeroen]

Hey Ginter,

"...I didn't ever post about my rust issue. I had been talking to Brant on the phone ..."
That's why I couldn't find it (IMG:style_emoticons/default/biggrin.gif)

"...Did you mean this pic?
I saw it. I need to print it and take it out to the car with me to get a better orientation..."

Yep, that's the pic I meant.
About the orientation: this is the inside of the passenger side frame rail
Your looking up from the firewall to the rear shocktower
The "donuts" on the left is where the outside pickups for the trailing arm are

Cheers,

Jeroen

[Bleyseng]

I have that pic too of my rust bucket, mine is worst off.
Geoff

[Van914]

Someone sent an email about the brace for the inner mount arm. Here is the body of the email telling how to do it. I have a picture I will try to find it and post later:

>>>>>>>>>>
The brace runs from the suspension swing-arm inner mounting point towards the center of the car. I clears the exhaust and runs below the corner of the engine sheetmetal. Thus to remove the engine the brace has to be removed, and it would not work to weld in a piece of tubing for this reason. Additionally the brace I have is threaded so that it can be put into place and tightened.

The repair is straighforward. I purchased a new suspension console from ? (Stoddard), and then had it welded in in the location of the torn one.

After it is welded in, you attach a means for the brace to mount. We used a piece of heavey stock (1/4 inch ?) with two holes drilled in it. Our piece was approximately 4 inches rectangle. One of the holes was the same size as the swingarm bolt, The other was the same size as the brace bolt. These mounting points pieces are then welded in with the swingarm bolt hold lined up, and the new piece pointing down to the ground.

On the firewall, A heavy U shapped tab is welded on, to provide a mounting point for the other end of the brace.

When completed this keeps the swingarm from flexing towards the center of the car, thus relieving the G-forces from the stock suspension console.

[Brad Roberts]

A lot of people used this setup. We figured out how to weld them in and keep them out of the way of the valve covers.

[seanery]

Hey guys, looking at the discussion about flex, will this device support the flex by triangulating the rear shock towers?

Thanks,
Sean Lee

[Jeroen]

Hey Sean,

IMHO that is complete overkill
I've cut the firewall between the rear shocktowers out or my car and I can tell you that is one sturdy piece
I think it's very unlikely that it's gonna flex THERE

What you could do is make braces that run from the rear shocktowers to the dogbone, right above the trannymounts

Cheers,

Jeroen

[seanery]

So, the problem is not the shock towers flexing it is the different flexing between where the frame ends and the shock towers?

(sorry if this sounds dumb, I just haven't seen one cracked)

thanks,
sean

[Jeroen]

hey sean,

take another look at the closeup pic of the rearshock tower on the previous page
You can still see where the firewall used to be
(or go have another look at your own car for comparison)

You'll see how poorly the end of the framerail is connected to the rear shock tower

Cheers,

Jeroen

[Brad Roberts]

Cool. A Indy Guy.

Sean. No 914 needs a rear brace. The shock towers have NO side load on them. If I could..I would brace the shock towers straight down from the top.. cant exactly do that soo... We brace the front of them and the back of them. The load is from the ground up (spring and shock)

I'll see if I can dig up pics of a cracked tub.. I'm normally repairing them fairly quickly (at the track)

B

[johnhora]

Hi,

Thought some might like to see why not to box trailing arms. The picture is my 914 that had a dance with another 914 on the track. Broke the 901 tranny left mount, shattered the inner and outer CVs, ripped the fender off, and bent the trailing arm. But because the arm bent and was not reinforced, the inner trailing arm mount had minor damage and the outer had none. I feel that by take the impact and bending the trailing arm was sacreficed and saved the body to trailing arm mounts. Can't find the picture of the armby itself.

As they say on FOX...I reported...you decide.


John

[Brad Roberts]

HOLY COW.

John I recognize your name, where do you normally race ?? I try and try to tell these guys that the tub is more important than stiff arms. Thanks for backing me up with real world experience. Now, my question is: will the car be ready for this season ?? Is it back together ??

Thanks for posting.


B

[johnhora]

Hi..

Yep...not a pretty sight...quick turn in for autox though.. (IMG:style_emoticons/default/biggrin.gif)

I race mainly in the Mid-West.

That happened about 2 years ago and I ran the car for a season just fine until in pre-season shake down I found lots of metal fatigue in the front pan at suspension points. The metal had just cracked. No rust problems...just flexing. Like taking a piece of metal and bending it back and forth and it will break. I was really shocked as to how it looked. Sorry now I did not take any pictures.

I decided to scrap that body since I had another one that was from AZ and very rust free.
That of course is another story about starting with a good body. When I first started racing I always wondered why so many people used such nice bodies to race. Now I know...start with only the best body for the track car. The street car can live with flex and bondo. And the extra weight.


John

[r_towle]

All,
I have been thinking about doing something like creating a triangle between the shock tower, the rear top of the firewall (where the seat belt bracket is) and the lower "frame" member.
Then another in front of the firewall to the rocker.

I have enclosed a drawing that looks like my kid did, but it is the best I could do right now.

The black is the existing car, the red is the new tubes I am thinking about...

In front of the firewall I have also considered a 6" inch high ladder truss going along the rocker to pick up the load from the tail.

Rich