My sub frame connector install *56k warning*

[JamesD]

I finished the install of my sub frame connectors on my 69 Camaro. While I installed them I also put in some new sub frame bushings. Both came from Detroit Speed & Engineering. Installing these SFC's is a lot more involved then your standard SFC install on a late model Camaro. The way these are design they are virtually invisible when looking at the side of the car, unlike bolt in ones which hang about 5 inches from the bottom of the car, these follow the contour of the floor pan allowing them to be very low profile. Here’s the write up:

The first item I installed was the sub frame bushings. As some of you may know the first and second generation f-body’s came with a removable front sub frame. The car was a sort of hybrid uni-body. The front sub frame is held in with four body mounts and two that attach to the radiator core support. Here’s the kit from DS&E.


The bushing in the center is for the radiator core support the other two are the body mounts. The new ones are made of aluminum and are hard coated. They came with stainless steel washers.

Here’s a side by side with the old poly bushings.


I never drove the car with the original rubber sub frame bushings, so I can't really tell you how the new ones compare. I was hesitant to switch to solid aluminum bushings fearing that solid bushing would destroy the ride quality, but it did not change at all from the poly bushings. The main reason I went to aluminum bushings is that when you add weld in SFC's there can not be any flexing in the front sub frame, the flex caused by rubber bushings would put stress on the welds connecting the SFC to the sub frame and likely cause the weld to fail over time.

To install them I loosened all the bolts on one side of the sub frame, and then used a pry bar to help lower the sub frame a little bit, I then repeated the same procedure on the other side. The four body bolts were torqued to 80 ft/lbs the fronts to 35. This is the rear bushings installed.


You’ll probably notice I don't have grade eight bolts for these. I needed longer bolts for the new bushings and Home Depot did not have the size I needed (3/4" x 3 3/4") in grade eight. I'll replace them with better one as soon as I can find them.

For the fronts I was able to find the proper bolts, here they are installed.


Before I started the SFC install I made sure that the front sub frame was aligned properly with the rear. This is critical, because as you can probably guess if the front sub frame is out of alignment it will be locked in place when you weld in the SFC's. The GM service manual I have outlines the whole procedure. Basically there are some alignment holes on the front sub frame and on the rear frame rails (which can be seen later on in some picture). With the car level you string a plum bob from the center of these holes and measure diagonally. The two measurements were off by less than a 1/16", which corresponds to what the alignment guy told me when it was aligned.

After disconnecting the battery, ignition system, and fuel/brake lines I started tearing apart the interior. First to go was the front seats, they are held in with four 1/2" bolts each.


Then the rear seat, the bottom comes out by forcing your knee up against the front part of it to unhook from the floor. The seat back comes out by simply pulling it up.


Next out is the rear carpet section; this comes out by loosening the sill plates and a bolt at the end of the center console, which is hidden under the ash tray.


The old asphalt sound deadening is the next thing to come out.


This is why people in the north hate us southerners. 36 years old and the floor boards are solid as a rock.


In my haste to install the connectors I forgot to take a picture of them before I began the install. Here’s a photo from another site

(Photo credit to Scott over at lateral-g.net)

These types of connectors are installed by cutting a slot into the floor pan through which the connector is slid, this is how the connectors are able to maintain such high ground clearance. Templates for all the cuts are provided by DS&E.


The template is placed on the underside of the car. Using magnets to help hold up the template is a big help. The template it located using the rear edge of the front sub frame and the pinch weld by the rocker panel.


I used dykem blue and a scribe to transfer the lines onto the sheet metal


Next a section of the seat riser must be cut to gain access to one of the joints that needs welding, again a template is provided and is located using two of the seat bolts.


Here the seat riser has been cut and the floor pan has been partially cut. There are also two spot welds that need to be drilled out.


All the cuts have been made. The exact same procedure is repeated on the other side with the same template.


Now every install is not complete with out an unforeseen obstacle. Mine came in the form of a crushed rear frame rail. This is most likely due to improper jacking technique by a previous owner.


This is an issue because the rear part of the sub frame connector welds to this part of the rear frame rail. With the SFC dry fitted it was clear that the part of the rail that would normally meet with the back edge of the SFC was way below the edge of it. The gap, which should normally be about 1/16", was about 1/2". This is the main part were the SFC attaches to the rear frame rail, and I wasn't about to try to fill in that gap with globs of weld. My first idea was to use an auto body stud welder. This however did not work, the rear frame rail is about 1/8" thick and the slide hammer simply slipped on the stud. I tried heating the metal and then pulling on it but the slide hammer still slipped on the stud

The only way the indentation could be removed would be by hitting it from the opposite side. I saw that the spot I needed to hit was just on the other side of some sheet metal on the inside. An access panel was made


I discovered that after my initial cut there was another piece of sheet metal between me and the frame. I used a pneumatic body saw to cut the inner piece of sheet metal. This allowed me to fit a 1/2" extension through the cut and pop the indentation out.


Here you can see that the fit it much better then before.



Now that that problem has been solved we can move on to preparing the SFC's. First they have to be dry fit and cut to length. I cut them so that there was about 1/2" in-between the edge of the connector and front sub frame.


Next an end cap in welded on to seal the end.


After that the connector is put back on the car and the side brackets are place up against the side of the connector, when welded these connect the front sub frame to the SFC. The design of the SFC does not allow you to weld around the full perimeter of the bracket, the floor pan gets in the way. So you have to tack the bracket in place and then remove them from the car. Now you can weld all the way around


Plug welds are also done on each side


Here are the finished connectors ready to be put back on the car


After they are in place you tack them on along the front and rear frame rails



To keep distortion to a minimum when welding along the length of the SFC, I welded an inch them moved to the other side of the car, then back to the other side and so forth.


I welded along the under side of the connector too, using the same technique as described above



The access panel is welded back in place and ground smooth.


The flap I cut to get to the back of the rear frame rail was also welded back up.

I then hit the entire area with a coat of epoxy chassis paint






The last thing to do is reinstall the drain plugs with some seam sealer and put the interior back together.
I took it out the other day to see what it felt like with all the new stuff. As I said before there was no noticeable increase in noise or vibration. The car really didn’t feel any different with the SFC installed, although I was on the street and I did not push it at all. I guess I will be able to see the difference one I hit the track.

[CAMAROBOY69]

Now THAT is the most informative, specific and detailed write up I have seen in a long time. Any question I ever had about the DSE subframe connectors or the aluminum body mounts has been answered. Very Very impressive!!!! I cant wait to eventually get mine.
I had concerns that they might interfere with my 4th gen seats but after reading this I know I will be fine.

[Flyboy]

Holy cow! I'm with Adam! That write-up is nothing short of perfect! I've got my DSE SFC's sitting in a box in the garage right now waiting to go on the car. You can bet i'll be using your write-up along with DSE's instructions when it comes time to put them in!

[Todds69]

That is one beautiful write up man. Very nice and informative with detailed instructions and the very important photos... You need a new line of work and I think you found it. Tech Advisor

[BA.]

<<sniff, sniff>> it's beautiful man!! <<sniff, sniff>> Awesome write-up. Right, clicky, save!

[qwik1320]

Great job, you answered some of the questions I had! I can't wait to start cutting and welding mine in the 67.

[zbugger]

So good it's worth a sticky. If we had gold stars, you'd get one. Thanks!!!

[jamesg602]

One word "AWESOME," it is people such as yourself which make this pro touring site the best on the web. Great detail and professional job keep up the good work, and hopefully you will benefit from others as well as the rest of us just benefitted from you.

[zman1969]

nice article wish i saw this before i did mine !

[z06fromhell]

great info. first post ive read here. if this is the kind of info to come, thanks to all.....

[RJW]

[what kind of motor do you have all stock ?=JamesD]I finished the install of my sub frame connectors on my 69 Camaro. While I installed them I also put in some new sub frame bushings. Both came from Detroit Speed & Engineering. Installing these SFC's is a lot more involved then your standard SFC install on a late model Camaro. The way these are design they are virtually invisible when looking at the side of the car, unlike bolt in ones which hang about 5 inches from the bottom of the car, these follow the contour of the floor pan allowing them to be very low profile. Here’s the write up:

The first item I installed was the sub frame bushings. As some of you may know the first and second generation f-body’s came with a removable front sub frame. The car was a sort of hybrid uni-body. The front sub frame is held in with four body mounts and two that attach to the radiator core support. Here’s the kit from DS&E.


The bushing in the center is for the radiator core support the other two are the body mounts. The new ones are made of aluminum and are hard coated. They came with stainless steel washers.

Here’s a side by side with the old poly bushings.


I never drove the car with the original rubber sub frame bushings, so I can't really tell you how the new ones compare. I was hesitant to switch to solid aluminum bushings fearing that solid bushing would destroy the ride quality, but it did not change at all from the poly bushings. The main reason I went to aluminum bushings is that when you add weld in SFC's there can not be any flexing in the front sub frame, the flex caused by rubber bushings would put stress on the welds connecting the SFC to the sub frame and likely cause the weld to fail over time.

To install them I loosened all the bolts on one side of the sub frame, and then used a pry bar to help lower the sub frame a little bit, I then repeated the same procedure on the other side. The four body bolts were torqued to 80 ft/lbs the fronts to 35. This is the rear bushings installed.


You’ll probably notice I don't have grade eight bolts for these. I needed longer bolts for the new bushings and Home Depot did not have the size I needed (3/4" x 3 3/4") in grade eight. I'll replace them with better one as soon as I can find them.

For the fronts I was able to find the proper bolts, here they are installed.


Before I started the SFC install I made sure that the front sub frame was aligned properly with the rear. This is critical, because as you can probably guess if the front sub frame is out of alignment it will be locked in place when you weld in the SFC's. The GM service manual I have outlines the whole procedure. Basically there are some alignment holes on the front sub frame and on the rear frame rails (which can be seen later on in some picture). With the car level you string a plum bob from the center of these holes and measure diagonally. The two measurements were off by less than a 1/16", which corresponds to what the alignment guy told me when it was aligned.

After disconnecting the battery, ignition system, and fuel/brake lines I started tearing apart the interior. First to go was the front seats, they are held in with four 1/2" bolts each.


Then the rear seat, the bottom comes out by forcing your knee up against the front part of it to unhook from the floor. The seat back comes out by simply pulling it up.


Next out is the rear carpet section; this comes out by loosening the sill plates and a bolt at the end of the center console, which is hidden under the ash tray.


The old asphalt sound deadening is the next thing to come out.


This is why people in the north hate us southerners. 36 years old and the floor boards are solid as a rock.


In my haste to install the connectors I forgot to take a picture of them before I began the install. Here’s a photo from another site

(Photo credit to Scott over at lateral-g.net)

These types of connectors are installed by cutting a slot into the floor pan through which the connector is slid, this is how the connectors are able to maintain such high ground clearance. Templates for all the cuts are provided by DS&E.


The template is placed on the underside of the car. Using magnets to help hold up the template is a big help. The template it located using the rear edge of the front sub frame and the pinch weld by the rocker panel.


I used dykem blue and a scribe to transfer the lines onto the sheet metal


Next a section of the seat riser must be cut to gain access to one of the joints that needs welding, again a template is provided and is located using two of the seat bolts.


Here the seat riser has been cut and the floor pan has been partially cut. There are also two spot welds that need to be drilled out.


All the cuts have been made. The exact same procedure is repeated on the other side with the same template.


Now every install is not complete with out an unforeseen obstacle. Mine came in the form of a crushed rear frame rail. This is most likely due to improper jacking technique by a previous owner.


This is an issue because the rear part of the sub frame connector welds to this part of the rear frame rail. With the SFC dry fitted it was clear that the part of the rail that would normally meet with the back edge of the SFC was way below the edge of it. The gap, which should normally be about 1/16", was about 1/2". This is the main part were the SFC attaches to the rear frame rail, and I wasn't about to try to fill in that gap with globs of weld. My first idea was to use an auto body stud welder. This however did not work, the rear frame rail is about 1/8" thick and the slide hammer simply slipped on the stud. I tried heating the metal and then pulling on it but the slide hammer still slipped on the stud

The only way the indentation could be removed would be by hitting it from the opposite side. I saw that the spot I needed to hit was just on the other side of some sheet metal on the inside. An access panel was made


I discovered that after my initial cut there was another piece of sheet metal between me and the frame. I used a pneumatic body saw to cut the inner piece of sheet metal. This allowed me to fit a 1/2" extension through the cut and pop the indentation out.


Here you can see that the fit it much better then before.



Now that that problem has been solved we can move on to preparing the SFC's. First they have to be dry fit and cut to length. I cut them so that there was about 1/2" in-between the edge of the connector and front sub frame.


Next an end cap in welded on to seal the end.


After that the connector is put back on the car and the side brackets are place up against the side of the connector, when welded these connect the front sub frame to the SFC. The design of the SFC does not allow you to weld around the full perimeter of the bracket, the floor pan gets in the way. So you have to tack the bracket in place and then remove them from the car. Now you can weld all the way around


Plug welds are also done on each side


Here are the finished connectors ready to be put back on the car


After they are in place you tack them on along the front and rear frame rails



To keep distortion to a minimum when welding along the length of the SFC, I welded an inch them moved to the other side of the car, then back to the other side and so forth.


I welded along the under side of the connector too, using the same technique as described above



The access panel is welded back in place and ground smooth.


The flap I cut to get to the back of the rear frame rail was also welded back up.

I then hit the entire area with a coat of epoxy chassis paint




The last thing to do is reinstall the drain plugs with some seam sealer and put the interior back together.
I took it out the other day to see what it felt like with all the new stuff. As I said before there was no noticeable increase in noise or vibration. The car really didn’t feel any different with the SFC installed, although I was on the street and I did not push it at all. I guess I will be able to see the difference one I hit the track.[/QUOTE]

[cad]

Nice write up...not sure if anyone knows about Global West's frame connectors. They are tubular, powder-coated, and only require welding to the kickups on the rear frame rails, just inside the front leaf spring perches. They can easliy be welded to the subframe.
NO CUTTING.
I have them on mine.
Here is the installation article.
http://chevyhiperformance.com/howto/68238/

[CAMAROBOY69]

The nice advantage of the DSE SFC over the Global west SFC is that you can also weld it right to your floor adding even more strength to the body since it connects the front frame, rear frame, and the body all into 1.

[Bowtie racing]

Thank you JamasD for an excellent topic!!!!!!!!!! There was few red x`s?? Am i missing some pics?

[Ackattack]

I'm assuming once you weld these to the front sub frames, you're not taking off the front subframe, and I correct?

[JamesD]

I'm assuming once you weld these to the front sub frames, you're not taking off the front subframe, and I correct?

That is correct. When I first installed them I was considering making bolt on brackets like what was done on the mule, but then I thought about how many times I would need to drop the subframe. I don't intend on going to an aftermarket subframe, and the underside sheet metal is in perfect condition. This decision did force me to go to aluminum subframe mounts earlier then I had planned, because you can not change them once the subframe is welded on, but as I said in the write up you need to move to solid mounts anyways.

Thank you JamasD for an excellent topic!!!!!!!!!! There was few red x`s?? Am i missing some pics?

Thanks, you might try refreshing your browser and see if the pics come back.

[Steve1968LS2]

The nice advantage of the DSE SFC over the Global west SFC is that you can also weld it right to your floor adding even more strength to the body since it connects the front frame, rear frame, and the body all into 1.

I agree that technically the DSE SFC's are better both functionally and asthetically, but they are also a ton more work to install and you are screwed if you have to pull your subframe for some reason. However, they do work better and look great.

The GW units are the nicest ones of the "bolt in" type (you do have to weld the back side to the rear frame rail) and they fit very very well. Since they bolt to the front sub instead of weld you can pull the sub if you have to.

Both have thier pro's and con's.. I would think the DSE units are MUCH stronger overall due to thier design.

[1Fine69]

how much does it effect the handling? alot or little? is it worth it cause i ordered them i dont know if i wanan put htem in though

[zbugger]

I agree that technically the DSE SFC's are better both functionally and asthetically, but they are also a ton more work to install and you are screwed if you have to pull your subframe for some reason. However, they do work better and look great.

Steve, look closely at the rear of the subframe in this picture.

Notice the bolts on the rear of the subframe?

Also look at this picture.


The holes in the bracket are so you can actually bolt the front sub to the connector. The bracket itself is welded to the subframe. This gives people the option of changing subframes. It's permanent to the chassis, but not the subframe.

how much does it effect the handling? alot or little? is it worth it cause i ordered them i dont know if i wanan put htem in though

You'll notice the car feels stiffer. This also allows the suspension to work without dealing with chassis flex. Also, remember to install them with the solid body mounts.

[1Fine69]

is it worth the install time and money?