CRG Discussion Forum

Camaro Research Group Discussion => Restoration => Topic started by: GI JOE on September 05, 2012, 06:15:36 AM

Title: Are the any differances in sub frames?
Post by: GI JOE on September 05, 2012, 06:15:36 AM
Are there any differences in sub frames?  I have a 68 L78 car late production with a bent frame... I have access to a 69 fire-bird frame... but the mounts are rusted out...  I was thinking of sand blasting the fire-bird frame, fixing (welding up) the mount areas and transfer all the other stuff to the fire-bird main frame.... Any suggestions? I really hate to not use the OEM frame... it is in better shape but she is bent and I am unsure if it is worth straightening.

Also I was wondering how to get that factory OEM frame paint color.... to many of the restored cars appear to glossy to me...

Any suggestions are welcome...  I need to do this correctly the first time...  Thanks JOE
Title: Re: Are the any differances in sub frames?
Post by: Mark on September 05, 2012, 04:08:55 PM
Yes there are differences.  Mostly its in the lower control arm bump stop braces.  67's didn't have any, the 68's had them on the rear of the spring pocket, and the 69's have them on the front of the spring pockets.  theres also some differences in where the lightening, or tie down holes are located on the front frame horns.  don't know if there are mor differences between a Camaro and FB sub frame, although I think the the fuel lines in a FB come down the drivers side of the car, so there would be fuel clips on that side of the frame instead of the passenger side on the Camaros.  May be some differences in engine mount hole locations, as the FB's did not offset the big blocks to the passenger side, like the Camaros did, the BB FB's definately have different cross members, but maybe the FB front mounts made the difference instead of relocating the actual holes in the frame.
Title: Re: Are the any differances in sub frames?
Post by: Sauron327 on September 05, 2012, 05:08:28 PM
Mostly its in the lower control arm bump stop braces.  67's didn't have any,
67's have them and are welded to the lower rear of the pocket, the conical rubber stop bolts to it. When converting to 69 style calipers, they contact the flex line banjo. Monte calipers offer more clearance, but not entirely.
Title: Re: Are the any differances in sub frames?
Post by: BlackoutSteve on September 07, 2012, 09:01:16 AM
As mentioned, bump-stops are the easiest way to tell.
The early production 67 frames don't have the large ~3" bumper bracket bolt access holes (The aren't tie down holes -all frames have those. :) )
67 frames had fuel and brake line clips riveted in place, 68-69 had two holes, a 5/16" thread and locating tab for each clip.
67 front-most body mount braces were a different design.
67 only had two rad support holes on each front "horn". -perhaps in 1968, the frame was used in another application as they weren't for Camaro use.
Later 69 frames had 3/8" threads instead of 5/16" threads for the swap bar brackets. I think this coincided with the new design bracket.. Not sure.

I think there are few other minor trivial things but I forget.  :-[
Title: Re: Are the any differances in sub frames?
Post by: GI JOE on November 02, 2012, 07:33:55 AM
I scraped the idea of using the 69 firebird frame and its up for sale.

I bought a very clean frame from out west...but its a 69 frame... so I have not got to the point of what is involved to make it correct for the 68...if that is possible...

Can anyone suggest what tool to get to remove BB springs??? I found several coil spring compressors at sears website but they all seem a bit weak for BB springs...
Title: Re: Are the any differances in sub frames?
Post by: Mike S on November 03, 2012, 01:44:39 AM
Can anyone suggest what tool to get to remove BB springs??? I found several coil spring compressors at sears website but they all seem a bit weak for BB springs...

Hi Joe,

  I highly recommend the OTC 7045B spring compressor. By design, it is impossible for the mechanics to unwind by itself when compressed (something an internal hook compressor does very easily and suddenly) and it uses a ball bearing thrust plate to make compressing very easy and smooth. I got mine on Amazon for $125. Yep, it costs more but after almost being killed by an internal hook compressor in the late 80's and then a few months back in 2012 having the internal hook type suddenly and violently uncompress with BB springs twice in the same day when removing them from the chassis, I figured my life was worth the extra $$$ and bought this to install them. It's in my tool box now and I will never use the other types again.

Mike
Title: Re: Are the any differances in sub frames?
Post by: BillOhio on November 03, 2012, 04:56:41 AM
I have heard its a bad job when there is no engine to hold the frame down. Very dangerous. Sounds like mike has a good idea.
Title: Re: Are the any differances in sub frames?
Post by: tmodel66 on November 03, 2012, 03:15:40 PM
I might be preaching to the choir but I have always used a piece of 1/4" cable to keep these things from killing you. It's old school but I was taught by old school mechanics. Take a piece of cable and circle the spring a couple of times and put a couple of clamps on it. This way if the compressor slips it can't go anywhere. The cable will keep it from expanding any further than it was when you captured it. It works real good and might save a disaster. 
Title: Re: Are the any differances in sub frames?
Post by: BlackoutSteve on November 04, 2012, 07:57:35 AM
I bought a very clean frame from out west...but its a 69 frame... so I have not got to the point of what is involved to make it correct for the 68...if that is possible...

Very easy if you can find a junked 68 subframe and unpick the bumpstops..
I did with a 69 Nova frame to convert my 67 to 69.
http://www.usmuscle.com.au/Forum/showpost.php?p=13994&postcount=27 (http://www.usmuscle.com.au/Forum/showpost.php?p=13994&postcount=27)
Title: Re: Are the any differances in sub frames?
Post by: GI JOE on November 13, 2012, 10:39:04 AM
Thanks everyone... it takes a community to build a car.... LOL

Title: Re: Are the any differances in sub frames?
Post by: 69Z28-RS on November 13, 2012, 06:29:55 PM
I might be preaching to the choir but I have always used a piece of 1/4" cable to keep these things from killing you. It's old school but I was taught by old school mechanics. Take a piece of cable and circle the spring a couple of times and put a couple of clamps on it. This way if the compressor slips it can't go anywhere. The cable will keep it from expanding any further than it was when you captured it. It works real good and might save a disaster. 
I also learned from 'old school' mechanics, and similarly I use a heavy chain around a couple of spring coils and around the frame as a 'safety precaution' when removing or installing coil springs...

Gary / 69Z28-RS
Title: Re: Are the any differances in sub frames?
Post by: firstgenaddict on December 02, 2012, 07:01:29 PM
If the subframe is out and upside down (as the factory did it) the job is a piece of cake.
1. installed the upper control arms then flipped over the subframe
2. installed the spindles on the upper balljoints and loosely screwed nut in place
3. compressed the spring and the lower control arm together then dropped it into place.
4. installed lower control arm pivot bolts
5. installed lower ball joint nut torqued to spec
6. Cotter pins - safety
Title: Re: Are the any differances in sub frames?
Post by: GI JOE on January 01, 2013, 06:49:25 PM
here is an up date....

I purchased the tool Mike S recommended "  I highly recommend the OTC 7045B spring compressor. ..."  not wanting to take any chances with BB springs and working by myself... it costs me about $170 with S&H... and it works great.   

It is a bit tricky at first to set up but once you get it down it is pretty quick and most of all safe...  I did find i had to grind a little metal off one of the solid bearings as it would not fit through the lower A-arm hole... but again it worked wonderful. 

My only trouble doing this with an open frame, (as suggested I had the frame up side down), if you drop the locking stud and or lower solid ball they fall into the frames spring area and it is a bit frustrating to get them out (even with tool grabber and or magnet) as the access is limited with the a-arms..etc....  I got a bit smarter afterwards (actually after the second time) and put a piece of card board under the lower part to catch the parts if i dropped them...until I had it assembled. That solved that issue and saved time.. it's always those little things.. LOL

I will post some photos later tonight....

Also everyones suggestions and advice here helped me getter done... or closer to done that is... :D



GI Joe
Title: Re: Are the any differances in sub frames?
Post by: Mike S on January 01, 2013, 07:04:56 PM
Hi Joe,

  That's good to hear that compressor type worked for you. Didn't it make you feel safe handling those compressed springs?
I didn't have to grind anything however with my '67 frames. I figured your A-arms would be the same  ???
I wish I had known you would be interested in that compressor because I would have lent mine out for the cost of shipping.
Glad to hear it worked though.

Mike
Title: Re: Are the any differances in sub frames?
Post by: GI JOE on January 07, 2013, 12:55:19 PM
here are a few photos... I got busy and forgot to get back to post the photos ... The one frame photo is of the donor frame... after getting the spring out...

through in a few extras... showing the original OEM disc brakes... note the bearing dust cap...  sweet...  :D