Frame material and engine compartment size ???

[baddawgcustoms]

Just wanting some opinions in frame rail size. I'm going to buy the steel tomorrow and still in the fence between 1 1/2 x 3 or 2x3. I know 1/2 can be a lot when trying to cram a lot of parts in a small frame and I'm running an almost stock 307 and 3speed manual so I'm not running high HP and not building a race car so I'm thinking 1 1/2 x3 is plenty strong enough with some good cross bracing and crossmembers. Also the 1 1/2 will allow me to mount the 1 3/4 elliptical springs on top of the frame rails on the font the way I would like to a little easier. The body I'm getting from RPM isn't channeled yet so I won't have any gaps to fill in with the smaller size.

Also I'm wondering about opinions on distance between fire wall and radiator shell in sb chevy setup. My intentions are to simply mount the radiator and shell in place,mount my electric fan and shroud I'm building, and set the engine in as tightly as I can get it, then just do the same with the body. I'm considering the extra deep model T grill shell that is 5" deep. This will tuck the radiator I have and the 2" deep shroud and fan nice and neat up inside, which I believe will look really clean. But.....I'm wondering if there is a "standard" size to keep proportions in order. The body I'm getting is a 10" stretch in the cowl area so I'm thinking the tighter the better. I'll just have to wait and see what it looks like. Trying to stick to a 4 1/2" scrub line, and 6" ground clearance on the frame Up front and 7" in the rear, so basically the engine will sit pretty high. I know it will be a wait and see thing but any opinions? Especially on frame rake size.

 

[smokeyco75]

Either should be fine, but if it were me id use 2x3 since it will be longer. There should still be plenty of room for your parts unless it is a narrow frame design. 26 inches seems to be the standard width these days but some are 23 inches. Ultimately it is your call.

 

[409T]

My frames are all 2 x 3, actually 2 x 4 in the Model A. I think the 2" width looks better, but as smokeyco75 said, either works. It's all personal preference.

 

[EX JUNK]

My frame is 1 1/2"x 3"x 3/16" and the distance from the firewall to the rear of the grill is 33". With that distance I'm able to run an HEI distributor with 1 5/8" clearance to the firewall. My small block Chevy has the short water pump and I have a 1 1/2" spacer on my mechanical fan.

Here is a profile shot to give you a better idea of the proportions.



Jim

P.S. I might add that my body is stretched 6" with the '26-'27 type cowl.

 

[bobs66440]

Mine is 2x3. I wouldn't go smaller, though it will work. I would rather over-build than under-build. You never know, you may want to change over to a supercharged Hemi someday!

 

[Keeper]

Its not so much the 1 1/2 or 2 inches wide, if you make the 1 1/2 with thicker tube, its should be stronger frame.

Mine is 2x3 10g (I think) tube. Looking back I would have much rather had 3/16 frame as it allows you to thread the frame to (more securely) accept clips, and other small mounts. Plus the 3/16 has a rounder edge and IMO looks a bit better.

If you are building your frame, I would not start cutting things until you got your body, engine, shell all together. Then grab some 2x4 or 2x3 wooden studs, and make your frame. Wood is cheaper, and easier to work with. Once you get things to your liking, build it out of metal.

There are a few threads on here with folks using wood to make a frame template.

 

[Screaming Metal]

What they said....3/16 will handle almost everything....if your into really high horses, ie, blown big blocks and slicks, go with 1/4" wall.
Theres been alot of substandard Mexican Steel, ie, like the really soft F36 grade rectangular tubing. Its not the size, but some of that stuff is soft and spingy, ie, flexes more than normal. Yes, they're making steel cheaper, too. Cutting costs.
While some have noticed, some haven't. Its more the fab. folks that are seeing this.
If the trend continues the 1/4 " would be the way to go. Yes it adds some weight, and makes the suspension attach points stiffer, this affects ride quality.
Just my 2 Pecos....

 

[Mike J]

here is my wood mock up.

 

[Mike J]

here is my wood mock up.

 

[baddawgcustoms]

http://www.tbucketeers.com/threads/project-obie-got-its-first-parts.15529/

Decided to go ahead and start a project page since I built a mock up wood frame and have a few parts stashed away now. Thanks for all the help, and I pretty much decided on the 1 1/2 x 3 and At least 3/16 wall. My steel shop buddy is looking into 1/4 wall for me, and checking the weight difference. I really like the idea of being able to tap the frame for fasteners and such better which I had not even thought of. And yes as Bob mentioned I may decide to add a few horses later on. Thanks for all the advice again guys.

 

[EX JUNK]

Here are some shots of my frame that may give you some ideas. I chose to install a "K" member rather than just having a ladder type frame as it helps counteract the torsional stress on the frame.







Jim

 

[baddawgcustoms]

Here are some shots of my frame that may give you some ideas. I chose to install a "K" member rather than just having a ladder type frame as it helps counteract the torsional stress on the frame.







Jim

Definitely plan on building a k member setup very similar to what you have done. Especially in the area around the drive shaft. This is a picture of from the build thread that DonsRods did on his car, and I really like the way he built the transmission tunnel, and I think this would be a great place to do a k type member under the drive shaft tunnel. Will have to see how high my transmission will set in the frame. I have some 1x4 in 3/16 that I may be able to incorporate the transmission mount into as well. I'm with you, I will have some type of cross bracing other than just the ladder style. Don built a beautiful car and I enjoyed his build thread, but to me it looks like under his tunnel was a good missed opportunity to put a nice K member underneath, and just build the tunnel over top of it. The couple of drag car suspensions I've done I probably over did, IF there is such a thing. I will gladly trade a little weight for smart engineering. excuse the blueprint of what I had drawn up on my cheap walmart drafting paper. I'm no engineer but I've drawn up every inch of the car in my hours of spare time spent in hotel rooms these last few months. (my job has had me traveling quite a bit). Hope it will save me a lot of time in the shop. I've drawn out most of my mounts and brackets on draft paper, then transferred them to thin plastic that was actually bath tub liner from home depot, then cut them out to use as patterns I can take to my buddies shop and wear out the blade on his band saw. My wife has accused me of having way way tooooo much time on my hands.

 

[baddawgcustoms]

One more thing Jim. about how much ground clearance do you have on your frame just behind your front springs, and about how high is your oil pan? thanks again.

 

[EX JUNK]

One more thing Jim. about how much ground clearance do you have on your frame just behind your front springs, and about how high is your oil pan? thanks again.

At the rear of my front spring, which is 3 1/2" from the center of my motor mount, I measure 6 7/8" to the ground and I have 3" of ground clearance at the bottom of my Slam Guard oil pan. Another measurement that you might want is the ground clearance at the bottom of the rear kick up which is 9 1/4". Since I live in Florida where the roads are in good shape, I've had no problem with my ground clearance and that includes going over speed bumps.

Jim