Landracing Forum

Bonneville Salt Flats Discussion => Build Diaries => Topic started by: mkilger on January 02, 2010, 03:42:55 PM

Title: roadster firewall help
Post by: mkilger on January 02, 2010, 03:42:55 PM
trying to put the firewall in the roadster, but want to see how others have been done theres. thanks mike
Title: Re: roadster firewall help
Post by: jww36 on January 02, 2010, 05:25:57 PM
Mike;
I'm in the process of building a '34 gas roadster. Some of the things I'm doing might be a little more time consuming during the fabrication of the car, but I think in the long run that extra effort is worth it and may make life easier down the road. My fire wall, .250 6061-T6 aluminum, will bolt into frame. Engine can either go in/out from the front with the fire wall in frame, or, engine, fire wall, bell housing and tranny can go in/out as a unit.
Good luck on your build. I can email some pictures if you like.
John
Title: Re: roadster firewall help
Post by: Skip Pipes on January 03, 2010, 03:36:09 AM
Hi Mike,

I'm in the same stage of fabrication. I'm inclined to steal as many good ideas as I can find so I've been known to take some pics here and there. Here are some firewall pics from the Wilson & Waters roadster. Also included a pic from the Lee's Metalworking roadster site.

Skip Pipes
Title: Re: roadster firewall help
Post by: mkilger on January 03, 2010, 11:11:11 AM
Skip thanks for the photos, it looks like if you run a flat firewall you must also cover the trans along with it?? I dont really want to build a (dog house) as it will take too much room behind the motor. ok lets see a few more.  whats the web site for Lee's shop? thanks
Title: Re: roadster firewall help
Post by: Joe Timney on January 03, 2010, 01:20:15 PM
I find it easier to service the car by making a second smaller midplate that allows the motor and trans to come out forward, thru the primary motorplate. It is just an inch or two bigger than the clutch can flange. 
I'll try to find some pictures showing one setup.
joe
Title: Re: roadster firewall help
Post by: Skip Pipes on January 04, 2010, 12:36:24 AM
Hi Mike,

Lee’s Metalworking
http://www.bonnevillebadboys.com/

I didn’t want a dog house either so I built my car like Joe suggests and will be using a midplate (pic attached). I’ll plan to let the trans sandwich the midplate to bell housing and leave the trans exposed, ala Wilson & Waters. My plate is attached with many bolts; however, cordless impacts make quick work of pulling the midplate bolts allowing the engine, trans and midplate can come out together.

Skip Pipes
Title: Re: roadster firewall help
Post by: jww36 on January 04, 2010, 08:47:59 PM
Firewall pictures.
Title: Re: roadster firewall help
Post by: jimmy six on January 04, 2010, 11:03:39 PM
As you build firewalls in Gas/Fuel roadsters it is wise to look at the definition of a step pan. Most place the firewall between the trans and bell housing because it fits well with the 25% set back and placement in the body. If your firewall is in 2 planes or stepped, the step pan can only go from the "aft most" one by definition. This could leave a large hole in the bottom of your drivers compartment.

Any paneling not meeting the definition of a step pan must meet the definition of a floorboard above the frame and driveline components....Good Luck
Title: Re: roadster firewall help
Post by: jww36 on January 05, 2010, 10:12:48 AM
Roadster firewall pictures.
Title: Re: roadster firewall help
Post by: NathanStewart on January 07, 2010, 12:11:36 PM
Our roadster is a '28 on a '32 frame.  There is a flange that goes around the inside of the body between where the cowl mounts and the leading edge of the doors.  Mounted to this flange is an aluminum sheet (I forget the thickness but it's probably eighth inch thick) that extends from the top of the inside of the body all the way down to the lower edge of the frame and out to both sides.  About where the tranny goes through there is a square hole. 

Between the bellhousing and the back of the block is a half inch thick motor plate.  The motor plate mounts the motor to the frame and then bolts to the firewall.  We seal the bottom of the motor plate to the step pan with a piece of angle aluminum that spans across the width of the frame.  So, the bellhousing and trans are totally inside the driver's compartment.

I think a lot of the cars that were built around the time ours ways (late 60's, early 70's) are this way or something similar.