DB4 tub problem

[Westroc]

Going thru the car I have found a crack in the heavy metal surround piece behind the aluminum at the rear bulkhead. Iam trying to remove the 2 thin aluminum sheets and gussets but they seem bonded to each other and to whatever is behind- first problem. Second once I get it off they'll probably need to be made but how am I going to weld the crack ( one seen so far) without melting or destroying the composite. Can anyone tell me the rivet lenghts (assuming I get by all that) for installing the new aluminum. Third I am only assuming that the heavy metal surrounding the outside edge of the tub IS metal you can weld. Fourth does anyone supply precut jabroc?

[Paul LeCain]

The structure around the fuel cell (I assume that's what you mean) is square steel tubing. The rear aluminum sheet is probably bonded to it (it should be, anyway).

[Steve O'Hara]

Here are some pics of the back area with the rear panel removed. The panel is made of honeycomb aluminum and the outer edge has the honeycomb removed so the two skins can be squished together. When you remove the panel you need to be very careful to get a stiff blade under both layers of the thin aluminum skin or it will get bent up pretty easy. The main structure is approximately 3/4" x 1,1/4" rectangular steel tubing that is bonded and riveted in all the way around. Getting it out looks like it would be a major task! Is the crack you found in the upper half where the glass/carbon mates to it or in the bottom where it meets with the aluminum?
Can you post some pictures showing the problem? I'm working with Dave McLerren on my DB4 tub a few afternoons each week and I can talk with him about your repair and see what he suggests. Dave was one of the fabricators at Swift when the DB4s were built owns the original DB4 jig and a large inventory of parts.
Regards,
Steve O'Hara

[Westroc]

Steve thanks for your reply complete w/pics. Nice of you and appreciated. Have a new digital but my son has it you know how that goes if you are a parent. Will post pics then. The crack is circular right under the embossment where the left lower engine mount bolt threads in. It's the only problem area at least until I manage to get the alum. skins off. Called Keith Averill who gave me Kris Kaiser's phone# and I called him. He said even if it was in his shop he could do the repair but wouldn't attempt it but send it to Pat Prince. Sounds like your guy knows the DB4. How about a ballpark guess. Just for the repair I'll do the reskin. Ask him how lond the rivets need to be. I could calculate it but it is always easier to just ask. You are a old karter like me I see. Old Rupp A-bone up on the wall and MAC91B1 I thought I saw. My first kart was a Bug Stinger. Started racing w/Mark Dismore @ Comet. Used his stuff a long time until we were at Gratton one day and the new PCR engine showed up Franklin boys and blew us all away. Decided I was not changing engines for the millionth time and went "big car" open wheel racing. Were pretty big karters 2 chassis each 6 engines each and 26 sets of tires mounted. When I sold it all it didn't take much out of pocket to go FF racing.