How structural is the rear latch panel?
 

Has anyone removed the rear latch panel completely? I have heard of some race cars that have this panel removed for easy access/removal of the engine. Anyone have any thoughts on how structural this panel is?

I picked up a 912 project a few months back and it looks like the car was backed into a pole at some point. The latch panel was bent right in the middle and then someone attempted to pull it back into place. It's completely mangled and I'm toying with the idea of either deleting it completely or just using the outer skin of a replacement panel and making it removable. The idea is to have easy access to the engine and also to save some weight.

Here's a picture of the panel I'm talking about, this is not my car though.

http://forums.pelicanparts.com/uploa...1266441883.jpg

It may not be "structural" but they do serve a purpose. Way back when, the story goes, engineers noticed that the conventional rear deck of a 911 in the wind tunnel was floating generally horizontally at high speed. The deck had not been latched and upforce raised the deck. Further research led to the introduction of a whale tale to kill the downforce and enhance highspeed handling.

Forgot to mention that I'll be using the rubber 911R/RS style latches so that shouldn't be a problem. Thanks for the input.

The 935's that you are referring to, had a bolt in rear cross member to box in the back of the chassis. Removal of the engine involved unbolting the rear cross member and then the motor could be removed from the rear of the car without raising the car.

I would say it is structural. The rear engine mounts attach to it. I had to buy the entire panel to fix an accident in my 70. The outer member was damaged and rather them cut out the entire panel, I seperated the inner from the outer (spot welds), did the same on the new part and only used the outer.

On a 912 the engine mounts are more towards the center of the engine compartment. They are not attached to the rear panel at all. I think I'll just have to cut the panel out and see for myself.

It seems to me that the quarters and the frame rails would be more than enough to support the weight of a 4 cylinder engine.

My track car is a '68 912 Targa, upgraded to 911 before I bought it. I concluded that this crossmember contributes to the torsional rigidity of the car, helping to hold the forces the motor imposes, both torsionally, and just resisting Newton's first law when cornering. The best deals involve cutting it out and making it and the motor mounts all remove as a piece, so the engine can just be slid straight back and out. Like these, where I think the shop made the motor mount into a kind of truss to do double duty:

http://forums.pelicanparts.com/uploa...1266557675.jpg
http://forums.pelicanparts.com/uploa...1266557813.jpg
http://forums.pelicanparts.com/uploa...1266557835.jpg
http://forums.pelicanparts.com/uploa...1266557934.jpg

The last three I scarfed from Peter Dawe's shop website.

Here is the halfway measure I did on my car:

I sawed through the cross member on each side, just inboard of where the motor mounts ended. I made four plates of the same dimensions, paired them up, and put two in each cut so they stuck out beyond the crossmember like flanges. I welded them in place, and drilled holes through them. On one plate on each side I welded nuts. Allen screws went through the other side and into the nuts. So I could unbolt and remove just the center section. But this left enough of an opening that I did not have to jack the car up super high to get the engine out. I could get the alternator through the opening and the engine back far enough for the tranny to separate. Then I'd lower the engine onto a dolly, and I could maneuver the carbs through the opening.

I don't think there is weight to be saved here. Sheet metal structural forms are very light (the virtue of a unibody, really) for their strength, as their sections are relatively large. And the combo cross member/rear motor mounts that I have seen have all been made of pretty sturdy stuff, looking like it isn't saving much weight.

It is the convenience that is useful. But for a 912 with its shorter engine, maybe not worth while? This is kind of a race car thing, where you can expect to have the engine out a couple of times a year.

Thanks Walt. I figured someone on this board had to have tried this already.

My original plan was to do exactly what you did on your car. I just figured maybe I could get away with leaving the panel out completely. Looks like I'll go back to plan A.

Every body part on these cars is structural including the rear apron that ties the back end of the longitudinals together.