Fender frame? What is this called?

[Bwales]

Trying to find out what this is called. Obviously needs some correction and replacement.  I have also been looking through threads regarding chassis stiffening hoping someone has reinforced this and could offer advice on how to repair this if i cannot source a replacement 

[LLave]

It is really the top frame rail of the front of the car. No idea what is is actually called. Many people (me included) add a bar from the end of the rocker up diagonal to that frame to supplement it. 

[grannyknot]

That top frame box is a very difficult piece to find, you maybe able to find a used one from a wrecked  Z but they are hard to come by. I would drill out the spot welds on that piece, remove it and repair it as best you can.  Here is some of the reinforcement I did to my car. Nothing was welded yet , just test fitting.

 

[Bwales]

Thanks guys. I have seen where some folks remove the whole piece and make a tube front for rigidity. I'm doing a rebuild on an old v8 swapped car and will most likely be replacing the inner and outer rocker panels as well(along with floors). The car was supposed to have driven fine but i'm trying to do this build some justice and do it right. I also am trying to keep it somewhat stock appearing  and am not wanting to fully cage the car. We will see as we continue o dig into the car.

[Bwales]

Grannyknot, That is a clever looking modification. Seems like it keeps most of the original piece as intended but would really stiffen it up.

[unterbergamotten3]

That section is called "Inner Fender Apron".

Edited September 21, 2018 by unterbergamotten3

[260DET]

5 hours ago, Bwales said:

Thanks guys. I have seen where some folks remove the whole piece and make a tube front for rigidity. I'm doing a rebuild on an old v8 swapped car and will most likely be replacing the inner and outer rocker panels as well(along with floors). The car was supposed to have driven fine but i'm trying to do this build some justice and do it right. I also am trying to keep it somewhat stock appearing  and am not wanting to fully cage the car. We will see as we continue o dig into the car.

 

The few examples I have seen pics of made me wonder how well those tubular fronts are attached to the original body to avoid a flex point. At least some of the attachment points should run well back into the body eg through or under the rocker panels.

[JMortensen]

Agree with Richard. The huge attachment point of the upper frame rail and its connection to the the cowl which is a torque box is an important part of the already weak Datsun structure. 

If you're going to replace it there needs to be a load path, can't just weld a plate to the firewall and then run the brace off of that. Running it to the A pillar bar of a cage, which is then reinforced by door bars is a good way to handle it if it needs to be removed.

Grannyknot's mod looks fine, but I would weld the original frame rail back to the tube that he added, so both are structural.

[grannyknot]

8 hours ago, JMortensen said:

but I would weld the original frame rail back to the tube that he added, so both are structural.

 

Here is a later pic with everything welded in, I think I did what you are recommending.

 

[JMortensen]

Yep. Nicely done.

[Bwales]

@grannyknot what is your plane for tying that in beyond the firewall? I am not wanting to do a full cage in the car and was curious what you were doing. I have seen the old Z tech article about tying the rockers together without a cage. I'll see if I can find it again.

[m1ghtymaxXx]

Often referred to as a "frame horn" or similar.

[Zetsaz]

5 minutes ago, m1ghtymaxXx said:

Often referred to as a "frame horn" or similar.

 

Was just about to add that this is what I've always called them. Most people I've talked to that own S30s usually call them frame horns as well. 

[grannyknot]

5 hours ago, Bwales said:

@grannyknot what is your plane for tying that in beyond the firewall? I am not wanting to do a full cage in the car and was curious what you were doing. I have seen the old Z tech article about tying the rockers together without a cage. I'll see if I can find it again.

I didn't know it had a name I just saw some aftermarket bolt on "horns" for newer imports and thought that to make them really effective that they should be welded into the car. I put a bmw s38 in the Z and that bloody engine is so tall I knew I would never get a strut tower brace over top so started looking for other ways to stiffen the front. As it turned out the car is much stiffer now then it would have been with just a strut tower brace.