Greatest DIY Bash/Skid Plate in the World

[Red XS]

Another DIY Bash/Skid Plate in the World

The old DIY sump guard was looking a bit second hand and I wanted something to stop those plastic wheel linings from catching and ripping of like the've done so many times before. So I decided to make a new better, stronger skid plate that protected the entire front underbody of my Red.

The sides follow the bumper line reasonably closely and go right to the edges so to protect all the plastic bits. And angle is bolted on so that it won't scollop out like the old one did. The angle doesn't go the entire way so the plate will still give under major impacts, but I don't plan on any of those happening.

In the background Zola lies in wait for her next opportunity to get under my feet.

I was going to leave the blue plastic on to protect it from scratches but then decided it would probably just rip off and kill some dolphins or something. So I took it off to reveal the shininess.

Lets see how long that lasts.

Having that bend further forwards has greatly increased the gap between the sump and plate while not compromising on ground clearance. Unfortunately it meant I had to extend my extra light duty recovery point.

In the top left hand corner is that plastic lining that kept catching.

I had to create spacers between the chassis and the plate

And the final product

To anyone who wants to make it, this plate is quite a lot more difficult to make then other DIY projects and incredibly difficult to fit as the close fit to the bumper makes it impossible to see the bolt holes when fitting it. Also it's not ADR compliant. But if anyone wants a good project to work on I'll draw up the plans sometime.

I'm also open to anyone elses ideas to improve it...

 

[Ratbag]

Gidday Red

Well done, mate.

Just one small question.
Does that centre bit of angle reinforcing run directly under your sump?

If it does, it might be a very good idea to remove it and replace it with one each side of the sump ...

When I fitted my SubaXtreme guard, I packed out the rear bolts with 3x 1/2" washers each side, because I thought that the guard was too close to my already beaten up sump. Mine is a bit bent up in the middle from some fairly hard use, but even if it weren't, it's still too close to the sump for my liking. I might even pack one 1/2" washer under the leading edge, as it will push it down just a little further away from the sump. Currently there is about 1/2-3/4" between the guard and the sump.

When I get to Brissy, I will whip it off and have some reinforcing bar welded along each side, away from being under the sump. It also needs a few dodgy bits welded up, and another reinforcing bar across the angle at the leading edge.

 

[Red XS]

A good point, I can't actually see where my sump is at the moment with the plate in place. But I can see that there is a good 3/4" inbetween the steel angle and the exhaust/header system at the closest point and well over an inch further back where I think the sump is. But that is something I will have to look into. I don't suppose you remember exactly where the sump was?

Edit- The sump was further back then I thought and is directly above the rear beam that runs across the width of the plate. There is a solid 1 3/4" between the angle and sump. Personally I can't image bending it that far as I mostly do sand and I want to try to be gentler on rocks. But that is still a very valid point that I didn't even think off.

 

[Ratbag]

Red, at a very rough guess, I reckon that the dead centre of the sump and the point at which your cross brace and in-line brace meet ... .

IOW, there is effectively a very nice "punch" located directly under the middle of your sump.

Worth checking out.

Take it off, and measure from the centre of the two back bolts to the rear, front and centre of your sump; then measure that same point using the bolt holes on your guard to establish the corresponding point on your guard.

Measure the width of your sump from the centre line between the centre of the two chassis bolt holes and centre of the big hole in the front cross member.

It seems to me that you need to modify your reinforcing angle pieces so that they form a 'loose' box that is clearly outside the perimeter of the bottom of your sump.

All my sump guards on my cars in the olden days had a big pad of fairly high density rubber at the 'touching point' to cushion the blow. I reckon that this might be a good idea, if I can find a reasonably suitable material. IIRC, it was about 3/8ths inch thick, and about as dense as tyre tread - speaking of which, I reckon that might just be the answer.

I reckon that rock to metal and metal-rubber-metal contact has to be less of a shock than rock to metal, then metal to metal contact ... Just a thought.

 

[Red XS]

You're right, the centre beam and rear beam meet directly under the sump. But with just under 2" clearance between them and the sump there is heaps of room to place some of that HD rubber. Do you think I should get something a little softer then tyre tread? and should I fill up the entire gap, or just do about 1" of it?

Also I have a large but surprisingly neat dent in my sump due to lack of strength in the old plate.

 

[Ratbag]

Red, I would still move the reinforcing angle, if I were you. How it is ATM is just one hard rock away from a really buggered sump ... .

I agree that you should have some space between the padding and the sump.
No matter how you slice it, air is softer than anything else ... :iconwink:.

It occurred to me that tyre sidewall would be softer than tread, and provide more shock absorbing, so agree with you on that.

 

[Kevin]

Good job - like all prototypes, some mods are usually necessary :iconwink:

 

[Red XS]

Yeah, deep down I knew there would be. That's half the reason I posted it up on here. Now to look for the laziest way out...

What if I were to weld a flat sheet of aluminum on top of the angle bracing, then put a rubber pad over that? It would distribute the impact better so it won't 'slice' into the sump. I know there will still be a lot of strength from the bracing in an impact, but I don't think it would be any worse than having the normal plate hit it considering it would having near by bracing.

Hopefully that made sense, I don't know how to word it better.

 

[Ratbag]

Red, what you have is easy to fix properly IMO.

Just remove the centre-line angle.

Cut the cross-brace just outside the line of the sump (3/4", perhaps?).

Run two new centre-line braces back to near the rear mounts so that they butt up against the (now) cut cross-brace ends, and weld them to the central ends of the cross-brace.

I would also be inclined to run another cross-brace up towards the front. Make sure it clears the headers and is well in front of the sump ...

None of the above is even tricky. And it should end up being stronger than your current one, but still with a fair bit of flex (and clearance ... ) to absorb the shocks before they hit anything squishy, like our sumps .... .

 

[Kevin]

An afterthought - be careful that you don't block too much airflow with whatever you do.

 

[Red XS]

I'll give the beam a trim before I offroad again, I won't add any extra beams as it should be plenty strong enough for sand and that's really all I do, and after the lift I don't bottom out that much any more.

I may need to cut air vents in it, but I'll do some testing first to see if there is a difference in cooling.

 

[Ratbag]

Gidday Red, while I agree with Kevin in principle about air flow, the OEM ABS cover doesn't have any vent holes in it at all, and covers the entirety of the bottom of the engine bay back to that rear cross member behind the sump.

I do agree totally with him about prototypes ...

These days I have learned to make cardboard or whatever templates for small things (in particular) before I waste a whole lot of time and material making it out of the proper stuff, and getting it wrong ... .

 

[stilson]

Red remove the centre brace entirely, it's a bad thing.

If it needs bracing, (and it does), run them either side of the sump.

 

[t.ridden]

Just a thought, if you decide to go nuts and get up to around 180kmh, that plate will act like an upside down spoiler
Just to keep in mind

I'm agreeing with the guys about that centre brace, run one either side of the sump.
It's not hard and its much better design for the "unlikely" event of a hard knock directly under the sump. Not so much for improving strength as for removing a design flaw that could potentially compromise the function of the protection.
Win win win situation.

 

[Red XS]

It's the cross-brace that runs under the sump, the centre brace is in front of it. I can't move the cross-brace back too far because it will hit the exhaust on the RHS. So I'll just give it a trim in the centre, that way it's just flat metal there.

 

[blanket25]

Remember that time at the pines when your car kept over heating? While that guard looks awesome id definitely look at airflow.

 

[NachaLuva]

Nice job, looks great!

Can you use a bit of alloy flat bar instead of the angle and placed further forward?

For ventilation, esp on sand, you can cut some flaps. Drill 2 holes about about 3" apart then use a jigsaw to cut a U shaped flap about 1" wide, then bend it up. It will deflect sand & water down so it wont go through but will allow air to escape :biggrin:

 

[Red XS]

Yeah I probably should of just used flat bar to start with.

That's a nice neat idea for the air vents. I'll test it out 4wding first to see if there is any difference in cooling. The wider plate won't be good for cooling, but the larger gap between sump and plate and larger gap at the back might improve airflow. Just see how it goes...

I do remember that Pines trip where I kept over heating. But I probably shouldn't be doing any more 42deg C 4wding days any more. I'll be happy if the cooling is equal to the old plate, but I wouldn't want it any worse.

 

[Ratbag]

Gidday Red

Yeah I probably should of just used flat bar to start with.

That's a nice neat idea for the air vents. I'll test it out 4wding first to see if there is any difference in cooling. The wider plate won't be good for cooling, but the larger gap between sump and plate and larger gap at the back might improve airflow. Just see how it goes...

I do remember that Pines trip where I kept over heating. But I probably shouldn't be doing any more 42deg C 4wding days any more. I'll be happy if the cooling is equal to the old plate, but I wouldn't want it any worse.

Do remember that the OEM engine bay guard reaches from wall to wall, and it doesn't seem to cause any engine cooling problems with mine. I went for a 200 Km trip on a day when it reached 46°C according to the weather bureau, and the o/s temp gauge on mine agreed with them, mostly crawling on dirt tracks up around Gembrook. With the air-con on pretty high constantly. No over heating at all. Engine temp gauge never budged off normal.

This leads me to ask a question.
What oil, type and viscosity range are you using?

 

[Red XS]

At the time it was Castrol Edge Full synthetic 10W30, I was waying up going to 10w40 after that, but I'm pretty sure I stuck with the 10w30 because I didn't find any full synthetic in the 40 at the time.

It was that very boggy fine black sand with lots of hills