skidplate mounting pics/idea

[///M42 sport]

As ya'll know I recently got a skidplate. Being the anal bastard I am, I didn't want to drill or modify the subframe or skidplate any to mount it. The skidplate had two holes that matched up to the subframe so I wanted to figure out a way to used these. After a trip to the hardware store, this is what I came up with. FYI, davelength mentioned getting crush washers which was my original intention, but these only fit into the rectangular holes in the subframe.

grounded down the diameter to these washer/bolt recievers






Threaded the piece through the subframe with a hanger.




Now ready to attached skidplate after I lower the car.


What do ya'll think?

[blunttech]

i basically did the same thing except i used a tool called a nutsert. it puts a threaded steel receptical in the subframe. i had the tool from a long time ago when i worked for a fastener house. youve acheived the same thing. i also used it to install my mirrors on my 02 instead of the cheesy stock hardware. nice job

[DanGillan]

i just welded nuts to the subframe and radiator support and bolted it up.

[thejimlab]

where does one get this skidplate?

[PiercedE30]

you can get them 666Fabrication

[e30vert]

i just welded nuts to the subframe and radiator support and bolted it up.

Much stronger method there! That ground nutsert method has a good chance of deformation from a good frontal skid plate whack and potentially pull right out of the subframe.

[LINUS]

couple of pics of my skidplate :

[blunttech]

couple of pics of my skidplate :

while that certainly looks nice and the workmanship is top notch i dont think its going to help in a substantial hit. its part of the oil pan now.
i think in a minor crunch it may help but a brick at 60 mph or a speed bump you dont see until its too late may take out the pan anyway.
ive hit both a large brick and a speed bump with my factory plate and it didnt phase it. nice work though

[e9nine]

while that certainly looks nice and the workmanship is top notch i dont think its going to help in a substantial hit. its part of the oil pan now.
i think in a minor crunch it may help but a brick at 60 mph or a speed bump you dont see until its too late may take out the pan anyway.
ive hit both a large brick and a speed bump with my factory plate and it didnt phase it. nice work though

I agree - The thing is you have actually lowered the clearance with your design and all the stress is going to be borne by the oil pan. Believe it or not the drain plug area is a weak area and prone to hairline cracks causing leaks as well and you've left yours uncovered.

Take a look at skid plates such as the OEM one, the ones used on rally cars and off-road cars and you will notice similarity in how they are totally separate of the oil pan and are designed to cover either a wide area or only the area of the exposed element they are trying to protect.

Just my observation/comments.

[LINUS]

I'm not really worried about hitting major items - if I take that hard of a hit I figure I probably need to call AAA anyhow. When I decided to make this it was more the idea of a little insurance for the baseball sized rocks you see on Chuckanut Drive - I might run one down and at least this way there was extra aluminum to help stretch and deform rather than just take a hole punch. I didn't want to build a boat anchor, and this ended up as my idea.
Didn't know the drainplug was a weak area, but now that you say it makes sense. Maybe I'll build a new one and do some pickpoints from the core support to the subframe, but I need to get the car running first - motor should go in this week. Then I'de be able to see the size / distance type stuff to do a real skidplate.
I just had my oilpan out at work to hot tank the oil off it and since unsupervised time is personal project time, this was the outcome. No worries if you don't like my idea - rather somebody point out a weak spot than find it out for myself the hard way.

---Ben

[blunttech]

I'm not really worried about hitting major items - if I take that hard of a hit I figure I probably need to call AAA anyhow. When I decided to make this it was more the idea of a little insurance for the baseball sized rocks you see on Chuckanut Drive - I might run one down and at least this way there was extra aluminum to help stretch and deform rather than just take a hole punch. I didn't want to build a boat anchor, and this ended up as my idea.
Didn't know the drainplug was a weak area, but now that you say it makes sense. Maybe I'll build a new one and do some pickpoints from the core support to the subframe, but I need to get the car running first - motor should go in this week. Then I'de be able to see the size / distance type stuff to do a real skidplate.
I just had my oilpan out at work to hot tank the oil off it and since unsupervised time is personal project time, this was the outcome. No worries if you don't like my idea - rather somebody point out a weak spot than find it out for myself the hard way.

---Ben

dude you obviously have some fab and welding skills. this piece is a step in the right direction. i think you could improve upon it though. nice work

[AndrewBird]

I think that design would protect the bottom of the oil pan well, but if you hit anything big, I would think it would take the entire pan off instead of just breaking a hole in it.

Since you obviously have the skills and tools, you should try making a completely custom oil pan out of 1/4" thick aluminum. Something like that would take any kind of hit.

[LINUS]

I don't really plan on trying to build a whole new oilpan - BMW gave us a pretty good one, plus 1/4" thick alum for a pan....don't know what to think about heat shedding ability there. I'm good on tools, not engineering - so I know when to leave some stuff alone. 'Just smart enough to know when I'm too dumb' sums it up best.

Plus we'de be right back to the whole idea of load / impact ending up on the wrong side of the motor mounts.

I really like the idea once my motor is in on doing a piece that ties the core support to the subframe - that's probably the direction I head once my car is a runner. Maybe a steel frame with alum sheet bolted to it to allow access. Don't know yet. I haven't seen the 666 design so maybe they are already doing what I'm thinking.

[IS]

Or even better - make one out of steel, which has a higher Young's modulus.

You guys have no idea how much skill it takes to weld aluminum cleanly. It is a whole 'nother world from steel.

[LINUS]

ive hit both a large brick and a speed bump with my factory plate and it didnt phase it.

You have any pics? I didn't know there was a factory skidplate. I really don't know that much about the whole BMW thing, so just like the rubber plug for the clutch area I welded up (shows in one of the pics) maybe there's an easier way than me breaking out the welder all the time. Custom is cool and all, but in the end I spend too much time in the garage.