who still has an underbody tray?

[lostforawhile]

I picked up a pile of stuff today at the yard for 10 bucks including an underbody tray in excellent shape, who else still has theirs? I've never seen a car with one at the yard in all the years I've been hunting parts, I posted this in performance because I'm wondering if this is actually an aerodynamic item? with it in place and bolted down it really seems to smooth out the entire front end and bottom of the engine, there's a lot of stuff under there to create drag, and this seems to cover all of those items. I know sports car makers have used these for decades to improve airflow.. It not only does that,it also helps your cooling system to work better by creating a vacuum that draws air through the radiator, and it keeps water from soaking everything,when you go through a puddle.

[ecogabriel]

From your description, you seem to refer to the plastic piece that encloses the area between the radiators and the engine from below.
From the sides, it has openings for the front suspension rods and the crank pulley.
I do have mine installed; someone made an opening for accessing the radiator drain valve.

[lostforawhile]

yea it's a good size piece, has one rip which I can fix with plastic repair compound and fiberglass cloth. I was reading on another site where a piece like this caused 12 horsepower less to be needed at 125 MPH on a BMW, if you look at the car from underneath,the front cross member,radius rods,and everything else is just hanging out in the wind, with this in place,air from the radiator would be draw along the tray,along the oil pan and along the transmission,before going out the back, this is caused by the vacuum created under the car. without it, air would just be sucked out in a big turbulent mess,plus you have the big square cross member pushing through the air. My car has never had one, although pieces of the original are still attached to the bolts, I suspect a lot of them get removed for repairs and never installed again.

[89HatchbackLxi]

I believe my hatch still has this on it... Although it is scraped up a little in one area.

You are referring to this piece right?
http://i48.tinypic.com/2ijitg.jpg

[lostforawhile]

yea, I've had my eye out for one, but this is the first one I've found, I'll need it anyway with the alternator at the bottom now. The only issue I'll have is getting out the broken bolts, but they will come out, I broke off every one at the yard, and several of mine are broken. I got under the car in the sand and fire ants to get the radiator bushings out and holy shit! it's all there. It will go back in with all stainless socket head bolts

[obdriver6]

I still have mine but its slowly disintegrating since I lowered my car! lol

[import racer]

Yeah my SEI has one still but my other cars never did.

[Tdurr]

Ive only evervseen one of those things and it was on an elderly laides mint 4door like my old one, cpt it was carbed. I almost shit a brick when it came in to the shop for an aglinment cuz it was so minty.

[A18A]

only one of my cars had one, i threw it out. i wish i didn't though :(

[gfrg88]

I've seen plenty at the jy...

[ghettogeddy]

i always take mine off and toss them cause there half there and there just a pita to put back on

[DBMaster]

I still had mine. If the thing weren't needed why would the engineers have even bothered to design the overly complicated thing? I had actually cut out a hole in mine to access the radiator drain, too. I even had plugs in the holes that access the radius rod adjusting nuts. It kept those things super clean.

[import racer]

Yeah I find it keeps the front end from rusting up so bad.

[MessyHonda]

i always take mine off and toss them cause there half there and there just a pita to put back on

yeah same with my car. I do believe the purpose of the tray is to keep water out of the engine bay. because once i took mine off and lowered my car. drove in the rain= failed alternator, changed it with a napa performance one 80amps and never had a problem

[lostforawhile]

yeah same with my car. I do believe the purpose of the tray is to keep water out of the engine bay. because once i took mine off and lowered my car. drove in the rain= failed alternator, changed it with a napa performance one 80amps and never had a problemwell it's an aerodynamic item too, if you look at the difference with it on and off, you can see why. It's also supposed to be part of the cooling system shroud for the radiator, it basically creates a better vacuum under the car and helps move air through the radiator.since my alternator is now where the AC compressor was,definitely gonna need it

[cruzetheskye]

Still have mine.

[Dr_Snooz]

yea, I've had my eye out for one, but this is the first one I've found, I'll need it anyway with the alternator at the bottom now. The only issue I'll have is getting out the broken bolts, but they will come out, I broke off every one at the yard, and several of mine are broken. I got under the car in the sand and fire ants to get the radiator bushings out and holy shit! it's all there. It will go back in with all stainless socket head bolts

I still have mine and it's in relatively good shape. You've pretty much discovered why they are all gone though. The bolts rust up and strip out, fall out, etc. The original bolts are a special design made of aluminum or some other very soft metal that fails easily. BUT....they have a special shank design that doesn't compress the plastic. If you replace them with standard bolts, they will squash and break the plastic, leaving you where you are right now with shards of the old shield under your car. You want to spend the money at the dealer for the special bolts and they are quite expensive for what they are. Also, expect that there won't be any remaining useful threads in the body to hold the bolts in. I have a number of bolts that are nothing more than ornamentation. I'm not really sure how to repair the threads. The metal there is so thin that HeliCoils aren't an option and you can't tap it out and put a larger bolt in, so you just tighten your bolts into thin air and hope, I guess. If you come up with a better solution, let me know.

Also, the thing takes about 15 minutes to remove and another 15 to put back on. It's a real time sink.

[DBMaster]

I think if you can find bolts that work in the stripped out holes you could use some plastic, or metal, washers to spread the force. And, don't make them too tight. I think I have a few in my parts bin that I pulled from a junkyard because my mechanic, of all people, left out a few of them. I literally had all of them in place and functional.

[A18A]

or use bolts from most cam belt covers, just add a washer to them

[lostforawhile]

I still have mine and it's in relatively good shape. You've pretty much discovered why they are all gone though. The bolts rust up and strip out, fall out, etc. The original bolts are a special design made of aluminum or some other very soft metal that fails easily. BUT....they have a special shank design that doesn't compress the plastic. If you replace them with standard bolts, they will squash and break the plastic, leaving you where you are right now with shards of the old shield under your car. You want to spend the money at the dealer for the special bolts and they are quite expensive for what they are. Also, expect that there won't be any remaining useful threads in the body to hold the bolts in. I have a number of bolts that are nothing more than ornamentation. I'm not really sure how to repair the threads. The metal there is so thin that HeliCoils aren't an option and you can't tap it out and put a larger bolt in, so you just tighten your bolts into thin air and hope, I guess. If you come up with a better solution, let me know.

Also, the thing takes about 15 minutes to remove and another 15 to put back on. It's a real time sink.

the ones that came out of the other car just look like regular 5 mm metric bolts, it's just plastic like the inner fender liners, every body bolt that I take out gets replaces with stainless anyway, you just put a fender washer under each one and don't over tighten it is all. I will get the damaged bolts out of my car, not a big deal

[import racer]

I used some of the bolts I saved from old cars I junked,mostly from under the dash.I also put some synthetic aircraft grease I use on most bolts I take out and reuse.

[ShyBoyCA6]

I still have mine.

[Legend_master]

Might is still on, but the previouse owner did not understand ground clearance. Its seen better days.

[Dr_Snooz]

I think if you can find bolts that work in the stripped out holes you could use some plastic, or metal, washers to spread the force. And, don't make them too tight. I think I have a few in my parts bin that I pulled from a junkyard because my mechanic, of all people, left out a few of them. I literally had all of them in place and functional.


or use bolts from most cam belt covers, just add a washer to them


the ones that came out of the other car just look like regular 5 mm metric bolts, it's just plastic like the inner fender liners, every body bolt that I take out gets replaces with stainless anyway, you just put a fender washer under each one and don't over tighten it is all. I will get the damaged bolts out of my car, not a big deal

I'm the only one with any OE bolts left apparently. They don't actually apply any force to the tray at all. The fender washers will. The OE bolt shank flares out where the threads end. Slightly farther up is the flange/integrated washer that holds the tray in place. The shank tightens to the body of the car and the flange holds the tray in place without applying any real force to it. If you think you can just put a fender washer on and be fine, maybe you can. Just know that is not how it was designed to work. All the torque you apply to that bolt will be transmitted through the plastic of the tray to the body.

Like I said, the OE bolts fail very easily and I suspect they got changed out with regular bolts + fender washers over time by mechanics who believed this was just fine. The end result was a cracked, broken and ultimately discarded underbody tray.

Do what you think is right for you, of course. I just thought you would want to know how the OE setup works so you can make an informed choice.

[DBMaster]

I also had the little plastic pop clips that were on the front part of the pan. The pan was a bit beat up from scraping pavement a number of times in its life. Truth be told, you probably do not need ALL the bolts in place to keep the thing secure. There sure are a lot of them - about 10 as I recall?

[lostforawhile]

I also had the little plastic pop clips that were on the front part of the pan. The pan was a bit beat up from scraping pavement a number of times in its life. Truth be told, you probably do not need ALL the bolts in place to keep the thing secure. There sure are a lot of them - about 10 as I recall?
the fender washers won't hurt it, I know the hardware snooze was talking about, you just don't overtorque them, it doesn't take much to hold it, I use stainless anyway then they don't corrode like the originals, I'll probably make one of my special tools with a piece of allen key on a piece of rod for reaching the back one, I would say you need all of them or it will sag at certain points

[lostforawhile]

I think I could make some crush sleeves to go over regular bolts,this wouldn't let you over tighten the bolts, I think a fender washer with a rubber washer behind it is the best bet. once you replace all that mess with stainless, you never have to worry about rusted bolts again, I fixed a lot of hardware issues,I got rid of the awful plastic push rivets holding the cowl, and replaced them with nutplates riveted on, then I just use regular bolts with special washers I made, on the fenders I'll be installing rivnuts into the fender sheet metal to hold the plastic liners on, they install like rivets with a special tool,and they are threaded in the middle,same thing to install the liners, small fender washers with rubber washers behind them,easy to remove and install with no damage

[lostforawhile]

I have a friend of mine on another forum who can sand cast aluminum, what about if I make a mold off of the section that goes around the exhaust and have it cast in aluminum then rivet it on? this would prevent melting around the headers, the other option is to make a piece with heat resistant fiberglass, and use it.

[Dr_Snooz]

once you replace all that mess with stainless, you never have to worry about rusted bolts again

That's the hope. The bolts, however, don't rust because they are made of some cheesy pot metal. The bolt holes in the body are what rust. By contrast, the threads on the crappy bolts simply mush flat and/or strip off. They are truly remarkable feats of engineering: highly specialized, expensive to produce and still inadequate to the job. There should be an award for that.

[lostforawhile]

That's the hope. The bolts, however, don't rust because they are made of some cheesy pot metal. The bolt holes in the body are what rust. By contrast, the threads on the crappy bolts simply mush flat and/or strip off. They are truly remarkable feats of engineering: highly specialized, expensive to produce and still inadequate to the job. There should be an award for that.

blue locktite to keep them from falling out and it also prevents the threads from galling to the steel

[pickupman6]

I'm with mike. I was thinking the same thing when someone mentioned threading it into nothing. I have used those cheap black plastic "christmas trees" tons of times on customers vehicles when the bolts strip out or the thin metal they screw into strip out. The 2 piece push clips are even better yet, but tend to be sightly more expensive and sometimes don't work as good.

Edit forgot to mention, I have had good luck with using metal lines (like the off the shelf brakelines. I've found them all the way up to 3/8") for shims to keep from crushing the plastic. Just find one that slips over the shank of the bolt and cut it to the thickness you need so that when you tighten it down, it snugs up against the plastic just before it tightens on the bushing.