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Cutting hole for air cleaner in bonnet already painted

Started by Torryhead , Aug 16 2014 02:31 PM

bonnet hole scoop cowl

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14 replies to this topic

#1 Torryhead

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Posted 16 August 2014 - 02:31 PM

Hi guys and girls.

It has been a long time since i have posted in the forums! I has had a scout around and haven't found anything specific to my question.

I have an LH with a 383 small block and a decent air cleaner doesn't fit under the bonnet. I moved the engine forward about 25mm to ensure my dizzy didn't hit the drip channel so that probably isn't helping much either. Anyway I have had a miserable 8" air cleaner on the car for a while and it's starving for a decent gut-full of air.

The car is a mock A9X so i have a bonnet scoop already fitted. The problem is everything is painted quite nice.

My question is - What is the best way to cut a hole in the bonnet and only have to feather in with spray gun to keep it looking neat?

Also, should i add any support to the bonnet? everything I have seen on the forum shows there is no real need as the bonnet is of sturdy construction.

I have attached a pic to show the bonnet open and closed. Notice the pathetic little air cleaner. Notice LS1 Hatch photo bombing :-)

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1085091_10153051341255507_1341051633_o.jpg 307.87K 7 downloads
1085084_10153051341235507_2063643371_o.jpg 304.6K 5 downloads

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#2 ls2lxhatch

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Posted 16 August 2014 - 03:39 PM

You could try talking to someone with a water jet cutter.

https://www.facebook...111137065627784

Edited by ls2lxhatch, 16 August 2014 - 03:40 PM.

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#3 wot179

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Posted 16 August 2014 - 04:00 PM

Mask it up with lots of 2 inch masking tape, 2 or 3 layers, and use a jigsaw.

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#4 V-SLR5000-P

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Posted 16 August 2014 - 04:31 PM

Sunroof installers cut roof turrets without respraying them everyday.

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#5 _LS1 Hatch_

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Posted 17 August 2014 - 08:00 AM

I forgot just how small the air cleaner you had was, lol...

I would agree with the comparing to sun roof stuff getting cut out a lot. Lots of tape and all, plus don't forget to paint/seal the cut edge so there is no rusting around it.

I wonder how a thin slitting disc on an angle grinder would work compared to a jigsaw ? (with the good point, might put too much heat into it? Not sure...) I used that method on mine, but the paint on mine isn't all that nice, ha ha..

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#6 _Bomber Watson_

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Posted 17 August 2014 - 09:32 AM

If you buried the ultra thin in and hacked it it would melt the paint.

But if you just lightly ran it around, scoring it, going back over again, etc etc untill you were through you would probably be ok.

Jigsaw is the usual method, make sure you have a really fine blade on it.

Shears would probably be ultimate, good quality ones, but lots of work haha.

Cheers.

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#7 _LS1 Hatch_

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Posted 17 August 2014 - 09:50 AM

If you buried the ultra thin in and hacked it it would melt the paint.

But if you just lightly ran it around, scoring it, going back over again, etc etc untill you were through you would probably be ok.

Jigsaw is the usual method, make sure you have a really fine blade on it.

Shears would probably be ultimate, good quality ones, but lots of work haha.

Cheers.

How about a chainsaw ? I've got lots of chisels I could loan him too.

Air chisel even too...make quick work of things.

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#8 dattoman

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Name:Neil
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Posted 17 August 2014 - 01:44 PM

Nibbler

Lots of tape

http://www.harborfre...bler-96661.html

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#9 _LS1 Hatch_

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Posted 17 August 2014 - 02:29 PM

I've got that actually..

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#10 wot179

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Posted 17 August 2014 - 02:51 PM

Stuff using a nibbler.

That's the worst advice ever, Datto.

They are the messiest bloody tool ever created, and leave an edge that needs plenty of finishing, not to mention they hate painted surfaces.

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#11 mitchg

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Posted 17 August 2014 - 03:04 PM

Seen Chip Foose cut a hole in a painted bonnet with no masking or anything with a grinder.... id never try that though lol

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#12 EunUCh

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Posted 17 August 2014 - 04:57 PM

Big low profile air cleaner that hides the carb..saves a hole...

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#13 _Viper_

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Posted 17 August 2014 - 08:36 PM

As mentioned cover the area in masking tape (about 3 layers is plenty) Mark out your hole, then measure 5mm inwards from each corner and center punch... Then use a 10mm drill bit and drill a hole in each corner... this leaves you with nice rounded corners rather then sharp square ones... you can use a 12mm drill bit or 14mm etc to achieve whatever radius you want just put your centerpunch hole in half the diameter of your final drill bit... ie 14mm hole measure in 7mm.

This also gives you a place to start with your jigsaw... As mentioned used a very fine tooth blade and a new one at that... a wider blade is better for straight cuts... if its a nice sharp blade a jigsaw will create very little heat and wont burn the paint past the cut line, helps to start with a cool panel too ie dont have the car sitting out in the sun a black bonnet can easily get to 90 degrees C. Can use a file or even a orbital to clean up the cut if needed after. Be sure to paint the edge to stop rust.

For a neat finish you can get nice C-section rubber (small pinch weld) to put over the exposed edge too.

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#14 Torryhead

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Posted 28 September 2014 - 05:47 AM

Awesome,

thanks guys. Sorry for the late reply, the car only just went to the shop to get the work done. Thanks for all the info on cutting the hole. I have tonnes of info to go with and I have had a lengthy chat with the bloke who is going to do the job so i'll keep you all posted. Cheers!!!