75ZT Community

Hi members this is my version/preference of the plenum spy hole mod, which helps you to regularly check the lower plenums from getting blocked with debris ie leaves and muck, thus filling up with water and potentially damaging the ECU (Engine Control Unit) which in turn is very costly to put right.

First remove the scuttle cover by releasing the two clips and lift away and put in a safe place, fig 1
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Second pull back the rubber moulding which joins onto the bulk head peel it at least half way. fig 2
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Thirdly remove the scuttle clips being careful not to lose them as they can ping off but i lost none as i put my finger over the top and prise up remove at least first three,keep in safe lace for later figs 3/4
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Fourthly remove the arrowed bolt or screw which ever you have i have a bolt because i changed mine from the plastic screw.fig 5
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Fifthly lift scuttle and tray slowly wriggle the scuttle tray back and forth to the wing it is not hard to move so do not worry,fig 6
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keep wiggling as you do pull forward toward you and it will soon release,figs 7/8
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scuttle tray removed and ready to be drilled creating the spy hole for future prodding and to keep those plenums clear.fig 9
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Right lets now mark and measure for the hole to be drilled i used a 25mm wood drill bit, mark a line at the end of the plastic ridge in photo 1 using a metal rule if you have one.
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From this drawn line measure back 100mm draw a small line photo 2/3
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Next use a 10p coin to mark the hole for drilling or measure in from ridge 23mm or 7/8" which ever you feel best with and find the centre.photos4/5
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Once the centre as been marked you are ready to drill the hole with a 25mm wood drill bit in my case you may have a hole cutter.photos 6/7/8

You will need some wood support under the tray for drilling.
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The hole now finaly drilled photo 9,it can now be cleaned up round the edges phots 10 for the rubber bung to be fitted which is 23/24mm depending on what you can purchase £2.00 for 4 or you maybe able to purchase just one for pence ? but always best to have a few incase you ever misplace it.

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Rubber bung fitted ready for the scuttle tray to be refitted to the car, photo 11
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Quick reference remove scuttle tray mark & measure
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Drill out with support underneath tray
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note the chamfer on the ridge thats why i marked two lines 95mm and 100mm for ease of measurement also note the far 180mm mark for more reference.
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I mean of cause it is easy for me and quick now becasue i have a template
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I have infact already purchased some scuttle trays and pre drilled them for exchange at the nano meet should anyone want to have this mod,
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Remember this mod make it easier in the future for you to rod those plenums so no water damage can occur to the ECU its now fast and efficent.
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Save having to do it the old way as below removing all the scuttle everytime you need to rod the plenum, note the water imagine if left unchecked how it would soon fill up and damage the ECU.
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Now nice and dry and will remain that way with a weekly quick check thanks to the spy hole mod.
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Now i know this mod can be done in situ but it is a smaller hole than mine and works well so i am told but does it make sure all the gunk is removed from the plenum i know this way does ? you makes your choice as the saying goes.


Also when drilling in situ dont forget what is under the hole being drilled the ECU and its wiring one slip and who knows the out come.
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good luck and take it carefully if you intend to do this mod Arctic.

Or---You can leave your car unatended when "RovingDenis" is around... heh heh..
...

a good mod but what happened to the shatter proof ruler. peter.