ALFAGTV6.COM

[kevin]

Removed side windows after much sweat but got them out. Fiberglass bootlid is a perfect fit. Just need to figure out which is the best way to fix the lexan glass to the lid. If I use rivets I heard if you use rivets you must drill holes larger for expansion otherwise window bends in the hot sun.
Should I put any silicone under first to waterproof. Ideas , input ....
MD, Jes, Mats etc what did you do ??

[MR2 Zig]

I'd say put some silicon under the lexan and around the edges.

Why not use bolts to fasten the lexan? Wait a minute ....the silicon should do just fine by itself...maybe a bolt in each corner to make sure it doesn't come off when racing. Small bolts at that...3-4 mm?

[kevin]

MR2, I am worried if i just used silicone it would blow right out with front windows open at high speed. maybe few small bolts ..

[Mats]

Mats, strange you ask as I had three new rear boxes from 1985 for the GTV 6 2.5 . Which ever car i have put them on over the years its had that similiar sounding 2.5 v6 whine. This car is just deeper though. This rear box was made here in South Africa for Alfa Romeo, its a 63mm ''free flow'' box.
The rest of this 3.7 has 45mm headers into 57mm downpipes converging into 63mm then into first silincer box under gear lever and then 63mm through to end box.
I have found that you can vary the note of these v6 engines if there was a scale from 0 to 100. My 3.2 sounds like another car altogether with one box , but then it does have a different bore.

That's exactly what I have found as well. Volume in the boxes is mostly volume, diameter of the pipe affects both volume and tone.

2.5" eh..?

[MR2 Zig]

You could go more if you want...say 3 across the top and 3 more across the bottom. I'd use bolts so you can replace the lexan easier than with rivets is all...that stuff seems to attract scratches.

[MD]

Kevin,

Regarding your hatch window.

Never use silicone around any panel work that may require painting. It's a pain in the arse 'cause it will reject any paint application and once you contaminate the area it's a nightmare to get off.

Forget silicone-sorry Ziggy.

Use polyurethane instead. Comes in variuous grades of bond strength. I use a Jap product called "Sikaflex". Takes time to cure but once it has, your window will be watertight and secure.

Trick is, you need to double mask the window on the inside and the outside around the recess it will go into. This is to limit the ooze of the poly from spreading over the areas of the window that you dont want because getting it off is a bugger.

First step is to place a small bead of sealant around the recess completely followed by insertion of the window. Place some weights evenly across the window edges for it to sit well and equally everywhere around the hatch well. Leave it to cure for 24 hours.

Second step is to decide whether or not to use additional mechanical fixings like rivets or bolts. Using rivets will eventually cause the window to crack. Using bolts I have no experience with. Either way, the holes in the plastic need to be bigger than the holes in the metal edges. This is to allow movment of the plastic with heat from the sun otherwise it will crack if the sun around your place is anything like around here.

Finally, you need to apply the balance of the sealer on top of the previous two stages and make a tidy finishe of it as you go.

Remove any excess when pulling off the masking tape.

Not as simple as it first seems...

[scott.venables]

For expansion rates, have a look at:
http://www.engineeringtoolbox.com/linea ... -d_95.html


What about a rubber rubber gasket the lexan can skate around on? And some M4/5 button head screws with large washers on the lexan side, and nyloc nuts on the hatch side, so you can tighten them up to just put a little bit of pressure on the gasket. And oversize holes in the lexan.

Scott

[kevin]

Ok,MD I dont get sikaflex here but the problem is i am using a light weight fiberglass bootlid and for some reason the lexan it gets badly damaged , it will be impossible to get it out. From what you MR,scott said I will stay away from rivetts. If I dont find a gasket(scott) then I will use slicone in conjunction with 3-4mm bolts drilles through larger holes with washers.
Great when you guys find a solution!

[MR2 Zig]

If you haven't already, try a glass shop. They will likely have generic window moulding like that used to keep windows in the old landrovers. that would allow for expansion, etc. and make replacement easy as well.

[Mats]

I think mine is only held on by the std rubber bits, plastic lid and PC window. Seems to work fine...

[kevin]

Got rear windows in today doing two cars at same time hence different colour boot lids in pics. I used a one side sticking gasket strip for the PET to rest on . Then used 4mm cap screws with nyloc nuts through a 4.5mm hole. Next step will be to wipe a thin coat of silicone around edges to seal off. Thanks guys for info on fixing.
Cost was 200 euros complete if covert rands.

[MR2 Zig]

you didn't say anything about not needing to see thru it or I'd have suggested sheet carbon fiber

[kevin]

These are clear sheets with protective plastic each side , which I will take off once I have finishes everything. (less scratching).

[MR2 Zig]

I know, i know ....just joking around

[kevin]

Sorry missed that humour, its early Sunday morning after heavy night, i forgot to see you hiding behind sandbags(like my eyes at the moment).