I've gotta cut a hole in my bonnet for my air filter (pinto), it's an ITG sausage filter so it's not as straight forward as the usual "square" type ones. Has anyone done this and what's the best way to get the hole the right shape?

Also, what is the best way to cut a hole in fibreglass? I did my exhaust exit hole with a junior hacksaw but in a fair few places the fibreglass has chipped off so I'm going to have to do it again

Cheers

Pete

[Edited on 18/8/04 by scoobyis2cool]

mark it out, use a hole saw to get the corners all nice n neat, then cut the straight lines, does that make any sense ? prob not............

Thats how i did it two big holes and stright line with a jigsaw use lots of masking tape as this stops it chipping and then file the edges(see photos) had to do it twice for the twin socks.
barrie

My hole won't really have any straight edges, it will be more like an ovally-egg type shape. I'm not sure how to mark it out as the filter and bonnet are both curved making it very difficult to figure out where they will be in relation to each other. I was thinking of just making a small hole, seeing where the filter still touched, then making it bigger, and repeating until it looks ok

Pete

I just covered where the hole was to be with masking tape. then took the bonnent off put the sock on and measured from the nose to the edge of the sock then transfered the measurements to the bonnent .
Is your ITG sock like mine(sorry dont know how to link but in my photos under ready for sva) if so i will measure hole size tonight for you and post better photo
barrie

For precision work, the most useful tool I have is the Dremel - very handy and has got gazillion attachments.

Maybe you should make a kind of a template of your filter - or at least the part which should stick out; lay that on top of the bonnet, mark and cut along those lines.

I saw a nice thread on hotrodders.com showing how to make a template using fibre/foam? tape.

Good Luck.

Bend a piece of card or cardboard to the curve of the bonnet then cut it to fit round the filter. Tape the bonnet with 2" masking tape then tape your template to it. Either draw round the hole in the template or leave it in place, then drill a hole big enough for your saw blade inside the line somewhere and cut out inside the line with a fine tooth blade. If you can get a blade that cuts on the downstroke it will lessen the splitting.

Stick a sharpend bolt in the carb /airfilter mounting screwhole with masking tape on the bottom of the bonnet. The sharp ends make the marks on the tape transfering the position of the carb to your bonnet. Base of air filter marked out on the bottom of the bonnet( right way round!!!!!!!!!) then drill the holes through to the other side. You will then go thru to the finishing others have described in the post.

Hi

These are good !

Rough cut hole small, then final shape with one of these.

Paul G
Rescued attachment flappers 004s.jpg

worth laying up a few layers of GRP on the underside of the bonnet where you are going to cut the hole. This will give stop the bonnet sagging / flexing when you have cut the hole.

just my 10p's worth