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Making an engine "dummy"

trogdor - 29/3/08 at 02:47 PM

Hi all,

I am trying to get started on my saab project and get this V6 and gearbox trial fitted to the saab. However i will have to modify the engine bay it will sit in.

It would be simpler to make a dummy of the engine and gearbox and offer that up then trying to do it with 300kgs of engine and gearbox.

My first idea was to use a length of wood as a "keel" and attach cross sections of the engine and gearbox made out of ply at intervals along it. However i am having trouble finding ply at a decent price that is wide enough. My second though was too use some type of foam to hack into the right shape but am unable to find any decent sources.

Does any one else have any better ideas?

Cheers

akumabito - 29/3/08 at 02:51 PM

I'm guessing it doesn't have to be overly heavy duty if it is just for a mock-up. Perhaps you could try cardboard? A few layers glued together can be pretty stiff. If it has to be stronger than that, perhaps you could cannibalize some shipping pallets and use the wood to make a box approximately the same size as the engine..

Dickyboy - 29/3/08 at 03:05 PM

MDF is cheap, easy to cut and fairly light. Or get 4 inch polystyrene insulation, sandwich with PVA adhesive (not contact adhesive) and carve from that.

Hammerhead - 29/3/08 at 03:08 PM

old cardboard cut and slotted egg box style (or like you were going to do with the ply) I've used this method for mocking up furniture before and its pretty good. Try not to get it wet

liam.mccaffrey - 29/3/08 at 03:57 PM

http://www.cfsnet.co.uk/

i would do something with expanding foam, vacuum bag the engine and encase within a cardboard box. use 2 part expanding foam to make a female mould in sections.

split the sections and remove the real engine
apply a release type medium to the inside of the mould and rebuilds inside the card box. then fill the void with more expanding foam

Benzine - 29/3/08 at 04:01 PM

I don't know about the dummy engine but can you please take me out for a drive when it's done? I can't emphasize how much I love old saab 96s

trogdor - 29/3/08 at 04:46 PM

will deffo take anyone who wants a ride, but it is awhile in the future. Have decided to strip the car completely as will have to take windows out for welding etc

I like the expanding foam idea, if i can find a big enough bag and box will try that.

How do you vacuum bag something? is it literally a case of putting it in a bag then using a vacuum cleaner to extract as much air as pos?

NS Dev - 29/3/08 at 05:29 PM

Have to say that making a dummy will actually end up making work for yourself.

You are better to get and empty block (which won't be THAT heavy) and an empty head (again not too heavy) and use them, bolted together, for the dummy build.

here's a pic of my locost when i had a dummy engine in it for making the mounts etc.

A "model" dummy engine is of limited use as all the mount holes etc need to be in exactly the right places, so a real block is much better.

XE dummy engine front view

trogdor - 29/3/08 at 05:58 PM

i must admit when making the engine mounts a real block would be much easier. though i not sure i would be able to put the engine back together. It does need a bottom rebuild but i would want to get it running to see how bad it is.

Hmmmm i guess i will have to find a bare block v6 duratec, does anyone have one?

liam.mccaffrey - 29/3/08 at 06:14 PM

ive never done it, but i think a vacuum cleaner would be fine.

despite offering a solution to your query, when i did this i used a stripped down block like NSDev said

NS Dev - 29/3/08 at 06:22 PM

quote:
Originally posted by trogdor
i must admit when making the engine mounts a real block would be much easier. though i not sure i would be able to put the engine back together. It does need a bottom rebuild but i would want to get it running to see how bad it is.

Hmmmm i guess i will have to find a bare block v6 duratec, does anyone have one?

if it needs a bottom end rebuild then strip it down and use it.

they are not tricky to find in decent condition, and you've got plenty of work to do getting the car ready for a running engine.

From my experience, if money is tight,get it stripped down and then take your time getting the car completely ready for the engine. A bare block and heads lets you get everything in place, even down to the brackets etc that always need welding in for bits and bobs.

Then you can sort all the plumbing etc in advance too.

As you get the car ready, and save some money, you can keep an eye out for a good engine to drop in when the time comes.

trogdor - 29/3/08 at 07:55 PM

that is starting to make more sense now, stripping down the engine is prob best. It wasn't expensive anyway, can start saving for a better one, one from a ST220 for instance!

Have been looking at the price of expandable foam and to make a foam engine and gearbox would require alot and its not particularly cheap!

thanks for all the replys

NS Dev - 29/3/08 at 08:08 PM

Also, if you strip the engine, you'll know them inside out for when you get the "real" one to fit later on.

It will seem more work and cost now but trust me its worth it in the long run!