My freind and I wanted to make a "long game" sceneraio with 30 civs in it. What happens though the game goes by so fast because of all the civs trading. What we wanted to do was disable all wonders of world except manhatten project and alike ones.

And add more resources so the game came down to more trading for resources and happiness...can anyone help?

Well, if you want a longer game with more resources and 31 civs, just play DyP :p

Back to the title question, I know of no way to disable tech trading. What you can do is disable the great library, kick the tech rate for the map up and increase the min/max number of turns to research; some or all of those should slow research down.

Additionally, delaying or removing the ability to trade communications could slow down tech (and all other) trading as the civs will all have to explicitly meet each other first.

If you make tech no-era it should prevent tech trading.

To be more specific, any Era "None" tech cannot itself be traded, but techs from the 4 standard eras can still be traded in that game. My assumption was that the initial request was for a generic "never trade any tech" ability.

I've limited tech trading by increasing cost of advances 50-100% and lowering ai to ai trade to 110. Bigger cost of advance seems to work better than just bigger tech rate. Ai cost factor should be also low: Then it's relatively easy for ai civ to research stuff for itself but it will not go around selling it for two cents like it usually does. This way the lesser civs will not keep so updated and the game won't be like a big world wide commie conspiracy against your civ.

edit: Oh yes, also minimum research time I have 7-8 and maximum 25. I've also added some twenty new techs - in my last two games i hit the middle ages in 700-800AD and industrial in 1650-1700AD.

Unfortunately you can't prevent tech trading.

The propensity for AI civs to trade techs for a dime with each other and extort the human has frustrated me for awhile.

Reduce AI to AI trade rate helps the most. At 100 they theoretically trade at 1 to 1, but they almost certainly still cheat some. Below 100 and the AI will have a disincentive to trade. But, this affects resource and map trading to.