scobo wrote:If you can get to 55 minutes, I'm pretty confident you'll be able to go much longer by adding extra cooling (heatsinks).
The longest I've tried so far is about a 7 print which finished perfectly.
The only times I have trouble with PLA now is if the print slows down too much (less than about 15mm/s) but even then it's rare.
Thank you scobo, your mod is very smart and worked great, i added the heat sinks from an old motherboard 
Just finished a 12 hour print with no extrusion problems (had to narrow down the time from the previous try, halved height) and i am posting my results.
Compared to a very similar print with abs but also using slic3r instead of simplify3d, there are some quality issues. I don't know yet if it's about the settings or the material itself so i'm posting my results with the settings.
Some major positive facts using PLA is the far less warping and the reduced preheating time compared to ABS.
The quality issues are focused mostly at the horizontal surfaces (gaps inside the top infill), in areas with more detail (lines are not smooth but curly) and also there are randomly some bumpy spots in the vertical surfaces.
I'm also attaching most the settings used to print this model.
The temperature was set at 225 degrees for all layers.
Post's attachmentss3d_settings.jpg
s3d_settings.jpg 732.86 kb, file has never been downloaded.
You don't have the permssions to download the attachments of this post.
