maxing out at 250? something isn't right. firmware wasn't updated properly, or something...
I was just recently running some nylon at 270 with no problems at all.

1 thing to check - make sure the E3D fan is not below the bottom fin of the cool side - a misaligned fan can cause issues.

I just had another issue with extruder temp, it was struggling to get 240 and when I tried to see if it would get any hotter it would only max out at 250 C. All fans are running like normal without issue, anyone else seen this?

Here are a few pics of some items that developed cracks 2-3 weeks after printing. This was with old solidoodle head at 200-210 C.

I have never had parts crack several days later, either... if they are going to crack/split, it is usually during printing, or right after taking it off the print bed from cooling too quickly (impatience) .. days later? nope.

FWIW, printing too hot can cause just as many issues as printing too cold. you need to find that sweet spot that is just right.

I am thinking that the cracks you are experiencing are from using the incorrect layer height - using 0.3 as a layer height will cause rounding errors in the steps on a Solidoodle with the stock 5/16" threaded rod which will cause problems in your layers not adhering together well enough.

Wardjr is not just making up numbers, either - using the RepRap Calculator gives the same results as what he is suggesting...

Try it for yourself: http://prusaprinters.org/calculator/#stepspermmlead

I use 260 C for ABS because at colder temps my prints grow cracks in 1-2 weeks. When I acetone smooth it is very evident of multiple white cracks. My friend goes up to 270 C with ABS for better adhesion, he read this somewhere else in this forum site.

As for first layer here are some items
- with old solidoodle head I had a nearly perfect flat first layer, no weeds or anything, no plastic bulges or bumps. Now with E3D it is a mess. I only use Hatchbox, only variable that changed was printer head and temp of printing.
- build plate is level, I have a zebra plate attached with binder clips and I have sanded it many items so it has created a little waviness that I live with.
- For my first layer I jam the plastic into my build plate so I get perfect adhesion and no lifting during print. I know that causes some sputtering or irregularity in some areas when combine with my worn zebra plate.

How can I make solid infill lines of plastic be spaced out while keeping spacing for everything else?

Slic3r is version 1.2.9, how would I check Marlin version?

For filament when I get roll open I check first couple feet at multiple points.

The biggest concern about all this is that when I printed at 200 C with old Solidoodle head there was no issue at all, perfect extrusion, then just switching to E3D and 260 C printing overextrusion.

If I only print the walls and no solid infill it is still good, solid infill is the problem area for too much plastic.

260C is a bit hot for ABS - should be more in the 235-245 range - 260 is more of a nylon temp...

for Marlin version, toggle the log on in RH when you first connect to the printer it should show.
Will look something like this:
07:40:28.073 : FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:https://github.com/ErikZalm/Marlin/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:Rumba EXTRUDER_COUNT:1 UUID:00000000-0000-0000-0000-000000000000

i would also suggest reducing the overlap a bit.

not really sure why, but Hatchbox ABS seems to 'expand' more than other filaments on that critical first layer - even with overlap set to 0, it goes down like it is over-extruding - subsequent layers even things out, but that first layer always looks like an overgrown weed field. and it is ONLY the Hatchbox that does this. Octave & Inland ABS don't do this.

increasing the first layer height a little does help a bit - my usual 1st layer height is 0.29, increasing that to 0.31 helps the HB go down a bit smoother on that first layer

For filament when I get roll open I check first couple feet at multiple points.

The biggest concern about all this is that when I printed at 200 C with old Solidoodle head there was no issue at all, perfect extrusion, then just switching to E3D and 260 C printing overextrusion.

If I only print the walls and no solid infill it is still good, solid infill is the problem area for too much plastic.

- I have done extruder stepper calibration just to make sure steppers give correct amount
- I have done single wall calibration successfully
- I use hatchbox ABS with typical setting of diameter 1.66 mm and extrusion multiplier of 0.85-0.86
- Printer settings I set nozzle diameter at 0.48 mm
- BEFORE E3D I never touched Print advanced tab, I left everything at 0.
- From reading this I went and updated my print advanced tab to everything being 0.48 mm and first layer as 100%, infill overlap at 15%

From all this I am still getting overextrusion. What settings do you guys have that work? Just frustrating I did E3D upgrade and prints are worse and I know it is software related. I am attaching photo of print I am doing right now.

Upgrading the driver, if possible, is a great work around to a 1.8 motor. If it is not possible, upgrading to a .9 motor is a great work around for the inability to work on integrated drivers. Regardless, the Goblin upgrade is a solid step in the right direction.