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GretchenGotGrowl · 11-11-2012, 10:03 AM

Sorry for the confusion. Here's the back story.

Right before CFest we had an issue with the LLT (broken valve cover and subsequent leak down in two cylinders). Decided to run it anyway and just buy a new motor for a forged build. We suspected it was the tune so we were a bit apprehensive about not being able to at least see the logs going forward. We investigated swapping ECUs and even buying an LFX but it all looked a lot more expensive than just trading the car in. So, we pulled the LLT motor from Gretchen and put the new one we were going to build in her. That car was then traded for the 2012. Before we got to far with this build we wanted to know exactly what failed on the original LLT motor so we could address any weak spots. Here's what we found.

About 1/8th of the ringlands on two cylinders broke off. Because the tolerances are so tight on these motors, they stayed in place and the block/heads look fine. That's the bad news. The good news is that these rods are something else...they should take a lot of punishment. The bearing are also tough -- as much as I put that engine through they look brand new. The crank looks fine as well. These are very well built motors, but the Bosch ECU is not as friendly as we would like.

So the take away is we are ordering some forged pistons and lowering the compression ratio. That will take about two weeks. After that we should be ready to tune. Hopefully we'll have some numbers early December.

Again, sorry for the confusion.

11-11-2012, 10:03 AM	#151
GretchenGotGrowl Drives: 11 F150 EB/13 Sonic RS/15 Z06 Join Date: Sep 2010 Location: Little Rock, AR Posts: 7,129 View My Garage	Sorry for the confusion. Here's the back story. Right before CFest we had an issue with the LLT (broken valve cover and subsequent leak down in two cylinders). Decided to run it anyway and just buy a new motor for a forged build. We suspected it was the tune so we were a bit apprehensive about not being able to at least see the logs going forward. We investigated swapping ECUs and even buying an LFX but it all looked a lot more expensive than just trading the car in. So, we pulled the LLT motor from Gretchen and put the new one we were going to build in her. That car was then traded for the 2012. Before we got to far with this build we wanted to know exactly what failed on the original LLT motor so we could address any weak spots. Here's what we found. About 1/8th of the ringlands on two cylinders broke off. Because the tolerances are so tight on these motors, they stayed in place and the block/heads look fine. That's the bad news. The good news is that these rods are something else...they should take a lot of punishment. The bearing are also tough -- as much as I put that engine through they look brand new. The crank looks fine as well. These are very well built motors, but the Bosch ECU is not as friendly as we would like. So the take away is we are ordering some forged pistons and lowering the compression ratio. That will take about two weeks. After that we should be ready to tune. Hopefully we'll have some numbers early December. Again, sorry for the confusion. __________________ New Ride -- 2015 Z06 2LZ (stock) -- Journal Old Ride -- 2012 Camaro 2LT/RS (647 RWHP & 726 RWTQ) -- Build Thread Last edited by GretchenGotGrowl; 01-17-2013 at 04:23 PM.