Here's the deal. I rebuilt my own 2003 Boxster 2.7L 5 speed engine after IMS failure. VERY clean rebuild, new shaft that was remachined for the triple row bearing upgrade. Followed factory rebuild specs, new valves on the head that jumped time, new lifters, etc. I can't get the engine to stop the "misfire bank 4-6" on this car.
Let's start this off thinking I am EXPERT level with engine rebuilds. My high end racing motors are ALL still together to this day and I have rebuilt at least 20 racing engines for overhead cam type motors. This includes a Subaru 2.5L engine that makes 400HP to this day on road-racing season #4. I am "familiar" with what it takes to build a modern-ish boxer engine.
This car cranks just fine, but it coughs and sneezes when it runs at idle and has a very rough idle. It cleans up a good bit at higher rpms 3-6k, but runs like crap and makes very little power when trying to drive it. I have checked the cam timing by going to TDC 3 times. The green plugs look good, I followed the factory timing layout by threading in the tensioners while the cam pulley bolts are loose and rolling things into timing positions before tightening cam bolts. I am quite confident that I have everything timed right...
A couple of things to note:
1) I was sent the wrong gasket kit for this engine. Things I noticed specifically were the orings that go between the lifter guide plate and the cylinder head were thicker than factory and a different color...but they went in. Brown was what came in the car, green is what went in the car. I DID reuse one side of brown ones because they just looked perfect and my engine was only 24k miles before IMS failure. I tore one of the other brown ones so on the other side I used green ones. I honestly can NOT remember which side had green and which had original brown, but I know they are different. When it comes to the lifter guide plate, would this cause the plate not to seat well enough?
2) I think the oil light comes on at idle, but I don't know if it's because its SO LOW of an idle and the engine is new.
3) The brand new lifters in one bank did NOT slide in nice and easy...they were kind of sticky and I NEVER should have run them in like this in hindsight. It should have been evidence of an issue, but I thought being NEW lifters they would run in a bit. Is the the source of my problem??? Do those guide plates warp? Maybe the thicker orings were on this guide plate and it's warped because of that?
I am asking these questions just to make sure there is nothing I missed electronically, etc before pulling the engine back out to check the lifters, etc. I'm quite confident the bottom end is together very well and I know that all the wristpins, etc went in fine (checked all with borescope).
I'm out $5k on this so far and I'm exhausted with it. It is SOOOO MUCH work to get done and I just don't want to do more than I already have so far.
ANY input is greatly appreciated.
Patrick Harris
