Exhaust temp imbalance

Your cams are out of time. I know you checked them, and I do believe you are competent to do cam timing. It is very possible that your exhaust cams have been swapped by some evil gremlin right to left so that marks line up but not lobes. So, everything checks out, but something's wrong. Check the part numbers on the cams. Also, check the valve 180deg from #1tdc and make sure it's in time. Verify valves opening in same time as firing order.
Ask yourself....how can leakage be fine and compression not....that's the only answer....valve timing.

 

+1 I think Bruce's logic seems spot on your compression numbers are way too low because i think the cams are not sealing during compression.

 

With those numbers and good leakdown this is a great possibility
You seem to have covered everything else.

 

OK tiem for an update:

Ran leak down on Cyls 5-8 all OK - 2% loss.
Removed cam cover to discover something quite unbeliveable.

The cam timing was out, buit it is the extent to which the cam timing is out which is the surprise. I'm not sure how but it looks like the engine must have moved off TDC when the valve timing was originally set.

I'm not putting it back together until tomorrow, but I will post a video when all is well.

The amount an engine can mislead is astonishing. The bit I still cannot get my head around is how what we now know to be the bad bank would even run, let alone run quite smoothly, and how we could not get what we now know was the good bank to run on its own at all. Then their is the mystery of the air/fuel ratio being good on both banks.
All very odd.

 

Back together.

After a bit of fetelling of the thrittle balance here is the result. F355 powered P4 Replica startup - YouTube

Be aware the ignitiona nd fuleing have only be calibrated at idle hence the richness and flame spitting on blipping the thottle.

I'll be keeping the flame spits when its properly mapped though. The video is with the silencers in "quiet mode"b

 

Glad you got it sorted. Wat kit is this the car is going to look as good as it sounds. Of course I'm biased.

 

Its a one off, but does have some DNA from one of the many kit cars copied from the original Lee Noble version.

 

Great glad you got it running better

Looks like fun toy

 

SoCal/Taz,

I tried today to see if I could actally drive the car forwards and backwards a few feet and see if the gear linkages work. (the P4 has the gear lever on the right of the driver and they are right hand drive, so essentailly I have moved the F355 shifter to the right hand sill and built a rather complex linkage system. The jury is out on whether it will give a precise enough change for track driving.

Anyway, no success in having the car move under its own power at all, although it fires up and idles quite sweetly.

The clutch hydraulics are all bled and appear to function - I removed the whole clutch/flywheel assembly and the release bearing moves towards the clutch about 3/8" over one pedal stroke. You can pump up the bearing, so it would appear to be compensating for any clutch wear.

The car the engine and box are from have only done 9k miles, and the general condition of things is good. I have not dismantled the clutch from the flywheel as I do not have a suitable clutch alignment tool.

I think the clutch either slips or semi disengages as when I started the car in gear, I could apply the brakes and I got a good whiff of clutch linings rather than the engine stalling.

I have worked out all the ratios between the clutch and slave cylinders and I have a 1.97:1 master to slave ratio which I think is good given the master pistion has a 1.12" stroke.

So is there any known issue which effects release of the clutch if the car has been left standing for many years? This clutch as not been disengaged since the F355 that it was in was wrapped around a tree in October 2003.

Thanks in advance....