I was still suspicious of broken ringland(s) and did a compression test. It showed 11.5-12.5bar when cold. Warm engine had 10 on first cylinder and the rest were the same. There were also signs of oil on 1. and 2. cyl. pistons.
A week ago on Sunday did a teardown and pistons were okay. There was oil on top of every piston so it was because of piston rings even though they felt and seemed to be ok. T4/T5/T6 has three different types of pistons and naturally I had a ring set for a different type. Swapped the pistons to ones with presumably good rings and slapped bottom end back together.
Luckily 240 has an easy access cross member
Checked the valves with brake cleaner and almost all were leaking. Seems like the compression drop on cyl 1 was because of them. ~2.5 years ago after I got the engine together I adjusted the cams. While engine rotated freely by hand, the sound it made when running meant that intake valves did meet the pistons. It has worked fine ever since so I wasn't too worried. Head got machined on Monday and installed it the same evening. Wastegate inlet flange showed signs of leakage and I filed it straight.
On Tuesday evening installed the rest of the stuff, ran it hot with a "cleaning" oil and changed driving oil and filter.
Radiator(Griffin) had been dripping between left end tank and upper fins for almost two years already and lately it had developed into a leak. Soda blasted the spot, gave it some heat and dropped car body solder on to it. For now seems to be holding fine.
On Wednesday swapped in FWD coils which this engine had before and now it has again good enough spark for higher boost. Friday was the day for a routine check before going to the track, change of front brake pads and install of new 224/45/17 Federal RS-PRO on to Comets.
Vrcf trackday on Saturday was on Botniaring which is a 800km/500miles round trip. Basic operation is to drive there and back including the track time. With the longer layout it's a nice track.
First set went smoothly but on the second run the car started shaking bad like having a broken u-joint. Engine died and shaking stopped when depressing the clutch so it wasn't a driveline issue. Rolled in to the pits and found a broken harmonic balancer that had ground the crank sensor and bent the sensor bracket. Trigger wheel kept the piece in place and nothing else was broken.
Removed the disc, bent the sensor bracket back and it fired up just fine. Revved the engine some and no apparent changes in behaviour. Curiosity got me and decided to take it back to the track with low rpm. Drove two sessions gradually driving faster but leisurely, until front brakes got too hot, without any issues. Drove all the tighter turns on 4th gear and it went surprisingly well. Braked like a granny too
I'm really liking the tires, good grip all round and more quiet on the road than the old 205/50/16 RS-R.
An incar lap and a short outside shot:
https://www.youtube.com/watch?v=r8p7nUrYUdM
After getting home made a check up and replaced the balancer. Still couldn't make a clear difference in resonances. If there is going to be consequences then there is
Some assembly required?
Didn't find anything big while going through the car, just a leaking left rear wheel bearing inner seal and a deteriorated fuel tank cap seal. It spilled a little on tight left turns.
Liking the Comets as well, didn't think they'd fit to the look. A shot of a dirty car after the track time.
Around 1400km/875miles driven after last Tuesday evening. Before there were visible oil puffs every now and then after a long engine brake, now it can't be seen from the mirror so something went right