I ordered one valve spring from the S62 motor, to compare to the one valve spring I bought from the 4.6 M62 motor. I am cautiously optimistic that it will work since it is dimensionally identical, with the exception of being roughly 2mm taller. I think this is how they increase the force required to compress it, since the wire gauge looks the same.
I need to squish them both down fully, and measure the height since this “coil bind height” is apparently a critical measurement. Bad things happen internally I’ve read if the coil binds up while the motor is running. I’ll also weigh them, as this should tell me if the S62 springs are just stretched a bit, or are wound from a tiny bit more wire.
****update***
dimensionally the same, except for the coil bind height. The S62 spring is roughly 1.5mm taller when it binds, which tells me that the spring has added windings, versus only being stretched out a bit more. Beyond my capabilities to determine if it’s safe to use the S62 springs, so the 4.6 M62 and S62 springs went to the machine shop with my heads. He can measure the installed height with a special tool and figure out how much margin the S62 spring will have with the valve open, from that.
Assuming the two springs are the same, I’m going to use new S62 springs in my motor. The S62 cam lift is only a couple tenths of a mm less than the 4.6 M62 cam lift, and they cost a lot less than the 4.6 springs. The 4.6 cams have 1.5mm more lift than the 4.4 cams.
***obviously this is on hold until the machine shop can sort it out***
Hopefully I can get those damn cam bolts off today and get the heads to the machine shop. My impact t55 bit arrived while I was traveling for work, so time to put it to good use.
***update***
The remaining three bolts zipped right out with my impact. I suspect the heat I had used, followed by a couple days of sitting with a 40 deg temp drop did it. Heads are dirty, but they look great. Cams and journals look pristine to my u trained eye. The upper plastic guides had deep grooves in them, but were intact, until the impact wrench broke pieces off knocked some free.
I labeled and hung on to all the lifters, just in case something goes wrong with my 4.6 cam plan and I need to rebuild with the 4.4 cams. The younger me would have tossed it all, but I am a bit trainable in my older age. I’ll buy new lifters to use with the 4.6 cams however.
VANOS have been sent off to JimLev for an overhaul and I’m at a standstill on the heads now. The machine shop is very backed up so I’m expecting a couple month wait to hear from them about the springs and see some refreshed M62 heads and valves. In the meantime, I can turn my attention to the bottom end. I need to get the big bolt off, drop the oil pans, pull the lower cover, test the bearings with plasticgauge, and finally pull the pistons and clean them up. They will be going to the machine shop to have the valve pockets relieved a bit to accommodate the 4.6 cam lift.
Aside from the piston work, my plan for the bottom end is new rings and bearings (if needed). Hopefully the crank and rod bearings are as pristine as the cams, but time and plastiguage will tell.