Evening all,
(Apologies, this ended up being a long post, TL/DR at the end)
Final stages of the 998 turbo rebuild. I bought a Powerlite starter (RAC803) during the first build to give me the clearance I needed for the intercooler, and all worked well. It engaged perfectly well with the MED Stg1 verto flywheel. I also used the starter when we switched back to the 1275 (fitted with a MED flywheel as well).
Now, however, something has changed. The starter only just catches the edge of the ring gear. Fine while cranking with no compress (to test oil pressure), but as soon as I put the plugs back in the pinion slips and disengages.
Wedging the pinion and inspecting with the wok removed shows that there is barely 1mm of engagement which means it's right on the chamfered edge of both gears (explains why it can't hold on with compression).
My first thought was that the flywheel assemble was sat too far down the crank tail, maybe I'd missed some crud that was stopping it seating. I also had a problem where the pressure plate bolts were catching the wok slightly (on the raised section for the engine mount thread). Seemed an obvious answer to both problems. But having inspected the engagement between the clutch center and the crank tail - it's damn near perfect (and appears the same as an OEM clutch center I have on the bench).
So I'm left with two other options - either the crank has moved (it's the same crank and thrusts as the first build showing end float of 0.004"), or the transfer case is sitting closer to the block (it's the same case, I don't remember the gasket thickness used in the last build but the clearance on the idler gear was on-spec with the same thrust washers).
And then there is of course the option that this is two issues - a slight movement in the transfer case which caused the catch against the wok (as it wasn't enough to stop rotation), and something else which means the starter isn't engaging fully.
To make this even more confusing - I have an unmodified 998 waiting on the bench, the starter is even further away from the ring gear on that one! Was it just a fluke that it worked last time?
Before I mill a small amount off the starter (I'll speak to Powerlite first), is there anything that jumps out that I may have missed?
TL/DR: Powerlite starter doesn't engage with the ring gear, along with clutch catching on the wok slightly. Engine turns freely, with correct crank end float and other measurements in spec. What gives?
A similar question was asked here but no answer was given. The distance quoted in that post is very similar to the spare 998 I tested with.
Edited by Icey, 02 May 2022 - 08:34 PM.
