Elvira : Rebuilding the 36hp, episode 9 : Flywheel and Cluch
episode 9 : Flywheel & Clutch
OK, time to put the flywheel back on... Where is it, by the way?
Confession of the day : I've spent hours upon hours, month after month, looking for my flywheel. I completely emptied my 3 garages, twice, and I was still unable to find the bloody thing.
I finally came to the conclusion that I possibly had thrown it away by mistake (!), and right before I started looking for another one (they're not easy to come by, them 36hp flywheels), I gave a call to my friend Laurent, to ask if I had not left my flywheel at his workshop when we closed the engine block...
I didn't expect much as I thought I remembered him telling me it would be better to keep all the parts together...
But he told me "yes, sure your flywheel is here!!".
GRRAAaaaaRRRGHh!!!! So much time lost! Damn, I could kick myself in the ass! #StupidOfTheYear
On my flywheel, the oil seal running surface was pretty dull : some pitting, lots of oxydation... In order to avoir any oil leakage from there, I had to do something about it.
So I polished the running surface, starting with dry sandpaper 320 / 400 / 600 grit, then with oil (WD40 is your friend) 800 / 1000 / 1200 / 1500 / 2000 grit. I ultimately use 3 polishing compounds, of increasingly finer grit, applied with a felt wheel on my Dremel tool.
I take this opportunity to ever so slightly round the top angle, to make sure the oil seal won't get damaged when putting everything together.
And Tadaaaa! Shiny-shiny!
Now comes the time to adjust the axial play of the crankshaft ; it has to be comprised between 0.07 mm and 0.13 mm, ideally in the lower part of this range, to take into account the parts wearing out.
That's the opportunity for me to bring out my BIG torque wrench, the one I use to reach the 35 mKg needed to properly tighten flywheels and rear wheels' central nut.
First step, find a set of shims, cuz' as expected, the ones I have don't allow me to adjust the play correctly... And as usual, the 36hp shims aren't the same as Type 1's, and much harder to source!
Long story short, I buy a couple of 0.32mm shims from VW Classic Parts, take out the ones in my original engine, and I end up with a pretty good assortment of shims in various thicknesses, plus 3 paper gaskets of various thicknesses.
Without the paper gasket between the flywheel and the crankshaft, I get a little over 0.03mm of end play, measured with a dial indicator. After 4 assembly/torquing/disassembly sessions, I manage to find the right set of 3 shims (always install 3 of them, for relative rotation speed reasons) to get 0.10mm of end play with the paper gasket on. I would have prefered it to be a tiny bit tighter, like 0.08mm, but it will do. I give the oil seal a good dose of lubricant, put the flywheel on, and torque the central nut (with a drop of blue Loctite medium threadlocker).
Just for later reference, if you ever had to look for 36hp shims : here are the VW references. Good hunting! :
111 105 281 : 0.24 mm
111 105 283 : 0.30 mm
111 105 285 : 0.32 mm
111 105 287 : 0.34 mm
111 105 289 : 0.36 mm
You can get reproductions from BBT, but at 6€ a piece, I find it a bit expensive... And make sure you deburr them before use!
The flywheel had been re-surfaced and balanced with the crank and clutch assy (work done by Slide Perf in March 2012!! It's really high time for me to finish this engine! ).
A "1" mark had been stamped to make sure the flywheel is in the same position as it was balanced ; same for the clutch assembly, with a "0" mark. At least, the bloody thing shouldn't wobble around.
The flywheel, clutch disc and clutch mechanism running surface are thoroughly cleaned using brake cleaning fluid before assembly.
The clutch assy screws are torqued (2.5 mKg) and secured with the usual drop of Loctite.
That's it for today! Yet another checkbox ticked out!
Hopefully this engine should run in no time now! (wishfull thinking...)