Loving these wrte-ups Dave, but I think the thread title should be changed to 'What Could Possibly Go Wrong? - DaveDND Explains'
Keep up the good work, and keep your fingers, toes, etc.

Agreed, keep it up Dave, your write ups are excellent

[WARNING ! Check Your Nuts !]

WARNING !  Check Your Nuts !

As a result of VW ownership you have probably got a garage full of various nuts and bolts and if you have got to this stage yourself, then you also now have a floor littered with a pile of bits that once resembled a Subaru. Now is the time to be very careful as all is now not as it may seem.

The VW nuts and bolts we have grown used to are metric. M10 is a 10mm bolt, M8 is an 8mm bolt and so on. We are used to this and if you are in need of a 10mm bolt then you probably rummage around the floor for something that looks the right length and wind it into the hole. If you are not careful, then you can cause all sorts of damage because M10 VW bolts and M10 Subaru bolts have different threads. Subaru has what is known as "Metric Fine" with a lot more threads per inch.





If you put a VW bolt (1.5mm threads per inch) into a Subaru hole (1.25mm threads per inch), or vice versa, then to those that were not aware of this, the bolt will initially just seem very tight. The internal threads can easily damage (called cross threading) if a spanner or tools are used when you think it just needs a bit of force. Be careful as an engine can turn into a large pile of scrap very quickly. Separate tubs for VW and Subaru bolts are called for and double check everything before you fit it.

And am I the only one puzzled by the designation of "threads per inch" on a "metric" bolt? 

yes, and whatever you do don't take a fine thread nut off and chuck it in your box of 200 standard ones - unless you want to spend an hour searching for it as they look pretty much identical! - You can guess how I know that...

That's a top tip Dave 

Time to take a look at the business end of the Subaru engine. The first thing you will notice is how much larger the flywheel and clutch plates are, but that's about it. The cover plate and flywheel are remarkably similar to the Beetle one we are used to and can be dismantled in exactly the same way.





That battery impact wrench I bought earlier made short work of removing the flywheel bolts and managed it in a few seconds without even having to prevent the wheel from turning - I am so impressed with that tool. I have no idea at the moment what those two cover plates are for and will resist the temptation at this stage to take a peek as I will save that for when investigating the engine at a much later stage. What we do need to deal with though, is the thin plate at the bottom of the engine that sat on top of the front cross member mentioned previously.





The black plate is held to the engine by two small bolts. Obviously, if you remove this then there will be a big exposed hole at the bottom of the engine that will need to be filled, and as far as I am aware the aluminium angled plate shown came as part of the adaptor plate kit. However, I cannot be certain of this as my parts were a collection of second hand bits, but it should be fairly easy to fabricate one though if you do not have it





This is how the plate is supposed to fit. There are a few gaps around the edges, but lets face it, the original one had a great big hole in it too, so I guess that small gaps are not that critical.





The adaptor plate is trial fitted in place and has just indicated something that I was unawares of. Ignoring the obvious four bolts for the VW gearbox, there are three holes on either side used to attach this to the Subaru engine, and right up until this point, I incorrectly assumed that I would be looking for six bolts to use. The bottom 2 studs will of course be removed in place of bolts, but the 2 holes halfway up on either side are for locating pins, not bolts, one of which I will now have to go and recover from the gearbox as its still stuck in there.





There are many threads on the net about this conversion, and one of the driving forces behind this write up is that most of the websites I have seen have either lost most of their picture content after the Photobucket fiasco a while back, or fail to include some of the really silly details that can hold you up for quite a while. For instance, had I known that I needed four bolts with special threads rather than the numerous VW ones littering the floor of my garage, then I could have ordered them ready for this bit instead of twiddling my thumbs now - But what size do I order, and when they arrive, what torque settings do I use? Its these little details that can prove quite frustrating and very time consuming to research.

So, I have ordered four engine bolts  M10 x 50mm length x 1.25 pitch of 8.8 strength and according to the Subaru Manual, will be tightened to 36 ft-lbs.

If you put a VW bolt (1.5mm threads per inch) into a Subaru hole (1.25mm threads per inch)
And am I the only one puzzled by the designation of "threads per inch" on a "metric" bolt? 

No, because it's not 'threads per inch' - it's pitch spacing. M10 coarse is 1.5mm from thread to thread, fine is 1.25mm, extra fine is 1mm.
M12 is 1.75mm, fine is 1.5mm, EF is 1.25mm, etc, etc.

Most japanese and european engines will use fine pitch fasteners for anything critical, btw, both on cars and bikes.

If you put a VW bolt (1.5mm threads per inch) into a Subaru hole (1.25mm threads per inch)
And am I the only one puzzled by the designation of "threads per inch" on a "metric" bolt? 

No, because it's not 'threads per inch' - it's pitch spacing. M10 coarse is 1.5mm from thread to thread, fine is 1.25mm, extra fine is 1mm.
M12 is 1.75mm, fine is 1.5mm, EF is 1.25mm, etc, etc.

Most japanese and european engines will use fine pitch fasteners for anything critical, btw, both on cars and bikes.

Learned something new there - 

Many of the threads I have read speak of problems in getting the engine and box to fit together, and quite a few say that they have really struggled. Nobody has appeared to have posted the reason why this may be though and my initial thoughts were that maybe the clutch was not centered properly as some said that it took a bit more force to tighten all of the bolts up than they were expecting. That really set alarm bells off in my head as that just doesn`t sound right. This is where trial fitting everything together comes into its own as I have fitted the adaptor plate to both engine and gearbox so many times with absolute ease, and it is not until you start trail fitting some "assembled items" and not just individual parts that you can actually see what is going on.





Because its not until you fit the engine bolts that you can see where the problem lies. The back of the bolts are pressed hard against the engine mountings. Now this is one of those things I am really glad I came across before trying to finally fit the engine into place, as it is not a problem I would have relished finding at the last minute.





I cannot tell you how many botched conversions I have seen now where people just wind the hell out of the lower engine studs so that the nut is forced into a now severely deformed rubber gearbox mount. That puts so much stress into that area when the solution is actually very simple. The holes in the adaptor plate allow you to mark on the rubber where the bolt heads will go, and a few minutes with a die grinder, (or something similar), will result in a small slot on the gearbox mount just large enough for a bolt head to sink into.





Making sure that you do not go too deep and only remove as little material as possible. The hole has to be Deep enough for the bolt head and no more.





There would be slightly different solutions to this depending on whether you have rubber mounts, Rhino, or solid ones, but at least you have a heads up as to what to look for and solve prior to trying to fit it all together.

That's good work Dave. 

Good idea there Dave, with solid mounts you could go straight through, just an unfortunate position with the engine bolts.

Dave,

Found this link and thought of you. Maybe you've seen it, maybe not

http://forums.aussieveedubbers.com/viewtopic.php?tid=77027

Paul

Not seen that one - really good one too - 

Time to look at the flywheels and the first thing you notice is how much larger the Subaru one on the left is, but what you cannot tell is how much lighter it is than the large lump of modified VW flywheel is on the right.



The VW flywheel has a large spacer due to it having the thickness of the adaptor plate to contend with, and has the eight holes drilled in the middle so that it can bolt to the Subaru crankshaft which according to the Subaru Manual, are tightened to 58ft-lbs



With the flywheel fitted, its now starting to look a bit more familiar - Almost identical in appearance to those with a 200mm clutch



Something it does mention in the Subaru manual that seemed important, was to make sure that you do not wash these flywheels down with a petrol wash or anything similar due to the sealed bearing in the middle. I must admit that rightly or wrongly, I always put a blob of grease on the end of the gearbox shaft when refitting them just to make sure that everything is lubricated when sliding them back together.

Yes, they're fine to wash down so long as you give the roller bearings a dab of grease - we always convert our flywheels to run a spigot bearing.