Eric's 07K dumb questions thread

[elaw]

Dammit, you guys are going to talk me into an 01E aren't you? Although I still think that if I have $1K to spend on a transmission or an oil pan, it would be better spent on an oil pan because the engine won't run very well without one.

I think if I went that route I'd definitely want a 6-speed, and I don't think I'm ambitious enough to pull apart a 5-speed and convert it. Question: the TDI transmissions everyone talks about: are those USA or from overseas?

And another topic for discussion: output flanges. Do the ones the transmission comes with work with B3 inner CV joints (100mm)? From what I can see they look a little different. If not, can 016 flanges be used?

[PRY4SNO]

The stock 01A has 100mm output flanges. If you upgrade to an 01E, you'll need either 4kq driveshafts, or the output flanges off a 4kq (or the rear of a B5A4q) to run the stock 80/90 20v front driveshafts.

I opted to run the stock 100mm shafts on the 108mm output flanges with the frame of mind that if I get to the point of twisting axles then I'd rather be able to go to any FLAPS and get something to get me going again. Then it's time to save the 1k for upgraded ones from A1CVTECH or TDSS.

[elaw]

Okay now I'm confused... or even more confused, as I'm always confused to some degree.

You can bolt 100mm inner CVs to 108mm flanges?

It sounds like you're saying the 01Es (all of them?) come with 108mm flanges but 016 flanges can be installed - is that right?

If so I'm set, as I have 100mm 016 flanges on the 016 that's in the car now.

[varia]

you can use 01E:
you need the rear flanges from a B5 A4, turned down to match the length of the 01e flanges.

[PRY4SNO]

you can use 01E:
you need the rear flanges from a B5 A4, turned down to match the length of the 01e flanges.

Precisely. Or, fronts from a 4kq.

[DE80q]

Remember me asking you about the flanges in your pile of 016 parts? The 100mm outputs is what I was after.

[elaw]

Hey just for everyone's information/amusement/ridicule, I've created a drawing showing the differences between the 07K flywheel-mounting flange on the crankshaft and that on an 7A engine that Austin was kind enough to let me measure... it's attached.

Disclaimer: I'm not a machinist or a draftsman and most measurements were taken with a cheap HF caliper so don't trust this too much and especially don't expect it to be accurate to 0.0001"! Or the equivalent in mm, as the drawing units are mm. Also the flywheel-centering "snout" on the 07K engine has a large chamfer at the end which this drawing does not reflect. I might measure that later and update the drawing, although I don't think it's terribly relevant.

Anyhow the important part: the 07K flange at its farthest point sticks out 28.1mm beyond the trans mountng surface. The corresponding number for the 7A is 9mm. So the 07K sticks out 19mm farther... meaning to make this work with an 016 transmission I'd need an adapter plate 3/4" thick. That's not impossible of course, but it would take away from the shortness advantage of the 07K.

It's also possible that a thinner adapter plate could be used by machining the crank. But that in itself is a lot of work, and it would make it harder if I ever wanted to switch to an 01E in the future.

[DE80q]

Yes, you would loose your your shortness advantage, but makes your 016 adaptor plate more feasible.

[elaw]

One other thought that comes to mind is if I did go the 016-with-adapter route, I might want to get the pilot bearing bore enlarged to the 24mm diameter of the earlier I5s.

That would allow me, by swapping pilot bearings, to either use an old 016 like I currently have in the car where the input shaft diameter where it goes into the pilot is 18mm, or a later 016 or 01E where that diameter is 15mm.

Another consideration is that while the "snout" on the 07K crank sticks out 19mm farther than the one on the 7A, the flywheel mounting face is only about 10mm farther out (~15mm vs. ~5mm). So I'd need a flywheel 9mm thicker.

I don't suppose anyone has a measurement of the depth of a 3B/MC2 flywheel? I've got a 7A FW that I've measured at 30mm from mounting surface to friction surface, and I'm pretty sure a 3B FW is thinner. If it turned out to be 9mm thinner, that problem would be solved!

[ChrisAudi80]

When you have a V8 you don't need 1st.

Greg W.

[elaw]

So a couple of days ago I got myself an interesting "measuring tool"... specifically a transmission spacer from an A4:

The cool thing about it is it has the bolt patterns for both the 5-cylinder engine (like the 016 tranny) and the 4-cylinder engine (like the 07K).

The not-so-cool thing is it's revealed a big problem. As others have noted, when mating an 01E to the 07K you have to cut a little off the top of the bellhousing to clear the timing cover on the back of the 07K. But I think (someone please correct me if I'm wrong) that the cut-off part of the transmission doesn't contain any mounting bosses that are used to secure that tranny to the 07K.

It looks like for the same reason, a big chunk of the 016 would also have to be cut off to mate it with the 07K, even with the 3/4" spacer/adapter that would be necessary to mate the tranny to the engine (and have the input shaft not bottom on the crank). But... it looks like the cut-off area *would* encompass one or more of the mounting bosses which IMHO is not good.

I'm going to have to do some more thinking/measuring to be sure the above is correct, but if true it sure throws a wrench into the works...

[audifreakjim]

The part you have to trim has two holes. One of them does line up and bolt to the 07k. It's tempting just to cut off the whole thing and forgo that bolt. If you look at my pic you can see how I maintained that boss

[elaw]

Yeah I just looked a little more carefully at the photo you posted. Clearly there's a lot more to it than a few minutes' work with a hacksaw!

[audifreakjim]

It can be that simple. I guess Audi sport cut the whole thing off for easy transmission changes to clear the rack. The 07k has a seal on the back cover where this bolt is so you probably should torque a bolt down if you don't do what I did.

[deaner]

I was just about to mention the bit about Audisport hacking the whole top off, but Jim beat me to it. The way I see it too is that the engine and tranny are bolted to the chassis seperatly. Once you mate the two and crank the motor mount bolts down, they're now moving together and would really only need a couple bell housing bolts.

[elaw]

Hey sorry for the delayed response but I've actually been thinking about that issue a lot: exactly how much strength is needed for the attachment of engine and transmission?

It's pretty obvious what Audi thinks... using a large number of heavy bolts plus all the small ones that go into the oil pan and such.

The attachment does get subject to a lot of forces in a lot of directions. Here are the ones I can think of:
1. Holding up the front of the transmission. The engine pretty much balances on its mounts IIRC but doesn't the tranny have more weight in front of the mount plane than behind it?

2. Reacting the engine's torque. All the engine's torque goes through the input shaft, causing the transmission to want to rotate one way and the engine to want to rotate the other way. I think resisting that torque falls mostly onto the engine-trans bolts.

3. When you accelerate, the torque from the front axles (assuming the front wheels haven't broken loose ) twists the engine-trans assembly around the axis of the front axles. That force can be considerable... if my math is correct it's equal to the engine's output torque times the overall drive ratio (selected gear ratio * final drive ratio). In first gear the overall drive ratio is about 14.5:1 so suppose your engine is putting out 400 ft-lb of torque the axles are seeing (400 * 14.5) or about 5800 ft-lb... can that be right?

4. When you accelerate, there's a reaction force to the torque coming from the output flange to the center driveshaft (assuming the rear wheels haven't broken loose ). That would be the engine torque times the ratio of the selected gear, so maybe 1400 ft-lb.

5. Vibrations of various sorts in various planes. I have no idea how you'd quantify this.

Anyhow I'm not sure what the end result of all the above is, except that the engine-trans connection needs to be fairly strong. How strong? I have no idea!

[elaw]

Hey one more thing: the 01E 1-2 shift collar issue... is that only on the 6-speeds, or 5-speeds too?

Stuff I see here implies it's all 01E's, but looking at places like JH motorsports I only see 6-speeds mentioned?

[audifreakjim]

I have only had the problem on my 6-speeds. I had a wide 5-speed for a year or so that sifted perfectly up to when I decided to put a 6-speed in.

A lot of people will start the swap with a 5-speed and then find a 6-speed to rebuild.

[elaw]

Hey here's another one, that's maybe a little unusual...

The A/C compressor used on these engines apparently doesn't have a clutch, but uses an electrical valve to regulate the variable-displacement function of the compressor to effectively shut it off when not needed.

My question is: does anyone know if that valve is just an on-off device, or does it use PWM or variable current to regulate the compressor's output?

Needless to say it'll be easier to implement A/C on this car if it's the former, but if it's the latter I'll find a way to deal with it.

[elaw]

And another question: has anyone ever checked to see if a thermostat cover from an older I5 can be used on the OE 07K thermostat housing in place of this one?

07k_121_121_b_-4.jpg (8.76 KiB) Viewed 45023 times

Or... does someone have an older outlet around they might be able to take some measurements on?

It looks close to correct to me, but I don't have another cover to test with.

[audifreakjim]

It's definitely an issue. See below what I am using with a remote thermostat and electric water pump so I can use the stock radiator location. If you plan to use the stock accessories on the 07k, you either need to cock the radiator like hank did or use a front mount radiator. For both you can just fab up a coolant line to work with the thermostat cover. This is why you almost have to have a tig or welder capable of making these things. It's all custom.

[elaw]

Yeah there's no doubt I'm going to have to step up in my fab skills on this project. I know it sounds like blasphemy but I think I'm going to buy a spool of aluminum wire and try my hand at MIG welding aluminum. I used to work for a guy who MIGged aluminum from time to time and it came out pretty well.

That said, I definitely don't want to go with the stock radiator location. That's actually a big part of my motivation to go with the 07K - I'm hoping I can put the radiator and A/C condenser in front of the motor. The oil cooler and intercooler locations are TBD.

[audifreakjim]

MIG with aluminum can turn out fantastic, it's feeding the wire that's the issue. You have to have very little tension on the feed roller to keep it from buckling, but just enough to keep the feed rate consistent. No bends in the torch feed is best. Or better yet, use a spool gun.

[elaw]

Changing the subject yet again... those of you using Hank's 07K flywheel: did you get it balanced or just bolt it up and run?

I'm going with stock internals on the engine so wasn't planning on doing any balancing.

[ringbearer]

It's harder to make a seal with mig than tig imo, but worth a try