Bill K's old 412

Discuss with fans and owners of the most luxurious aircooled sedan/wagon that VW ever made, the VW 411/412. Official forum of Tom's Type 4 Corner.
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gearheadgreg
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Bill K's old 412

Post by gearheadgreg » Sat Jul 11, 2020 3:00 pm

So, many of you on here know I've got Bill's old 412, which he developed a LOT.

It got used a lot (which is great) and some things have worn and some things needs some reworking, but the amount of work and development he did still astounds me. And on a 412 - not a Porsche 911, but a 412. Because of his huge amount of work, I call it Bill K's 412, because whatever I do, it will still be on top of his mountain of work.

Anyway, I have been slowly trying to fix things here and there and get it back up to a status capable of daily driving, which I believe it is now. I host a monthly Cars & Coffee event at my shop and a loal VW cluub uses it as a jumping off point for their weekly cruises. I just started up the Cars & Coffee events again, so thought I would take the 412 on the cruise. Other than driving it to and from the shop a handful of times, this would be the most miles I've put on it (maybe 50) and on a sweltering hot day, and through some very slow driving traffic.

It did great overall. It has some issues, which I knew about, but wanted to shake it down a little more. On the plus side - if the battery has a decent charge, it starts up pretty easily. It is cold blooded and needs to warm up a fair amount to prevent stalling. I think it could use a high-idle control or switch, which might be integrated into the SDS EFI, but I think a simple electro-mechanical setup will be great. Like the CIS auxiliary air regulator - it allows more air through a passage until it warms up, only needs a 12V signal.

It has a juddering problem at low rpms and very small throttle opening. It reminds me of vehicles I've diagnosed with throttle cables anchored to the body so when the engine rocked under load, it affected throttle opening, creating and back and forth rocking unless more throttle was applied. It could be a rich condition, or something else, but needs to be sussed out.

Another issue is that leaving from a stop, it shudders. Like a slipping clutch or loose/worn transmission mount. But the clutch holds well under all other circumstances, so I suspect it is something with the mounting.

There is still some shimmy in the steering at certain speeds and loadings. I have the newly made radius rod bushing 'inserts' and will install them soon, along with a nylon washer on the other side, per Ray's recommendation. It isn't awful, but you can definitely feel it in the steering that everything isn't 100% solid,and with the other upgrades and bushings on this car, I can't imagine on a car that doesn't have those.

Shift linkage feels really good most of the time. Once in a while, on an aggressive downshift into 2nd, I got reverse and it ground of course. Shifting into gears was usually great, but I suspect i need to bleed the clutch setup again.

The power is good, but not impressive - remember, I am at 6500ft, so lose 20-25% normally. The punchiness is good, and pull from lower end is nice, but it feels like it runs out of breath around 3500rpm (I haven't installed a tach yet, so guessing). I'm not sure if it is the cam, or heads, or what yet. I am reinvigorated to install the IDF manifolds and motorcycle throttle bodies to see if that is part of the restriction. Plus, the sound from Webers/ITBs is just great.

The exhaust is a little bit loud for my tastes, but there isn't much room for adding a resonator, etc. I think maybe a slightly larger turbo muffler in place of the EMPI item might help, but that's low on the list at this point.

A smaller sportier steering wheel and a Recaro type driver's seat are also on the list.

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raygreenwood
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Re: Bill K's old 412

Post by raygreenwood » Mon Jul 13, 2020 3:27 pm

Niiiiice car!

So....please remind us of what exhaust system is installed and what muffler.

Ok...the shifting issues. Aside from the possible clutch salve.....the adjustment for the shifter is tricky on this car. And...only the Haynes explains how to do it.

But....the biggest shifting issue with the 411/412 manual 004 trans....is the rear shift coupler. It has a ball vertical stud mounted....I think on the trans shift rod....and a hoop or cup that fits over the ball on the forward shift rod attached to the shifter.

So to understand how it works.....the ball stud attached to the shift rod....moves from side to side in an arc.....rotating the shift rod selector fork inside of the trans.

Where the "cup" intersects this ball....affects the arc travel.

Let me try to explain. For instance.....lets say from the center line of the transmission shift rod to the centerline of the ball on the ball stud....lets say its 2.0 inches. Lets say that when everything is perfect....the cup attached to the forward shift rod intersects the ball on the trans shift rod...exactly at that 2.0 inch mark.

So when you rotate the shifter to move say....from 1st to 3rd....it rotates the trans shift rod an exact amount of degrees.

BUT....if for some reason the cup from the shifter shift rod....is intersecting the ball stud either a little above or below that exact 2.0 inch mark that is the centerline of the ball......it changes the number of degrees that the ball stud rotates...by more or less....causing improper or incomplete gear selection.

So why did they make it this way? Because the tail end of the transmission "floats". It is not mounted solid. This is designed to take stress and flex off of the trans housing to prevent damaging its 32" long main shaft....and...prevents oscillation and vibration of the shifter (this being a luxury car and all)

So what can cause the cup to slip up and down on the ball?

Working from front to back....his can happen from a worn out center hole in the round plastic plug in the body tunnel...which is the height support setting for the shift rod. Also if the tunnel plug/support disc is missing...it can cause this.

Or.....if the rear drivetrain alignment either at the top hanger shims, rear hanger bar end vertical hanger studs are incorrect....it forces the tail of the transmission to be higher or lower at the ball stud to cup.

Or if either the tail cone bushing is missing or the hanger bushing or teh center rear hanger bar bushings are shot....it can cause this.

There is a mod I have been working on that pins the cup to the centerline of the ball...and lets teh rod float up and down at its tunnel plug....keeping the shift linkage geometry uniform even if the engine oscillates a a bit. I can get into it if you want. Ray

gearheadgreg
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Joined: Fri Mar 08, 2013 8:25 pm

Re: Bill K's old 412

Post by gearheadgreg » Mon Jul 13, 2020 3:51 pm

Thanks Bill. I'll try to get the car up in the air this week to look at the transmission and shifter components to have a better idea what I'm working with.

The exhaust is stock heater boxes, and then an Empi 4 into 1 header and Empi muffler (which are notoriously cheap, poor flowing, and loud). I'm hoping a Dynomax super turbo will flow better and quiet it down a touch. Maybe add a resonated tip, since there is no room for a resonator anywhere before the muffler. Building a header-back system for one of my vanagons now, which I've done before. With a resonator to replace the cat and a good muffler, they turn out to be the perfect level of sporty vs. quiet for me.
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raygreenwood
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Re: Bill K's old 412

Post by raygreenwood » Mon Jul 13, 2020 8:07 pm

So....its been so long since I have had one of the old Thunderbird mufflers on one of my cars....which the EMPI should be a stainless steel copy of....I have no memory of how long of a pace between the collector flange and the side of the car there is for a muffler.

But I am thinking about 16" to 18" maybe? How big is the hole in the collector flange?

Yes...I am in total agreement....a "resonator" is what is needed...between the muffler and collector (if you had room).

For your consideration...and no I have not tried one of these but might just with the same EMPI four into one set up.

These look very interesting because if you dig through the links about the tech inside of these mufflers....you will see that some of them are combination resonators and mufflers.

Thee are truck mufflers. But if you look at their charts they have exact measurements and very accurate flow rates for each size.

Donaldson truck mufflers
https://www.donaldson.com/content/dam/d ... -Guide.pdf
Look at style #1 and #2 on pages
Part # M085056 can be found for $135/ 8.5” body diameter 21” long or
M085408 which is 8.5” diameter and 19.75” long both have 3” inlet
Or
M065034 with 2.5” diameter inlet and 6.62” diameter and 18.56” length
M065139 with 2.5” diameter inlet and 6.62” diameter and 17.75” length about $117


Take a look on page 2 at that first link of their three styles of muffler. Their top one with a million mile warranty is very similar to type 4 muffler design. Some are all stainless steel. The same design with 500,000 mile warranty is aluminized steel.

If you look on page three you can see all of the offsets available for inlet and outlet. Ray

Hulken
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Re: Bill K's old 412

Post by Hulken » Tue Jul 14, 2020 5:45 am

Just love that Bill's car is on the road, followed all the mods he did on it. I actually bought some part of Bill, moded centerlink and parts for rebuilding McPherson strut tops. Not mounted on my car yet, but the plan is to mount it during summer.

gearheadgreg
Posts: 292
Joined: Fri Mar 08, 2013 8:25 pm

Re: Bill K's old 412

Post by gearheadgreg » Fri Jul 24, 2020 9:01 pm

OK, so it only took a second to look, but the Empi header is ceramic coated, and has a straight through (perforated core) stainless steel Dynomax muffler, so the quality is actually good - Bill spent more bucks on this exhaust than most people would.

However, there is no 3 bolt flange for the muffler, and it isn't a turbo/chambered muffler. Its straight through which means really loud (think Bug with a baffled stinger). I'll get a Dynomax or Thrush turbo so that it quiets down significantly, but still flows more than enough for this power level.

I also jacked up the rear to start looking at the shifter and rebleed the new clutch slave. I want to remove the late offset Cayenne wheels and run Fuchs wheels, as they look more appropriate to me, and a little dish to a wheel on a 70s car is just correct.

Bill made custom spacers for the rear, behind the rotor, and for the caliper to match where the rotor ended up with that custom spacer. I need about an inch or so to pull the rotor back towards the center of the car. I'm not sure how far back we can go, but I'm hopeful I can use stock 944 spacer or just machine this one down to suit. I'm hopeful that will allow me to put a 16x8 Fuchs in the rear, and maybe a 215 wide tire.

On the front, there are 12mm spacers already, on a 7.5" wheel, and I'll drop to a 7" wide wheel, with no spacer, and should be pretty close, and stop the inside of the wheel hitting the inner fenders so much, and allow a little more steering lock (the stops are adjusted WAY out. U-turns in this car are impossible).

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