engine and drivetrain Which Tii Throttle Body Is Early And Which Is Late?

[JohnS]

FWIW both my 73 and 74 have throttle bodies like the one on the right in Rob's photo.  I'm not sure of the build date on my 73 #2764396, but I think it's a fairly late one

 

[jgerock]

Rob - 

You mention your distributor was rebuilt by Advanced Distributors.  If so, it should have included a piece of paper with the recommended timing.

[MatthewCervi]

My 73 tii (production date 10/72) came with the throttle body style on the left (screw acting on the short section).  Around 2005 I ordered a new throttle body and received the style on the right (screw acting on long lever).  Because of this, I'm almost positive that left is early-style and right is late-style and whatever the cutoff is was not the plastic to aluminum runner changeover.

 

Unless the profile of the cam is different between the two throttle bodies, then the style isn't going to make a difference in WOT positioning.  I think it really is just ease-of-adjustment.  Looking at the two types you can see that it'll be much easier to make fine adjustments in the later design.

 

Regarding the problem you're having, it sounds to me like something is wrong with the 85mm linkage since that would affect the ratio between throttle opening and pump output.  What I would do (any maybe you've already done this...):

 

1. Disconnect the 85mm linkage at the throttle arm to take the pump and pump linkage out of the picture, back off the idle screw and make sure that the accelerator pedal moves the throttle plate from full closed to full open.  If not, adjust those linkages until that works.

2. Make sure the 85mm linkage really is 85mm and reconnect.  

3. Loosen the bolts that hold the linkage arm to the TB shaft and lock the pump at the lower hole.  Adjust the linkage arm-shaft connection so that the throttle plate is just closed.  Ideally, that means the hole at the top is slightly covered by the cam, but that isn't a big deal.  Tighten.

4. Lock the pump at the top hole.  Hopefully now the throttle really is wide open, but if not, I guess it's time to start tweaking the 85mm linkage until bouncing between steps 3 and 4 results in fully closed and fully open throttle.

Edited April 28, 2013 by MatthewCervi

[BillWilliams]

Amen to the words above and I am with Ben, the two throttle bodies will not make a difference in performance. I also believe that after 42 years of fiddling and wear, there really is not a difference in Kugelfischer pumps to year of car.

 

I really like Matthew's steps.

 

I find many folks just do not do steps 1 and 3. They do not see how that affects the ratio so those steps are just overlooked.

 

Sometimes to get the car to WOT you have to adjust the linkage just outside the pedal box.

[thehackmechanic]

Thanks all. I will take a deep breath and look at this again.

[Wattfab]

Pic of my throttle body guts. 2761350 /April 7th 1972

[PaulTWinterton]

I feel for ya man. Been down this road for 20 years.

I still have a lean condition, but live with it. No AFM, but very dry plugs.

Some easy inspections:

I had my TB out and noticed that the lower shim on the bottom (where the rod enters) was loose and falling out.

I could wiggle the rod sideways. That's not right I thought. I had a machine shop create a new shim.

I also found a slight scar in the face of the TB that might have caused an air leak. Had it planed off.

I do believe it made a difference, at least in throttle response.

Pix attached.

[jgerock]

Based on some of the others pictures, I guess my 73 has the "wrong" throttle body - but cannot tell for sure since I can never find any date stampings in them (unlike the rest of the injection parts).

 

2764081 & 2762332 engines both have the same TB along with my spare TB

 

Hmm - wonder if my TB cover plate is date stamped on the underside (edit: not)!

 

Should I make up a tee shirt for Vintage that says on the front: "Show me your tuna can?

 

On the back: "I can tune a car but not a fisch"

Edited April 29, 2013 by jgerock

[PaulTWinterton]

My pictures never made it. Hmmmm?

2 pictures, less than a meg.

[thehackmechanic]

Jim, I would TOTALLY buy that shirt.

 

:^)

 

Still sorting... the Cervi "special sauce" is interesting... will get the car out tonight and wail on it.

[jgerock]

 

Still sorting... the Cervi "special sauce" is interesting... will get the car out tonight and wail on it.

Always good to have folks like Matthew Cervi in your convoy. 

 

My car has been messed with so many times - it runs great so I'm leaving it alone.

[MatthewCervi]

Always good to have folks like Matthew Cervi in your convoy. 

 

 

...so I can blind people with my shiny white head!

 

On a serious note, after I replaced the damaged filter on my in-take pump I haven't had any more injection pump problems so hopefully that issue is behind me.

[saaron]

Hey Paul - attaching pics is a two-stage process.  Learned the hard way.  Try it again - you'll see.

 

Scott

[thehackmechanic]

Tried Matt's recipe. First, I should note that I have both the Asvander tii tool kit with the 85mm rod measuring jig, and new linkage rods from Jack Fahuna. The Jack Fahuna linkage rod is actually slightly longer than the measuring jig, and I have no idea which one is "correct," as I have no idea how anyone measures the center-to-center accurately with a caliper. Curiously, when I use Matt's method of adjusting the length of the rod to synchronize the full opening of the pump with the full opening of the throttle body, the resulting rod length is substantially longer than both the Asvander jig and the Fahuna rod.

 

And, when I run it, the AFM still reads about 15 - 15.5 at WOT.

 

I offset the synchronization, pinning the pump at P1 and rotating the cam in the tuna can progressively further and further over the pin hole. I did this in steps until the entire hole was covered. The car ran eye-wateringly rich, 9-10 on the gauge, except at WOT where it STILL read about 15.

 

I'm flummoxed.

 

Note that for all of this, I've left the idle mixture screw at the same setting -- with the arm just barely touching the cam when the can is pinned.

 

Note that the kfish pump is fully capable of running richer, so I know this isn't a fuel delivery issue. If I put a penny under the verboten screw, the car will go to about 13.5 - 14 at WOT, but it'll be pretty rich everywhere else too.

 

I must be missing something.

 

I'll call Hans Utke (who rebuilt the pump) tomorrow and ask him if there's any possibility it could be set wrong at WOT.

 

Jeremybd had a throttle body on eBay. I snagged it just to have something else to try. I'm not sure if it's an early or a late one, but the majority of posts here, and other things I've read, seem to land on the side of the TBs being interchangeable. 

[bnam]

Rob,

Some questions

 

 

I offset the synchronization, pinning the pump at P1 and rotating the cam in the tuna can progressively further and further over the pin hole. I did this in steps until the entire hole was covered. The car ran eye-wateringly rich, 9-10 on the gauge, except at WOT where it STILL read about 15.

As you move the eccentric further over the hole, it has to turn a larger arc to get back to WOT (or does it not)?  If it does, do you also lengthen the linkage correspondingly?

 

BTW, if you are looking for a later model TB to compare and the one you bought isn't, let me know I have a spare late TB you can borrow.

 

Byas