Itinerant Air-Cooled

It was all so simple when Colin was here...OK, now I'm stuck in a new quagmire. I have the engine at #1 TDC, and the fan notch at zero in the timing scale. However, as you can see in the pic, the distributor gear (as set in place by Adrian) does not line up in the 12 degree fashion. Dare I pull it up and reset it myself? I'm concerned with being a tooth off, or is that really apparent as you look at it? Is the lesser section of the offset towards the fan housing? My thinking is becoming muddled, and I need forum input. It's that, or beer o'clock.

To my T1-trained and T4-muddled eyes, the drive pinion looks to be one tooth out. I think it needs to rotate one tooth counter clockwise.

I know the FI setup is crowded, and I'm guessing you have a vacuum advance can on your distributor. Because of this, I think it is important to have the drive equipment indexed correctly. Someone else with more experience can tell you if everything will fit with it one tooth out, but I would not put it off for later once the ancillary equipment is in the way of the puller tool. If you do decide to change it, do it now so you can forget about it forever.

Do you have the puller tool? If you don't, I'm happy to send mine your way if you send it back.

When installing or reinstalling the pinion, the helical nature of the crank gear and pinion gear mean that the pinion will have to rotate SLIGHTLY as it seats downward. It rotates clockwise, (when viewed from the top,) as it seats. This means during installation, you'll want to initially lower it with the drive teeth over-compensated compared to where they are now. (I wildly speculate this is the reason some neophyte engine builders have their gear one tooth out, just like yours.)

No time for beer! There are engines to tend to! ;)
Robbie

Best way to tell is to do a test-fit with your distributor, the one you plan to use in this engine. Get it seated with the drive dog engaged and see where the rotor is pointing with #1 @ TDC. Turn the distubutor so the vacuum can is approximately at 2-3 o'clock as viewed from the back of the bus looking down (this is just a starting point). Turn the engine so the pulley is at the 7.5 degree timing mark.

Hook up a test light so you can see when the points open or the Hall-effect unit triggers. The test light should be unlite at this point. Slowly rotate the distributor body counter-clockwise until the test light lights up. If all is copacetic, the vacuum can should be somewhere in the vicinity of 1 o'clock. At this position there is a fairly tight interference with the cold-start valve harness connector. This seems to be the defaut position using the Bentley-blessed 12-degrees position that I'm assuming you are referencing. Since your slot seems to be one tooth clockwise from the officially-sanctioned position, that may give your vacuum can more wiggle room in the available space between the CSV valve and the cooling flap actuator rod.

SlowLane wrote:Best way to tell is to do a test-fit with your distributor, the one you plan to use in this engine. Get it seated with the drive dog engaged and see where the rotor is pointing with #1 @ TDC. Turn the distubutor so the vacuum can is approximately at 2-3 o'clock as viewed from the back of the bus looking down (this is just a starting point). Turn the engine so the pulley is at the 7.5 degree timing mark.

Hook up a test light so you can see when the points open or the Hall-effect unit triggers. The test light should be unlite at this point. Slowly rotate the distributor body counter-clockwise until the test light lights up. If all is copacetic, the vacuum can should be somewhere in the vicinity of 1 o'clock. At this position there is a fairly tight interference with the cold-start valve harness connector. This seems to be the defaut position using the Bentley-blessed 12-degrees position that I'm assuming you are referencing. Since your slot seems to be one tooth clockwise from the officially-sanctioned position, that may give your vacuum can more wiggle room in the available space between the CSV valve and the cooling flap actuator rod.

3 o'clock. The vacuum can should be directly lined up with the breather bail/bale.
That photograph disorients me totally. Flip it upside down and it will be right side up. Then you can see the 12* is approximately 11:00AM on the clock-that-is-the-hole.
Colin

Thanks for this info. I do not have the engine installed yet, and have no power to it, so the test light is not an option yet. I am refreshed mentally today, and here is my thought about resolving this dilemma. I have just pulled the drive gear out, using a magnet. The horror, the horror, of that washer on the bottom falling into the engine was giving me great anxiety, I can tell you. When I reinstall, I'm going to stick it on with a gob of grease.
1) get #1 at TDC.
2) notch and single white mark on pulley lined up at zero on timing scale.
3) fit drive gear onto cam gear at correct 12 degree angle.
4) post another pic to get feedback if it is correctly aligned.

Will that work correctly?

Jivermo wrote:Thanks for this info. I do not have the engine installed yet, and have no power to it, so the test light is not an option yet. I am refreshed mentally today, and here is my thought about resolving this dilemma. I have just pulled the drive gear out, using a magnet. The horror, the horror, of that washer on the bottom falling into the engine was giving me great anxiety, I can tell you. When I reinstall, I'm going to stick it on with a gob of grease.
1) get #1 at TDC.
2) notch and single white mark on pulley lined up at zero on timing scale.
3) fit drive gear onto cam gear at correct 12 degree angle.
4) post another pic to get feedback if it is correctly aligned.

Will that work correctly?

You must be sure that #1 valves are closed and #3 valves are at overlap.
Fit drive gear in at 25* or so, the helical cut will rotate the slot clockwise as it engages. Do not pull it out entirely. Just lift about half way up and rotate in place to your 25*.
Once down all the way, it should then be at 12*.
ColinISITSODIFFICULTTOPUTINCORRECTLYDURINGINITIALBUILD??

Here is where I am with the gear. However, when I put the distributor in, I find that I must not have #1 at TDC, but #3. Looking at Colin's post above, I will begin this process once again. Are we having fun yet?
Yay! 12 degrees!


Bummer! Position of distributor, and notch on rim! Arrrrgggg! I gotta lot to learn in this game!

At $7.25 minimum wage, this type 4 engine has cost me roughly $15345.50, and it's not in yet. I should bought a new 'Vette, but they laughed at me when I asked about the air cooled option. Screw Chevrolet!

Jivermo wrote:However, when I put the distributor in, I find that I must not have #1 at TDC, but #3. Looking at Colin's post above, I will begin this process once again.

If you find that the rotor isn't pointed where you would like after ascertaining that you are indeed at #1 TDC by checking the valve positions, then it's entirely possible that the drive dog on your distributor may have been installed 180 degrees out, which would make the rotor point to the position expected for #3 when you are at #1.

If you don't get too wrapped up about the rotor pointing at the notch in the distributor body when at #1, then you can simply move the spark plug wires around on the distributor cap to where they'll deliver the spark to the correct cylinder at the correct time. With the distributor body installed where you like it (eg. can at 3 o'clock) simply note which quadrant the rotor points to when at #1, fit the distributor cap on the body with the indexing tab in the slot on the body, then put the wire for #1 in the nearest cap tower. Cylinders 2, 3 and 4 then follow counter-clockwise from there on the distributor cap.

Not to throw more confusion on the issue, but here is an interesting article written by Bob Hoover on the subject of distributor orientation: Flaming Distributors, Batman. Just something to mull over when deciding which "o'clock" you want to put your distributor can at.

PS. Don't forget to put in the compression spring between the drive gear and the distributor. A bicycle spoke or similar piece of stiff wire is handy for installing the spring so that it doesn't accidentally disappear down the oiling window in the distributor bore. Simply slide the spring onto the spoke and hold it in place while you pilot the spoke into the pocket in the center of the drive gear. Then slide the spring down the spoke into the pocket and seat it with a nudge of the finger while you withdraw the spoke.

Jivermo wrote:Here is where I am with the gear. However, when I put the distributor in, I find that I must not have #1 at TDC, but #3.
Yay! 12 degrees!
Bummer! Position of distributor, and notch on rim! Arrrrgggg! I gotta lot to learn in this game!

What are you confused about? The valves of #3 are at exhaust/intake overlap, yes?
#1 cylinder is at TDC firing, yes?
The drive dogs are at 12*, yes?
Then the rotor should face towards about 4:30 if it were a clock. AS IT DOES in your photograph.

To hell with that stupid notch incorrectly cut on that distributor.
Factory distributors have the notch at 4:30 when the vacuum can is facing the breather.
Get it set up right. The spark plug wires lay correctly when #1 is at right rear of cap, when #4 is left rear of cap, #3 is left front of cap, and #2 is right front of cap. Do it right. Only in this position, can you get the wires properly clipped down without crossing anywhere.
Also, the condensor should be on the other side where it won't interfere with the cold start valve plug
Here's the BobD top shot again. You can see the wires correctly positioned on the cap and no condensor banging into the cold start plug:


Colin

Great! You have made my day! Damn notch, anyhow.

No, it's not a dual distributor type 4. After Colin's post, above, I dug out a old distributor, approximated the 12 degree alignment of the drive notch, and held it in position above the engine mounted distributor. Whaddayaknow! THIS one lines up perfectly with the notch and rotor. What the hell is with the notch in the wrong place on the new distributor? What a revolting development. Anyhow, I'm moving on...interesting stuff, this engine assembly.



AAAAAAAAAAAAAAARRRRRRRRRRRRRRRRGGGGGGGGGGGG!!!!!!!

Jivermo wrote: What the hell is with the notch in the wrong place on the new distributor?

I've highlighted my curiosity. What is the story on this "new distributor"? Whenever a new part goes near my bus it is on immediate probation until I vet it personally through trial by fire. Yours apparently failed the cosmetic test, but functionality is infinitely more important!

Robbie

Hi, Robbie! This thing works, because we had it in the previous leaking engine for the initial breakin run. When we stuck it in that engine, I don't recall Colin mentioning the notch deal on it. There is a lot that Colin says that I miss, whether by design, age, bad hearing or intent, I cannot say.

Jivermo wrote:Hi, Robbie! This thing works, because we had it in the previous leaking engine for the initial breakin run. When we stuck it in that engine, I don't recall Colin mentioning the notch deal on it. There is a lot that Colin says that I miss, whether by design, age, bad hearing or intent, I cannot say.

If I wasn't driving all over Creation, I might be able to answer questions in a timely fashion that would help you maintain "associations". Stupid notches anyhow.
Colin