TheSamba.com :: View topic - Good 'spare' engine for my '71 deluxe?...(link)

Fri Jun 22, 2012 4:58 pm

When the crank is centered on the painted mark (which, itself, is aligned with the right most notch), the rotor is off centered:

When the rotor is centered on the notch (on the rim of the distributor), the crank is waaaaay off!:

I don't feel like 'guessing' what's right here...My pictures don't really mesh with what is shown in 'How To Keep Your VW Alive'...

I'd really appreciate some wisdom/experience here, please!

Fri Jun 22, 2012 5:13 pm

Your drive gear is a tooth or two off. It does not matter. With a stock cam close counts.

Fri Jun 22, 2012 5:16 pm

When the crank is at TDC the rotor will not point to the #1 mark because it has a few degrees of initial advance... typically 7-13*.

Use the crank to set the engine at TDC and not the distributor.

Fri Jun 22, 2012 5:17 pm

Glenn wrote: When the crank is at TDC the rotor will not point to the #1 mark because it has a few degrees of initial advance... typically 7-13*.

Use the crank to set the engine at TDC and not the distributor.

x2

Fri Jun 22, 2012 5:21 pm

...So go with the funky white mark on the crank, and ignore the other notches?...

Fri Jun 22, 2012 5:22 pm

Herebebears wrote: ...So go with the funky white mark on the crank, and ignore the other notches?...
The dimple on the pulley edge closer to the rear is the TDC mark. The while mark is nothing. The V is 7.5* BTDC.

Read this topic: TDC (finding Top Dead Center)

Fri Jun 22, 2012 5:40 pm

Unless your valve were way off, get it close to TDC and see if there is a gap or spins freely if you have steel push-rods. If in doubt turn it a few degrees either way and see if it gets looser. Or look at the other side of the motor and witness that valve is fully open.

Fri Jun 22, 2012 5:45 pm

Glenn wrote: The dimple on the pulley edge closer to the rear is the TDC mark. The while mark is nothing.

Wow...never even saw the dimple till you mentioned it. I guess the Muir instructions are kind of deceptive. Thanks for the clarification!

Fri Jun 22, 2012 5:49 pm

Muir is good bathroom reading but hardly technical.

Get the Bentley shop manual.

Fri Jun 22, 2012 5:54 pm

Glenn wrote: Muir is good bathroom reading but hardly technical.

Get the Bentley shop manual.

It's on my list! I had ordered a used copy on Amazon, but the vendor then cancelled the order stating "unavailable"...I am working on it! :-)

Fri Jun 22, 2012 5:55 pm

In the meanwhile, I appreciate all of your help, everyone!

Sat Jun 23, 2012 3:08 pm

Ok, so I adjusted the valve clearance for the first time...pretty smooth. :-)
This was how the right side looked when I opened it...no oil, pretty clean looking.

On the left side cylinders (3 & 4), image below, there was LOTS of accumulated oil...and it kept dripping for the duration of the valve adjustment...A lot dirtier on this side... What's going on here? Is this bad?...

Sat Jun 23, 2012 6:17 pm

Looks like maybe 1-2 side has been worked on more recently than the 3 -4 side.

Also looks like you have the fairly rare dimple on you pulley. That's TDC. When at TDC adjust the valves of the cylinder that the rotor points to. Turn crank 180 degrees CW and adjust the next one the rotor points to. Then another half turn and then another one. It will be in the order of 1-4-3-2. (4-3-2-1 and 3-2-1-4 and 2-1-4-3 are the same order) It's easier if you put another mark exactly 180 from the dimple.

The big notch is the only original VW notch. Ignore it since you will never use it for anything. The little marks were added later for some reason.
You will use the TDC dimple to set the timing. And set the timing 28-30 degrees BTDC (to the right of the dimple) with the engine reved to max. advance which will be around 3,000 rpm.

If oil drips out of the rocker box on one side that means that it's not sitting level and that side is lower than the other side.

Sat Jun 23, 2012 6:28 pm

Desertbusman wrote: Looks like maybe 1-2 side has been worked on more recently than the 3 -4 side....
....If oil drips out of the rocker box on one side that means that it's not sitting level and that side is lower than the other side.

Awesome, thanks! The bus was up on blocks, but the ground was not level...the bus *was* tipping more to that side. Glad it was not anything more than this. I adjusted them all...bus runs fine, so I probably didn't screw it up! Yay! :-)

Sat Jun 23, 2012 7:01 pm

To be certain, you or helper can turn the crank (generator) nut, and watch the rocker arms push down the valves, when the center valve comes back to it's relaxed position, the cylinder is coming up on TDC of the compression stroke. It really doesn't matter where the crank is, so long as both valve are closed. There is about 180* of CRANKSHAFT revolution for the piston to get to TDC.

Remember, it takes two revolutions of the CRANKSHAFT; or 720* of CRANKSHAFT revolution to complete one 4 stroke cycle (360* X 2 = 720*)

The following is approximate valve timing sequence:
If you count the intake valve opening as the start of the "CYCLE", it's fairly ez to plot.

Consider the intake valve opens at TDC (0 degrees). The piston is now moving downward on the intake stroke, allowing the air/fuel mix in. At 180* the intake valve will close (exhaust is already closed). The crank rotates, and the piston starts to move up for the compression stroke. THIS IS WHERE BOTH VALVES ARE CLOSED SUFFECIENTLY FOR ADJUSTMENT

At about 332*, the spark will fire (irrelevent to valve timing/adjustment), and the piston will continue moving upward/ The crank will reach TDC (360*), with fuel/air burning, and will continue to to burn on the power stroke as piston if forced downward. At 540*, the exhaust valve opens, as the piston moves upwards to expell the exhaust gas. at 720* (or before), the exhaust valve closes and intake opens at 720*, now 0* for the next 4 stroke cycle.

0* = Intake Open
180* = intake close (exhaust already closed)
332* = ignition event
360* = Power stroke (both valves closed)
540* = Exhaust opens
719* (theoritically) = Exhaust closes
0* = Intake open

Re,member, the reason for using 720* is because cranks rotates twice.

Now the cam, only rotates 360* for a four cycle event, so it has a 2:1 gear ratio.

This is basic stuff, and may be usefull to you, depending how your wired...

Sat Jun 23, 2012 7:50 pm

VAVWFAN, Thanks for all that! I got it figured out & done...I found a few tight valves and fixed 'em. It seems to be running fine now.

Sat Jun 23, 2012 10:19 pm

VAVWFAN wrote: To be certain, you or...................... .

Oh please- you've got problems there. :roll:

Sun Jun 24, 2012 10:26 am

All that I felt was necessary, was getting that dimple on the crank positioned, and doing the pencil trick (with the spark plug out) to see if it really indicated that piston #1 was properly positioned. Sure enough, when I moved the crank back and forth, everytime that dimple reached the top, so did piston #1...after that, everything was a piece of cake! you guys are awesome.

Sun Jun 24, 2012 10:35 am

Herebebears wrote: Ok, so I adjusted the valve clearance for the first time...pretty smooth. :-)
This was how the right side looked when I opened it...no oil, pretty clean looking.

On the left side cylinders (3 & 4), image below, there was LOTS of accumulated oil...and it kept dripping for the duration of the valve adjustment...A lot dirtier on this side... What's going on here? Is this bad?...

Am I the only one who notice's the missing pushrod tube retainers :?

Sun Jun 24, 2012 10:37 am

bugger101 wrote: Am I the only one who notice's the missing pushrod tube retainers :?

I thought they were Type 4 only? Those aren't type 4 heads. Am I mistaken?