Changed Marelli to Bosch dizzy, can't get the timing even close!

BottleNose · 10-22-2009, 10:38 PM

I have a '71 Targa that I've been restoring the past year. It had sat around for about a year before that, but all fuel was removed before storage. Supposedly ran great before going into storage.

I've recently gotten the bodywork done, so i installed a new fuel tank, lines, and factory pump, as well as new plugs and plug wires. Went to start it...turns and turns and turns and doesn't even TRY to start at all. First suspect, Permatune box. It checks out fine. It has a Marelli distributor, so I look and notice the points are corroded, and the irreplaceable cap is worn. Luckily I parted out another '71 last year with a Bosch dizzy, so i grabbed it off the shelf. Nice condition with no shaft play. Installed brand new points (set them to spec in the owners manual), cap, and rotor.

I had set the dizzy to TDC and the crank pulley to Z1 before removing the Marelli. When I install the Bosch dizzy, the center of the rotor tip wanted to be slightly before or slightly after the TDC mark on the dizzy. Which way should this be? I tried both ways, still won't even try to start. Hooked up my timing light, and the timing is way off...the strobe shows the double notches after the Z1 notch. I thought maybe the PO had messed up installing the Marelli somehow (engine supposedly hasn't been apart recently, but I'm running out of ideas), so I removed the dizzy, cycled the pulley around one time, and reinstalled. This time I could see no marks on the pulley at all w/the strobe.

Can the pulley be installed incorrectly? I checked and I am getting spark on all six plug wires, and you can smell the fuel in the exhaust as you turn it over. Thanks for any ideas, I'm stumped.

Here's a pic of my almost completed Olive Targa...can't wait to get her on the road!

red67 · 10-23-2009, 01:54 AM

theres a marelli dizzy cap on ebay now for a buy it now of 50 dollars - if you decide to go back to marelli to simplify the problem.

Porsche 911 NOS Original Marelli Distributor Cap:eBay Motors (item 260403021707 end time Oct-28-09 07:16:26 PDT)

the points you can still buy anywhere.
theres a rotor here for 20 dollars also

Porsche 9/69-71 911T marelli distributor rotor:eBay Motors (item 350266337334 end time Nov-16-09 09:22:10 PST)

docrodg · 10-23-2009, 02:05 AM

There is something wrong here, is the new dizzy rotating the correct way? You can get the timing closer by rotating the dizzy once it is in.

TR · 10-23-2009, 03:11 AM

Not flooded is it--watch out for a bloody fire.

Always liked the clean design of the marelli--I would buy the ebay items and worry about the bosch when you really have to.

good luck with it

69911e · 10-23-2009, 03:35 AM

You will need to pull the valve cover, verify Z1 on compression cycle, install dist. Set initial timing by rotating dist. until it sparks #1 plug. Note: It should still be on TDC. Lock distributor down.
It should start for you. When running, set ignition timing using the light to spec.

Walter_Middie · Walter_Middie's Garage

The PO of my car put the plug wires on the distibutor cap in the correct order, but plug wire #1 wasn't where it was suppsed to be. Double check that with Z1 indicating TDC, the rotor is pointing to the position on the distributor cap that spark plug wire #1 is attached to. If the cap and rotor line up close, and the wires are on in the correct order, it should start.

Jeff Higgins · 10-23-2009, 05:34 AM

Sounds like you need to go back to square one. Everyone here has great advice, so here is what they said, in order:

1) Pull the upper left valve cover and watch the intake rocker open and close to make sure the "Z1" mark on the pully is in fact at 12:00 on the compression stroke. And no, it should not be possible to install that pully wrong, if the dowel pin is in place.

2) Drop the dizzy in its hole until it's seated. The tip of the rotor needs to line up with the hash mark stamped into the top rim of the dizzy body, where the cap seats. The gears are helical cut, so the rotor will rotate as the distributor seats. You may have to try a few times to get it to line up with the hash mark while the clamp stud that holds it in is centered in the clamp slot. Keep pulling it out and moving it a tooth until it's perfect. Put the clamp nut on and snug it down once it is.

3) Make sure the wires are on the cap properly. I like to take a magic marker and label the posts on the cap. Draw a line on the distributor down the side, lined up with the stamped in hash mark, and put the bare cap on. Label the terminal over the line as "1". Take the cap off and label the rest clockwise from there. Put the wires on before re-intalling the cap. Make sure the spark plug ends of the wires do, in fact, go to the correct plugs. #4 through #6 are particularly prone to getting crossed up.

4) Fire 'er up. Let it warm up completely and set total advance per spec.

BottleNose · 10-23-2009, 06:11 AM

Thanks for the tips guys! I don't think it's flooded, as I've tried to start it on several different days. The puzzling thing for me is that it never even tries to start...usually you'll get at least a kick from a cylinder or two when you have fuel issues.

As for the Marelli, it was very stiff when I tried to rotate it by hand, I could barely twist it, while the Bosch rotated smooth as butter. Those are good prices for the Marelli stuff, but I noticed the cap was a "short cap" while mine is a really tall one, so I don't think that cap would work. The ebayer has a pic that doesn't make it obvious that it's a short cap. Wonder what that cap is actually for.

I'll give Jeff's steps a go now and report back.

docrodg · 10-23-2009, 06:13 AM

I have a marelli for sale.

moneymanager · 10-23-2009, 06:54 AM

No need to pull a valve cover for this task. Loosen spark plug number one a few turns. Turn the motor over by hand. You will hear a hissing sound from cylinder 1 as you enter compression stroke. The rotor should point to the cylinder one wire in the distributor when the piston reaches the top. If it doesn't, the distributor position is wrong.

steve911T · 10-23-2009, 09:11 AM

Agree with previous post, sounds like the distributor is 180 degrees off. It will not fire in that position, done it many times myself. Line up the rotor to the notch on the distributer and the pull the distributor out. Listen for the hissing sound, install the distributor, make sure that when it is going in that the gear on the bottom of the distributor goes into the correct position. It is possible to put the distributor in wrong even when correctly on top dead center. When you are on TDC, make sure the rotor is directly under the #1 piston/wire position. Good luck, also, if you do go with the Bosch distributor, make sure it has the correct advance setting, ie, an S does not have the correct advance for the T motor. Good luck. Keep trying, you will get it. Steve

Rich Lambert · Rich Lambert's Garage

Are you sure the points are opening?

Jeff Higgins · 10-23-2009, 10:29 AM

Quote:

Originally Posted by Rich Lambert

Are you sure the points are opening?

Why would anyone continue to run points these days?

Great idea on loosening the spark plug and listening for the hiss.

Rich Lambert · Rich Lambert's Garage

Quote:

Originally Posted by Jeff Higgins

Why would anyone continue to run points these days?

Great idea on loosening the spark plug and listening for the hiss.

Got me...nothing but heartbreak.