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bradelporsche · Joined: 29 Mar 2008 Posts: 51 Location: VA

Did some more work on the car. Cam timing was off. Lined up both marks on crank(flywheel) and camshaft pulley and reset the distributor rotor. (the lead for cyl 1 was on cyl 4)...

Now I am thinking the Carburators are running lean. What I do find weird is that the mixture screws on cyl 1&2 carb don't do anything. While 3&4 are working as they should...

The car is using an autozone fuel pressure regulator (These should run 3.5 psi?) so no idea how much PSI is getting to them. I am thinking of using a T in the middle of the carbs rather than have it run as it does now.

Thoughts?

https://www.youtube.com/watch?v=HU1cjMw5q8Y&feature=youtu.be

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2596 Location: MI

if the mixture screw does nothing I would bet that that jet path is completely clogged....

it being clogged it would act like your mixture screw was ran all the way in to a stop (lean)...

sometimes bottoming out these screws and pulling them all the way back out will dislodge the clog..

count turns in to bottom on your good one where it runs best and copy that onto your other one..

if that doesn't work run your bad screw almost all the way out to open up that path, get it running, rev it up to a few k rpm's, put your palm over the carb intake and hold the throttle butterfly wide open to induce a massive vacuum inside the carb... more rpm=more vacuum

a lot of the time hand choking carbs like that will suck any BS through the ports, you should end up with a gasoline soaked hickey on your palm...

kindof like a self cleaning oven

if that fails bring the carbs in the kitchen, strip them down to every little spring and pin, gently set the carb bodies in the sink and tell the misses she has some dishes to do while you attack the finer pieces with carb cleaner..

compressed air and fine wire are great through small jet paths..
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80 Turbo - Slightly Modified

bradelporsche · Joined: 29 Mar 2008 Posts: 51 Location: VA

Fantastic worked as described! Night and day difference! Thanks for the tip

Now the set of carbs that was fine isn't pulling as much vacuum when I choke it by hand. (must be leaking at the gasket)

I did remove and re install the 1st set to make sure it didn't have a vacuum leak. I have ordered the soft mounts. I'll install them, hand choke the second set and start driving it on the street.

Much more drivable now. After the carbs are set I will look at retrofitting a Ford EDIS system.

Then a few bit after that build a 88mm block with forged VW flat top pistons, lightweight flywheel, should net a 11:1 compression ratio.

https://www.youtube.com/watch?v=63NENp6aa1g&feature=youtu.be

nickthompson · Joined: 26 Mar 2013 Posts: 873 Location: Central Georgia

Msd works well with carbs.

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2596 Location: MI

bradelporsche · Joined: 29 Mar 2008 Posts: 51 Location: VA

I will give that a try.

Any tips on how to and where to hook up the vacuum advance and retard for the distributor?

I am assuming the source for retard can be taken anywhere post carburators. The advance will need to be before the venturi... Is that what those white caps are for?

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2596 Location: MI

I know carbs but im pretty new to the 924 or any Porsche for that matter...
I was able to dig this little tidbit out for ya though...

bradelporsche · Joined: 29 Mar 2008 Posts: 51 Location: VA

Thanks for the info.

My car being a 77' with the 77 distributor is a plus. I'll set initial timing at 2 degrees BTDC.

Endwrench recommended hookup the vacuum advance to manifold vacuum for an extra 4-10 degrees of advance when cruising.

Ideally I will just convert it to full EDIS ignition and not deal with weights, springs or vacuum timing.

Also found the generic fuel pressure regulator that was used

http://www.oreillyauto.com/site/c/detail/MRG0/9710/N0514.oap?ck=Search_N0514_-1_-1&pt=N0514&ppt=C0128

Looks like the numbers on the dial are 1:1. I'll run the car on the 3.5 setting as I have been running it on 6 per previous owner recommendations

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11732 Location: PacNW

Dizzy advance should not go to manifold vacuum.

The only way to do this right is to send your dizzy in to be recurved. There is a place here in town that does it quite reasonably: Philbin.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Joes924Racer · Posted: Fri May 09, 2014 12:28 am Post subject:

Sounds 10x better.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

bradelporsche · Joined: 29 Mar 2008 Posts: 51 Location: VA

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11732 Location: PacNW

More like 35 degrees of total advance.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

bradelporsche · Joined: 29 Mar 2008 Posts: 51 Location: VA

Yes,

I'm actually just going to skip recurving the dizzy and go with an EDIS-4 solution.

Got lucky at a local salvage yard. Now just buy Ideolas trigger wheel and a trip to the hardware store for anything I can use to rig up a sensor mount.

After it's all setup getting a megajolt JR.

bradelporsche · Joined: 29 Mar 2008 Posts: 51 Location: VA

It looks like I may need a new spill jet.

The old ones are inconsistent and filled with muck causing the ball inside to move at inconsistent rates.