WUR Replacement?

[jsmithcds]

79sc 3.2SS conversion with 964 cams

symptoms:
-Starts immediatly and idles at 1K for about one minute
-Good deal of white smoke at start up
-after one to two minutes it starts to hunt at idle
-If I start and drive immediatly it will be jumpy/jerky
I shift into a higher gear to calm it down.
After 1 to 2 min that goes away.
if I stop at a stop sign it will hunt after 3 to 4 minutes that stops
-Car runs perfect after it is warm
-O2 sensor gone from car
-at some point PO had removed the vac retard, I reinstalled

info:
-it did the same thing before the conversion
-every line, seal and component that could be was replaced on the motor
-Control pressure is well below spec at start
-Runs rich at start up
-New WUR is in the mail
-I plan on taking it to my mechanic to istall the WUR and tune.

Questions:
Is the WUR the culprit here?
Is there anything else he should be looking for in addition to the WUR?

Thanks for your opinions and help.

FYI I had two hours of track time at Road America yesterday in the rain for three sessions and dry for the last. The 3.2ss is a monster on the track......

[Gunter]

Originally Posted by jsmithcds

79sc 3.2SS conversion with 964 cams

symptoms:
-Starts immediatly and idles at 1K for about one minute
-Good deal of white smoke at start up
-after one to two minutes it starts to hunt at idle
-If I start and drive immediatly it will be jumpy/jerky
I shift into a higher gear to calm it down.
After 1 to 2 min that goes away.
if I stop at a stop sign it will hunt after 3 to 4 minutes that stops
-Car runs perfect after it is warm
-O2 sensor gone from car
-at some point PO had removed the vac retard, I reinstalled

'79 has no vac retard. What is the Bosch number on your distributor?

info:
-it did the same thing before the conversion
-every line, seal and component that could be was replaced on the motor
-Control pressure is well below spec at start
-Runs rich at start up
-New WUR is in the mail

Why a new WUR before checking/cleaning your old one? What is the Bosch number on the old and new WUR?

-I plan on taking it to my mechanic to istall the WUR and tune.

Questions:
Is the WUR the culprit here?

With CP well below specs, WUR is suspect.

Is there anything else he should be looking for in addition to the WUR?

Make sure that the WUR gets power and check the power sequence from Starter Solenoid to Thermo Time Switch (TTS) to Cold Start Valve (CSV)

Thanks for your opinions and help.

FYI I had two hours of track time at Road America yesterday in the rain for three sessions and dry for the last. The 3.2ss is a monster on the track......

WUR numbers and distributor numbers, please.

[jsmithcds]

-wur last numbers are 045 for both
-distributor is from a 1980 sc was in the car when I bought it. Difference single vs double.
-found a WUR new in box for $250 so I jumped on it just in case
If the old one is still good I figured i could clean it up and sell it for close to that anyway.

[Paulporsche]

JS,

The WUR certainly sounds like it is off, but have you checked the mixture to see if that is the reason? Most likely, though, if the warm running is good, then your cold cp is too low, giving you that too rich condition. Have you tried resetting the ccp rather than going for a new WUR? These things can be adjusted quite easily. There are many threads on this. I have several!

You may find that, even w/ a new WUR, it may still have to be adjusted for control pressures.

Also check to see the the AAR is operating correctly to raise the revs during cold warmups.

I'm assuming all ignition components have been checked out.?

Your 80 diz should have both a vac retard and advance. I think Peter Zimmermann has suggested plugging the retard line for better starts and idle. I did it on mine (which only has a retard) and like it that way.

BTW my engine is similar to yours, as is Gunter's. It's a nice upgrade.

[jsmithcds]

If the AAR was shot it would just cause rough high idle would it not?

[Paulporsche]

Not necessarilly. It could be stuck open or closed.

Sounds like the WUR. If you can get it to the right ccp, I think that may do it.

Have you tried raising the ccp?

[Gunter]

JS,

I have a SS 3.2 and tried all SC distributors and found the '78-'79 type worked best.

'80 distributor 0 237 304 016 is wrong for your set-up; Springs and weights are different giving you a different curve.

You'll need a 0 237 306 001 vac advance only, I have one serviced for sale, check it out:

Distributor 0 237 306 001 Reconditioned and checked

WUR number ending in 045 is good.
I take it that you have a CIS for '79 with large intake runners?

[jsmithcds]

Originally Posted by Gunter

JS,

I have a SS 3.2 and tried all SC distributors and found the '78-'79 type worked best.

'80 distributor 0 237 304 016 is wrong for your set-up; Springs and weights are different giving you a different curve.

You'll need a 0 237 306 001 vac advance only, I have one serviced for sale, check it out:

Distributor 0 237 306 001 Reconditioned and checked

WUR number ending in 045 is good.
I take it that you have a CIS for '79 with large intake runners?

What would this exactly do for me?
cis is a 79

[T77911S]

have you checked the mixture? or try leaning it out a little. if i get mine too rich, it will idle good for a minute or so then start hunting.

what are the warm/cold CP's?

you also need a vacuum line connection to the WUR for the 79 CIS.

[jsmithcds]

at 60 degrees cold pressure was at .7bar/10 psi and warm was 3 bar /43 psi

[boyt911sc]

Originally Posted by jsmithcds

at 60 degrees cold pressure was at .7bar/10 psi and warm was 3 bar /43 psi

JS,

The cold control pressure may help you in starting the engine (cold) but the WARM control pressure is LOW!!! Check your system pressure too. The FP maybe not delivering enough fuel pressure.

Check your fuel pressures (control and system) both cold and warm conditions. This will give you the information if your WUR is working correctly within spec. Do not replace CIS component/s unless verified defective. Keep us posted.

Tony

[T77911S]

if you do not have the vacuum line connected or the car is not running, the W/CP will be low.

[Miguel Antonett]

Hint - if you post this thread on the 930 forum u might get more ideas.

[Paulporsche]

Originally Posted by T77911S

if you do not have the vacuum line connected or the car is not running, the W/CP will be low.

And yet, in Ricks911s's movie, he got 3.5 bar "warm" w/ the WUR connected and FP running but the engine off, per stevemfr's (and others') procedure. I did the same w/ my recent test and set the WUR to 3.5. When I ran the engine @ idle I got a warm reading of 3.5 bar w/ 15" hg vacuum. BTW the chart in Adrian Streather's book shows approx a 13.7 to 17.7" Hg range. This has been something I have been wondering about. Should Rick and I have set the WCP w/ the engine off to about .5 bar lower? I'll have to PM him and see if his wcp went up when he warmed up the engine.

[Gunter]

Originally Posted by jsmithcds

What would this exactly do for me?
cis is a 79

When I built the SS 3.2 with a '78 CIS, I first tried a 0 237 304 016 with vac advance and retard and wasn't quite happy with the curve.

JW advised me that, with a '78 or '79 CIS, he found a much better performance with one of the earlier 0 237 306 001 with vac advance only.

I took his advise and confirmed a better performance with the 0 237 306 001.
Then I had Steve Weiner recurve a distributor to run without vacuum and found no difference in performance between the two.

I am keeping the recurved distributor without vacuum and selling the one listed.
It all comes down to different weight/springs in the two types giving a different curve to suit your set-up.

You can have your distributor recurved (About $400.-), or get a good working 0 237 306 001, or buy mine which is reconditioned already.

Distributors are generally neglected but curves are important and often don't suit the engine. Detonation is the enemy.

Why not get max performance without risking damage?

[Bobboloo]

Originally Posted by jsmithcds

at 60 degrees cold pressure was at .7bar/10 psi and warm was 3 bar /43 psi

As you previously stated your cold pressure is too low. At 60 deg. F you should have ~2 bar of control pressure. Your warm pressure looks good if you are testing without vacuum.
With a vacuum of 350-450 mmHg your warm pressure would be 3.2 to 3.6 bar.

Hunting idle while cold also confirms your rich as well.

Either replace the WUR or adjust it to spec. There are posts on the board about adjusting them if you want to go that route.

[Drdogface]

Side question for you if I may. I also have a '78 SC and have considered the 3.2 SS and cam. Did you notice a huge increase in performance ? About how many HP do you think you now have ?

[Paulporsche]

Check my name, stevemfr and/or ricks911s for info on adjusting/testing WURs.

[T77911S]

Originally Posted by Paulporsche

And yet, in Ricks911s's movie, he got 3.5 bar "warm" w/ the WUR connected and FP running but the engine off, per stevemfr's (and others') procedure. I did the same w/ my recent test and set the WUR to 3.5. When I ran the engine @ idle I got a warm reading of 3.5 bar w/ 15" hg vacuum. BTW the chart in Adrian Streather's book shows approx a 13.7 to 17.7" Hg range. This has been something I have been wondering about. Should Rick and I have set the WCP w/ the engine off to about .5 bar lower? I'll have to PM him and see if his wcp went up when he warmed up the engine.

hey paul,
i have not seen the chart. but i would check warm pressure with it running or with a vacuum pulled on the WUR. then i would remove vacuum to check the difference.
mine is 3.6 bar with vac, 2.8 with out.

[Gunter]

Originally Posted by Drdogface

Side question for you if I may. I also have a '78 SC and have considered the 3.2 SS and cam. Did you notice a huge increase in performance ? About how many HP do you think you now have ?

Paul isn't really sure what he has for P/C's or cams etc.

Making a SS 3.2 with 964-cams plus SSIs will add a good 40 horses with CIS.
With a '78, you already have the larger intake runners and head-ports.
Your distributor is good but needs to be serviced and the curve checked.

The regrind of the SC-cams is not that expensive but the 98 mm P/C's are very costly.
My SS 3.2 loves to run, especially past 4k RPMs.

You will notice the extra 40 horses.