1983 SC CIS Pressure Test Evaluation

[2jmotorsports]

Hello folks,

After a nearly 4 year engine and fuel system rebuild, I just conducted my first set of CIS fuel pressure tests. Using our favorite CIS reference thread and various other resources, I was able to obtain the following data:

1. Year of engine: 1983
2. US or RoW (Rest of World): US
3. WUR model number: 090
4. Ambient temperature at time of test (in degrees C): 32.7 deg C
5. WUR Resistance (in Ohms): 25.6 ohms
6. System Pressure (in bars): 4.75 bar
7. Cold Control Pressure (in bars): 2.1 bar
8. Warm Control Pressure (in bars): 3.4 bar
9. Time delta for Cold -> Warm Control Pressure (in minutes & seconds): 2:20
10. Residual Pressure @ 5 min (in bars): 1.9 bar
11. Residual Pressure @ 15 min (in bars): 1.7 bar
12. Residual Pressure @ 30 min (in bars): 1.7 bar
13. Residual Pressure @ 60 min (in bars): 1.6 bar

Everything seems to check out per the Bentley except for the cold control pressure per this chart. It seems I need to be in the 2.8-3.2 bar range:



What do you guys think? Is the Bentley accurate? My FD and WUR are freshly rebuilt by Mr. Tony Donato. Well rebuilt about a year ago with zero miles on them.

Thank you in advance.

[patkeefe]

Probably OK. Test the cold control pressure again when it gets colder ambient. 32C is already half warned up/ Did you have any problems starting the engine? Or, was the 2:20 time period from cold to warm using only the electrical heater in the WUR?

[2jmotorsports]

2:20 was the period from cold to warm using only the electrical heating in the WUR.

It is nice and toasty at the moment, so tough to test "cold". May repeat a couple more days to see what happens.

As far as starting goes, everything in this current engine setup is brand new or rebuilt, and I have not started it yet. Im trying to set my fuel and spark for engine break-in next week.

Prior to the engine and WUR rebuilds I never had any issues cold starting either.

[patkeefe]

You should be OK on the fuel side to start it up. Low cold control pressure will richen it up a bit, which should be just fine for start up. Is your -090 WUR adjustable, or just a regular WUR? Tony is pretty good with CIS stuff, so that should be the last of your worries. Good luck when you start it up.

[2jmotorsports]

Regular 090. Good to know its ok for the start up. Thanks for the feedback Pat!

[tirwin]

I’d wait until cooler weather and check it again.

[manbridge 74]

Your system pressure is in spec (4.5-5.2 bar) at 4.75 bar. I’ve found with today’s fuel that adjusting to the upward side of spec allows for much better starting/running. Adding a shim to the PRV and also replacing its o-ring(s) might be something to think about.

[boyt911sc]

Jose,

Are you having problem starting the engine? I set the CCP particularly for this WUR below the chart value. That was intentional. I am away from home right now but still able to communicate via email. Keep us posted.

Tony

[2jmotorsports]

Will do Tony. I am starting it up next Saturday 8/3 so Ill report back.

[pmax]

2jmotorsports,
Is your engine (including rest of the CIS system) factory spec otherwise ?

[2jmotorsports]

The CIS is 1983 spec. The engine is factory spec except for some 964 cams and 1mm larger intake valves.