Mrmerlin

found this on another thread

Instructions for rebuilding the WUR

http://www.ferrari400parts.com/Warmu...atorrepair.php

Jadz928

Good stuff, Stan!

SeanR

Yes, very nice find Stan. Thanks

karl ruiter

Nice write up. Only trouble is, often the screen just won't unclog. Carb cleaner, compressed air etc, all to no avail.

jpitman2

Remove the screen. I have seen one with 5 layers of brass, different fineness. Or , remove carefully, and burn the crud off with a lighter, replace. That guy also sells kits of WUR Orings etc, and for the distributor, and replacemnet distributor shims. On a distributor rebuild he advises polishing/truing the half faces on a good flat surface with very fine wet&dry.
jp 83 Euro S AT 54k

linderpat

thanks Stan. good find

9two8

Very useful, thank,s for posting.., (in my 928 info now.)

Ken
80 928 S
5 Speed

UK

smiffypr

Here are two diagrams (with vacuum and WOT) of the actual insides of a 928 WUR. May be useful for anyone trying to understand how the 928 full throttle enrichment works when the vacuum/air hoses are connected the opposite way around to how they are in all of the bosch documentation.

DremekT

Hi Smiffypr
I have been searching all around the net to find what you have posted, i.e. the pictures of the vac controlled WUR. As you correctly mentioned, it is the type that works the opposite way to those described in all known to me Bosch publications. I worked out the principle easily but wanted to find the confirmation either in a correct cross-section diagram of such WUR or picture of one being disassembled
Finally came across your post !
My 911 has WUR just like this one.
Would you be so kind and let me know which Bosch publication you have found it?
I found couple of them in pdf on the net and printed them for an easier use, but none contained that type of WUR.
Would you by any chance have a pdf copy of it?
I could then print it and add to my small collection
Regards
Tom

smiffypr

DremekT,
I modified the pictures myself.
Email me at smiffypr (at) gmail (dot) com and I'll send you the jpegs.
Smiffy

SMTCapeCod

Once again pleased to be free of CIS, despite the fact that it rocks on 928 once squared away.
:-)

tailpipe

A couple drops of muratic acid will clean the filter screens very well doesn't seem to bother the WUR at all just flush with water after and let dry. Put some oil on the steel parts right away or it will start to rust.

jpitman2

None of the diagrams I have seen show the heater arrangement in my WUR - an 086 version. It has a set of points in it that look like they cut off the +12V once the engine heat has moved the bimetallic strip.
jp 83 Euro S AT 56k

GlenL

It makes sense the the upper port gets vacuum. The diagrams that show it show the upper being "atmosphere" and the lower being "vacuum."

How does the upper get more vacuum at WOT? Special ports in the throttle body?

DremekT

Actually Smyffypr wrongly described his two pictures. They are both of the same WUR but in two different stages of load . ( see the inscriptions next to the pictures).
This WUR has atm. on top and as it has a special sealed chamber for vac. ABOVE the membrane. In the open throttle stage the pressure rises in the inlet manifold and "vac" becomes "less" of a vacuum and the membrane is pushed down as the "air" forces are similar on eitjhr siede of the membrane but the inner spring helps push the membrane down. etc.
Those WURs that have vac. on top do not have a special small chamber ABOVE the membrane.