re. need help setting up Blaufergnugen 272 cam in 86 4000Q

[Ben Swann]

I have an ELGIN 270 (similar to a 272) in my NG equipped '87 4kq.  It has had a similar problem that was difficult to tune out - probably even more so with CIS-EIII because there is little adjustability in the system.  I found an adjustable cam sprocket helped by allowing to advance the cam for better low idle and emissions.  The problem is simply too much overlap for low RPM operation and some intake charge is going straight out the exaust at low RPMs but at higher RPMs scavenging comes into play and you can really get some serious power.  The car was doing good on emissions when running the treadmill test, but the bozos were afraid the Stebro exhaust was going to hit the rollers and aborted forcing and idle test - I knew I was screwed!

I found once I set the cam advance to where I thought it should be - depending upon whether I wanted to pass emissions or go fast, that I'd have to play with the timing to get the engine marginally happy.  It is really touch with the timing and with the NG, you only have a few degrees where the engine runs OK at all.  I expect it to be a little easier with CIS, because at least you can set the idle somewhat.  CIS-EIII on the other hand decides to mess with spark timing,  fuel-enrichment and idle, so not much that could be done to really smooth out the idle completely.

BTW, while doing research on which cam to use, ELGIN suggested that anything over 268 would mess up a low compression engines idle  and the high duration cams are more applicable to higher compression engines, so base on that, I'd suggest the cam is simply too much for the KX.  I have a Crower 264 in our '85 4kq and it idles nicely with a 7 deg. spark advance and no cam advance or retard.  

If you don't have an adjustable sprocket on hand, try slipping the belt one tooth to advance.  Then back off the timing.  I bet you'll see a better idle without losing much on top end.

In my NG engine with 270, it ran lumpy at idle with 4 deg. cam retard but once off idle pulled wildely to the redline around 7200 RPM.  Setting the timing at 4 Deg. advance got me a happier idle without losing much on top end.  I still felt it was spewing a little too much unburned fuel(sniff test), so slipped another tooth to advance to 12 deg.  Engine is down on power but pretty much putting out water as an emission, esp. when cool.  I have yet to see what wil happen on emissions, but feel it should pass - well see.  Then I'm going to set the cam timing pretty much back to 0 - no advance or retard, or 4 deg. advance where it was happy but not down on power.

You may also want to check all of your idle stabilization gadgets, including the throttle adjustment screw, throttle body and plate for sticking, the funky hose that looks like an intestinal tract, the switches as well as the ISV - should not pass air AFAIK when not energized (different than the 3 wire NG ISV).  Any of those can cause the problems you describe as well.

HTH.

Ben

[Date: Tue, 22 Mar 2005 22:17:18 EST
From: VFChris at aol.com
Subject: need help setting up Blaufergnugen 272 cam in 86 4000Q
To: quattro at audifans.com
Message-ID: <1c2.24eeba93.2f7239be at aol.com>
Content-Type: text/plain; charset="US-ASCII"

I just installed the Blaufergnugen 272 cam in my 86 4000Q.  I also  installed 
a new timing belt (timing set per the Bentley manual), spark plugs,  fuel 
filters, lifters, Oxygen sensor, and other tune-up-type stuff.   The car is 
stock, other than I removed the catalytic converter.
 
The car runs OK, but has two key problems.  When coming to a  stop, the idle 
hunts around, going from almost a stall (about 400 RPM) to over  1000, and 
oscillates.  Eventually it settles down, after about ten cycles  of this.  Also, 
it has poor acceleration below 2000 RPM, kinda like it is  starving for fuel, 
and stumbles.  Once the rev's climb, it kicks in quite  strongly.  Both of 
these problems are noticeable only after the car warms  up.  I've set the timing 
to about 15 degrees (versus the stock recommended  6 degrees), and I get no 
pinging.  Also, per the instructions from  Blau', I richened the idle mixture 
screw by about one turn.
 
I really like what this cam has done to the performance during higher RPM  
operation, but am bugged by these two issues.  I'm hoping someone has  some 
experience that can help me.
 
Thanks very much,

Chris 
 
_VFChris at aol.com_ (mailto:VFChris at aol.com) ]
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