technical question re: MFI
 

I got my new 2.7mfi solex cams motor running used Lee Rice info and other books to set the mfi got pretty close. Pump rod is 114.0 mm. The linkage rods are 147.00. If I go to 149.5 they hold the throttle open. The vacumn advance/retard doesent move the distributor? I can suck on the line to make it move not much effort to move. The motor has 30min on it can I run it to 6000rpm for timing check? Any tech info on setup will help...thanks Matt

Sounds like there is a clog in the vacuum line somewhere.

My favorite wrench says he never revs a motor to 6k for a timing check, no matter how old. He sets them at 3k and so do I. I'm sure someone will disagree.

THere are cam grinds that work perfectly with MFI other than the factory grinds? I always thought the pump and the engine cams had to be tuned together? Know I'm not offering much help here, just trying to learn more. Hoping Warren or John would like to weigh in...

Matt,

There isn't any problem running the 6000 rpm timing test/check after you have warmed the engine up fully to an oil temp. of 180 degrees F, or more. That is the way the factory set the timing on new engines before the one-hour break-in run on the dyno ... or used to back in the days of the glorious MFI engines!

But, first, I think you should take a look at the vacuum ports on stacks #1 and #4 ... a pipe cleaner dipped in B-12 Chemtool may help clean out the carbon that is surely clogging the ports. It may even take a small drill bit held in the hand, or stiff wire, such as a paper clip to break through the carbon.

As far as checking the timing goes, the following graph justifies making the test ALL the way to 6000 rpm:

<img src="http://www.pelicanparts.com/ultimate/image_uploads/72adv-crv.jpg">

If you have not partly disassembled and cleaned & lubricated your distributor recently ... I suggest you do so NOW! Wear and play due to worn bushings and thrust washers is a chronic problem on older 911 engines whose distributor has been neglected! All of the pertinent data for your engine was posted in the following thread:

http://www.pelicanparts.com/cgi-bin/vb/showthread.php?s=&threadid=5432&highlight=distribu tor+lube