Vacuum Gauge Readings

[Aidan]

OK, following on fom a comment by Simon Baxter in another Simon's post about his new lambda gauge I did as suggested and read up and found some interesting info and I picked up one off ebay cheap.

So this is an MV 2.1 engine, ie low compression with ecu timing and fuel management and lambda feedback

Reading at idle is steady slightly buzzing 13.5, drops down close to zero on rapid acceleration and up to around 25 on fast overun, at a couple of thousand rpm a steady buzzing 16, all in no load situation.

reading up on this site http://www.secondchancegarage.com/public/186.cfm

suggests to me that this is a bit worn, a bit retarded timingwise (actually running 7'BTDC at 2500rpm in timing mode which is fractionally advanced) and that wbx is a high overlap performance type engine.

so scenario 3 and scenario 11 seem to be closest to what I have

does anyone know better

[toomanytoys]

Mmm.. I'd be resetting the tappets to 1/4 turn in from just touching (or even zero lash as an experiment) repeat the test and see what affect it has .. I suspect a lot of times a valve is "letting by" with the std 2 turns preload... not generally enough to cause an issue, but enough to be visible o that vac gauge.. (of course long intake runners could cuase that to, as the resonant frequency would pulse back.. bear in mind the info is prob based on a I4 or V8, where the intakes are relatively short compared to the wbx)

As I have said a couple of times.. I'd try more static advance with your setup/fueling... but make ONE change at a time and repeat the test.. that way its a real quantative test and result..

Oh.. and how many miles has it got on it?? er.. a good few... so yes it prob does have a little wear...

We should do a few tests on mine as well..