Author Topic: Intake cam ajustment (Read 8496 times)

cristimm · « **Reply #15 on:** May 01, 2010, 09:17:44 AM »

I opened my valve cover to change the gaskets and I took some pictures. As you can see the intake sprocket is not set in the middle of the oval holes.
Please tell me it is optimised for low-end torque or high rev power?

Another question: what do you think are the chain and sprockets original parts? (120k miles on the dash).

flyinglizard · « **Reply #16 on:** May 01, 2010, 12:22:10 PM »

The intake is back. This should idle very well, but without a crank reference, you have no idea where they really are. It may be at zero or not, you have to look at the crank mark to get it spot on. As the guide wears, the cams get later.
The chain wheels look very good, IMHO.

cristimm · « **Reply #17 on:** May 01, 2010, 01:19:54 PM »

Thanks. I was pretty pleased myself when I saw the condition of the chain and sprockets. Do you think it is plausible that they are the factory parts or have been changed at some point? (120k miles on the dash)

bmwconnect · « **Reply #18 on:** May 01, 2010, 01:24:20 PM »

mine were in similar shape and my motor has 230,000kms on it

cristimm · « **Reply #19 on:** May 01, 2010, 01:30:09 PM »

Thank you. So probably the parts are the factory ones. Are there any chances that the intake cam adjustment to be factory as well?

TomO2UT · « **Reply #20 on:** June 27, 2011, 05:02:08 PM »

My 1991 M42 failed emissions this year (Utah changed its emissions law and now includes a test at idle). It turned out my intake cam was advanced 7 degrees, as best I could tell using a protractor. I moved the intake cam back such that both cams were aligned with a straightedge (having no tool available) at TDC. I passed emissions easily and now have a nice smooth engine instead of a rough idle.

Centerpunch marks on the intake cam and sprocket indicate the PO had horsed around with various positions.

Fortunate for me I first tried to replace the vacuum and coolant hoses. I say fortunate because the plastic coolant pipe crumbled at all four connections upon removal. The throttle heater and vacuum hose delete worked out nicely, too.