I'm resurrecting this thread to get some input.
How many of you have tried or now running an aftermarket camshaft that is different than the factory stock...... AND have experienced ANY differences in cold starting.
The reason I'm asking is because I am working on figuring out why my rebuild has a problem with cold starting. I have not completed all the tests on all the "sensors". It's still not completely broken in, according to the experts who seem to agree that it takes about 500 to 1,000 miles.
The engbldr 261C cam I have installed has more overlap (6 degrees according their cam spec) than most of the aftermarket 22 cam profiles. The factory stock 22RE camshaft overlap is 2.6 degrees according to my DD.
I'm curious whether or not the amount of overlap can affect the cold cranking compression, or otherwise affect what the ECU sees during initial cold starting.
I measured the valve lash on #1 cylinder intake. I measured the lash at the bottom of the base circle, and then with the crankshaft at zero degrees on the oil pump tab. I was surprised that the measurement at the base circle was to spec - .007". However when I measured the lash by the crankshaft position, the lash was tighter, about .006". Which would indicate that the intake valve will be opening earlier than the stock profile. Should there be a difference in measurement between the two areas on the camshaft?
I believe this confirms the increased overlap in the 261C cam. Since increased cam overlap increases high RPM power and lowers low RPM power, I'm curious why the 6 degrees of overlap was designed into a "crawler cam".
I will take some more measurements.
Any comments and information will be appreciated.
Thanks,
Gnarls.
