Cam dowel length

[pa formula 78]

So if you have seen my thread lately you'll know I recently destroyed a Delphi opti in about 7 miles. I measured the cam dowel yesterday, and it measured at .400". From what I am seeing online it should be closer to .600". Could this be an issue that could cause early failure of the rotor?

[SSlowBoat]

So if you have seen my thread lately you'll know I recently destroyed a Delphi opti in about 7 miles. I measured the cam dowel yesterday, and it measured at .400". From what I am seeing online it should be closer to .600". Could this be an issue that could cause early failure of the rotor?

If it was longer i see it blowin the opti apart not shorter. I have heard stories of cheap rotors just exploding from overtightening and spinning too high. Is your car pin drive or spline?

[pa formula 78]

Its a 95 so it is pin drive. I did lock tight the rotor on before installing it, but the base of the rotor is perfectly fine. I figured it I over tightened it that the base would show damage also.

Here is a picture of what is left of the rotor.
IMAG0624.jpg

[huntr1117]

I think it should be somewhere between .620" and .650"

[Injuneer]

From Shoebox's cam install writeup:

Before you install the cam, it is a good idea to check the dowel pin length. Compare the new length to the old and make any adjustments if needed. If the dowel pin is too long, it can ruin a vented optispark in a short time (non-vented optisparks aren't driven by the dowel pin). Some have said GM specs indicate that the dowel should be .620" long (protrusion from the front face of the cam) for the vented optispark. Others have said it is supposed to be .685". Mine was actually .650" and still was in no danger of bottoming out in the optispark drive (I'm thinking .685" might be the max it could be).

http://shbox.com/ci/ci289.jpg

[Spartan7]

I ran a cam that had a .50 pin and had no issues. I doubt a short pin would cause that. What does the inside of the cap look like? Any signs it was touching while spinning? Also, where did you get the opti base from? Cheap reman. bases have shit for tolerances.

[pa formula 78]

It was a Delphi Opti from RockAuto. I really don't see that having the dowel shorter would be an issue either. Here is a picture of the cap after I pulled it off. I does almost seem like it caught while spinning which is what destroyed it?

IMAG0623.jpg

[Injuneer]

How did it run for the 7 miles BEFORE the rotor grenaded? A short pin may not have gone in the correct hole, and been pushing against the more solid part of the drive (not in the "cloverleaf" reliefs), forcing the rotor forward. But it wouldn't run real well if that was the case, unless it was just on the edge of the correct hole.

Looks like scrapes on the "ridges" in the cap, particularly at 9:00 - 10:00 in the pic you posted.

Do you have the correct flow limiter in the vacuum line to the Opti, and is the air supply line from the intake elbow flowing? Excessive vacuum can pull the cap inwards.