Major Issues

[boxster_s_boy_34]

Okay, first of all I have had an IMS bearing failure that I repaired myself, but after that I have had some cam issues. It started with snapping the intake cam on the passenger side bank in half because of my impatience with the cap hardware. Now my current issue is that the exhaust cam has jumped timing on the same bank. Does anyone have any advice to lend to the situation, because I am getting really tired of living underneath my car?

[insite]

Originally Posted by boxster_s_boy_34

Okay, first of all I have had an IMS bearing failure that I repaired myself, but after that I have had some cam issues. It started with snapping the intake cam on the passenger side bank in half because of my impatience with the cap hardware. Now my current issue is that the exhaust cam has jumped timing on the same bank. Does anyone have any advice to lend to the situation, because I am getting really tired of living underneath my car?

uhhhh sounds like you need a little help. how did you repair the IMS bearing failure? how exactly did you snap your intake cam in half? no offense, but it sounds like you don't really know what you're doing. M96 is not exactly a simple engine to rebuild. i recommend getting a seasoned pro to finish your work.

[seningen]

assuming you want to still tackle this your self.

Seems like all you need to do is readjust the exhaust camshaft
alignment relative to the intake.

More than likely when you re-installed the camshaft you didn't have the proper number of teeth between cams. I think it is either 7 exclusive or 8 inclusive links.

You've clearly been here before -- just take your time and check your chain/sprocket alignments.

Mike

[Jake Raby]

If you had a full blown failure the cam timing would have been compromised.. Did you re-time the cams after the bearing was replaced? How bad was the failure? How much foreign object debris was in the engine? How did you clean it?

Where did the intake cam break? Do you have pics?

These are heavy interference engines, the cam timing is super critical, mess it up and the entire engine can go to hell in seconds.

Having improper cam allocation won't snap the cam unless you experienced piston to valve contact. When the intake cam broke you could have had more secondary failures as well, do a leakdown and compression check to ensure you haven't already hurt the engine deeper.

These engines can't be manipulated in a hurry. period.

[boxster_s_boy_34]

Okay, I have already retimed the cams once when I was home (currently deployed to Iraq for the 3rd year long tour) after the installation of the new IMS bearing. Seeing as I have had my hand held by Don for some of these things and the fact that I do work on Blackhawk helicopters for a living (not trying to sound smug or rude) with much closer tolerances, I'm pretty sure that I'm mechanically inclined enough to do all of this work myself. I still have the intake cam in the garage just so that when I do get to feeling cocky or over confident I can look up and realize that the score is car 1 me 0. Now, the intake cam snapped in half on the middle journal from me trying to tighten one side of the cap too far without tightening the other side. Seeing as this is such a close tollerance the cam was trying to twist with the cap and then it snapped from what I was told. My fix for this was to tighten everything one revolution at a time and then torque it to the specified 90 in/lbs in 30 in/lb steps. I did take the car out immediately after finishing with the engine the first time and ran it up to about 140 mph repeatedly waiting to hear something happen (doubting myself). Nothing ever did until about 250 miles later, if that explains the situation a little better. I'm thinking that I may just have not had the cam gear's teeth seated in the chain properly. I would hope that my custom tune would not have a negative effect on what I did, but I'm starting to think that it is a possibility.



P.S. Jake, I talked to you on the phone at length one time, but never remembered to call you back after I got back from some training that I had to do for 3 weeks. Please PM me when you find the time, thanks.