Camshaft timing findings

After pulling the LT5 this past weekend I finally got around to checking to see what the issue was before taking off the heads. I wanted to confirm how far off the timing was due to lower compression by 20-25 lbs on the entire bank of left side.


Set the camshaft locator



Right side no problem and pins placed.



Left side confirmed timing is off, did not check approximately how many degrees off but I'm sure the experts can tell by looking at this.



Removed pin to try to show how far off.

A shot of the other cam alignment for pin.



On a different note, here is the other piece of the key for the crankshaft/torsional damper that was left in. Easily taken out with tap of punch and ready for new key from Jeff. Still can't figure out how and when this happened, but not during my ownership of this Z.

More to follow. I'll start taking off the heads now that I am satisified I at least checked before disassembly. I was very afraid of all of this (right Jeff, Carter, Tom, Brad, Rick and others?) I feel more comfortable the more I read, watch the CPT video and work on this LT5. Thanks to this great Z brotherhood, even I can do this.

[flyin ryan]

Can't say it's surprising...last one I had apart looked about the same, was out to lunch . Works good now though .

Originally Posted by flyin ryan

Can't say it's surprising...last one I had apart looked about the same, was out to lunch . Works good now though .

flyin ryan,

Do you think being this much off was the root cause of the lower compression across this entire bank and also the smoking issue I was having? I can't imagine I have piston ring issues causing the lower compression and smoking with only 53K miles.

Thanks!

[tomtom72]

Subscribed!

It's okay if I just sit here in the corner & watch? I promise I won't make any noise... I wanna learn.

[carter200]

Tom,
Pull up a seat and watch the show. It promises to be a good one

[jonszr1]

craig , ryan would be the best one to run all your findings through . he has forgot more about motors than most of us will ever know .jmho

[Pete]

I can't tell from the pictures.

Looks to me like the cams retarded if i had to guess i would say at least 4 degrees basicly going from 114 to 118 +-2
When i checked my cams way back to start all the port work they were out on left field right bank was 119 109.

Looks like the same thing on yours looks like cams retarded
Intake 118 +-2 Exhaust 108 +-2

I pretty sure this is the reason for lower pressures.

I have my notes somewhere different pressures with all the different cam timings i just need to find them.

By the way 118+ intake timing is over/past the best power curve.

Good luck.

Pete

Just remembered,this is a big if, if the exhaust moved to 106 or lower you are very close to having the ex.valves hitting the piston,look at your pistons for marks if so then the low pressures could be bend valves.
Don't mean to scare you but better to check now then find out later.

Originally Posted by Pete

I can't tell from the pictures.

Looks to me like the cams retarded if i had to guess i would say at least 4 degrees basicly going from 114 to 118 +-2
When i checked my cams way back to start all the port work they were out on left field right bank was 119 109.

Looks like the same thing on yours looks like cams retarded
Intake 118 +-2 Exhaust 108 +-2

I pretty sure this is the reason for lower pressures.

I have my notes somewhere different pressures with all the different cam timings i just need to find them.

By the way 118+ intake timing is over/past the best power curve.

Good luck.

Pete

Just remembered,this is a big if, if the exhaust moved to 106 or lower you are very close to having the ex.valves hitting the piston,look at your pistons for marks if so then the low pressures could be bend valves.
Don't mean to scare you but better to check now then find out later.

Pete,

Thanks for all you help and advice. I am starting to actually understand what you are talking about......very scary. I have been reading and trying to be a sponge and I'm all ears. Hey, low 11s and the quickest 350 is doing many things right in my book. I'll pull the heads tomorrow and see what is going on. I am praying that I don't have bent balves or and piston damage.

What causes these to go out of timing like that?

Originally Posted by jonszr1

craig , ryan would be the best one to run all your findings through . he has forgot more about motors than most of us will ever know .jmho

Brad,

Thanks Brad. You're right and I'll definitely solicit help from flyin ryan too. Someone else already passed my invaluable infomation from Ryan. Thanks Ryan!