Adjustable cam sprockets

[DonE]

Here are a couple of pics of the adj cam sprockets I installed a couple of months ago. I have the engine out for a valve job and got the heads back from Xtreme Cylinder Heads about a week ago. The process of timing the cams now takes all of 10 minutes - both sides. I have GT II cams (high lift) and it still took 10 min. The ability to dial in timing is absolutely exact.

You can also see the Jerry Woods oversized cam pulleys since my chains had too much slack.

[x98boardwell]

I have a few things to ask and tell... nice picture by the way. I wish you lived closer.

Story: I just had my heads rebuilt, cylinders honed with new rings, my cams reground to SC specs (use to be 964.. I didn't know, they were done in 1998), rocker arms and shafts micro-polished and replaced if out of spec, and finally exhaust ceramic coated inside and out.

My questions:

1) From what I have heard, I need to "break-in" ny cams at about 2,500 rpm's for 20 minutes. Is this true? What is the best break-in process?

2) The company who did my exhaust (many turbo applications) recommended starting the car for a few minutes and then letting the exhaust cool... then repeating this process for longer to reach a higher temp, then cooling. Finally, driving the car to where they see the hottest temperature. They cure at 600 degrees and they recommend increasing that curing temperature incrementally to increase strength and longevity.

3) If I need to do question #1, how in the hell with I be able to do #2 at the same time?

4) Lastly, my tensioner pistons looked less compressed than yours in the pictures above. I purchased the master link chains (since I'm not splitting the case) to replace the old ones. Should I even replace my chains if they appear to be ok since referencing your pictures or should I still replace since I have the motor out and apart?

Your help is greatly appreciated. Just to reference, my car is an 87-930 with 97,000 miles on the clock.

Bryan

[A930Rocket]

Don,

Sounds like a great idea! Did you get all the cam/tensioner parts from Jerry Woods? Not sure I'm reading your post right.

Here are a couple of pics of the adj cam sprockets I installed a couple of months ago. I have the engine out for a valve job and got the heads back from Xtreme Cylinder Heads about a week ago. The process of timing the cams now takes all of 10 minutes - both sides. I have GT II cams (high lift) and it still took 10 min. The ability to dial in timing is absolutely exact.

You can also see the Jerry Woods oversized cam pulleys since my chains had too much slack.

[A930Rocket]

Bryan

I would say you need to break in those cams first. 20 minutes at 2000-2500 rpms works. Keep an eye on oil pressure, temps, leaks etc. I've never heard anything about bringing the exhaust up to temp. If you have an exhaustcyou can swap out, you may want to try that, especially if you are going with a new turbo.

As far as the chains go, I would install new ones. I don't think it matters if there are split chains or not, the length should be the same.

I have a few things to ask and tell... nice picture by the way. I wish you lived closer.



Story: I just had my heads rebuilt, cylinders honed with new rings, my cams reground to SC specs (use to be 964.. I didn't know, they were done in 1998), rocker arms and shafts micro-polished and replaced if out of spec, and finally exhaust ceramic coated inside and out.



My questions:



1) From what I have heard, I need to "break-in" ny cams at about 2,500 rpm's for 20 minutes. Is this true? What is the best break-in process?



2) The company who did my exhaust (many turbo applications) recommended starting the car for a few minutes and then letting the exhaust cool... then repeating this process for longer to reach a higher temp, then cooling. Finally, driving the car to where they see the hottest temperature. They cure at 600 degrees and they recommend increasing that curing temperature incrementally to increase strength and longevity.



3) If I need to do question #1, how in the hell with I be able to do #2 at the same time?



4) Lastly, my tensioner pistons looked less compressed than yours in the pictures above. I purchased the master link chains (since I'm not splitting the case) to replace the old ones. Should I even replace my chains if they appear to be ok since referencing your pictures or should I still replace since I have the motor out and apart?



Your help is greatly appreciated. Just to reference, my car is an 87-930 with 97,000 miles on the clock.



Bryan

[sand_man]

I'm very seriously thinking about the JB Racing adjustable cam sprockets. One left over winter project I still need to tend to is a chain box oil leak. While I was in there, I also planned on doing the "anti collapse" spacer mod in each pressure fed tensioner.

[911nut]

Don, very cool hardware.
Tell us about the performance of your cams, please.

[sand_man]

Hey Don, if it's not too much trouble, can you please explain the cam timing procedures with these sprockets? I'm familiar with how to set cam timing using the factory parts.

Queue up the Kraftwerk for ze Sprocketz..."now ve dance"

[DonE]

Originally Posted by A930Rocket

Don,

Sounds like a great idea! Did you get all the cam/tensioner parts from Jerry Woods? Not sure I'm reading your post right.

No, I just got the pulleys from Jerry Woods. The adjustable sprockets came from JB Racing.

[DonE]

See my below comments.

Originally Posted by x98boardwell

I have a few things to ask and tell... nice picture by the way. I wish you lived closer.

Story: I just had my heads rebuilt, cylinders honed with new rings, my cams reground to SC specs (use to be 964.. I didn't know, they were done in 1998), rocker arms and shafts micro-polished and replaced if out of spec, and finally exhaust ceramic coated inside and out.

My questions:

1) From what I have heard, I need to "break-in" ny cams at about 2,500 rpm's for 20 minutes. Is this true? What is the best break-in process?

- 2000 rpm for 20 min

2) The company who did my exhaust (many turbo applications) recommended starting the car for a few minutes and then letting the exhaust cool... then repeating this process for longer to reach a higher temp, then cooling. Finally, driving the car to where they see the hottest temperature. They cure at 600 degrees and they recommend increasing that curing temperature incrementally to increase strength and longevity.

- don't know what to tell you here. The cams are far more important to break in.

3) If I need to do question #1, how in the hell with I be able to do #2 at the same time?

4) Lastly, my tensioner pistons looked less compressed than yours in the pictures above. I purchased the master link chains (since I'm not splitting the case) to replace the old ones. Should I even replace my chains if they appear to be ok since referencing your pictures or should I still replace since I have the motor out and apart?

- I would split the case, replace the chains, replace the bearings, check the crank. It's not difficult at all

Your help is greatly appreciated. Just to reference, my car is an 87-930 with 97,000 miles on the clock.

Bryan

[DonE]

Originally Posted by 911nut

Don, very cool hardware.
Tell us about the performance of your cams, please.

Not sure what you mean but the motor is 525 hp, 496 torque. Do you want cam specs?

[DonE]

Originally Posted by sand_man

Hey Don, if it's not too much trouble, can you please explain the cam timing procedures with these sprockets? I'm familiar with how to set cam timing using the factory parts.

Queue up the Kraftwerk for ze Sprocketz..."now ve dance"

Freak....

The sprockets come in two parts - a stainless hub that has the stock key channel to mate with the cam, and is drilled and tapped, and the second part is the sprocket that has channels cut into it that gives about 1/4 inch adjustment.

For my cams, you install everything like stock - thrust washer, shims, then the stainless hub. Then, install the cam nut and torque to final spec. Now line up the cams.

Install the sprocket and line up slots so that the hub's holes are in the middle of the slots (advance or retard adjustments. Install 2 hex screws to secure the sprocket. Apply tension to chain and turn the crank to top dead center. Note dial gauge.

If the dial gauge did not move, unscrew the two hex bolts and use the cam nut to turn the cam to the exact timing (hopefully the hub holes align to the slots - if not slip the sprocket off, advance the chain by two teeth and slip back on the hub). Reinstall the hex screws and tighten. Turn the crank 720 degrees to check timing. Most likely, the timing is dead on.

Move to the other side and repeat.

Double check the timing on both sides. OK? Then install all 6 hex bolts on each side using locktite blue and torque. Install tensioners.

Here is a pic of the sprockets: