Difficulty Installing Camshaft Woodruff Key and Sprockets - 3.2L
 

Had a welcomed snow day, so I headed back out to the garage to install my camshafts, timing chain sprockets and timing chain housings.

Man did this turn into a flail-x.

Background

I'm installing new GT2-102 camshafts from Daugherty Racing. I've had excellent support from John in choosing the cams and a quick turn around on the order. Today's episode further confirmed my choice to go with him.

The camshafts inserted in the cam towers without a hitch.

I reused my woodruff keys - they were in good shape (no idea how I managed that...).


Installing the Woodruff Keys in the Camshafts

I spent ~ 2 hours attempting to get the woodruff keys inserted in my camshafts. I would have sworn the slot was considerably smaller than the key.

I took a break and searched Pelican to find I'm not the only one who's run into this problem - some keys seem to fit in the cams pretty damn tight. I also found a couple of recommendations to try out.

I started by putting the woodruff keys in the freezer for ~1/2hr - no chance, I still couldn't get them started in the slot :(

Next, I decided I would lightly polish the sides with 600 grit sandpaper. Eureka! This allowed me to get the key started in the slot.

From there I tried a trick that I think Henry Schmidt recommended - using a large channel lock pliers to squeeze the key into place:

I put electrical tape on the ends of the pliers so they didn't dig into the cam or the key:
http://forums.pelicanparts.com/uploa...1390365364.jpg

Success! I felt like I deserved a medal (or at least a beer).

Unfortunately my elation was temporary...


Installing A Tight Fitting Camshaft Sprocket

Moving on, I attempted to mount the inner timing chain sprocket on the camshaft - and ran into another show stopper.

I could barely get the sprocket started on the end of the camshaft let alone close to the woodruff key that I just installed.

Back to the computer for some Pelican know-how. This time though I didn't find anything regarding installing / I only found posts related to the difficulties of removing a stuck sprocket.

Feeling like I'm in unchartered waters and not wanting to get the sprocket stuck in a bad way - I called John Dougherty. It went to voicemail, but I think he was able to hear the sound of my desperation over the noise of his machine shop and picked up.

John said the tolerances are tight and recommended I lightly heat the sprocket to see if that helped.

I'm game - it's a snow day and I have a perfect parts warmer in my garage:

Sprocket on top of the wood stove for ~ 4 minutes:
http://forums.pelicanparts.com/uploa...1390366138.jpg

The sprocket was hot to the touch, but not burning hot.

The heating allowed the sprocket to expand enough to slide onto the camshaft and woodruff key. It still required some coaxing with a brass drift to get it fully seated.

This was a 4 hand job: my son - pulling on vice grips that were attached to a bolt that was screwed into the end of the cam (to pull it outward) and me - lightly tapping the sprocket with the brass drift to seat it on the camshaft.

This upcoming weekend I will be measuring my sprocket alignment.

Hopefully it turns out well - I absolutely dread the idea of having to remove the sprocket to install or remove shims.

Fun stuff :rolleyes:

Gordo

You should do the sprocket alignment before installing the woodruff key because you need to remove the back sprocket and woodruff key to change the stack of shims
Bruce

Yep
 

Thanks Bruce,

I actually started down this route but decided to go ahead with the woodruff key installation since I found the sprockets were so tight.

The thought process being that if I find that I need to disassemble for alignment - it's going to be quite painful getting the sprocket off; woodruff key or not.

With the keys installed, I'm hoping the the moons align and and so do my sprockets...

That way I'm done with it, in one shot.

Thanks, Gordo

To pull the sprocket/hub off, use a small two jaw gear puller from the local auto parts store in their selection of crappy Chinese made tools. The gear puller does not put a lot of load on the hub, so don't worry about harming it. Install the bolt in the cam to give the puller draw bolt something to bear upon.

Hopefully you nailed the parallel alignment on the first try so you don't have to pop it all apart again. If you do have to go back in I found a straight pick tool into the front edge of the key where it meets the cam drove it out with the least drama. A little lube on everything can also help the sprocket move more easily for installation and removal from the camshaft.

By the way the two jaw puller does not even require a wrench. You typically can turn the draw bolt by hand (w/your GI Joe kung fu grip fingers) to pull the the sprocket hub off the cam snout.

Gear Puller
 

Clearly I'm going to have to buy a gear puller if I need to remove the sprockets to adjust for parallelism. They're not going to budge without.

Kind of odd that I didn't need a gear puller for disassembly. I just pulled the sprockets off the old camshafts by hand - no biggie.

Must have been my incredible GI Joe kung fu grip.

That or I didn't apply enough bar muscle when I tried to install the sprockets on the new cam ;)

Thanks, Gordo

Camshaft Timing Stabilizing with Tight Sprockets
 

I have 2 posts/threads that are addressing a related topic.

This thread addresses cam timing as it relates to inner & outer timing chain sprocket movements: http://forums.pelicanparts.com/911-engine-rebuilding-forum/793044-camshaft-timing-concept-question-3-2l.html

This thread provided some ideas on how I may be able to stop the camshaft from rotating with the timing chain sprocket.

My Planned Approach to Holding the Camshaft Steady As I Rotate The Crankshaft

I ordered a couple of bolts to insert in the end of the camshaft to allow me to use a wrench to hold the cam steady as I turn the crankshaft.

I could have used the original timing chain sprocket bolt (- spring washer) and bottomed out the bolt in the camshaft, but I was ordering a bunch of fasteners from McMaster-Carr, so I figured I may as well add another bolt to the mix.

I also think it will be easier to remove the bolt from the camshaft if I double nut it to tighten in the camshaft as opposed to bottoming it out in the cam.

The original camshaft bolt isn't fully threaded, so you can't double nut it (or single nut for that matter).

I think I ordered the correct bolt:

M12 with 1.5 pitch, 70mm length, fully threaded (original bolt is 60mm partially threaded).

Hopefully I will have everything I need by this weekend so I can dig into the cam timing & see how it works out.

Thanks again,

Gordo

When using new billet cams it is not uncommon for the need for custom fitting.
Hand fitting the Woodruff key by gently sanding the sides of the key works well.

The cam end/ sprocket index collar fit is another issue. It seems that there is an inconsistency to the cam end. This may be a specification error or an anomaly caused by Parkerizing the cam. This question is, so far, unanswered.
We have found that polishing the cam mounting surface to precisely fit the indexing collar works best for us. Remeber that the chain sprocket must also fit the cam end without binding. If the collar must be heated to fit, something is wrong. The collar should fit snugly but you should be able to turn the collar on the cam with the Woodruff key removed.
We use a lathe and crank polishing tool (400 grit abrasive) to gently polish the mounting surface until the desired clearance is attained.
This is not a process that we found necessary with any factory cams.

Gord, I checked both my stock and DRC 964 regrinds and in both cases, the sprocket was a nice easy fit on the cams. As Henry said, probably time to reduce the OD of the cam ends until you get the fit you need.

Just had a set of DR cams in my hands same issue but not quite as bad. Needed the vicegrip trick on the key and had to use a small round screwdriver to adjust the cam/gear. I think it's a coating or heat treat issue.
You could try lightly polishing with 600g paper.

Polish Camshaft Ends
 

I tried to remove one of the sprockets last night - definitely too tight.

I bought a gear puller but couldn't use it - not enough clearance between the sprocket and the housing (right side cam).

I ended up using a small pry bar wedged behind the sprocket to pry it off.

Good tips on lightly polishing the end of the cams. I think I will remove them this weekend and hit the ends with some 600 grit (good call Mark, I was thinking the same).

Appreciate the input Henry - glad to know its a common issue / my cams aren't unusual. Don't think I will have to remove much to get a good fit - if not will look to have my machinist give them a quick go.

Gordo

Very common, we hand file the keys frequently with a jewler's file.

Gear puller works on the inner hub, not on the outer sprocket.

I can mask the snout of the cam easy enough before I coat them. If you have a collar that fits tight (that I can keep as a sample) send it to me and I will make sure the snout is sized correctly.

No worries John.
We hand fit everything on these old dinosaurs anyway.
Your attention to detail is why we use your service so it's my pressure to send you a collar for a reference/ QC tool.
Cheers

Thanks!!

Camshaft Sprocket Fitment - Polished Camshaft
 

Thanks again for the tips folks.

After having a difficult time removing the sprockets I decided I would go ahead and lightly polish the camshaft ends to remove enough material to allow the chain sprockets to install and spin more freely on the cam.

I wet sanded the ends with 600 grit sandpaper. I checked fitment a few times as I polished to confirm I didn't remove too much material.

It didn't take much polishing to get a good tight fit - quite snug, but loose enough that I could spin the chain sprocket on the camshaft without binding.

The camshaft on the left has been polished, the one on the right is not:

http://forums.pelicanparts.com/uploa...1394421124.jpg

I think all that I removed was the surface material from the parkerizing process - just enough to allow better fitment of the chain sprockets.

Gordo

Henry sent me a "go - no go" gauge (new sprocket). I mask the snout before they are coated and make sure it slides on and off.