I'm surprised this thread has lasted so many years since my first post , nearly 100k views now,

as to your question on the cam tool

the cam sprocket that the chain goes over is not ' fixed ' to the cam by any teeth or single notch , it is a slip fit , and the cams relation to the sprocket is irrelevant, its the position of the cam , the tension applied to the sprocket from the chain and the engine being at TDC that is important

if you only lock one cam down , there is a possibility that when the cam sprocket retaining bolt is removed the other side may well slip with spring and compression tension acting on that cam , but not transferring the force to the other cam as the chain sprocket is not fixed to it

there are many ways of doing this job successfully , but don't take risky shortcuts to save a few bucks on buying or hiring another tool

just my thoughts eight years after doing this work to my own car

good luck

BB

 

Thank you Brake buster. I wondered if you would chime in. You expressed my concern about the other side and I may have a second thought on this. You say it's not a tight fit on the cam lock down, OK, now I see were movement on the other side, if only very little can cause trouble. I have the kit and will lock the engine down with the plug in the fly wheel, plus my best friend runs a machine shop. I'll get him to make another lock down bar.
Thanks for the heads up.


Wayne

 

Brake buster, The more I thought about what you observed about the cam sprocket the more shocked I became. It really doesn't have a key or anything to make sure it goes back in the same place? I can't see any reason for that as the VVT could only effect it if some sort of slip was going to be happening and at 70LB torque that's not a option and that is the exhaust side. Now I see the tie method being maybe better than lock down, as the slack of the chains when putting the sprocket on could be as much a 5 degrees off or more if the primary tensioners were worn.
I'm just going through the details in my mind, as I am prone to do before anything I undertake which is new and if it seems a bit over kill, SORRY. LOL
Thanks for your concern and when the time comes, we may need you on speed dial!!
Wayne

 

Wayne, I have not chimed in for a long time, but thought I might as well add my 2¢ worth too, although I admit I am not a professional mechanic... just a DIY hack. Some may not agree with my advice on this.

Since you are taking the safest route by acquiring the second lock down bar, I am wondering if you have the pre-load tool. If so, disregard my comments, but for those looking, it is used immediately before tightening the sprocket to the camshaft. Brake Buster's photos from the beginning of this enduring thread show the tool.

It is used to put tension on the chains before start-up. The replacement tensioners maintain that tension, but it is a good idea to have the tension correct before they take over. If your friend can build you a lock down bar, the tensioning tool would be pretty easy for him.

Good luck with the procedure

 

"Now I see the tie method being maybe better than lock down, as the slack of the chains when putting the sprocket on could be as much a 5 degrees off or more if the primary tensioners were worn."

Tie method is easy; but a lot depends on mileage on the motor, how big is your garage, what other work are you going to do, do you have a helper (easier to do the primaries with bonnet removed), how much downtime is acceptable. For most of us doing it ourselves in our driveway, just secondaries via tie down is quick and resolve the latent tensioner breakage (and eventually they will break and destroy the engine - with some notable very lucky exceptions - search Danielsand). Once the cam caps are installed and torqued, rotate the engine from the crankshaft and confirm the intake and exhaust are still aligned; then pull the fuel pump relay and crank it to pump up the tensioners (i think the metal 3rd gens leak down faster than the superior designed, but fragile 2nd. See what you think when you hold both in your hand with mouth agape over the tear on the plastic one). What else works: battery powered screw driver with 8mm/5/16 and 7mm socket; breaker bar extension to provide leverage for turning engine; disconnecting the plastic hose from the radiator to the reservoir at the radiator (plastic on these crates is a synonym for fragile).

But you have a buddy, with a machine shop, probably a garage: why not do it right?

 

JWT and Jhartz, Thank you for your interest and comments.
I do have the cam sprocket tension bar and the lock engine insert, so the extra lock bar will do the trick. I have a 3 bay with lots of walk around room on pads to keep your feet comfortable, air tools, welders, press and lots of light. If I can ever get the concrete guy to come back and confirm the floor will hold a lift, that is next. I do this for enjoyment believe it or not, just helping others is what it's about. I gave up on being rich with money, found out this makes me happy.
Thanks again and will take you advise in with all the good wishes and direction.


Wayne

 

If the concrete is suspect, you can spread the load with a steel plate fastened with many small anchors.

 

Since my valve covers are leaking I thought I would have a look at my secondary tensioners. Below are pics of the right side. I measured with a depth mic the amount of wear on the chain track and there was about 0.80mm worn into the plastic. I do not have the maintenance records but could anyone identify my tensioner as perhaps a 2nd gen and may have already been replaced?

 

I can't tell if they are 1st or 2nd gen by the pics, but the 2nd gen only added a spring assist which helped keep them tensioned on start up until oil pressure came up enough for the hydraulic part of the design to work, they still have the plastic body and this part will fail, eventually, just like the 1st gen.

Some say the spring design of the 2nd gen limited the "warning rattle" on start up and are worse than the 1st gen because you lose the some of the tell-tale audio signal of a failed or broken tensioner because of this.

Replace them with the 3rd gen, metal bodied units and you will have one less thing to worry about.

At 174K, it might be time to check the primary guides and tensioners too.
Vector

 

i agree with the above post, you have plastic tensioners and the NEED to be changed for the latest revised ones available

one note on your observed wear, this is not the face that you need to be concerned about, the one that fails is out of sight , and sits under the tensioner, see my original pics

either method is easily done, full tool setup or zip tie , as long as it gets the job done and gives peace of mind

BB

 

Ditto brake buster. You are on borrowed time. These look like 1st gen. Need third, metal.when you pull these, you will most likely see a crack along the piston barrel; this is the failure most common causing jumped timing chain.

 

Thank you very much for the replies. I will change them before I drive the car again.

 

Dear Brake Buster,

Any way to repost (or email) the pictures on how you did it? They seem to be gone from the site "talkphotography.co.uk" where they had been posted. Thanks for the great work!

 

Look in the stickies. You will find the seminal instruction. Plus, there must be at least ten other threads on this subject. Also some over on the xk8 side

 

Can anyone give directions on how to move the cams into the "sweet spot" position where there is no pressure on them, and how to know when you get there? I want to try to replace the tensioners myself, and don't understand that step. Also, as to Donzi's question about tilting the cams, doesn't the zip-tying the chain and sprocket prevent the cam moving? Thanks!

 

jhartz,

I apologize for being such a noob, but I look at BrakeBuster's original post (March 2008) with great instructions and a series of photographs, but the links to the photographs are no longer active. If his instructions are also on another thread, with the photos, I would be very grateful for help in finding it -- I have been unable to.

 

LOOK IN THE STICKIES! Also Google it; there are some youtubes. robertDIY has some that cover everything but tensioner switchout.

Once you have the cam covers off, it will become obvious where the minimum valve spring tension point is as you rotate the exhaust camshaft. But, here is how I did it:

Check the alignment of of the flat spots on the intake cam with the exhaust cam using a flat edge: the flat spots are just aft of the tensioners. Then, turn the engine using wrench (I think it is a 24mm socket on a long-handled socket wrench) on the crankshaft bolt. Go slow until you find a point with the least cam pressure/tension on every exhaust valve -- 1 or 2 might just have faint pressure, but the others will have none at all. Then lock the sprocket and cam with the tie (this is precautionary in case you screw up lifting the shaft slightly to remove the old tensioner; slide the new metal one in, reseat the shaft gently; bolt down the new tensioners with the new shorter bolts. Install the cap bolts holding the cam shaft, tighten slightly as you would head bolts (inner center, outer aft end, inner forward end, outer center, etc; then torque in the same sequence); test the torque a second time. The pull the retaining pin on the new tensioner. Cut the plastic tie, Turn the engine -- 24mm socket on crankshaft -- to assure the cam flats are still aligned. Then, turn the engine back to the minimum tension position. Button everything up; pull the relay in the trunk that controls the fuel pump; crank the engine to pump the new tensioner with oil. Reinsert the relay and start the engine. If you have done everything right, have a nice bourbon. As the old ad says: IT'S MILLER TIME!

Do not do this until you have read and reread the blackonyx' instruction in the stickie (a thread at the top of this forum) enough times to have it memorized. Watch all Youtubes, find at least two other threads (look for ones replacing broken timing chains -- one by danielsand is particularly good). OR GIVE THE JOB TO A RELIABLE JAG TECH.

 

If you want to take the risk of using zip ties , the timing method is still the same. Look underneath the bell housing from under the car. You will find the crank position sensor. Remove it , and insert a similarly sized probe into the hole. Rotate engine by hand until probe lines up with hole in flywheel. Push it in and make absolutely certain the engine can no longer turn. How you lock the cams down at this juncture is up to you but once you do , go ahead and replace tensioners. I rented the tools but many parts suppliers loan them got free if you buy the parts from them, (see Jagbits).

 

Thank you very much for the detailed information, jhartz and maclarenf1fan !

 

I would add my voice to the recommendation that others have given you.

It does not sound like you are 100% comfortable doing this job. Spend a few extra dollars to rent the tools and your risk of doing something wrong will be significantly diminished. It may cost a few more dollars to do it right, but the cost of doing it wrong is REALLY high.