Help - 3.6 cam timing test - ??????

left · 10-07-2007, 01:05 PM

well i am totally perplexed.

I want to test the cam timing before i do anything - engine is a 3.6 and is in the car. and was running great. I have a few leaks to repair and want to get familiar with using the gage etc.

Here is what i did so far.

I set to TDC ( checked with dist rotors)
removed left tensioner -replaced with a steering wheel puller.

Installed a gage with a zbar tool and extension. Gage has a range of 0-25mm with gradient of .01mm.

I was expecting to to see the gage move 1.26 mm (+- .01mm).

But the gage moved almost 10 mm In REVERSE? I am rotating the engine clockwise.

I removed the gage several times and the same result.

I must be doing something wrong.

I appreciate all comments.

L

gottarideduc · 10-07-2007, 05:43 PM

Hi left,

Take a look at my post in the thread titled " Not your average Cam timing Question "
There I explain in detail how I set cam timing. You can apply the same procedure for checking. Would have been better if you had not pulled the tensioner, as chain tension changes timing. The reason a mechanical tensioner is recommended at rebuild is because the hydraulic one must be fully compressed to install. That bleeds out the oil. Hydraulic tensioners, unless defective, have such a slow leak-down rate that the chain tension does not change much.
Take a reading on the other bank. Set your indicator around TDC of compression (both valves closed, clearance can be felt at rockers). Check valve clearance and correct. Pesumably it was the correct .004 when the timing was last set. Then turn crank to TDC overlap and your indicator should show the intake lift.

left · 10-08-2007, 04:38 AM

Thanks for the reply.

I read you post before i posted. Thanks.

re: tensioner - its a 3.6 not the same as a sc.

the biggest thing i am struggling with is the dial moving in reverse. Is this normal.

thanks!!

left · 10-08-2007, 08:12 AM

Ok,

I tested # 4

Start ay TDC #4 ( 360 from tdc#1 right?) set dial reeading 2 MM 0
Rotatedengine to TDC #1 reading 1mm .9 ( this means it moved .1 MM right? in reverse?)

rotate to TDC# 4 (starting position above ) dial reads 2MM 0

note: dial move between 8 and 9 rotations? during the rotation of the engine.

I did the above several times with the same result.

The stock tension was not removed.

What do you make of this?

Thanks

Gunter · Gunter's Garage

Search at the rennlist for Mike Juzenas and his rebuild with pictures.

Eagledriver · 10-08-2007, 12:08 PM

What you are seeing is normal as far as the direction. You are setting the guage to zero with the valve depressed slightly and then turning the engine to a position where the valve will be closed. The amount of movement is wrong. If you are using the dizzy to set TDC then you don't have a hope of being accurate. The TDC must be located with the marks on the pully.

To test your timing you should set your guage to zero when the valve is closed (somewhere away from TDC on the overlap stroke (ie set the guage to zero for number 1 when the number 4 is open at TDC). Then rotate the engine to TDC for the valve in question and read how far down the valve has traveled.

Note....TDC happens twice in the four strokes of the engine. Once on the firing stroke and once on the intake stroke. You measure the cam timing on the intake stroke.

-Andy

gigem75 · 10-08-2007, 05:57 PM

put a mm or two preload on the guage and zero it. as you rotate the crank from TDC on the compression stroke of #1 the guage should not move until you are about 3/4 the way around. the the valve will start to open and the guage will start to move. I think the reason you are seeing the guage go backwards is that as the valve opens the guage is unloading thus the dial will go anti clockwise. That is ok.

left · 10-11-2007, 11:05 AM

Thanks for posting.
I have been away on business.

I will try the suggestions this weekend and post results.

Again thanks !

left · 10-14-2007, 11:18 AM

Thanks all. After checking the valve clearance on 1 & 4 and a week away - everything turned out as i would have expected both left and right set at 1.25mm. Thanks !!!

This gave me the courage to do what I started out to - re-seal the cam boxes.

Leads me to the next question-

What's the trick to getting out the key off the cam? Everything else if off or loose . After about andhr of trying and getting stung by a bee, I need a break .

Thanks again !!!!!!

PS - i am looking for an ac bracket - mine is cracked. If you have one or know of anyone who does let em know.

gigem75 · 10-15-2007, 04:43 AM

bee careful

I've always just gently tapped them out from the edge angeling up using a good punch.

WERK I · WERK I's Garage

I use a punch as mentioned in one hand and magnet extension touching the key with the other hand. I hate losing those d@mn keys!!!

left · 10-15-2007, 01:40 PM

update,

Got home an hour early

woodruff key out. Combination punch and locking pliers and it come out. Thanks for the advice.

One last ? - Can I get the chain housing off w/o taking off the rails?

If so how? I have everything off ( except the rails ) and it does appear i can get it off, at least the with the top rail on. Am I wrong?

If I have to get the rails off, is it simply(nothing is simple) of prying them off on the pegs?

Thanks again!!

Eagledriver · 10-15-2007, 07:31 PM

I haven't done this on a 3.6 but on earlier engines some of the rails have to come off and some can stay. You can figure out which ones by trial and error. The rails just snap off on the earlier engines. The problem is the plastic is old and brittle and the fingers that hold them on break when you snap them off. You would be wise to buy new rails for this project.

-Andy

left · 10-16-2007, 06:22 AM

I would like to know if I have to take them off to get the chain housing off. It sure seems it to me. I have no problem replacing them..

How do they come off and do i run the risk of breaking them and pieces of plastic dropping inside ?

Appreciate any help. This is all that is left to remove the housing - then clean everythingg replace seals and put back together. I really appecaite the advice !!!

thanks

left · 10-16-2007, 06:40 AM

It appears that on the 964 the ramps are held in place by pins - that can be removed . can someone confirm this for me.

I notice bolts/pins with allen heads that appear to hold the ramps in place.

Am I correct ?

thanks!!!

left · 10-16-2007, 02:53 PM

Update:

ramps are off - it was literally starring me in the face.

No snapping off on a 3.6 - there are two bolts on the outside of the case that hold the ramps in place. Just unscrew and they come off.

They must Snap on install though.

Everthing is off !!! Now to clean and reinstall - after I get the new ramps of course.

again thanks to all of you for your help!!!