ohh brother.....Carrera cam chain problem, Maybe

Hoffmanmotors · 10-23-2006, 05:58 PM

I started installing my carrera cam chain tensioner kit today and ran into a scary problem. I followed the tech article to the ‘T” and I successfully installed the right side with no problems, but when I attempted the left side the chain seemed really tight. When I Removed the tensioner the idler sprocket seemed to low and I couldn’t get the new tentioner in.

Now I kept tension on the chain by using zip ties and safety wire to keep things in there place, and when I kind of jiggled the chain it popped loose like it was snagged on something in the engine, and now everything seemed to fit right.

My main question is how do I check and see if the engine or chain didn’t jump timing? I remember the tech article saying you don’t want the chain to jump on the cam sprocket, but is there something in the engine the chain would jump? I hope I explained myself enough for some answers from someone. Please HELP! Don’t wanna kill my engine.

TIA
-Jeff

76carrera3.0 · 10-23-2006, 06:13 PM

What ever you do don't try to start the engine don't even turn it over by hand. It sounds like you ended up with a bunch of slack chain in the engine at the half shaft I think they call it. Sounds like you got rid of that problem but the cams will need to be re timed just to be sure. Not a big deal, I did the same mod myself this spring but changed the chains at the same time. Get youself the right tools and use the instructions in the manual to the letter setting the valve timing to the specs of you engine. Once done double check and then check again pretty simple operation if you take it slow and think it thru.

shbop · 10-23-2006, 06:15 PM

I think the only way to know for sure is to put a dial indicator on the #1 intake and check against the spec for your car. I certainly wouldn't try and start it, until you know for sure. Maybe one of the pros will chime-in and give you an easier path. I hope it works-out for you.

Zeke · 10-23-2006, 06:18 PM

Don't kill your engine.

All you need is to very carefully turn the motor over by hand with the plugs out. Very carefully and feel for any resistance. If there is any doubt, stop. Then, if you know that works, you can use a dail indicator on a vlve per instrucitons in the various manuals that cover this. I bet everything is OK, but don't start the motor until you're sure.

Also (and someone else can fill you in better here), there are marks on the cam sprokets for this purpose as well. I believe this, too, si covered in the Haynes and the Bentley, if your car is a late enough year of have a Bentley. Wayne's books cover this.

You didn't say what year, that might help. But, all in all, nothing to get too excited about, just check everything out methodically.

2.7RACER · 10-23-2006, 06:54 PM

Jeff,
Don't get too worried. If the chain jumped on the left side cam, it probably only jumped one tooth.
The first and simplest check is to rotate the engine crankshaft CLOCKWISE until you reach the Z1 mark.
At this point the marks or dots and keyways on both camshafts will be up or down.
If they are down, rotate the crankshaft Clockwise one more turn and stop at Z1.
Always turn the crankshaft Clockwise, never CCW.
With the marks or dots and keyways up the right and left side should be straight up.
If the chain jumped, the left side camshaft will be one tooth off and the marks or dots and the keyway will be slightly to the left or right when compared to the right camshaft.
Carefully examine the relationship. It could be ok. If it is off it should be fairly obvious.
Remember the camshafts turn CCW when the motor is running, reverse direction as compared to the crankshaft.
If it's off, jump the chain on the cam sprocket one tooth by holding the tensioner pressure off the chain.
If the marks and keyway are turned to the left, the cam has advanced one tooth.
If the marks and keyway are turned to the right, the cam is retarded one tooth.
Then recheck the timing relationship at Z1.
All I'm saying here is the right side is good, so match the left side to the right side.
The key here is too Carefully examine the right and left relationship when stopped at Z1.
If after careful examination the marks are both pointing up and not tilting right or left, chances are good the cams are ok.
If you're still not sure, take a picture with the motor at Z1, showing both cams and post it so we can all look at it.
If it's off one tooth, the left side cam will be off by over 13 degrees.
13 degrees should be apparent.
Remember turn the motor clockwise.

76carrera3.0, it's called the intermediate shaft.

Hang in Man,

Hoffmanmotors · 10-23-2006, 08:28 PM

Thanks guys, i am now positive its out of time. I took several pictures to show how its sits right now. I tried to crank it over by hand to TDC. but just before i got to the Z1 mark it stoped....yikes! I beleive its 180 out from TDC also.

heres the left cam

Heres the right

Heres where the crank sits just before it stops turning by hand.

2.7RACER · 09:37 PM

Jeff,
Notice how the right side cam is not straight up and down, and the left side cam has already passed straight up and down.
Remember both cams are turning CCW when the motor crankshaft is turning Clockwise.
If it was possible to turn the motor clockwise until the crankshaft was at Z1 the right side would be straight up and down and the left side would be further advanced, possibly two teeth advanced.
Take the left side and jump the teeth so that the cam is rotating clockwise.
Go two teeth and retry to get the motor to Z1 by turning it clockwise.
Once you have the cam in the correct position it should rotate ok.

From the picture of the left side cam, the numbers are upside down, I would say the motor is near TDC compression for #4 cylinder and at crossover for #1 cylinder.
If the distributor rotor is pointing at number 4, the right side is correct.

Hoffmanmotors · 10-26-2006, 02:08 PM

What’s the best way to move the cam? So let me get this straight, both the cams need to be perfectly parallel? God I am so upset at myself right now! Lol

I might just ask if any Phoenix pelicans want to come out and give me a hand so I don’t ruin my engine.

2.7RACER · 10-26-2006, 09:01 PM

Jeff,
The left side cam sprocket needs to be jumped Clockwise two teeth.
To accomplish this you'll need to compress the left side tensioner almost completely down so you can insert a small pin into the about 1/8th hole which will hold the tensioner compressed. A small nail or small allen will fit and hold.
Then remove the tensioner and jump the chain around the top of the sprocket so the sprocket turns clockwise 2 teeth.
You are backing up the left hand cam clockwise. Remember it rurns CCW when running.
From the pictures the left hand cam is too far advanced, so we are going to back it up.
Once you have the cam backed up 2 teeth, reinstall the tensioner and carefully remove the retaining pin. You may need to use pliers to pull the pin.
Then turn the cranckshaft clockwise to the next Z1 mark. If you have got it correct, the right side and left side will be straight up and down.
If the numbers are right side up, the #1 cylinder will be on the compression stroke, so the rotor should be pointing to #1 at the distributor.
If the numbers are upside down, #4 is at the compression stroke, so the distributor rotor will be pointing at #4.

Hoffmanmotors · 10-27-2006, 09:19 PM

Thanks Alot 2.7 RACER, I did as you told me and i finally got the car back together, cam timed and running Thank God. It was exactly two teeth off. It was a fairly easy install other than my mistake. Thanks to everyone who chimed in and helped me through it, otherwise i would be towing it to the local Porsche shop for a top end rebuild! LOL

Thanks again,
-Jeff