I NEED Help, cam timing!!!!!!!

Help

I have installed the carrera cam tensioner kit in my 77 with a 2.7

I was careful to try and keep tension on the chains, I thought I did good. But when I turn the engine over( by hand) I can heard a distinct loud click at each cylinder.

I KNOW I messed up the cam timing!

Now the good news, I have ALL winter and Bruce Andersons book. But it is written and I don't understand a few parts of it.

Is there aa article somewhere about all this?
Will I need any special tools?

I want to do this myself, but I don't want to wreck my engine. What do I do?

Thanks
Shawn

Ouch!!..
What would you say that click sound was? Valves meeting pistons? You will have an intimate relationship with the internals of that engine if you did bend the valves. I've done this job with the engine outside of the car. There's a tedious job of using a dial guage, breaking the Cam Nut loose (special tools), and setting it accordingly to the guage by way of rotating the Crank nut.
You should take the tensioners back out, and put those adjustable sprocket holders (special tools) so you will get an accurate reading by having the chains tight?
If I had to do it over again...I'ad park the car..save up the cash...and have a mechanic break the sweat.

Luck........... happy happy

Did the chain skip off the cog ay any point when you were working? This is the only way you could've lost the timing. Just letting it go slack would not do it.

If you turned the engine by hand only, you probably did no harm to anything. I am not sure I understand what you did, so this post will pose questions.

Did you turn the engine only AFTER, but not during, your tensioner change? If you did not witness a sprocket slipping, and if the tensioners were installed when you did turn the motor, then I'm not sure how your chain would have slipped.

Maybe you're suspecting that the noise is a valve tapping a piston, in each cylinder, when you turn the engine by hand. Well, perhaps a sprocket did slip.

folks, wouldn't the slipping likely happen at the cam sprockets rather than the crank sprocket? If so, then slippage is likely to affect just one bank of cylinders. Right?



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'83 SC

Shawn,

I think you may have a case of ears listening for impending doom, when there isn't any on the way ... sort of like when a driver is in the lead of a 24-hour race, five laps from the end!

I suspect the ticking was there before, but you didn't notice! If you had messed up the timing ,the engine would NOT be running smoothly! It would be rough and backfiring!

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Warren Hall
1973 911S Targa

seeing you have all winter back the valve adgusters on the rockers all the way off and turn the engine over, see if you still hear the noise. See how close the timming marks on the cam line up. I think you would have to of sereously changed the timming to get a CIS set up to make contact. Get the dial the peice that holdes the dial, the crows foot and the tool to hold the cam end when breaking loose the cam nut. Depending on the cost of the dial this may cost all of 100$ As Warren says relax.

How about a compression gauge. I don't think you would have any compression if the cam timing was wrong.

Thank you all so far

OK There is a distintive click at each turn. It is exactly at the point that coincides with the marks on the pulley. These are the marks that are used to check valve clearances.

Warren- the engine is not running it is still on my engine stand in my basement, so I'm not sure if that is what you mean. It ran fine before I took it out though.

ORB- I don't remember it slipping off the cog at any point, except the tensioner wheel???? If you know what I mean.

SUPERMAN. The engine was NOT turned during the change ONLY after.

MACKGOO- I will try to back off the valve adjusters and see. How Will I be able to check on close the timing marks will line up with everyting backed off?

Does anyone know about this compression idea, will that give me any indication?

The thing is I don't want to turn it unless needed. I know that it can't be good for it, so I'm hoping someone can help.

I will keep you posted, Thanks so much and please help Me

Shawn

I'm sending you images of the pages from the Porsche factory manual (thru '78) for valve adjustment procedure (located in the engine rebuild & reassembly section) in case you finally determine that you MUST do it by e-mail.

(Had to chop it up in little pieces since your (or my) e-mail server doesn't seem to like large files. )

3 pages =
pg1 a,b,c
pg2 a,b,c,d,e,f
pg3 a,b,c

By backing of the adjusters you should be able to turn the engine over with out fear of parts making contact that shouldn't. The ends of tha cams have flats, when you lign up the Z1 mark those flats should be relatively vertical. It seems really unlikely you changed the timming but I guess it's possible. The ticking happens every 120 degrees? Can you tell where it's comming from? It would be interesting to see if you still get the noise with the valves basically non functional, with adgusters backed off. I don't think you can check compression with the engine out of the car, probably couldn't turn the engine over fast enough. Maybe a leak down if you had the ability, but I think that should be done on a warm engine I don't know for sure maybe some one else does. Short of opening up the engine you probably need to try to pin point the source of the noise.

OK I have loosened off all the valves and the noise isn't there.

What I did was loosen the left side valves and the noise was gone.

I still loosened them all off, but when the pulley just passes the TDC point there is still a lot of tension at that one point only. The rest of the cycle is good.

Any ideas?

Also when I have the distributor pointing to TDC and the Pulley marks lined up #2 and I believe #6 valves are really tight?

Is this really messed?

Help.

Shawn

Warren how much is postage to Texas and Labour? haha
Shawn

OK, here's what I'm thinking. If you did not remove or tamper with the cam sprokets then the only way this engine could be off timing is if the chain slipped a tooth. So, if you get it back on the same teeth then you are 100% back to your original timing without having to go through the entire dial-guage procedure in the workshop manual. So, if you align the crank to TDC it should be fairly obvious which bank is off, and you should be able to slack the chain on that side only and restore the chain to it's original teeth. The way you know this is that when the crank is at 0 degrees both cam sprokets should have a little punch mark pointing directly up. If it's off by a few degrees then you know that it was the side that skipped a tooth.

Thanks so much

Orb and Mackgoo thanks again for the input. Orb I am going to try the marks tonight, not having a computer home now sucks!!!

Hopefully won't have to do the full dial in of the cams, but if I do TOG I can't thank you enough for those pics.

This site is great and I am really thankful for all of you.

Shawn

I'm curious What kind of condition your chains were in? When you have the crank pulley at the Z1 mark where is that mark on the cam end? I would expect these marks to be some where off vertical because I would think timming the cams does require slight adjustment. I don't know for sure though. Timming the cams is not hard but you do need the tools and that nut on the end of the cam is a bear to get off and torque when putting everything back together. What does your chain look like as you turn the engine through?

Shawn,
Is there any chance that whatever you used to hold the chains in place, (while you changed the tensioners) is still in there?

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Graham Archer
83 911SC Cab

Graham, NO I did remember that but thanks because one never does know.

Orb, I looked and don't see the notches in the cam sprockets! I think I see one it the right side one but it looks almost like a scratch?

Is there a certain area to look?

There does seem to be one tooth on the sprocket that has a pin hole in it? Does anyone know if this has anything to do with timing them?

Also if they did slip how would I be able to adjust them? The chain is still attached to them and to the crank? How is this done?

OK I am an idiot, When I went down to check for the sprockets in time I also noticed that I didn't install the spacers for the new style tensioners. Actually never knew I needed any until I noticed the slack when the chain was off, and then I checked an Automotion magazine. Damn!!!!! Now I haveto order it Wait and still figure out this problem to boot!!

This is why I love Winter, nothing but time

I will admit I am getting frustrated.....This is turning into a bigger job than I expected. But on the other hand I am taking it as a great learning experience

Thanks everyone, anyone have any more ideas for me?

Shawn

[This message has been edited by davis911s (edited 11-27-2000).]

Shawn,

If there is any doubt about the cam changing position, I would get a dial indicator and check it. There is no way of determining if the valve overlap is right without doing this.

One quick check is to set the #1 cylinder to TDC and check the intake/exhaust valves - rocker arms to see if the valves are closed. If they are, then the cam could be right, but if there is any doubt, dial them out.

Steve

The mark you are looking for is not on the sprocket, it's on the end of the cam. As I said before but let me clarify it a little. When you look inside the chain box you see the cam sprocket there should be a large nut on top of that, in the middle of the nut you'll see the end of the cam sort of an oblong deal two flats and the ends rounded off. At one of these rounded off ends is where you should see the gross timming mark for the cam. It could be a punch mark or just the part number of the cam. With the crank at the Z1 mark those flats should be vertical and the punch mark or number at the top of the engine. All of this is at the cam end not on the actual sprocket.

Shawn,

This is what happened to me when I did a tensioner change on a '71.

First, I set the timing to Z1 with #1 piston at TDC and changed the tensioner on that side. All was well. Then I went ahead and changed the tensioner on the right bank. All was NOT well. I did notice the chain move on the right bank but did not make much of it until I got the engine back in the car and started it. What a terrible loud knocking noise!

So, I droped the engine and checked the cam timing using the gauge to measure overlap and found the right cam had slipped one notch on the timing wheel. Set the timing back to spec and all was well.

What I found to be the problem was that after I had changed the tensioner on the left bank, I failed to rotate the enging to Z1 with #4 at TDC before changing the tensioner on the right bank. If I had paid more attention, there would not have been any problems.

BTW, no damage to the engine resulted from my mistake.

Cheers,

Al Bisel