One more....Cam Timing Issue!!! Okay?

[MKEDF]

I just finished setting the Cam Timing on my 78 911 SC

These are CIS Cams and everything else is stock.....

So i went by Wayne´s book Left side Okay....dial set up, and as stated on the book, adjustment was 1.0 mm (0.040 inch)...firing timming and compression match!!!.

But right side just wouldnt be okay by the book...

So me and the guy at the shop, decided to find right timming by following compression on each Cyl as firing order..


So we set up the right side timming by following the firing order... 1-6-2-4-3-5

Left side already has two conditions for considering timing correct

Each cyl has compression at the right time and following the firing order, so as we turned the crankshaft clockwise and just in time we had compression on each cyl...

We performed finally a test to the whole firing order...it went okay...1-Puff compression okay, 6-Puff compression okay, 2-Puff compression okay, 4-Puff compression okay, 3-Puff compression okay also, 5-puff compression okay...

Also set up the dial gauge and read the dial and surprise!! 1.0 mm (0.040 inch) set up achieved also!!..

We could not achieve this by following waynes book, so we manually set up the camshaft to achieve this compression - firing order...

Other way we did not have compression on any cyl, and timming was totally wrong...

Is this okay to do? or we should do everything one more time again...

The thing is that both sides mathc as measured by the dial, and also the timming can be checked by testing compression on each cyl following the firing order...

Any thoughts?, should i pass this as okay??

[gigem75]

I only had the rockers for #1 and #4 intake in and no plugs. You kinda lost me. As I understand it the cam timing is set with the piston at TDC but not on the compression stroke but rather the overlap stroke (that is when the exhaust valve is closing and the intake has begun opening) when the valve is open the amount given in the book for each engine.......
on mine the intake valve was open 90 thou when the piston is at tdc on the overlap stroke.

From the info you gave I would not say it's ok to pass, doesn't mean it's not, I just didn't follow your method.

[2.7RACER]

The fact that each cylinder was compressing at the proper time, (same as firing order), indicates the left and right cams are timed correctly.
The single biggest error timing cams is to set 1 (left) and 4 (right) to compress at the same time.

[MKEDF]

That is right, each cyl has compression as we follow the firing order...

Not two at the same time, but all of them as indicated 1-6-2-4-3-5, we installed a compression testing hose on each spark plug and checked there is compression by holding it with my finger, and as the firing secuence was followed, each had compression correctly as air was released by the cam and cyl....

We had all rockers installed and only valve clearance on valve 1 and 4 was adjusted 0.10mm (0.004inch).

Then as firing order proved to be okay, valve clearance was set up as stated on waynes manual...

And then again, firing order was timed with compression on each cyl...

Funny, but works...

[cstreit]

I think you got confused wtih Waynes rotation specs.

Howewer I'm wondering how you set the cam timing it were pleasently suprised to have had the valve lash end up at 0.10mm... Can you explain that? You should have set that last before you started timing!

[MKEDF]

We set up the timming using waynes method, just for left camshaft, it worked, the book states that left camshaft must be with the 930 mark up, this as fresh start for timming.left side..

This means the starting point for timming right side is with both camshaft marks upside down (Left camshaft mark ends up upside down once timed)...this did not work for right side (cyls with no compression and out of sequence).

We tried this using the dial on right side, and it did not work...

So the guy at the shop decided to move manually the camshaft until he can find compression for each cyl in the firing order needed....

He did that and as we checked compression it worked...he set time lets say by feeling on the right side...

As checked compression is properly timed so we decided to set up dial, and do the 1mm check...first at start by opening and then by doing a 720ş crankshaft turn and 1mm is okay..

Valve clearance was set only for Cyls 1 and 4...
After setting up the timming then we adjusted valve clearance..

[efhughes3]

I'm totally lost...

[MKEDF]

Dont be...

The thing is that we used waynes method on left side camshaft, and we did it "manually" on the right camshaft...

Firing order is our main proof that we did it right...

[cstreit]

Unfortunately your english makes it a little hard to understand what you did. I can tell you that you set the valve lash BEFORE timing cams, not after as you've stated.

[MKEDF]

You are very kind and encouraging...

Why dont we erase the thread...so my lousy english does not bother your fine eyes??

Thanks moderator

[munsonbw]

Originally Posted by MKEDF

You are very kind and encouraging...

Why dont we erase the thread...so my lousy english does not bother your fine eyes??

Thanks moderator

He man, you're looking for help here and I think cstreit was just saying that it is hard to follow your description of what you did. I am sure it makes perfect sense to you, but maybe not to someone who wasn't there.

Anyway, if you would like some advice from someone who screwed it up the first time... If you got the left hand bank following Wayne's method, then you have it. Like stated earlier you MUST adjust the valve clearance BEFORE you try and time the cams. Bad things will happen if you do not. The right hand bank is exactly the same as the left, except it is 360 off from the left. So once you have the left timed properly, rotate the crank 360 to do the right hand. The first time I did mine I had all cams 360 off, so I was only able to turn the crank about 120 before it would stop with piston to valve contact.

Good luck. If you don't get it with this little bit I posted, write back and I will detail it more. I don't have the steps in front of me and I don't want to give you details from memory... too expensive to risk bad advice. Also good avice is to really stop and think about what you are trying to achieve and how to get there. You are timing the cams by setting the lift at a certain crankshaft position. If you adjust this from the spec, you get different engine performance characteristics. You are essentially dictating when the cam opens and closes the valves. This is why you set the valve lash first. You want the lash to be in as running condition for the timing.

Ben

[gigem75]

just for the record, he lost me as well. had an uncle who had a hunting boat, they named it "The Hardway" cause that's how they did everything, tounge in cheek of course. We all know there are more ways than one to skin a cat, some eaiser than others. Speaking with all due respect I can't see why one would follow a firiing order, or deal with compression.
there is only one spot in the rotatiion of the camshaft where both valves are open at the same time on a given cylinder. The harder you make something the more ways one can find to to the process incorrectly. Not saying you did but there are much simpler ways to get to where you want to go. If #1 is at TDC on the compression stroke, #4 cam should be at the overlap on TDC, adjust sproket or if you can't turn the cam, poke and hope with crank roatation until you get it right to get the spec given in the book for your motor after you have adjusted the lash to .004 in. Everything will be right with the universe if you do that.

[cstreit]

Originally Posted by MKEDF

You are very kind and encouraging...

Why dont we erase the thread...so my lousy english does not bother your fine eyes??

Thanks moderator

I think your eyes are the fine and sensitive ones mate. You've written a very confusing post that I spent 15 minutes out of my life to try and interpret to help out a total stranger, you. Since I couldn't make sense of it because of your rather poor command of english and grammar, I thought to mention it so perhaps YOU would take the time to re-write it a bit more clearly. It would help your cause.

I hope you'll take note that compared to other question threads on this forum, you've gotten very little response. I'll offer you the reasons why:

1. It's impossible to read. Try using punctuation and write clearly. Get some assistance if you need it.
2. You spouted off with an insult at a rather simple mention of fact, your english is poor and it makes if difficult to read your post. That's not an insult, its a fact. You know it, so why get all in arms about it?

So if you want help, you should probably start with an apology, followup with a clearly worded question, and then thank the person that takes the time to try and help.

...or do it your way, insult the people that try and help you, that will probably work better. (not!)