cool.. I am at a similar stage in my build to you.. my cams from John are due back today / tomorrow.

Circlip are are far easier to install without the bottom row of head studs in place until you have the bank loaded
Bruce

I wish this was real progress but it's just the temporary assembly to test the piston to valve clearance. On hold now. Need to get the chain housings cleaned before I install them.

http://uploads.tapatalk-cdn.com/2016...c073d63926.jpg


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How crazy do I have to go with the sprocket alignment if I'm only assembling to check piston to valve clearance.


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I am no expert, but I think this depends on the build. If you are switching to high compression pistons and an aggressive cam, it is pretty important to get it dialed in close, and preferably at the high end of the spec range. Less critical if you have OEM parts, or are re-assembling what was already a working motor configuration. After all the work of rebuilding, you don't want to lose it when a simple extra base gasket would have done the trick.

Don't worry about it for your measurement, since you will do the sprocket alignment during your final assembly. For your measurement 3 or 4 spacers should work fine.

Thanks. I did a quick check without torquing the sprocket bolts. I seemed to be within spec on one side and very close on the other. I figured this was good enough to do the piston clearance check. Like you said. I'll dial it in better during final assembly.

Started working on cam timing. This is kind of practice because it's only to do the piston to valve clearance check. How do I know if I'm at TDC for no.1 or no.4 when I'm on z1?

At z1, set valve clearance on cyl 1 rocker to 0.1mm... rotate crank 360, then set 0.1mm clearance on cyl 4 rocker.
At least that's what I did....

When you start, as long as both cams have the punch mark or 930 at the top when the crank is at Z1 you are at ignition on #1. Remember the cams turn at one half the rotation of the crank and in the opposite direction.

Let us know how your measurement works out. I am at that exact stage on my motor.

Cam timing made easy.......
 

+1 to above suggestion. And to make it more convenient, install the ignition distributor with the rotor pointing to the scribed marker (1 o'clock orientation). So you could always refer to the position of the rotor when you do your cam timing. If you follow this procedure, you will avoid having 180° off timing problem.

Tony

Had another go at it but still not working out. I am shooting for 1.8-2.0mm. I have D.C.-15 cams and that is the recommended setting. I tried setting at 1.9mm but after doing the 720 dog rotation it ends up at 1.7. To get to 1.9 again the z1 mark goes slightly past the case line. What am I doing wrong? Is my chain not tight enough? Here's my set up.
http://uploads.tapatalk-cdn.com/2016...8732241b57.jpg


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Adjust one hole and try again. The measurement you get after rotating is the one that counts.

You might find there is enough "slop" with the pin installed, that you can rotate the sprocket fore or aft, before tightening the large nut.
At least that's what I found...

Taking it apart and will reset the cams to dots up and start over.

When timing is set should the dots be pointing up at cyl 1 tdc?


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Yes, when #1 is at firing position. Remember the crank turns two times, 720 deg, for every one revolution of the cams.

If you set the crank Z1 then turn it back about 30-40 degrees you can spin the cams without hitting valves on Pistons
Bruce

Ok. I think I got the left side done. The right side is now giving me trouble. Somehow both rockers are tight at TDC for cyl no. 4

Disassembly Done ... Time To Rebuild 3.0
 

I possibly had adjusted the rocker for no.4 at cyl 1 TDC. I'm not sure but I think I have it sorted out now. I have both cams pretty close at 1.9mm. Next is the valve to piston clearance check.

Can I do the method where I set the valve in and rotate the engine. Or do I have to do it in increments and check like the books says?

Here's everything set ready to check.

http://uploads.tapatalk-cdn.com/2016...edefb69e36.jpg

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Do the incremental. If you adjust the valve in and it hits the piston, you may bend the valve.

You can look in the spark plug hole and watch the exhaust valve and piston. Stop where they are closest and then adjust the valve in to check the clearance.

I marked my cam sprockets to keep track when I adjusted my cam timing.
http://forums.pelicanparts.com/uploa...1476665171.jpg

Well I realized tonight that I had the camshafts reversed. What an idiot I am. How the hell did I get something simple like that messed up. Probably the reason for all my troubles. Just took them out. Will have to put it back together again when I get the next chance. Ugh. Thought I was close to getting this part done.


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That is easy to do. On the up side at least you figured it out now and not when you were trying to start it up.

great thread! Me and my son are restoring a 1978 911SC for his first car. I know, I know! I got a good deal from a buddy after the car suffered a engine fire from a mouse nest. We have engine out and are looking at doing a rebuild/upgrade etc while its out. It only has 95K miles but little maintenance. Anyhow, anyway you can let me know how much and who did your heads? and cylinder's? cams? how did you decide what cam? I heard 964 cam grind works well for 3.0 with CIS but I see you have a DC-15? anyhow any cost info and places youd recommend would be great. My thought was do the pistons and cylinders and heads exactly like what you did, except id like all the exhaust studs replaced with new. change the cams,overhaul the rockers, install the oil tensioner kit, SSI heat exchangers or something like them (anyone have any for a 1978 please pm me) and a muffler to match the new heat exchangers.

There are tons of threads here and on the Porsche 911 Technical forum covering all your questions. Sounds like you need to spend some time searching.
Pelican also has a parts catalog and a used parts forum that are a great source.
There are two books you should have. Wayne's How to Rebuild 911 Motors and Bruce Anderson's Porsche 911 Performance Handbook.
Welcome to the board and post a picture of your car in the Technical forum.

A lot of questions. Welcome. I'll try to hit the specific ones.

Heads were done by a local machine shop. Not sure of your location. So that may not help.

Cylinders were done by EBS.

Camshafts were done by John from DR on this board.

Rockers were done by Craig on this board.

Reach out to each one for pricing. They'll be happy to give you quotes on your specific requests.

Getting it back together again with the cams on the proper sides this time. Timing made more sense this time. Left side timed up. Next to do the right side and then finally check the piston and valve clearance. Then I can pull it apart to put it back together again for real[emoji53]


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Cams are finally timed correctly! I was going 180 deg out of sequence on the right side and couldn't figure out why. Lesson learned. You can't rotate the crankshaft clockwise to the TDC point on the right side when you pull the pin. You have to go counter clockwise. At least that is what worked for me. Now I can finally check valve to piston clearance.


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Yea, with the newer style cams there is no way I know of to hold the cam when changing the setting. Not sure what Porsche was thinking. I guess they could save $2 on each motor.:rolleyes:

During my 3.0 build, I took the engine to a pro wrench after I did the cams. I figured I had so much time and money in the job it was just better to have an experienced person check timing and clearances.

Finally got my valve to piston clearance check done. Everything checks out. I started by finding the spot where the piston is closest to the top. Then I checked around those spots. Then after I was comfortable I did a full rotation with the intake out at 1.5mm and then the exhaust at 2mm.

Now I can rip this thing back down to the cylinders and start building it for real.

Making some actual progress. Heads and cam towers are installed torqued and sealed with 1184.
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http://uploads.tapatalk-cdn.com/2016...6f3c5a49e9.jpg



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Have you inserted the cams and made sure they can be rotated freely?

Yes. They do.


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result!

tell me, what method are you using for your rocker shaft install.. Will you be lubing them first, or installing them totally dry and oiling through the oil holes?

Probably lubing first since I'm using rsr seals.


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I'm back at the point of timing again. I have a question. I've already done the valve to piston clearance check during a pre assembly. Do I have to do it again during the real assembly. Or am I good from the first check.


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Think final assembly. I had the check made after the sprockets/drive chains/tensioners were installed and everything torqued.

It's a good idea to check it again.

10-4

Before I move on to install the chain tensioners. Can someone verify I have properly timed the cams.

Left side

https://vimeo.com/191300529

Right side

https://vimeo.com/191300713


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