Porsche 911 1966 cam timing

[joero]

Can any one help
I am just about to start stopping my 2.00 litre 911 to sort out a blown gasket
The issue I have is that when I set the timing marks for top dead on number one cylinder, to undo the large cam nut ( left side #1 cylinder)
I removed the tensioner, then in trying to undo large nut I did move the chain, thinking that taking up the slack would still align the marks I'd used + my own dots to satifiy my own nerves,
Only to find the nut is difficult to get off and turning the cam back to tdc, the marks would not marry back to original position.
I have only worked the spanner by hand and not been over forceful,
But I'm worried I can't reposition the marks as a datum, even before I start the strip down
Only the left hand side has been worked on,, I'm hoping that the right hand side chain tensioner has taken up the slack (causing the non alignment) but turning the cam on a spanner now seem to be locking up against some thing solid,,,
Any help appreciated
Thanks
Joero location England

[Flat6pac]

There is 2 chain and tensioners. Theyre independent of each other. If you cant turn the crank youre against the piston with a valve on the side you dropped tension. If you position both cams with the dot on the nose up along with the crank on Z1 you should get back to the original position. You ll have to rotate the loose cam independently of the crank and right cam.
You need to get the crank on Z1 and the dots up then set the tensioner. You need the flats parallel from side to side.
Bruce

[MBEngineering]

HI Joero
what engine have you and where are you?? if you are stuck, give me a ring and I will prob' know some one close who could set the cam timing for you.

regards mike

[joero]

Hi mike
This is new to me so not sure on spec of engine I'd say it's the 911 L all though it's been built up in the past
I'm near Loughborough in Leicestershire
Thanks any help is greatly needed as ive spent the majority of budget on buying the car,
Joe

[joero]

Bruce
Thanks this makes sense to me now, so just to confirm it'll need the chain off the left bank of clyinders (independent of crank & right bank)
Set dots to the top flats vertical and TDC ( top dead centre ) on the crank
Thanks
Joe

[Flat6pac]

Temporarly removing the tensioner you will be able to jump the chain over the gear, one cog at a time. when youre close, reinstall the tensioner and check parallel flats
If you turn the crank to the point of any pulley cylinder mark at 10 oclock from the center case you should be able to turn the cam without interference piston to valve.
At Z1 the flats of the cams have to be parallel otherwise youre still wrong and may have interference in the engine.. Notice, cams turn counterclockwise

Bruce

[joero]

Bruce
This is great info, thank you I am waiting for a 46 m/m socket and will start the strip from there,,
On the tensioner is this ok to depress all the way in with out damage, and will the new oil then do its job when engine started, ??
Thanks

[Flat6pac]

Are you going to strip the engine or just get it back to running? My explanations are just to get you back to running without interference.

A 66 shouldnt have Carrera oil fed tensioners so you just compress the tensioner with a large screwdriver when youre ready to put it in, compress and tap in with a hammer.
If you pull the 46 nut then youre into setting cam timing and thats a whole different training program. You will have to do both sides. My previous explaination takes you back to what was set previously as you didnt do anything to pull the pin/lock.
Bruce

[joero]

Bruce,
The problem is with gasket blown,, it makes lots of noise at the lower end of the barrel,
So the head barrel must come off number 1 cylinder,,
I was innicially trying to establish a datum point. For when this strip down would then proceed from,
So it seems that both sides will need attention for the timing, after the left bank #1 cyl has been sorted,
Please could you confirm what is meant in your text about " pulling the pin"
Is this the dowl behind 46 mm nut or pin that can be fitted in tensioner ???
Hey thanks alot Bruce for your help with this, I'd be lost with out it
Joe

[Flat6pac]

I realized after taking the position I had taken you needed to change the head gasket. Thats a large head gasket squeezed in the area. I have a hard time seeing it eaten up and leaking.
I never collapsed pre Carrera tensioners. just used a big screwdrive when collapsing it to install. There was some kind of retainer when new but I dont recall being reinstalled
You need a 17mm on the flats wedged to hold the cam. Sometimes you need an air chisel to turn the nut but the cams are castings so they will break.

Bruce

[joero]

Thanks for all this Bruce I'll keep you posted
Joe