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-   -   Doing cam timing when engine lock up? (http://forums.pelicanparts.com/911-engine-rebuilding-forum/734284-doing-cam-timing-when-engine-lock-up.html)

Walt Fricke 02-18-2013 07:29 PM

How does Bruce know a serial number detail like this? Amazing. Though he has worked on a lot of different motors. Unless, like me, he looks things up - the current parts manual for these cars only lists the 03 cam for the 3.3 turbo, showing the bolt attachment. But at least that is solved - the car has a stock turbo cam, and thus can be timed like a stock turbo.

However, the picture in the catalog also shows two small round looking pins which appear to attach to the far end of the left cam. The catalog says they are for the SC model with Sportomatic. I don't know if the Turbo could be ordered with the Sporto (I would doubt it), or if the turbo cams are drilled for these (drive pins for a Sporto pump?), or if they could possibly fit in there without the special end the MFI cams had and the seal, etc. And they are listed as "roll pin 5x24. If they are 24mm long, scratch that off the list of possible sources for the mystery pin which started this discussion.

Oheggem 02-19-2013 09:12 AM

That pin is shorter than the dowel pin so i don`t think it`s the one you mention. I should`ve maby just removed a cam to see the serialnumber or something. I just hought it was weird to put a cam from 1984+ as the cam number 930 143 03 means without it being something special. Guess we`ll know if i have to rebuild the whole shabang :)

They are timed to about .70 both now so to hell with it ;) Timed and torqued down and covers on. On with the MSD install which i have new questions with.

Thanks so much guys :)

Oheggem 02-19-2013 11:35 AM

Confusion time!! I should`ve maby made a new thread on this but i`ll see if i get an answer.

When doing the left cam timing i go 360* from Z1TDC and just before Z1 i read from the dial gauge and adjust it from there.
The right is the same procedure?

Quote:

Once you have completed the left bank cam setting set #1 to Z1 TDC on the compression point (your dial indicator will be back at 0 at this point and you should be able to, slightly, move the No.1 intake rocker arm up and down. Now rotate the crankshaft 360* to Z1 (this is Z1 TDC for #4) because #1 and # 4 fire 360 degrees apart. Set the valve lash for #4 and remove the Z block and dial indicator from the left bank and install it on #4 of the right bank and follow the same procedure you did on #1.
Ref: http://forums.pelicanparts.com/911-engine-rebuilding-forum/592101-cam-timing-again.html

Saying here that doing the right one should start at Z1 and turn clockwise and just before Z1TDC? Is this correct?

Quote:

Once you have completed the left bank cam setting remove your Z block and dial indicator and repeat the procedure for the right bank.
Ref: Porsche Cam Timing

Here it says do the same on both sides. Confused now :(

I suspect my right cam is 180* off now. Do i time the right cam at another point from the left?

fredmeister 02-19-2013 12:31 PM

Quote:

Originally Posted by Oheggem (Post 7282788)
That pin is shorter than the dowel pin so i don`t think it`s the one you mention. I should`ve maby just removed a cam to see the serialnumber or something. I just hought it was weird to put a cam from 1984+ as the cam number 930 143 03 means without it being something special. Guess we`ll know if i have to rebuild the whole shabang :)

They are timed to about .70 both now so to hell with it ;) Timed and torqued down and covers on. On with the MSD install which i have new questions with.

Thanks so much guys :)

That little pin could be a roll pin off the gear end on the distributor used to hold the gear to the dizzy shaft or it could even be the little pin that locks the star wheel inside the dizzy housing to the advance shaft under the rotor.
Both are very tiny pins and could maybe have worked there way into the chain housings and been thrown in there when the dizzy was spinning. Its worth inspecting the dizzy since you have it out of the car for this vlave train work anyway.
It looks too short to be a chain roller pin.

Fred

Walt Fricke 02-19-2013 07:34 PM

Ohe - the procedure for timing the right side cam is the same as for timing the left side cam. The cams all turn the same way.

The slightly tricky bit is to make sure they are in the proper phase with each other. When the #1 is at Z1 Firing (both valves closed, spark just went off if running), the #4 should be at the opposite Z1 - the one where both valves are open, with the exhaust almost closed, and the intake just opening - somewhere around a millimeter for stock cams, up to six millimeters (which is hardly just opening, though - that's about half open) for hot race cams on NA motors.

If you find that when #1 has both valves closed, and #4 has both valves closed at the same time, you have your cams 180 degrees out and need to reset one of them. Usually the right side ones, to keep from having to reset your distributor if you have installed it. So there is a sanity check for you.

Oheggem 02-20-2013 03:25 AM

Walt, if i had two dial gauges mounted one on each side would they be timed at the same Z1 and the dials would move at the same time? I remember that the #1 and #4 pistons where at the same location and that the inlet valves closed at the same time i think.

I think maby my left cam is out because i never touched the right cam. that has been on chain torqued down all the time.

Fred: i have found a small pin other places in parts list like on the crank. Still weird since that has not been loosened.

safe 02-20-2013 03:30 AM

Quote:

Originally Posted by Oheggem (Post 7284163)
Walt, if i had two dial gauges mounted one on each side would they be timed at the same Z1 and the dials would move at the same time? I remember that the #1 and #4 pistons where at the same location and that the inlet valves closed at the same time i think.

If it does that, then you have one cam 180 (cam)degrees wrong.

Oheggem 02-20-2013 07:08 AM

This means that I should`ve set left cam from Z1TDC on #1 cylinder and right cam at Z1TDC on #4 cylinder which is 360* apart from eachother or 180*on the cams. Will this be correct?

Ah the headache ;)

safe 02-20-2013 07:29 AM

Quote:

Originally Posted by Oheggem (Post 7284413)
This means that I should`ve set left cam from Z1TDC on #1 cylinder and right cam at Z1TDC on #4 cylinder which is 360* apart from eachother or 180*on the cams. Will this be correct?

Ah the headache ;)


Yes! You got it!

Been there and done this myself setting one cam 180 off... Luckily I discovered it before putting it back into the car.

fredmeister 02-20-2013 10:23 AM

Quote:

Originally Posted by Oheggem (Post 7284163)
Walt, if i had two dial gauges mounted one on each side would they be timed at the same Z1 and the dials would move at the same time? I remember that the #1 and #4 pistons where at the same location and that the inlet valves closed at the same time i think.

I think maby my left cam is out because i never touched the right cam. that has been on chain torqued down all the time.

Fred: i have found a small pin other places in parts list like on the crank. Still weird since that has not been loosened.

I know but the fact that the dizzy has not been loosened or removed does not mean that the pin is not from there. Its worth peace of mind to pull the dizzy and check it out in my opinion. Takes about 5 minutes to pull it and inspect it. you can check for shaft end play then as well. I found mine out of spec big time during my last rebuild and needed to shim it under the gear to bring it back in tolerance.
Plus you should lubricate the advance shaft with oil under the felt cap that resides under the rotor anyway. Too often the dizzy never gets lubed and the advance mechanism can seize up.
The fact that you have hard pins like that inside the case worries me though....it could cause tons of damage if it ever went thru the oil pump or through the chain and gear when they meshed.

Oheggem 02-20-2013 01:16 PM

You might be right fredmeister cause i meant that the crank not has been loosened but the dizzy is out and disassembled. Do you have a good thread on working on the dizzy? I need to mod it for my MSD.

Should`ve just gone with a standalone dizzy free system but don`t have the money now :(

fredmeister 02-25-2013 09:14 AM

Quote:

Originally Posted by Oheggem (Post 7285135)
You might be right fredmeister cause i meant that the crank not has been loosened but the dizzy is out and disassembled. Do you have a good thread on working on the dizzy? I need to mod it for my MSD.

Should`ve just gone with a standalone dizzy free system but don`t have the money now :(

I know there are one or 2 out there just dont have the link right now handy. Try doing a search on ignition and read thru a few of them. One posting had alot of photos on how to lock the distributor and I even posted my own solution to removing the springs and locking the counterwieghts with steel wire in a few pictures. Dont remember which posting it was though....
Basically I ran some steel wire around the counterweight to the post on the mechanical advance plate at their most advanced position to lock them from moving. This way I did not drill any holes or tap screws to lcok them down. Locking them in an advanced position is safe in case they break free of the wire as they can retard timing only at that point.....though centrifical force is going to keep them advanced when running anyway.
MSD is the way to go as you can program your boost retard curve which is all important.
Good luck.


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