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-   -   How Do I know If I am on TDC for number 1 or 4 (http://forums.pelicanparts.com/porsche-911-technical-forum/135196-how-do-i-know-if-i-am-tdc-number-1-4-a.html)

80sc man 11-10-2003 04:55 PM

How Do I know If I am on TDC for number 1 or 4
 
How do I know if I am 360 out of TDC for number one?? Also, should the valve be loose on number 4 when on TDC for number one??

Rot 911 11-10-2003 04:57 PM

You mean 180 degrees out? When you are at TDC on number one the rotor should be pointing to the notch in the distributor.

RoninLB 11-10-2003 05:04 PM

Re: How Do I know If I am on TDC for number 1 or 4
 
Quote:

Originally posted by 80sc man
Also, should the valve be loose on number 4 when on TDC for number one??
No

Wayne 962 11-10-2003 06:05 PM

Re: How Do I know If I am on TDC for number 1 or 4
 
Quote:

Originally posted by 80sc man
Also, should the valve be loose on number 4 when on TDC for number one??
The valves should have clearance (loose) on number one, and one or more tight on number four.

-Wayne

AFJuvat 11-10-2003 07:48 PM

Pop the distributor cap - the rotor will point at the notch on the dizzy housing for TDC #1

(which, I just noticed Kurt had already said)

AFJuvat

80sc man 11-11-2003 03:56 AM

Alrighty. Thanks guys,

80sc man 11-29-2003 06:00 AM

one more question on this. If the valve has started to lift when on TDC for number one then how could it have clearance?? Right now what I am dealing with is both of the valves for number one and for number four are tight at the same time and they are loose at the same time. It seems to make sense sense the piston travel is almost the same on number 1 and four. TELL ME WHY I AM WRONG!!! PLEASE

Joe Bob 11-29-2003 06:22 AM

I lurk on the 356 registry list....some guy is selling a screw in whistle for #1 cylinder. When the whistle stops....TDC......

ChrisBennet 11-29-2003 06:47 AM

Quote:

Originally posted by 80sc man
one more question on this. If the valve has started to lift when on TDC for number one then how could it have clearance?? Right now what I am dealing with is both of the valves for number one and for number four are tight at the same time and they are loose at the same time. It seems to make sense sense the piston travel is almost the same on number 1 and four. TELL ME WHY I AM WRONG!!! PLEASE
Maybe this will help:
At TDC for #1 both valves on #1 are closed. I.e. rockers will be "loose."
At TDC for #1 not only has the valve not "started to lift" the intake valve won't open until the engine has turned another 360 degrees (and the cam 180).
At TDC for #1 one of the valves on #4 is open, I can't remember which.
At TDC for #1 the pistons for #1 and #4 are at the top of the cylinder i.e. you cannot tell TDC for #1 from #4 by the position of the piston so the whistle thing won't work.
-Chris

HawgRyder 11-29-2003 08:31 AM

Just watch the intake valve for #1...when it's open you are on the downwards intake stroke....after it closes and the piston is coming to the top (timing mark comes to the top) then you are on the compression stroke and the plug fires at or near the top.
Bob

yelcab1 11-29-2003 09:00 AM

You can go into a thousand more complicated explanations, why not just pop the distributor cap (only 2 push and turn operations) and you will find out which one it is, 4 or 1.

80sc man 11-29-2003 09:36 AM

because i am in the middle of a rebuild and havn't dropped the distrib. in yet. BUT, I think what I did was get 180 degrees off on the right cam. What happens now is both the intake valves for one and four open at the same time. Does this sound correct to you all? Did I just get off 180 on the right side??

ChrisBennet 11-29-2003 10:59 AM

Yes, it sounds like you timed the right cam incorrectly. Easy mistake your first time.
-Chris

yelcab1 11-29-2003 11:41 AM

Well,

Since you are in the middle of a rebuild, then the only way to do this is to ... back out and repeat.

TDC number 1 means the rocker is just a little loose. If the number 4 is loose too, then that number 4 (all 4-6) is off and needs to be redone.


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