924Board.org

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

Hi All,

Ok, I have a standard timing gun without any adjustments dials on it.

I placed the inductive pickup on plug 1 and when the engine was warm I pointed it to the flywheel, and the +10 mark was steady in the window.

The three marks i have on my flywheel are -10, 0, and +10

What strikes me as strange is that I would have thought the -10 was 10º BTDC which is where my timing is supposed to be set at?

So I set the engine to TDC, and checked to see the mark on the cam pulley was also aligned, and the "0" was showing on the flywheel. I then wound the engine slightly back from the direction which the engine runs, and the +10 mark appeared in the window.

so am i right in saying that when looking at my flywheel:
"+10" equals 10º BTDC
and "-10" equals 10° ATDC

When driving she does seem a bit underpowered.
Thanks for the help all.
Tiny
_________________
*****1981 - 924 - Auto - London, UK******

Paul · Posted: Mon Aug 13, 2007 4:18 am Post subject:

Do you have an underhood sticker that describes the procedure to set the timing?

-10 means 10 degrees before top dead center.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

hi
no i don't, and the haynes manual is not very specific
regards
tiny
_________________
*****1981 - 924 - Auto - London, UK******

Paul · Posted: Mon Aug 13, 2007 4:26 am Post subject:

You need the procedure before proceeding since it will detail what connections might need to be disconnected or plugged, whether or not the car needs to be in "drive", etc.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Smoothie · Posted: Mon Aug 13, 2007 4:50 am Post subject:

I don't know if this applies to a UK-Europe-RoW car, but if you have EIS (if so, there'd be an extra box mounted over your Hall control unit on the front-left wheel well) - if you have this, disable it by unplugging the single wire connector that you should find laying on the wheel well nearby. EIS (electronic idle stabilization) alters timing to control idle speed, so it should be disconnected while you're checking/setting the timing (in addition to whatever else is required regarding vacuum lines, etc. as Paul mentioned).
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

Hey,

My model comes without idle stabliser, and i also read that the vacuum advance needs disconnecting and plugging during the adjustent so i did that.

I searched the board, but cant find out which flywheel mark the strobe is supposed to to be highlighting.
_________________
*****1981 - 924 - Auto - London, UK******

Paul · Posted: Mon Aug 13, 2007 5:03 am Post subject:

My wife had a 82 automatic years ago, IIRC the car needed to be in drive to adjust the timing. Don't guess, find the correct procedure.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Smoothie · Posted: Mon Aug 13, 2007 5:19 am Post subject:

Just to be real sure you're turning the engine backwards after positioning it at 0 (tdc) - put it in a forward gear (4th or 5th) and push the car backwards - the next mark that appears will definitely be the 10 before.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Paul · Posted: Mon Aug 13, 2007 5:29 am Post subject:

Our Aussie members should be waking up to Monday morning in an hour or so, maybe they will have the answer, or a underhood sticker they can look at.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

hehe yea i reckon ozzie will be able to gimme the heads up on this one.

and smoothie, i did think about pushing it back in gear...but its an auto

thanks again
tiny
_________________
*****1981 - 924 - Auto - London, UK******

Smoothie · Posted: Mon Aug 13, 2007 6:05 am Post subject:

Oh whoops..

Well then, turning the engine counter[anti]-clockwise (as viewed from the front) is also definitely backwards.
Obviously be careful not to be loosening any bolts in the process.

_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Rich H · Posted: Mon Aug 13, 2007 7:16 am Post subject:

The way I workedit out was set TDC on the front pointer have a look at the flywheel, it should be on "0" then turn the engine clockwise on the front bolt (So your doing the bolt up IYSWIM) until the next mark shows up, that will be 10 deg ATDC. Mark it wit chalk or paint so its different to the other 2 marks.

Or is that too easy?

Took me a while as the rust on the flywheel obscured the marks and the Haynes manual is wrong it says use the middle mark which is TDC...
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

scottc · Posted: Mon Aug 13, 2007 7:51 am Post subject:

Hey Tiny. Hows that fuel dizzy holding up?

From memory you only need the vac line disconnected from the distributor. But as others, its the first mark on the flywheel you're timing the engine too.

steeny · Posted: Mon Aug 13, 2007 10:57 am Post subject:

I have a funny feeling that -10 = ATDC and +10 = BTDC

completely non-intuitive, but i think its in the front of the haynes manual.

anyway, mine wont run anywhere near -10, and runs great at +7-+10, so thats whrere i have it set.
_________________
1978 924 N/A
she's gone.....

Smoothie · Posted: Mon Aug 13, 2007 11:50 am Post subject:

The Haynes actually contradicts itself on the issue of + and - timing marks (or they got it right and Porsche got it wrong while marking the flywheels (not likely)).
-But they start with some ambiguity -
In the US Haynes, pg.123,
for US '76-'77.5 it says -
"Ignition timing.... 10 ATDC at 925+/-75rpm with vac hoses installed"
"Timing mark....... '-' (+10 and -10 indicate degrees before and after proper timing mark)"
That's somewhat ambiguous, but leans more toward indicating that the "-" is ATDC.

Then for the US '77.5-'80 it says -
"Ignition timing.... 3 ATDC at 950+/-50rpm with vac hoses installed"
"Timing mark....... '-3' "
Now that's clearly indicating that "-" is ATDC, but...

then for "Turbo Models (All models except UK)" it says -
"Ignition timing.... 20 BTDC at 2000+/-50rpm with vac hoses installed"
"Timing mark....... '-20' "
-So there they're clearly indicating that "-" is BTDC..

_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox