924Board.org

[OliveRS]

Hello i'm a newbie in the 4cyl porsches, my dad just bought a 1980 2.0L N/A 924 .
I'm doing a few inspections on the car and find a weird thing .
Here is my question : is it possible that the flywheel was removed in the past and not right aligned ? is the distance between the fixing holes equidistant ?
i'm asking because i tried to check the ignition with a timing light, and i couldn't find the timing marks on the flywheel . the only mark i found was a painted dot that don't look like a factory mark . There is some marks on the flywheel ( -10 0 +10) but they don't match the "timing ignition" if i put my timing light .

Thanks .

[924RACR]

Absolutely!
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[OliveRS]

Thank you .
So, to find the signification of this mark ( TDC or timing point) can i remove cylinder #1 spark plug and try to find the "real TDC" ?

The timing belt has been changed, so i suppose they rely on this mark to do it ?

I also have a question about the timing marks of the camshaft pulley, will post some pictures to explain . I have 2 differents marks : a Dot and a groove, don't know wich is the good one .

[924RACR]

Yes, you'll want to use the piston position via the spark plug hole to be absolutely sure of the crank position. Most likely you'll find the front pulley to be correct and align with the pointer on the oil pump. Most likely.

Unfortunately, of course, the front pulley isn't as precise as the flywheel mark.

For the cam pulley, you must use the mark on the backside of the cam pulley, not the front.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[OliveRS]

here are the cam gear marks :
the dot :

in this cam position nothing match nothing (none of the dots on the pulley, marks on the flywheel) .

the "groove" :

in this position, the dot on the front pulley is near the oil pump point.
Looking through the valve cover filling hole, it seems that both valves of the #1 cylinder are closed . i think this is the "good" one .
In this position i can see this mark on the flywheel :
.

So if i'm thinking right the "pen mark" on the flywheel should be the TDC ?

thanks for watching .

[Ozzie]

Yes- would definitely say the flywheel has been refitted out of align.
Would agree large mark and front fully are correct but makes timing difficult.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[Fasteddie313]

Is it running? Well at all?

Your cam pulley dot should line up every other time the crank pulley notch lines up with the oil pump pointer, this is top dead center on compression stroke.

AFAIK both of those 2 pulleys are keyed to where you can't put them back together wrong.

You mentioned your cam dot doesn't line up with anything therefore your cam timing should be wrong.

It is non-interference so if this is the case your safe and it just needs to be reset.

Or maybe the cam pulley is on wrong too and they made the "groove" to correct it? IDK strange
_________________
80 Turbo - Slightly Modified

[OliveRS]

The car has troubles starting (cold, warm or hot) it looks like it floods very easily, but i can't say if it's the "common" starting problem due to the temperature sensor, or if it's due to a wrong cam timing . i will remove the timing belt cover, remove #1 spark plug to check the compression tdc and check the cam timing .
There is also some "kick back" randomly when cranking but not running (ignition advance?) .

[Fasteddie313]

[Shurick]

I use a strobe light with adjustable retard in situations like this. Mark the TDC position on a crank pulley or flywheel. If you need 10* BTDC for advance you just set strobe retard to 10* and aim for your TDC mark while adjusting ignition. Good strobe light with retard is not cheap though....
_________________
WBR, Shurick
'79 931 -- intercooled K26-3060-6.10 turbo @ 1.2 bar, EFI+EDIS, 951S brakes, stripped interior, 951 look.
'86 924S -- R.I.P.
https://www.instagram.com/ru_pacecar/

[OliveRS]

thank you for those advices. I've got a timing light with advance button (first time with the 924 but i also have a racecar) . Will check all this this weekend, thank you .

[OliveRS]

Hello
Just did the "tdc check" throught the #1 sparkplug hole . the painted mark on the flywheel is the tdc, so i set the ignition advance to 10°btdc . Also checked the cam timing with the strobe light, looks ok .
Thank you for all your advices .

[alan78924]

My flywheel has also been reassembled 180 deg out. Find TDC and use your own marks Or remove the engine and refit the flywheel correctly thats your only 2 options unfortunately