924Board.org

MrKrik · Joined: 11 Jun 2006 Posts: 21

Hyey guys.. had a machine shop do some work on my head and they returend all teh buckets unmarked in a speerate bag.. so now i need to adjstu teh valvse.. but i dont have teh proper guide... what should the clearence be when fuklly closed.. i got a feeler gauge and teh proper allen key jstu no specs.. thanks guys

Jaf · Joined: 08 Jun 2006 Posts: 194 Location: Oria. Spain

tux · Joined: 02 Jul 2006 Posts: 133 Location: Nottingham UK

What Jaf said! ^^^

The Haynes does say that after machine work the final adjustments should be made with a warm engine (oil temp at approx 80c) and the clearances should be
intake 0.20 (0.008)
exhaust 0.45 (0.018)

Don't know how "essential" this is though.
Good luck dude.
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Pete
Merlin Guards Red 1985 N/A

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

Porscheaddiction · Posted: Wed Jul 12, 2006 1:15 am Post subject:

I have done mine cold too with no problem once the tappets were put back in the right order with the proper adjusters.
Chris
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1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

torro · Joined: 07 Jun 2006 Posts: 61

I got a rebuilded engine cheap, but it was not running right. I tried to adjust the valves, but 2 of the adjusters could not open enough clearance and 2 other were sitting in too deep. Probably mixed up the buckets and I have to take out the cam and swap the tappets.

The clearance on the European engine should be:

Cold:
0,15mm intake
0,45mm exhaust

Warm:
0,25mm intake
0,50 exhaust

US specs. + 0,05mm

I got no pings with 10 BTDC and this clearance, but I am 0,20mm short on one exhaust- and 0,05mm short on one intake valve....one hour job for just 0,25mm

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-=Torro=-

Porscheaddiction · Posted: Thu Aug 03, 2006 1:05 am Post subject:

torro · Joined: 07 Jun 2006 Posts: 61

Yes, It did take some time, but now all of my valves is perfectly adjusted.

Now it is my mixture that might need some adjusting:

CO %vil - 2.82
CO2 %vol - 6.7
O2 %vol - 9.1
HC ppm vol - 138 (particles per meter/metre or minutes, not sure)

The readings are well withing the requirement in Norway. The CO reading is probably a bit high, but not as high as it would be if one of the valves were damaged?
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-=Torro=-

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

The CO reading is a lttle higher than the official range of 1 - 2%, but I think the cars run better betweem 2.5 and 3% (where mine is set). If the 2.8% figure is legal in your country then I would leave it at that.

The HC reading (particles per metre cubed) is very good for an older car.

The O2 reading seems high, but I'm not sure if it's a problem.

Where did you get the readings done?

I isn't clear to me how valve damage directly affects the CO reading.
_________________
1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org

torro · Joined: 07 Jun 2006 Posts: 61

I had the car at the emission test and I got the printouts from the. The timing is set at 10 BTDC, might be over-advanced, but I have no pings. No catalyst or other emissions stuff. EGR is totally ditched, just 2 vacum lines is left and no Charcoal canister either.

Could it be that the combustion chamber is getting too hot, as if one or several exhaust valves is not open long enough to release hot air and causing high O2 reading? Or could the header wrapping cause too high internal temp? I like my engine room cool and the hot manifoil is now wrapped.

....lots of speculations

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-=Torro=-

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW