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1980 Porsche 924 Restoration - Finally Coming Together!
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j03k64  



Joined: 26 Jul 2010
Posts: 114
Location: Urbana, Ohio

PostPosted: Wed Oct 04, 2017 9:50 am    Post subject: Reply with quote

Yeah The composite resin filling materials are half aluminumsilicate, release formaldehyde for 4 months, and the bonding agents contain aluminum oxide as a buffer; often not listed in SDS. I'm highly allergic to aluminum and can't break down formaldehyde well; causes metabolic acidosis! Anyway, tons of formaldehyde exposure sources in our shops/cars. I encourage all of you to please take care! Open the shop up and get fresh air any day you can! Not good for any of us.

Goldwolf, will PM you. Sounds like AAV is might be stuck mostly closed (gassing it on start bypasses that), but the fact it continues after it's warm might bring the WUR and other things into question. Maybe this chart will help you!


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If anything died in the OXS system, the car would run like it didn't have an EGR/emissions system. I noticed oil coming from the oil fill cap (thought the lid gasket might be worn) and poor oil control at the spark plugs, which is expected on a new motor; but it could also be non-vented gasses building up in the head? If components that trigger changes in the emissions system failed, it would cause mixture and idle issues. I have tons of documentation, but none explain the 1980 OXS well or its internal functionality. I pulled the OXS box. P/N's listed. The RPM relay metal seems very 'tin' like; it just seems abnormally 'beer can soft'.


Not being able to test the OXS or RPM relay on the bench, I moved onto microswitches and found a problem. The idle microswitch is NOT fully closed at idle! I unhooked the throttle linkage and moved the idle-rest to ensure that I hadn't caused it to do this when replacing the throttle wire linkage; still won't close the microswitch. Either way, the microswitch issue is a solid find and needs fixed. Starting there!

At idle


Manually triggering the microswitch to complete circuit (ohm readings vary)


The mechanical trip is touching the actuator, but it's not pressing it to complete the circuit. The full throttle switch functions, but adjustment is unknown.


UPDATE/S:
Switch actuators are worn Filled the cracks with JB weld; failed to withstand mechanical wear 24 hours after curing. Removed the JB. We cut tabs out of sheet metal and used steel epoxy to laminate them to the switch tabs. There's about 3mm of adjustment in the screws, which is plenty to accommodate an extra 1mm.



I'm screwed and have to re-calibrate the switches for the OXS. Anyone have experience doing this? Shop manual calls for Porsche Specialty Tool P228B / P 228 604 Degree Dial that was 'made locally' to calibrate the trip positions. I found very little online, but re-engineered the calibration tool from the information I could collect and shop manual. Idle-rest is at min, plus a bit to ensure it engages the switch when tuning.




I would think idle switch not closing would trigger a slightly rich state (assuming OXS works), not lean which I'm experiencing. The OXS box should think the throttle is in the 7+ degrees position, where both switches are open; unless OXS has an emergency mode of some sort? I could have the FD mixture slightly lean and this problem also exists. I need to get a an Innovate MTX-L Digital Wideband Air/Fuel Ratio Gauge Kit for this thing.

Calibrated, assembled, and pending testing. The idle stop creates interesting questions to calibration in terms of tuning. I set it a half degree rich and it should theoretically richen with wear as to prevent the development of a lean condition. I may write up instructions with photos if anyone is interested once tested.

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1979 Porsche 924 NA (Dead, pending restoration)
1980 Porsche 924 NA (In restoration)
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j03k64  



Joined: 26 Jul 2010
Posts: 114
Location: Urbana, Ohio

PostPosted: Mon Oct 09, 2017 8:03 am    Post subject: Reply with quote

Microswitches are calibrated and installed; took about 30 minutes to get it calibrated. As a heads up, the idle rest screw can disrupt the microswitch calibration and operation, so be aware of that when you go to adjusting things.

It still doesn't explain why it's running lean. Chatted with Goldwolf as our issues are similar. Thought on it for a bit and went through the post rebuild steps. Timing and mixture are all that caught my eye. Can't set mixture according to the shop manual without proper timing, so I started there.The head and distro timing match up perfectly, however, the timing mark on the fly wheel is not on zero when the head is at TDC! I rotated the crank to the zero line on the flywheel and it's out of sync with the head/distro by exactly one belt tooth. Guessing the belt slipped by a tooth when we installed it or the engine wasn't at perfect TDC when the head was removed for reconditioning. Explains why it runs like a golf cart, is lean, and seems to be causing excess valve heat.
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1979 Porsche 924 NA (Dead, pending restoration)
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Goldwolf  



Joined: 25 Jun 2017
Posts: 72
Location: Athens,GA

PostPosted: Mon Oct 09, 2017 12:46 pm    Post subject: Reply with quote

That's nice work with that protractor . Seriously though.
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j03k64  



Joined: 26 Jul 2010
Posts: 114
Location: Urbana, Ohio

PostPosted: Sun Oct 15, 2017 7:55 am    Post subject: Reply with quote

Thanks! It's functional wizardry

I got the timing belt sorted out and prepared to fine tune the timing, idle, and mixture. Painted a 0 deg line on the flywheel; it's horrible trying to get the timing perfect otherwise.

Started it up today to complete the above tasks and it blew the oil pump seal; the one at the front of the crank. Thankfully not the paper gasket. Better in the garage than on the road I guess. I'm starting to feel like this car hates me...

Any recommendations on a brand? Victor Rienz? National Oil Seal? Corteco? SKF has this Kit on sale? http://www.autohausaz.com/search/pn.aspx?sku=12952365-056109119AKIT&vehicle=1980%20porsche%20924&brand=SKF&utm_source=google&utm_medium=nonpaid&utm_campaign=froogleSKU_porsche&gclid=EAIaIQobChMIkMzD6Ozw1gIVQzuBCh06cwf1EAkYDCABEgKc9fD_BwE
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