Fnic99

Agree that I should proceed with caution. Currently not too bad.

MainePorsche

I spray not a thing on the engine. Loose liquids will get in places you do not want them to. I spray my degreasers on my shop rag and wipe it down till clean.

FBIII

As a kid always went to the quarter car wash and washed the engine. Then I bought a pressure washer and continued the practice. I tried to stay away from the electrics as much as possible. But in the 40+ years I have been doing it I have never experienced more than drying the inside of a distributor cap or in the 928's case drying the large terminal on the passenger fender. I figure if I ruin something at this point all the hours saved over nearly a half century are well worth it.

thezonster

I think that the problem here is that, at least on my '86, the top of the motor under the intake manifold, is a large open valley, that will hold a lot of water if you are not carefull, and would partially submerge the throttle body and other stuff that should not be wet.

17prospective buyer

Worf928 Good advice but i have to add a word of caution on the disassembly thing. If you're like me you start disassembling then keep going till theres nothing left of the car.

Fnic99

Not a total mess. I will proceed with caution, use little water, and try to spray the cleaner on to a rag instead of directly on the engine. Once I have everything clean, I want to do something with that intake.

thezonster

You can tape off and paper the area closely around the intake and do a pretty good paint job on what shows, without taking everything apart.

Fnic99

My mechanic had the intake off a few weeks ago but I decided not to powder coat. The work I was doing was already getting expensive and I decided to spend the $$$ on a new CPS. After seeing the results on that thread above, I believe the DIY job would be a great bang-for-the-buck.

MFranke

As you remove parts during maintenance just clean them to like new. This is the best time to use chemicals or detergents - when parts are segregated. Get a big can of Berryman from Walmart and just let the soaking do the work on the dirty parts as you work on the car.
You can also pick a small area at a time to detail. Then move to the next area. Do a bit here and there as you have time. After a while before you know it everything will be clean and the car will be a lot more fun to work on.

dr bob

Dtergents and cleaners tht are petro-based will speed the deterioration of rubber and painted parts. Citrus and other slightly acidic degreasers will react with the cad and zinc coatings on metal parts. Caustic degreasers like the Purple XXX products (Castrol dgreaser is a popular one) will generate a dark hydroxide coating on aluminum stuff that doesn't quit.

So, my recommendation for the top of the engine is to use nothing harsher than what you use on the paint. Got a car wash detergent (like P21S) that you love? It's a good choice for the engine bay. Got a lot of oil slime on the bottom of the engine and chassis that's well below the beltline and fine painted finishes? Petro-vased engine cleaners work fine.

Electrical stuff is always a worry. Cover switches, senors and exposed connectors with plastic before cutting loose with any water, including the sparky bits under the car.

renbry

I've posted this guy's videos before -

Here's one on Engine bay detailing. Not 928 specific, of course, but shows some good techniques...


<iframe width="560" height="315" src="//www.youtube.com/embed/V4ZHLRAX_tU" frameborder="0" allowfullscreen></iframe>

namasgt

Simple green eats Aluminum, there are other simple green products that are specifically for aircraft use compared to the green stuff you can buy from walmart.
http://www.simplegreen.com/solutions...query=aluminum

If you wash your engine bay with water spray you will get some water in the valley under the intake. There is no place for this water to go, it will just seat there until it evaporates. Imagine what it would do if you have simple green mixed with it. Do you really want your knock sensors swimming in water?

Look at post number 93 on this thread, do you see how the bottom of the valley is pitted? This is where the water and solution your using could seat for sometime until it evaporates especially if you don't drive the car much. Its possible for this block that the owner was used to washing the engine bay with water and whatever solution he was using and the mixture just sat in the valley until it evaporated.
https://rennlist.com/forums/928-foru...-thread-7.html

If I remember correctly on later blocks, 89+ cars, Porsche drilled a hole on the back of the valley so that any water or liquid would drain out, I'm assuming this was done to protect the knock sensors? But sometimes this hole also gets blocked from dirt and sand such that it would be hard for any liquid to drain out. Knock sensors started being used from 87 model year.

namasgt

To each their own, but seriously, do not wash your 928's engine bay with a water hose or pressure washer. That water/degreaser mixture will seat in the valley for days before it evaporates and will probably damage the surface.

I would only pressure wash 4 cylinder or inline 6 engined cars where there is normally no place for large amounts of water to get trapped and potentially stay there until it evaporates.

namasgt

Wipe your 928 engine bay with a moist rag, similar to what Stan has described that is about all I will do no water spraying or pressure washing of any kind.

dr bob

For casual 'cleaning', which is something just north of dusting, I use Invisible Glass window cleaner, a weak mixture of methyl alcohol and distilled water. You can make your own with denatured alcohol and distilled water in a spray bottle. Good enough to loosen light oil film, doesn't bother car paint, leaves no residue.

Still, don't spray electrical connections especially on a warm engine. Any water sprayed on will cool the sensor/connector, and even the sealed ones (not that there are any of those in the engine bay...) will inhale a little water/cleaner as they suddenly cool off. If you do get stuff electrical wet, one of the very few good uses for WD-40 is as a Water Displacer (the WD in WD) in wet connectors and sensors. No longer-term protection on its own, but stopping water and low-pH detergent corrosion from starting at all is the goal here.