StratfordShark

Thanks Dwayne - you've no idea how reassuring it is to hear that a guy with your mechanical savvy encountered same problem as me!

As you say it's a labour of love. I think my wife wishes I cleaned up around the house as assiduously! Must say I find the cleaning side almost therapeutic, if long-winded. It's a nice break from the real job, especially if that's thrown up a problem or two.

Just hope my S4 (only one I'm afraid) appreciates it...

928autobahndreamer

I was thinking of giving all of the cleaned up exposed metal a coating of rejex. It works great on wheels. Hopefully it will give an extra later of protection in the engine bay. I'll report back down the road and let people here know how it works.

928autobahndreamer

I spent part of the day cleaning and I managed to get at least some of the crap off the engine. For grins I also polished up a few parts with Mother's Mag and Aluminum polish and it worked pretty good.

Otherwise I pulled the drivers side cam cover and pulled apart the water bridge and removed the thermostat to test. Man, the inner thermo seal was completely shot. Also, the neck of the metal connector that goes to the thermostat had a lot of scaling. As I carefully scraped off the scaling it seemed to take off bits of corroded metal as well. Do I need to worry about this?

Also, I included a picture of my thermostat. I placed it in boiling water and it seemed to open pretty well. At 22 years old should I go ahead and replace it or since it still opens should I leave it be? I have no idea if there is really anything on this part that can fail. It seems the main thing is getting all of those seals replaced.

Next I am going to strip all the paint off of the cam cover and intake manifold, and prep for painting. I just need to drop by the parts store and pick up a 22mm deep socket to get that damn intake temp sensor removed before I can spray the stripper. My deep socket set only went to 21mm. I have a can of duplicolor engine enamel primer and a can of engine enamel cast coat aluminum. Anyone used this color on their intake? I figure if I don't like the color I can always cover it with another coat of a different color.

dr bob

Dreamer asked how to get the underhod parst clean and looking good.

Engine bay cleaning is a balance of cleaning/degreasing vs damage done to what you are cleaning. The common non-solvent degreasers can be harsh. The purple degreaser I bought (ZEP from Home Depot) is sodium hydroxide in butyl cellosolve. That's caustic soda. (!) It does a good job but can be tough on whatever you might be cleaning. Painted surfaces suffer, aluminum parts look clean but get a dull gray color after a short while. Plus it plays hell on your skin if you happen to get some on it. The stuff is fat soluble so it degreases/defats your flesh. Doesn't burn immediately like acid, so you may not appreciate the damage done until it's too late. This same stuff is not as tough on hardware as the acid cleaners.

The acid cleaner category includes most of the citrus and 'orange-oil' degreasers. Again, I sampled a bottle from Home Depot. This stuff lets you know a lot quicker that you have dangerous skin contact compared with the caustic stuff. It's tougher on plated hardware, especially the yellow zinc plating on underhood brackets and and to only a somewhat lesser extent to the cad plating on bolts. Aluminum brightens some with the acid cleaners, but will dull to grey oxide finish with extended contact.

Detergents and emulsifiers are probably a lot safer for what most folks are doing. Simple Green is pretty much pH neutral so it's safe for painted, plated and aluminum parts under the hood. I use Dawn a lot for lighter-duty cleaning since it rinses so clean compared with Simple Green. A few drops of Dawn in the water bucket is a good car wash, just enough emulsifier to flood the surface but not so much that it strips wax. More will eventually strip wax, but the foam is an excellent lubricant for claybar treatment. It also makes a great handcleaner, very easy on the skin.

Last in the arsenal are the solvents. Most anything can be degreased with common paint thinner/mineral spirits. There are more aggressive solvents, like the chlorinated stuff we used to buy as a consumer brake cleaner or electric motor cleaner. The current common consumer brake-cleaners are still pretty good, safer but not as aggressive as what we used to buy. Vapors have less chance of causing nervous system disorders now too. The real aggressive stuff will dull paint. Waste disposal for the high boilers and air pollution issues from the low boilers are often-forgotten concerns when using solvents.

This family also includes some of the common spray engine cleaners like Gunk. I have a long history with the foamy engine brite product for non-painted parts, like engines and gearboxes and the like. Great for general crud removal. Washes/partially rinses off with water. Needs a detergent wash and second rinse to get the last film off. Downsides are around disposal of the waste and where to rinse, since it will damage asphaly, stain concrete drives, and is genarlly considerd a water pollution hazard if it is washed to a storm sewer. The fine print on the spray can says I can't just hose it down the driveway into the ocean anymore.


Roger and Sean were discussing use of Simple Green in the parts washer. They recommended adding a heater to the recirc tank, which sounded like a good idea.

There are services like Safety-Kleen that will install a parts washer and cleaning fluids, and come recover and recycle your 'used-up' fluids on a regular basis for a small fee. If you are doing a lot of parts cleaning this is a good option.


I may be on the lookout for an old used dishwasher to use as a parts washer. Dishwasher detergent is very low pH in solution and does a pretty impressive job on most parts. Just no painted or delicate plated parts please. The machine can't tell most small engine and mechanical parts from a crusty pot when you run it. Big chunks are gathered in the catch basket, while emulsified stuff goes safely down the drain. Pull the top rack out and there may be room for a whole intake manifold in there. Cam covers will fit for sure. I wonder if K would notice if I ran those parts through the big pantry dishwasher? She never looks inside, and I could just run it empty a few more times to destroy any evidence. I rescued that dishwasher fair and square from the scrap pile, so I should be able to use it. Right???

Bill Ball

The Allen bolts you wire brushed but then found to rust were most likely originally black oxide coated. You can restore them to a similar finish that will resist rust. Caswell sells a kit for under $30.
http://www.caswellplating.com//kits/black.htm
Results are very good if your parts are super clean right before the treatment.

StratfordShark

Yup - it was the black ones which were most susceptible to rust after wire brushing.

Very interested to read details of the Caswell kit. Thanks for tip.

928autobahndreamer

Life has gone and interupted my working on the 928, but I should start making some more progress in the next couple of weeks again.

Of course while my 928 is completely out of commision for the intake refresh is when my daily driver craps out. The car is a 1996 Nissan Altima, and this is the first time it has had anything go wrong that prevented it from driving. So, I spent the better part of a week diagnosing and fixing my DD. Something that I was able to do succesfully I might add. Its funny, I never would have had an idea of where to start looking before I owned my 928. Everything I know about auto repair I learned on Rennlist. You know what, the same basic principles apply whether it is a 316HP Porsche or a 150HP Nissan.

Anyway, a little update on what I have accomplished on the 928. I have totally redone the Throttle Body with new ISV, bearings (thanks Dwayne, never would have even thought of attempting that before I saw your thread), TPS (even though the old one seemed to be working perfectly), and all new rubber.

Also, my injectors came back from WitchHunter looking all shiny and new. I have attached a picture of the data sheet they sent back. THe injectors, despite being 22 years old where working great with only a 3.5% variance from highes to lowest flowing. After cleaning all are within 1%. Also all the filters, pintle caps and O-rings are now new.

So, next is just finishing up stripping the paint off the intake and manifold, outgassing in the oven, and painting. Then it is reassembly time. Man I can't wait.
Also, I have a new set of rear rubber to replace the "slicks" I have been driving on.

Dwayne

The engine is cleaning up real nice - looks great! That polished fuel pressure damper is sweet looking too. Nice work!

I re-used my old thermostat because it looked and operated just fine. If you aren't experiencing high engine temps, I'd keep it. I also have a spare. So if you would like to have a spare around, you could buy a new one and put it in and save your old one for a spare.

The corrosion on the thermostat elbow doesn't look too bad and could be used again - especially if you were not experiencing any leaks before. If it does give you trouble later, it's an easy part to replace without a lot of engine disassembly required. Again, if you would like to have a spare around, you could buy a good used one and keep your original part for a spare.

928autobahndreamer

Progress is slow, but things are moving forward. If I had to do this again, I would fork out the extra dough to have the intake and valve covers media blasted and powdercoated. I have spent more time trying to strip the paint off of the intake than I took me to completely disassemble everything.

I do have a few quick questions. When replacing the thermostat O ring, the new O-ring has a totally different look and does not fit the same way. I took a few pictures and am not sure how well it shows, but the old o-ring was flat, and fit snugly around the thermostat. The new O-ring is more rounded and gapes a little around the thermostat. Is this correct? or do I need a different thermostat O-ring?

I have also included a few pictures of my painted valve covers. I decided to go with Duplicolor Cast Aluminum high temp engine paint, over high temp engine primer.

Also stripped and polished the engine cross brace (no pictures yet)

the flyin' scotsman

The round O ring looks like its for the water bridge to block.

928autobahndreamer

The O-ring was in a bag labled thermostat O-ring and looks like the one used in Dwayne's thread. It just looks different than the one I removed. It is definately not the water bridge O ring which is fatter, and with a smaller diameter.

The outer diameter of the new o-ring fits correctly and on close review looks like it should work. I will include a few more photos.

Also included a picture of the polished cross brace as well as a picture of the engine block number. This just for reference to the squirter block thread shows the engine number for a folding wing, ribbed intake, with solid fuel rail mounts. No idea if it has piston oil squirters.

the flyin' scotsman

I have my water bridge apart also but dont have the new seals or O-rings from Roger yet. My old tstat housing gasket sure looks flat............amazing what 20 years will do to rubber.

928autobahndreamer

I"m thinking my old one was originally flat. I don't think time and pressure did this. The new gasket looks like it should work, but it is definately different than the original.

Leon Speed

The originals are flat, I think the new ones are round. Sometimes you get the wrong O-ring with a new thermostat (too thin). Compare the thickness of the original and the new one. For me the final test was in putting the bridge back together: the metal piece the hose attaches to should make contact with the O-ring first. In my case the metal of that piece met the metal of the bridge first (you could feel and hear metal-to-metal contact when putting it together) which indicated to me the new O-ring that came with the thermostat had a too smal diameter. I reused the original flat one and no leaks until now.

928autobahndreamer

The new one is not too thin. If anything, it may be too thick. But, I think it will work as when I tighten the bolts it seems to compress well.