Hardware refresh, sheet metal accessory painting
Feb 8-12, 2020 - What I really wanted to do was replace all of Gretchen's engine bay hardware with new yellow zinc plated pieces, and have all the sheet metal parts re-plated in the original zinc chromate finish. But, being on a limited budget, that's not exactly what I did.
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| Old, weathered, yellow zinc plated hardware at the top, brand new yellow zinc at the bottom. The zinc plating is consumed over time; its purpose is to be a sacrificial coating and in this way prevents the fastener from rusting. |
Instead, I made a judgement call on the hardware pretty much piece by piece, replacing any hardware that was badly weathered, worn out, damaged, or was not original, with correct new yellow zinc plated fasteners from Bel-Metric.com. I guess I should make clear that it's not like I went through the whole engine bay at once and replaced the hardware in one go. I'm continually looking at and replacing old & worn out hardware in whatever areas I'm working on at the time, anywhere on the car.
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| The two bolts on the left are examples of what happens when you are too aggressive with the wire wheel. Almost all of the yellow zinc chromate is gone; these were actually not too bad looking before I cleaned them. New parts are shown on the right for comparison. |
Any fasteners that were judged to be in good enough condition to remain were either left alone, or were wire-wheeled and re-installed. You have to be careful cleaning old yellow zinc fasteners with the wire wheel. If you're too aggressive you'll just strip off the remaining yellow finish, leaving an old zinc plated part, which looks pretty dull.
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| These brackets had some corrosion on them, but after wire wheeling them and priming with a self-etching primer, they started to look pretty good. Two coats were used. The big gray box in the background is an exhaust fan used for paint fume extraction. |
The sheet metal that was just weathered to a dull yellow or gold would be left alone or gently cleaned. Badly corroded sheet metal brackets and heat shields would be wire wheeled, primed, and painted black. A couple of these parts were so corroded that instead of self etching primer I used a rust converting primer. This type of primer contains additives that are supposed to chemically convert the iron oxide (rust) to a more stable material that will stop parts from rusting any further. Being a primer, once it has dried you can apply a top color coat. Not exactly the factory look, but at least it would look better than it did and shouldn't corrode any further. And any or all of these parts could always be stripped and plated or even just replaced in the future.
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| This very corroded heat shield mounts down near the oil pan on the passenger side where the exhaust comes down. This is one piece that will be replaced in the future. |
Most of the parts that needed painting would have really benefited from being media blasted with aluminum oxide or glass, instead of just being wire-wheeled. I had a media blasting cabinet, but I had converted it into a soda blaster, and soda was nowhere near aggressive enough to remove the rust. The soda blaster was planned for use in refinishing the magnesium parts on the engine. This will be featured in a future blog.
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| This pulley that drives the power steering pump was also cleaned up and painted. Here it has three coats of rust converting primer. You can still see the rust in the crevice around the pulley; this is one part that should really have been blasted with aluminum oxide media to get all of that rust out of there. |
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| After the primer coats were dry, two or three coats of the final topcoat was applied . This was high heat, semi-gloss engine paint. The bracket on the right hadn't been done yet. |
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| The power steering pulley after the final top coat was applied. The semi-gloss engine paint was pretty glossy! I prefer a much less shiny finish, but I also don't like flat black. |
Balance Shaft Re-Seal
Before I could get to replacing the belts and rollers, the upper balance shaft had to be taken care of. These shafts carry an absolutely obscene price tag from Porsche, so it had been carefully oiled and wrapped up to prevent any corrosion or damage. The bearings looked to be in very good condition, and were not replaced. After cleaning and lubricating the block side bearing shell with cam break-in lube, the shaft was laid in it's housing.
The rear plug was cleaned and the new o-ring installed into the groove around its circumference, then the plug was laid into the groove in the housing. This is the plug that had been such a huge false air leak. The o-ring was either worn or shrunken, and you could move the plug easily as if there was no o-ring there at all.
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| Note the oil passages in the rear bearing of the balance shaft. In a turbo engine, this point is where the oil supply for the turbocharger is taken from. The hole in the shaft itself connects to a passage that runs up the shaft to the front bearing, providing it with a pressurized oil feed.. |
The front bearing carrier was prepared for installation with new oil seals and o-ring. The front bearing shell was also lubricated with cam break in lube. The old o-ring seal had been leaking a lot of oil, so careful attention was paid to the groove where it sat, making sure it was clean and burr-free. The new o-ring was carefully installed over the groove, then oiled again, and the bearing carrier assembly was slipped over the balance shaft snout and into position.
It's interesting how the oil system works in this part of the engine. The front bearing is supplied with pressurized oil from within the shaft itself. A hole is drilled into the shaft at the rear bearing, and oil is forced under pressure into this hole, to an intersecting passage that runs the length of the shaft. Another hole at the front bearing allows the oil to flow into that bearing, and as oil flows through the bearing it's returned to the main balance shaft housing via a small oil return hole drilled in the lower part of the front bearing carrier. From there oil returns back into the block and down to the sump. This central oil passage is the reason why Porsche recommends the application of Loc-tite 574 flange sealant to the threads of the balance shaft pulley bolts - to seal the front end of the oil passage.
At this point I was ready to apply the Loc-tite 574 anaerobic flange sealant to the mating surfaces of the housing and cover, and torque the bolts down. I found the torque sequence for the cover a bit confusing, because there are different torque values involved at different points and at different steps around the cover. But I got it done without any problems.
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| The mating surfaces have been cleaned off with acetone and are ready to have the Loc-tite 574 applied prior to mounting the cover and torquing it down. |
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| One of the few "after" shots I remembered to take. As I write more of these blog posts I'm realizing that I took a lot of pictures during the work, but hardly took any pictures of completed work! In this shot the upper balance shaft cover has been sealed with anaerobic flange sealant and torqued down. You can also see the plug covering the turbo oil port over top of where the upper balance shaft rear bearing is located. In a turbo engine, an oil line would be connecting this port to the turbocharger, which would be located in this area. The black pipe in the foreground is the coolant return line that brings hot coolant to the radiator. | |
Battery Tray
I had read horror stories in the Porsche online forums about rusted-out battery trays caused by original OEM batteries leaking and mixing with rainwater, and how they ate holes in the tray that allowed acidic water to drain down into the area occupied by the DME, directly underneath the battery, shorting out and destroying the expensive computer. I had seen Youtube videos showing whole missing sections of battery tray being replaced, and it was definitely something I wanted no part of. So when I first inspected Gretchen (before buying), I had taken a flashlight with me and had a good look down in there, but I hadn't actually removed the battery to look under it. This was a risk of course, but it turned out OK. As soon as I could, I pulled the battery and checked this critical area. It wasn't perfect, but it was very good; only one small spot with some light corrosion and most importantly no holes.
I sanded the corrosion down to bare steel, then made a paste of baking soda and water to neutralize any acid left on the surface. I brushed this on, waited about 15 minutes, and rinsed the area out. After drying thoroughly, I applied two coats of rust converting primer to the area, followed by two coats of zinc cold-galvanizing primer, which was not really necessary, but was a fairly close match to the paint color. The seam along the forward edge of the battery tray had also started to crack, so i flooded this area with the rust converting primer and once it was dry, I resealed the seam with 3M Dynatron seam sealer - excellent stuff. I used a 1" chip brush with shortened bristles and it came out just like the factory seam sealer, which you can see in the picture. Unfortunately, I have no "after" photograph of this!
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| Close-up of the affected area prior to repairs. You can also see the Battery Minder connection to the negative battery cable. The fuse block on the right was for an aftermarket audio system and is now disconnected. It may power a headlight harness for a new set of Hella e-code headlights in the future. |
Once everything had cured for a few days, I installed an acid neutralizing battery mat under the battery and reconnected it. I also installed a Battery Minder battery maintenance system. This device maintains the battery charge at the optimum level at all times, topping off the charge whenever necessary, and also performs full time desulfation, which keeps the battery in a like-new condition for up to 4 years beyond its normal life span. I also installed the missing battery hold down clamp and wire harness clamp with new M8 hardware.
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| New battery hold down clamp , M8 nut, and wire harness clamp were installed. You can also just see the edge of the yellow acid absorber mat installed underneath the battery. Also hard to see, but the fused connections for the Battery Minder system are hard wired to the battery terminals. Plug & Play! |
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| The Battery Minder keeps your battery in like-new condition and extends its life. It's well worth the $50.00 price tag. |
Next time: Threads!
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