986 3.2 home engine rebuild

[PaulE]

What did you use to clean up those pistons? I've got one souvenir piston from my engine before it was rebuilt. It's still on my workbench as it looks like your pistons before you cleaned them up. If I can get my old piston that clean, it will go from my workbench to my desk!

Are you going to check the cylinder bores for roundness, i.e., no ovalization?

Everything looks great!

[OldManMo]

Originally Posted by PaulE

What did you use to clean up those pistons? I've got one souvenir piston from my engine before it was rebuilt. It's still on my workbench as it looks like your pistons before you cleaned them up. If I can get my old piston that clean, it will go from my workbench to my desk!

Are you going to check the cylinder bores for roundness, i.e., no ovalization?

Everything looks great!

They got a blast with Carb Cleaner to get most of the oil off and soften the caked on crud. Then 10 mins in an ultrasonic bath with a degreaser at 65 deg C, then removed the piston rings, then another 10mins in the bath



Then soda blasted at 50 psi then 30 psi



They went back into the ultrasonic bath at 30 deg C wit a very mild carb ultrasonic cleaner and they came up like below.



I did start polishing them up with some autosol and a rotary felt pad and then read they are coated so didnt want to polish out the coating. Got into a panic at first as though I had to buy a whole new set of pistons (and still might do mind you) but from what I read they are alloy with an iron coating, so used a weak earth magnet to test the coating is still there and it was on crown and skirts as this weak little magnet was very happy staying on the pistons

Yes, once the casing are cleaned up I will check for roundness and magnaflux test for cracks. I prefer to work with clean components



casings need a good clean first as does everything else too

[OldManMo]

Ok, onto the home straight. At this point I have only the crank box and bank 2 on the engine stand.

BTW, before this point I realised I had the engine stand mounted across the two halves so I put the engine on the hoist, re-adjusted the stand so it would only be on bank 2 and then removed the bank 1 side. Forgot to mention this, so would have been far less hassle to get it right first.



So removed the end caps from pistons 4-6 and dropped them out carefully. then removed the last long bolt on the Bank 2 side, hooked up the engine hoist to four points on the crank box, lots of prayers and gentle coaxing and the crank box separated from the bank 2 half. Lifted up the crank box (with brown pants) and then set down on a trolley



Had a look into bank 2 half and looked ok, but wait...what the fanta is that in the top left corner, yep a nut, some rando nut, which looks like its been in there a while and defo not looking like its within the engine. I count everything I take off an bag it, so it is possible I dropped something while disassembly but very unlikely.



Next split the crankcase, very carefully. Its not really heavy but awkward shaped. Looking at crank journals and bearings, they were not too bad but not far off end of life.



I will need to take loads of measurements to check the crank to be sure but I was optimistic, then I reviewed my photos and my heart sank.



What are those marks, they looks like metal that has been stripped away!!!!! At this point it was late one night, I had just tested positive for covid and I thought sod that, if the crank is gone this car will be parted out, cannot justify an 5k cost on a new crank.

[OldManMo]

Fortunately the next day and in the sun, with a better photo I could see it was staining which was coming off with cleaning. The sprocket looked ok apart from some marking from the chain



Anyone know what is and is not acceptable here? Can the sprocket be rebuilt or would the crank lose its heat treat if it was?

[OldManMo]

Ok, parts all stripped down and bagged or waiting for cleaning.


I am going to look to get the crank box rebuilt first once I have taken measurements and polished. Aiming to complete this by Christmas. At the same time I will send the cases, sump and some other parts from the bottom end to be cleaned

Here is what I have ordered for this part of the rebuild

Oil Separator
(99610101000)

Main Crankshaft Bearing Shell Standard. Porsche 986 Boxster / 996 >>2001
(99610120510)

2 x thrust washer
(99610112952)

6 x splash valve
(99610101851)

Tensioner Blade. Porsche 996 1998-05 / Boxster / Cayman
(99610516555)

Tensioner Blade. Porsche 996 1998-05 / Boxster / Cayman
(99610516651)

6 x pan-head screw M 6 X 16
(99921800501)

Timing Chain. Porsche 996 / 986 / 987C / 997.1
(99610517158)

2 x Timing chain. Porsche 996 / 986 Boxster
(99610517753)

roll pin 6,0 X 16
(90009503101)

straight pin A 4,0 X 10
(90030202100)

14 x screw M 9 X 127
(99610111559)

[OldManMo]

Recap of what I did so far.

Remove rear bumper - Lots of great posts on this forum how to do this and YouTube videos

Remove roof (easier access) - Lots of great posts on this forum how to do this and YouTube videos

Remove Exhaust - Lots of great posts on this forum how to do this and YouTube videos, 101 projects, etc

Remove gearbox - Lots of great posts on this forum how to do this and YouTube videos, 101 projects, workshop manuals, etc

Remove engine - Lots of great posts on this forum how to do this and YouTube videos, 101 projects, workshop manuals, etc

With all the resources online, dropping the engine is not as daunting as first thought with the bike lift and going slow and checking and double checking it came out with little stress. It took about 3-4 hours start to finish.

That all said, the caveat to this is that I have already taken the gearbox off so all those seized and rusted nuts, bolts etc had already snapped and I went through the stress and time previously. As an example, I was going to reuse the original cats, but the flange bolts refused to come out and I had to sacrifice the cats to get them off. With Hindsight, if you want to reuse many of the items then plan for extra time to deal with the poor quality fasteners. If you plan to replace, then do what's most time effective

If there is anything specific someone would like to know then please do ask

Here are some of the tools I used

1. Bike Lift - to support and lower the engine
2. Trolley Jack
3. Jack Stands
4. Floor transmission jack
5. Various sockets
6. Camshaft holder tool
7. Impact Wrench
8. Impact Driver
9. Electric Ratchet
10. Engine Stand

[OldManMo]

As part of the tear down, I am cleaning many components which I wont be replacing. Once of these are the Variocam adjusters. So I have searched the net looking for info on there magical devices and some does exist, but there is not much that shows some of the internals. Understandably so when we consider the cost of these. There also seems to be no way to refurbish them.

I had originally used paraffin on one of the adjusters and a ultrasonic bath to clean it and I thought it cam our well. When I went to do the bank 2 adjuster I actually saw some of the brown plastic from the guides in the same bag, which there should have not been any. On closer inspection and through some dismantling I found more fragments, some even blocking the holes on the piston visible. So I decided to take the risk and dismantle these and use a ultrasonic sensitive detergent at around 45 deg C and totally flush out the parts.

So here is a caveat, I do not recommend repeating this experiment as at this time I do not know if it will fix or damage the part. I am only sharing what I did and my observations and not recommending the following to anyone to repeat.

Each bank has differences, not only in the solenoid but also in the unit itself. Bank 2 has extra holes which oil is pushed through that bank 1 doesn't, also more importantly, there is a oilway at the top of bank 2 and this is on the bottom of bank 1

Below are some photos after the units were cleaned.









Apart from the difference in part number stamped on each unit, there is a stamp indicating which cylinder it is intended for visible on the top of each unit next to the solenoid

So how I cleaned the units was to dismantle each one, one by one as not not mix up the internals.

Below are the internals for Bank 1





I next put the parts, not including the solenoid into an Ultrasonic bath with a sensitive detergent (metal and rubber) at 45 deg C for 10 minutes. I then gently moved the piston in an out (and I mean gently) and wow, the crud that came out and yes some more small pieces of plastic. On bank 1, there are only 3 or 4 places where fluid goes in and out so I just watched these as I GENTLY moved the piston. I then repeated the bath for another 10 mins and repeated GENTLY moving the piston and wow, even more crud and small pieces of plastic. Dont get me wrong, it was only 1-2 very small pieces but they were still there.

Between each 10 min clean I rinsed in warm water, submerged and gently moved the piston. I repeated one more 10 min clean in the batch.

I then polished the piston in the middle (below) and using a shoelace and oil only I polished the main piston in the unit.





BTW, before cleaning the pistons did not move freely, either the one inside the main or the main. Following cleaning, I submerged the unit in fresh oil and gently moved the piston to prime it and removed as much water as possible. Yes there will be some water remaining but this will hopefully be removed when I break the engine in following the rebuild and the 2-3 oil changes I am planning post run in. The amount should be insignificant....hopefully