Engine Removal, Rebuild, and Re-installaion

[Jamesp]

This is going to be a real time thread so it will be slow when progress is slow, or more to the point, when I am. I am not a mechanic, I'm an engineer. That may make this whole process a whole lot more entertaining to watch. Comments are welcome from all corners as that's part of the fun. Just know I give as good as I get, maybe better. Here is my favorite picture of my boxster. I did not post it on the my favorite picture string because I'b be mistaken for a troll, well maybe not mistaken.



Oh yeah, that's my new tractor pulling the Box, a 1979 8 speed Wheel Horse with 14hp cast iron Kohler. It was a uniform shade of rust when I bought it - nice ride.

[Jamesp]

To get the motor out I used to 101 Porsche Projects book. I highly recommend purchasing this if you are reading this string. 101 Projects step by step directions. It also has pictures for each step so I refer you to that text for pictures. Here is the engine out of the car



This is one of many photos I took of the engine. Walk around the engine taking photos at about every 45 degrees, from a distance and then close up. you can not take enough pictures. I have tons, and as I peruse them I realize I don't have enough.

[Jamesp]

So here is an interesting picture. I decided to label everything with blue tape and a sharpie. I used this everywhere - a blue tape flag and a description of what it is - that made me go find out what everything was as I disassembled. I'm thinking that will help with re-assembly. I also used this with as many bolts as practical keeping the bolts taped to the holes in the component they came out of. Also as many of the loose parts and associated bolts are in their own labeled gallon ziplock bags as possible. Also, note the AOS is failing, plenty of oil in the intake. Apparently there was no white smoke, but look at the oil on the manifold between the alternator and AC compressor mounting location near the power steering pump.

[Jamesp]

Note the overhead crane at the top of the photo. It is a 2X8 hung from the rafters at 90 degrees to them. There is a steel "A" frame hanging upside down with wheels on the legs of the "A" running on the top of the 2X8. A come along completes the set up and allows one person to slowly and carefully remove the split case halves, and remove the crankshaft and bearing block with a minimum of drama.

[particlewave]

Good show!

I'll be watching this closely. Thanks for sharing!
(Don't be stingy with all those pics you're taking)

[Jamesp]

Though the lower end looked almost new when it was opened up (including what appeared to be machining chips), due to mileage, and the failing AOS, there was plenty of oily carbon built up on the pistons. Cleaning it was a challenge. Various hydrocarbon solvents (Chem tool, carb cleaner, brake cleaner, lacquer thinner, etc.) were tried with limited success, the best success came with Chem tool. After doing a load of research a two step process seemed easiest. Buy an empty paint can and soak the piston in Chem tool overnight. After a little scrubbing with a plastic brush only a thin tan build up was left, which turned out to be water soluble. Scrubbing that with a hydrocarbon thinner has very little effect. Some soap and water (wrist pin and rings removed) with a little baking soda cleaned it right up. Rinse the heck out of the bare piston in hot water, dry completely with a lint free towel, Make sure water is out of every crack and crevice. Hit it with WD 40 just to be sure no water is left behind, then soak it with Mobil 1. Or the pistons could just be sent out for cleaning, but where's the fun in that?

[Jake Raby]

B12 is by far the best for this outside of an ultrasonic cleaner..

Meaure those cylinders with a dial bore gauge from different axis and at 3 points top to bottom and look for taper and out of roundness. Guilty until proven innocent!

[Jamesp]

Another tool to buy! One of the perks of doing anything yourself. Looks like a dial bore gauge will join the collection. Having the gear carrier and crankshaft out of the car its time to replace the main and thrust bearings. This engine was a daily driver, mainly freeway with 120K miles. The previous owner drove semi aggressively in Houston traffic and was a stickler for oil changes with the Porsche dealer. As the pictures show, the mains were shot with the babbitt missing in some spots and the backer worn clean through to the steel on at least one edge. The crankshaft mains were not scored and actually looked great so they got a light polish. My takeaway from this is the recommended lube results in worn out main bearings at 120K for a car driven mainly in top gear. The rod bearings, though not as worn as the mains, were also replaced.

[Jamesp]

The IMS bearing failed on this engine. Using this and other forums, the cause of bearing failure appears to be related to loss of lubrication. The root cause of the lubrication loss appears to be due to differential pressure created by the IMS tube heating and cooling pumping engine oil through the IMS bearing. Venting the IMS tube eliminates this, and should allow the grease sealed in the IMS bearing to remain with the bearing. The "new" used IMS shaft is from Ebay, and the original bearing with buna-n seals was replaced with a Nachi 6204 2NSE sporting full contact Viton seals. The bolt is from the Pelican Parts kit. A vent hole can be seen drilled between the teeth of the camshaft drive sprocket. Another is drilled in the same place 180 degrees out from the first hole.

[RawleyD]

Wow, badass.. you have a lot of guts. Great thread!

[pjq]

Wow, brings back memories,.... neat car eh!
You were lucky to find a used IMS in good shape. If you put the vent holes in did you also pin the gears to the shaft?
I see your old IMS on the lower shelf, can it be salvaged? I was lucky, LN was able to salvage mine.

Is that the original IMS to Crank chain tensioner? Did any of your chain guides or tensioners fail?

The first Pic is a keeper. Maybe the Admin. would consider it as the opening Pic for this DIY Project guide! Its great.

[Jamesp]

This is a 3 chain engine which may be why the chains look HD, the IMS to crank was redesigned to a gear type chain instead of sprocket type in the 3 chain engines. Finding an IMS took forever, and then 2 in one week on Ebay. I've seen several others since, but none with a gear drive. I considered pinning the shaft, but weighing the risk benefit (loose pins in the engine) and my novice status as a machinist, I'm staying away from that. The old IMS shaft took it on the chin and now has 0.015 wobble in the gear. It's dead. Maybe I can stand it up with a base under it and make it into a trophy. That is the original tensioner arm. The IMS gave up the ghost at idle there was only one chip out of the plastic on a tensioner that looked related to the failure. There were metal chips embedded in all the tensioners. They will all be replaced. And I'd be honored to have admin use that first pic as an intro!

[Jamesp]

More parts have come in so there is progress. The block half was tilted down and cleaned with brake cleaner. It didn't need much




The bearing carrier was installed in the block half



and pistons were installed

[Jamesp]

I was asked to bump this thread and report out how it turned out. 14,700 miles later this is still my daily driver and it just doesn't get old. Top down, wailing flat 6 every day, very nice. I hit redline at least 4 times today - I need to pick that up a little. I have to say that the forum was super supportive during the rebuild. It would not have come out nearly as nice without everyone pitching in, with a special thanks to Jake Raby and the other professionals on the forum for giving their encouragement, knowledge and advice. I planned to take the IMS bearing out at 15, 000 miles to inspect it just to see if my modified IMS shaft worked then replace it with new bearing for grins, but now I'm thinking more like 20,000 miles... Thanks to all.

[Disaster]

Originally Posted by Jamesp

I was asked to bump this thread and report out how it turned out. 14,700 miles later this is still my daily driver and it just doesn't get old. Top down, wailing flat 6 every day, very nice. I hit redline at least 4 times today - I need to pick that up a little. I have to say that the forum was super supportive during the rebuild. It would not have come out nearly as nice without everyone pitching in, with a special thanks to Jake Raby and the other professionals on the forum for giving their encouragement, knowledge and advice. I planned to take the IMS bearing out at 15, 000 miles to inspect it just to see if my modified IMS shaft worked then replace it with new bearing for grins, but now I'm thinking more like 20,000 miles... Thanks to all.

Awesome. I did a rebuild to a Fiat 124 spider years ago and it was a similar "get your feet wet" learning experience. The original engine in that car had a connecting rod failure that went through the side of the block at about 105k miles. I beat the snot out of that car...driving 90mph on the freeway on a long drive to work. Replaced it with an engine from a coupe that had a low 60k miles which I tore down. The valves were coated with a this layer of "coke." I used a wire wheel to remove the carbon build up and replaced the valve seals.

So the original owner got 120K out of the car before the bearing failed? Do you know what oil the original owner used? Do you know his oil change interval...ie. 5k, 10k?

[Lapister]

James, Quite a project to take on, glad everything worked out. Could you possibly explain in short what it takes to actually get engine out? Mainly, how high the car has to be for it to drop down.

[Jamesp]

Originally Posted by Lapister

James, Quite a project to take on, glad everything worked out. Could you possibly explain in short what it takes to actually get engine out? Mainly, how high the car has to be for it to drop down.

I found higher is better. It really depends on the jack used to lower the engine. I took out the rear crossmember after carefully marking its installed position with spray paint for reassembly. I then took out the entire drive train. There are many connections between the engine and the car. I suggest using the 101 projects book as a guide.

[Jamesp]

Finally got a few hours free to make a little more progress.

On to pistons 1,2,3, so I'm taking credit for "making" this tool too, since I wrapped painters tape around a 3 inch extension and snapped the rest together- it worked great!



Instead of using a mirror to check the piston wrist pin clip, I put my cell phone in the adjacent cylinder and snapped a picture.



next the head and valve train goes on:



I finally understand the valve timing. Took me long enough.

Then the valve cover



More to come

[RawleyD]

Love the pics, great progress!

[dbergondy]

Your project looks good (just saw your 12/23 post)!

I have a 2001 Boxster S with IMS failure ... trying to figure out what I should do!

Thanks for all of the pictures and information.