986 3.2 home engine rebuild

[OldManMo]

After degreasing the crank and giving it a bath I checked the main journals and all were 60.0mm using a digital calliper. I have a micrometer somewhere and will dig it out to double check , but with all honesty I don’t know if this is good or bad.

Lots if posts from people have measured theirs but there appears to be nothing published as to factory spec by Porsche. Without buying a new crank, is anyone aware of the factory specs for both journals?

[JFP in PA]

Originally Posted by OldManMo

After degreasing the crank and giving it a bath I checked the main journals and all were 60.0mm using a digital calliper. I have a micrometer somewhere and will dig it out to double check , but with all honesty I don’t know if this is good or bad.

Lots if posts from people have measured theirs but there appears to be nothing published as to factory spec by Porsche. Without buying a new crank, is anyone aware of the factory specs for both journals?

Porsche never published any internal clearance info on these engines as they didn't want anyone to work on them in the field. They didn't even publish engine internal torque specs. That is why Jake Raby's information is so important.

[OldManMo]

Originally Posted by JFP in PA

Porsche never published any internal clearance info on these engines as they didn't want anyone to work on them in the field. They didn't even publish engine internal torque specs. That is why Jake Raby's information is so important.

Thanks JFP in PA for confirming and replying, your help is very much welcome and appreciated. Got Jakes torque specs which is a God send as are his DVDs so far.

So the only way anyone can find out what the default factory spec for each journal is to buy a new crank and measure them and then publish them on the net to help others. Don’t really want to spend the money as my crank as far as I can see looks ok though I could be wrong as I don’t know what the original specs are

Nice (British sarcasm)

[JFP in PA]

A close approximation of the crank journal sizes could be obtained by torquing empty new bearing shells in the rod and mains carrier, then inside mic them.

[OldManMo]

Originally Posted by JFP in PA

A close approximation of the crank journal sizes could be obtained by torquing empty new bearing shells in the rod and mains carrier, then inside mic them.

Good call

[Homeoboxter]

It`s even easier to measure the clearance with plastigauge. You can check the old and new set and compare.

[Newsguy]

Originally Posted by Homeoboxter

It`s even easier to measure the clearance with plastigauge. You can check the old and new set and compare.

So, my question is: how do you use this when the bolts have to be torqued and then taken to the proper angle--and are one-time use?

[Homeoboxter]

Originally Posted by Newsguy

So, my question is: how do you use this when the bolts have to be torqued and then taken to the proper angle--and are one-time use?

Easy: you use the old bolts for plastigauging/mic-ing and use the new ones for reassembly.

[PaulE]

OldManMo you inspired me to clean up my souvenir piston from my engine before it was rebuilt as a 3.6. A week in a gallon of carburetor cleaner was all it took! Keep posting updates, I love following your progress!

[OldManMo]

Originally Posted by PaulE

OldManMo you inspired me to clean up my souvenir piston from my engine before it was rebuilt as a 3.6. A week in a gallon of carburetor cleaner was all it took! Keep posting updates, I love following your progress!

Thanks PaulE and others for the words of encouragement and really makes my day that I am helping others. My son and I are having lots of fun so far learning and seeing the progress. We had a great evening in the other day watching Jake’s DVDs with a bag of popcorn and a slushy. Me more than him mins you

Nothing so far has been daunting but that said I do believe I did the tear down at the right time before any damage.

Will share more progress in the next few days

Thank you all

[OldManMo]

So first round of cleaning for the carrier, crank and IMS

Before is yuk







After is much better and can really see what the situation is. Still not finished with the carrier though











Crank needs a little more work and I want a Machine Shop to check it. So will look to get it only micro polished

[OldManMo]

I use an Ultrasonic bath to do the cleaning and interesting what you fine on the bottom. This is from the Crank, which wasnt bad even though its what is all that.



I didnt take a picture after the carrier but there were loads of little bits of plastic once cleaning had finished

[pilot4fn]

Brilliant, very interesting thread and how you document the progress. Thank you and keep up the fantastic work

[Robert986]

May I ask, the parts that where mediablasted, eg the gearbox. Did you clear coat them after? Any trick to make them stay that clean?

[OldManMo]

Originally Posted by Robert986

May I ask, the parts that where mediablasted, eg the gearbox. Did you clear coat them after? Any trick to make them stay that clean?

Hi Robert986

Different parts had a different finish. For the gearbox, I didn’t mediablast as it was too big for my machine, but I cleaned it with degreaser, then wire bushes, then used a lot of carb and brake cleaner, scotch pads, then I gave it a light coat of alloy wheel silver paint. One year it is still holding up. With hindsight, I probably sent this out to be media and vapour blasted then had a anti-corrosion coating applied.

For other parts such as suspension parts I did media blast with soda and fine glass beads (taken care for smooth finished areas) then applied either silver alloy paint or anti-corrosion coating. For the exhaust,, this was a couple of hours spent using a fine scotch brite wheel then a polishing wheel with a polishing compound like autosol

I need to do the front suspension and brakes so I will share what I do, again not to say this is the “right” way to do this but just what I did/do

[OldManMo]

Hi all

I know, its been ages. Lots of reasons, Christmas, holidays, work, home, waiting on parts, waiting on parts, waiting on funds and so on

Spent most of the time since my last post cleaning, measuring, investigating, learning while I waited to order and receive parts. I should hopefully be in a position to start the rebuild in the next month or so. Dont get me wrong, I currently have a small mountain of nice new engine parts, but still quite a bit more to get.

While cleaning the many parts in the ultrasonic tank, I could clearly see particulates fallen to bottom. These were mostly plastic from the chain guides and some pieces of carbon. There was however, lots of pieces and they came out from almost everything that was cleaned, Crank, Cams, lifters, lifter housing, IMS itself once the bearing was removed.

All honesty, I am not sure I didn't find lots of damage as it does look (and maybe I am fooling myself) as I caught it in time

So while I get ready to start the rebuild here is some photos from what has been done so far.

In almost all cases parts started in the tank, then cleaned and polished by hand, then back to the tank, then cleaned with carb cleaner, then back into the tank, then polished by hand again, then back to the tank...well you get it. BTW, I dont mind cleaning and polishing by hand, I find it therapeutic and I get up close and personal with the part

[OldManMo]

The IMS took lots of nice gentle work but ha come up nice. Lots of nasty sludge came out from the inside but more so when I used a bottle brush to get to the end






Will still go through one more round of cleaning before I fit it

[OldManMo]

Crank took some time also and I found a lot of sludge and a small piece of plastic in the oilways. The journals where hand polished. I used 10,000 grit wet and dry on the heavily soiled journals. The specs where in line with what is published else where on the net. It has been crack tested, but will have it tested once more and run through final cleaning just before fitting

This is how I started




after a few round in the ultrasonic bath




And a number of hours later by hand

[palindrome]

Love watching the progress. What type of ultrasonic machine do you use?

[OldManMo]

Originally Posted by palindrome

Love watching the progress. What type of ultrasonic machine do you use?

Thanks @palindrome

I have a totally rubbish one as it went bang on Friday waiting to hear back as to replacement hence why I don’t want to say the make

When it worked It worked well. It was a home unit, 30L, 800w ultrasonic 600w heat but it did run both 28hz and 40hz which helped. Cost about £300

Going forward I think I am going to go bigger and more powerful though still limited to single phase unfortunately. Cost goes up significantly once you get around 50L and higher, but you get what you pay for

Ultrasonics are awsm. I have some great videos showing a parts which were cleaned using carb cleaner, degreaser, vapour etc then within 20secs in the bath (temp around 50-60 degrees C) and the crud that comes from out is amazing. Especially from internal parts for example the oilways of the camshaft.

Its a little mesmerising, like a lava lamp. You are watching the part and nothing really happening then in a split second this wisps of oil, oxidisation, etc just start coming off the part.

Below is a screenshot of one of the vids I had. The pipe was cleaned using carb cleaner and degreaser for about 10mins, outside looked like new, within 20secs the caked on oil inside started to cloud away. I put a snake cam into the first part and it was spotless




This is another screen shot of the IMS, lots of cleaning an polishing and the inside I cleaned using carb cleaner and a large pipe brush. The photo below shows the clouds of "stuff" coming from the inside. This dislodges some particulates which must have been caked on inside the ims.



Another great example of what is possible is the sump cover, vapoured, carb cleaner, pressure washer and again look at the impregnated crud coming off



My learning is to go as big and as powerful as possible. I now have two small units, which though are ok for small parts like nuts and bolts, are not really useful for otehr parts.

Also, learnt the hard way, the detergent or degreaser is important, had to replace some alloy parts which the detergent/degreaser, may in combo of the ultrasonic made them unusable. I now only use a sensitive metal detergent at the exact mix ration and I am getting some great results and ofcourse a rinse tank with anti flash added.