FYI: Official Alien Build thread Started 2003, Alien Resurection is underway. Boxster Transaxle Update for 914 Day Options

[rick 918-S]

Can't remember or find in this thread, is your 901 essentially a 4spd or are you able to make use of 1st?

I use 1st gear but I don't hammer it. (IMG:style_emoticons/default/huh.gif) That could be bad.

[rick 918-S]

Couple things I am figuring out. The custom flywheel I made and the stock 928 flywheel are the same from the crank surface to the tranny side on the ring gear.

[rick 918-S]

[rick 918-S]

I have two builds going at the same time. Af4ter pulling the engine out of the Alien because I thought it locked up, then discovered it was only the starter stuck in the flywheel, I decided work on upgrading the 901 to a Boxster 5 speed. I figured I would have less of an issue with the starter if I went back the the original location for the 928. The starter lived on the block side under the oil pan.

So I sourced a start mount and starter first. BTW Pelican is crickets and Rennlist has some great guys and others make posts that could seem like insults if you don't have a thick skin.

I fished for information on both sites. in my usual impatient manor I jumped in the deep end and just started buying used parts to get an idea of ring gear spacing and clutch size. I purchased a 928 Auto flywheel shown above. My thought was to use the ring gear on the custom flywheel I already have.

But then I purchased the 928 manual trans Flywheel with a single dis clutch and pressure plate used from a salvage yard in PA. when it arrived I was both disappointed then elated. The flywheel is actually the clutch disc surface and the trigger wheel for the ignition. The pressure plate is the massively heavy contraption that bolts the the trigger wheel and has the ring gear attached. I will be sending this off to the bin.

On the other hand the Auto flywheel has the ring gear attached and is the correct distance away from the block for the use of the 928 starter. I decided to set the 928 manual trans flywheel with trigger wheel on top of the auto flywheel. The match up was perfect. There is a slight step on the face of the auto trans ring gear. The trigger wheel dropped into the recess perfectly. So this will be the foundation for the next flywheel.

[rick 918-S]

I also finished one side header.

[tygaboy]

Lovely header!

[Root_Werks]

That header turned out nice!

Really interesting discovery on the flywheel differences. Assume you'll have to still mod to make work?

[rick 918-S]

That header turned out nice!

Really interesting discovery on the flywheel differences. Assume you'll have to still mod to make work?

Yes, Part 1 was learning about the distance the ring gear is from the crank mounting surface. The Auto flywheel afforded that answer. because it is also the same depth as the custom flywheel I had made for the 901 it also answered the question I had about how deep the adapter plate would have to be to clear the ring gear.

Part 2 was learning about the manual trans style flywheel and clutch kit. It clearly
would not be usable with the Boxster transaxle.

Part 3 is blending the two to make a flywheel with a ring gear that will line up with the starter and be shallow enough to limit the adapter length to 1".

The next step is to get a Boxster clutch disk and pressure plate to start mating the auto flywheel with ring gear, the manual flywheel to the auto flywheel and the Boxster clutch/pressure plate to the hybrid 928 part. (IMG:style_emoticons/default/screwy.gif)

Step 4 start figuring out the input shaft to pilot bearing distance.

Oh and I still need to find a machine shop. My old neighbor at my old house owned a large machine shop. He had one of his guys make the last two for me. I think he has retired by now. (IMG:style_emoticons/default/dry.gif)

[rick 918-S]

I just thought I would post a small update. I thought the starter would be a simple hurtle as the 928 block has one of these bolted to the back side of the block.



Or so I thought. I contacted 928 International and asked Mark to ship me one. I told him it was for my 1980 Euro Spec S engine. He says. "They didn't have one" I said, "mine did" ... He say's $ 75.00. I say " ship it!"

Well, never question someone that has lived and breathed 928's since they were made. Turns out Porsche Changed starter mounting system. Which means they changed the block casting to accept the steel bracket. Ya, they changed the block casting entirely. (IMG:style_emoticons/default/dry.gif) Turns out I need this design.



I think I located one. I have to tell you. the 928 guys are not like us 914 guys at all. Finding used parts to experiment on is tough. This is a small setback but I have a plan.

I was speaking with Clay about the spacer he used for his flywheel. He told me he may have a Boxster clutch disc and pressure plate i need to move forward with the clutch design. That is going to help.

[rick 918-S]

Update for 914 day. I found a machine shop that took on my flywheel project. I hope to have it back soon.

I have been working out the adapter plate. This will be very challenging as most of the bolt that fasten the Boxster transaxle to the Boxster engine end up on the path of the ring gear. I have a few ideas how to get beyond this but I need the flywheel back before I can move on the next phase of the adapter plate. Here is what I have been working on.




No one makes a adapter for anything for the 928 engine. It is up to me. I checked with a machine shop and sent them the diagram Clay shared with me for the Boxster bellhousing bolt pattern. The guy quoted me $ 2300.00 to pop the holes in a 1/4" aluminum plate and cut out the inner and out radius. And 10 weeks to get to it. NOT!

I have about 2 hours in figuring out the two patterns. Once I have the flywheel back this will be a cake walk to finish.

Here is the adapter I made for the 901 install.

[Root_Werks]

$2,300 seems a bit steep. Fabbing your own shouldn't be too much trouble given your mad fabrication skills.

(IMG:style_emoticons/default/smile.gif)

[Chris914n6]

My Nissan to 901 has a step in it and was the first for KEP to cast as it is ~1 1/8" thick. I have to mount the fly before the adapter.
My Nissan to Suby will be 2 layers @ 5/8" because a 32mm piece was extra pricey.

HTH

[rick 918-S]

My Nissan to 901 has a step in it and was the first for KEP to cast as it is ~1 1/8" thick. I have to mount the fly before the adapter.
My Nissan to Suby will be 2 layers @ 5/8" because a 32mm piece was extra pricey.

HTH

Mine will be 3 layers. 2 -1/2 aluminum plates to get out past the flywheel and 1 - 1/4" plate that mounts the Boxster transaxle to the 2 - 1/2" plates to start. Once I get the prototype worked out I may have one machined. But as you are aware the diameter from 901 to Suby is different.

This becomes an issue at least in my case with fasteners holding the Boxster transaxle to the adapter ending up in the path of the flywheel. I just resolved that yesterday. More on that later as I get further along.

Just ordered a Boxster Clutch kit.