Saving a 906

[Henry Schmidt]

Originally Posted by YTNUKLR

Is there anything special to the 906 trans? It looks different from a 901 outside, but the gear stack looks the same. Is that a one-piece bearing retainer? In 1966?

There are a plethora of differences but your general statement about the gear stack is accurate. I looks similar.
The major difference is the 904 main shaft, gear ratios and the additional oiling hole in the intermediate plate to lubricate the main shaft bearing. This design feature was transferred to the mid-engine transmissions used in the 914/6 but not the 914 /4 cylinder cars.
As you look at the case you will notice that it has extra fins for cooling and structural rigidity. Although it looks similar to the 901 aluminum case, it is in fact sand cast magnesium.
There are also additional bosses for mounting the trans into the chassis. Looking at the shift selection fork you'll notice a large bolt in the center. That is an additional detent designed to aid in rapid shift selection.
Looking through the hole you might be able to notice that the LSD is tiny. It is haft the diameter of the 901/915 LSD ad half the weight.
The output shafts protrude from the differential unlike the production piece. These shafts have an external spline design adapted from the 904.
I believe the flanges are identical to the 904.
The last major difference is the provision for the shift shaft. As you can see, the shift shaft is accessed under the bell housing. this design is different from either the tail shifter or side shifter of the production models.

[Henry Schmidt]

Originally Posted by chris_seven

Great picture - reminds me of a similar photograph in a very early Honda CB72 manual in a chapter titled 'How to Demolish the Engine'

The master technician behind the hammer is the legendary Dean Polopolus (the designer and builder of the Polo 4 cylinder 911 engine).
This adjustment technique proves that "old habits die hard."

[Henry Schmidt]

Originally Posted by dinobx

Hello Henry,

Absolutely beautiful work you're doing. Quick question. I thought we were all supposed to use a five or six arm engine yolk to hold the engine on the stand. Yours is just four arm. Any insight?

Thanks.

Dino

I use only 3 and 4 arm German made yokes. After 30+ years in the business I have never had or seen a problem. If you're buying a cheaper Chinese made yoke perhaps extra reinforcements makes sense. I really don't know.

[Flieger]

What was he adjusting with the hammer?

[BURN-BROS]

Endplay....

[JohnJL]

Hi Henry,

Do you have a pic of the combustion chambers? Those pistons have a huge dome. Whats the compression?

Thanks
John

[Gunzel]

Henery
It appears thgat you are using aluminum chain wheels. The 1973, and later RSR also uses those aluminum wheels. The RSR parts book shows an unusual Porsche part number for the RSR chains. Different from a normal split chain, or non split chain. Do you know why the RSR has a different chain number? Do you use anything special chain wise for the aluminum wheels in your engines,

Mike Curnow

[j911brick]

Originally Posted by LJ851

Henry, what coating/plating are you using on the mag parts? Looks really nice.

I forget what its called but its a standard coating for protecting mag. I think its called gold wash or something. I know you can order it from West Marine. There has been allot of discussion about using it on mag wheels before painting/powder coating. You can do a search. I know we discussed it at length on the NSR forum.

[Gunzel]

James
Apparently you like to answer other peoples questions, INTERNET expert I guess. This is the second question I asked that you have answered, incorrectly. If you insist on doing this, read the question.
What is unique about the 1973 , 74, 75 cam chain? Part # 901 105 529 02, that part number is not the solid or split chain part number. I thought it may have something to do with the aluminum chain wheels since they are the only real unique pieces in the RSR valve train. Anyone have any facts, and not opinions?

Originally Posted by j911brick

I forget what its called but its a standard coating for protecting mag. I think its called gold wash or something. I know you can order it from West Marine. There has been allot of discussion about using it on mag wheels before painting/powder coating. You can do a search. I know we discussed it at length on the NSR forum.

[j911brick]

Originally Posted by Gunzel

James
Apparently you like to answer other peoples questions, INTERNET expert I guess. This is the second question I asked that you have answered, incorrectly. If you insist on doing this, read the question.
What is unique about the 1973 , 74, 75 cam chain? Part # 901 105 529 02, that part number is not the solid or split chain part number. I thought it may have something to do with the aluminum chain wheels since they are the only real unique pieces in the RSR valve train. Anyone have any facts, and not opinions?

Really? I answered the question from LJ851 and not you; and only because Henry didn't have better information when asked. ...and how was my answer incorrect? Incomplete maybe, but I don't think incorrect. Sorry to have to hash this out on Henry's thread.

[Gunzel]

Originally Posted by j911brick

Really? I answered the question from LJ851 and not you; and only because Henry didn't have better information when asked. ...and how was my answer incorrect? Incomplete maybe, but I don't think incorrect. Sorry to have to hash this out on Henry's thread.

J911brick
Sorry, I thought you were answering my question to Henry.

Mike

[Henry Schmidt]

Originally Posted by Flieger

What was he adjusting with the hammer?

Attitude.............

[Henry Schmidt]

Originally Posted by JohnJL

Hi Henry,

Do you have a pic of the combustion chambers? Those pistons have a huge dome. Whats the compression?

Thanks
John

I don't have a picture of the combustion chamber. It looks like an oversight.
The heads are basically the same as a 69 chamber with 12mm plug holes.

The compression was measured @ 10.8:1.

[Henry Schmidt]

Originally Posted by Gunzel

Henery
It appears thgat you are using aluminum chain wheels. The 1973, and later RSR also uses those aluminum wheels. The RSR parts book shows an unusual Porsche part number for the RSR chains. Different from a normal split chain, or non split chain. Do you know why the RSR has a different chain number? Do you use anything special chain wise for the aluminum wheels in your engines,

Mike Curnow

We use the racing version of the Iwis link-less chain.
993-105-529-00/255

[Henry Schmidt]

Originally Posted by LJ851

Henry, what coating/plating are you using on the mag parts? Looks really nice.

Dow 7 is a chemical conversion coating which results in no appreciable dimensional change to the component. The surface of components coated with Dow 7 is changed to a brassy or dark brown finish depending on the alloy.

[Henry Schmidt]

Originally Posted by Zitzit

Hello!

is there any chance to have a picture of the center lube cam to chain housing seals. They are known to be unobtanium and never saw one...

Another question, hos did you do to "replicate" the 906 crank? is that something you are able to make on order? if yes, would you send me details by PM?

Thanks a lot!

olivier.

Seal




The crank was made from a std/std 2.2 911 "S" crank. It can be replicated for around $1.2K if you supply the crank.

[j911brick]

Originally Posted by Henry Schmidt

Dow 7 is a chemical conversion coating which results in no appreciable dimensional change to the component. The surface of components coated with Dow 7 is changed to a brassy or dark brown finish depending on the alloy.

Yep, that what I was thinking of. Also known as "Magnesium Dichromate".


Magnesium protection

[Matt Monson]

I really hope that some day I've got a good excuse to have Henry build an engine for me...

[daepp]

Matt - you will NOT be disappointed!

Hope you don't mind, Henry - it was a great experience (and mine was just a lowly T).

[daepp]