Saving a 906

[Henry Schmidt]

The following are pictures of a 906 engine we brought back to it's previous glory.
The case was the first challenge.

[Henry Schmidt]

The next challenge was the crank. This project came with a stock 2.0 counter weighted crank. We searched high and low for a 906 crank with no luck.
We wanted something special so we replicated a 906 crank.

Here's a factory 906 crank:




Here's what we made:

[Henry Schmidt]

Next the rods.
I wanted to build it with new GT3 Pankl titanium rods but the customer insisted we use the Factory rods that came with it. The set he had was horribly mismatched so we went on the search for more rods.
That meant, X-ray and Zyglow for cracks. Then we took the 10 rods we had and balanced them. Shot peening and re-sizing finished the job. We were also able to locate some NOS small end bushings.
The last touch was new titanium rod bolts and Supertec serrated, flanged nuts.
The same nuts we use on our head stud kits.
The bearings are unobtanium so we sent them to Calico Coating to ensure our best chance of survival.

[YTNUKLR]

Awesome!

[peon77]

That is awesome, I can't wait to see more of the assembly. Thanks for sharing Henry!

[parts4porsche]

Herry,

you said you "Shot peening and re-sizing finished the job"

I have some GT-3 rods(3 sets), but all of them are used and all show some king of wear/abnormal ovalization(egg shape) about 0.02mm (from 0.005 to 0.02mm)how do you feel about those numbers?

also I hear that those ti rods are no good for turbo charged engines even with ARP rod bolts, is it also proceed? engine will be for performance street most of time, and no more than 800hp and no more than 7500rpm

could you please tell me what you would do? use it or not, re-sized is good idea? re-coat the sides to prevent it seize with the crank? what coating would you suggest?

thank you
Tadashi

[tadd]

Henry:
Which process did you use for the rods?

It's my understanding that there is a standard mil spec for Ti, but then there is a different, more aggressive 'refurbshment' process as well. Chris mentioned it in another thread way back. It's supposed to 'zero hour' Ti fatigue by litterally beating the stress risers out .

tadd

[chris_seven]

Tadd,

I have always used these guys UK based operations. They have been in the business for a good many years and do a great deal of work on Turbine and Rotor parts for Helicopters.

Metal Improvement | Shot Peening Success Stories for Aerospace Applications

[tadd]

Henry:
Another question...can you give a rational for using serrated nuts on a Ti rod? This seems odd given the little I know about the properties of titanium.

tadd

[Henry Schmidt]

Originally Posted by tadd

Henry:
Another question...can you give a rational for using serrated nuts on a Ti rod? This seems odd given the little I know about the properties of titanium.

tadd

I use them because they are the highest quality nuts I can find and I use them on every 10mm rod bolt in my rebuilds.

[Henry Schmidt]

The crank and rods assembled. Note the piston squirters. You might also notice that there are no CaseSavers in the mag case. This is possible because of the additional thread engagement offered by the Supertec head studs.
We wanted to use 906 cylinders and custom JE pistons so we bore the cylinders to 81mm (stripping the Chromal coating) and replaced it with Nikasil.

[tadd]

Henry:
Thank you for the reply.

I'm sure they are a quality nut. The reason I asked is the notch sensivity of Ti, which you are well aware of or you wouldnt have peened the rods. Those serrations are going to damage the rod surface...right in an area of high stress.

Are you using a washer or some other way to avoid this? I can't tell from the pictures.

I apprecieate you taking the time to cure ignorance.

tadd

[Henry Schmidt]

[Henry Schmidt]

[Henry Schmidt]

Originally Posted by tadd

Henry:
Thank you for the reply.

I'm sure they are a quality nut. The reason I asked is the notch sensivity of Ti, which you are well aware of or you wouldnt have peened the rods. Those serrations are going to damage the rod surface...right in an area of high stress.

Are you using a washer or some other way to avoid this? I can't tell from the pictures.

I apprecieate you taking the time to cure ignorance.

tadd

The serrations do not damage the surface of the rods and the wide flange offers superior support to standard nuts with or without washers.

[neilca]

Henry,

You picture sequence shows the heads being assembled onto the cylinders prior to installing the cam housings. Since the cam housing to cylinder head interface is doweled and thus unforgiving in placement, shouldn't the cam towers and heads be mated before installing on the cylinders?

BTW beautiful work as always.

Thanks,

neilca

[Henry Schmidt]

Originally Posted by neilca

Henry,

You picture sequence shows the heads being assembled onto the cylinders prior to installing the cam housings. Since the cam housing to cylinder head interface is doweled and thus unforgiving in placement, shouldn't the cam towers and heads be mated before installing on the cylinders?

BTW beautiful work as always.

Thanks,

neilca

Either way works fine. Of course you can't torque the heads until after the cam towers are installed. By installing the heads on the cylinders you can check how even the heads are in relationship to each other. This also allows you to turn the engine over at each step.
This way also makes installing the head nuts and washers far easier. It also gives you a nice working platform.

You might also notice that the cylinders are installed before installing the head studs making it far easier to install the pistons in the cylinder then install the wrist pin and clip. Supertec head studs make this assembly technique possible.

[Raceboy]

Very nice work, seriously!

And very impressive case repair (welding magnesium+machining).

[andrew15]

Thats' some impressive welding skill!

[neilca]

Originally Posted by Henry Schmidt

Either way works fine. Of course you can't torque the heads until after the cam towers are installed. By installing the heads on the cylinders you can check how even the heads are in relationship to each other. This also allows you to turn the engine over at each step.
This way also makes installing the head nuts and washers far easier. It also gives you a nice working platform.

You might also notice that the cylinders are installed before installing the head studs making it far easier to install the pistons in the cylinder then install the wrist pin and clip. Supertec head studs make this assembly technique possible.

I had not noticed the head studs,, thanks for the heads up. That does make sense.