C4S993

Are you grinding the crank mains down maybe .1thou and using .1 oversize main bearings ?

trophy

Hey Reiner, Get some close up pics of the #4 and #6 journals for us...

lopro

where did you get the engine holding fixture for the engine stand? I have read a few threads recently were it seem everyone owns one of these fixtures.

ReinerFink

The grey P201 tool was borrowed. Had to machine the Al collar to get it to fit in the wonky harbor freight stand I bought.

zdmac has them for $225, I believe.

-reiner

ReinerFink

The camera I am using is terrible - it belongs to the kids I assume you mean the rod journals, not the case ones...

For cylinder #4:


And cylinder #6:


-reiner

ReinerFink

I'm going to let the machine shop do the legwork on this. I'm dropping it off on Monday and I'll have them assess the crank and we'll take it from there...

For those of you in the Seattle area, I am using C&D in Totem Lake. They come highly recommended and I have been very impressed with my interaction with them up to this point.

-reiner

Ed Hughes

Toss the blue ones-they tear too easily. Get the GREEN Viton versions.

Mike J

I would not do this unless I really needed to - the hardening process that Porsche uses on their cranks is hard to duplicate .... think it was called "tennifer treating" using a cyanide salt bath - just going by memory here....

Cheers,

Mike

Mike J

Great advice! Use the Wrightwood Racing gasket sets - they are all Viton - much hardier and just plain better than the stock ones....

Cheers,

Mike

Steve Weiner-Rennsport Systems

The factory journals are nitrided.

Mike J

Ok, but the core question was can a crank be turned and re-treated to be as good as original, or is it better to look for a good used crank?

I know there are companies around the US that can go various nitrating processes, but how do they compare to the original factory process? Any side effects to the crank (like issues with the factory plugs?).

Cheers,

Mike

Steve Weiner-Rennsport Systems

Yes,...there are a FEW outfits that do these critical procedures correctly and have proven to be quite durable after 30+ years. No issues with the factory plugs provided that everything is done properly.

While I've not had to use machined cranks in 3.6 race engines, we do this all the time for smaller motors when we machine them for smaller, NASCAR race bearings (FAR better than any Glyco). Such things have been quite reliable at RPM's exceeding 8500.

Its not cheap to do all this so with street engines needing work, it may be less expensive to source a good used, standard crankshaft.

ReinerFink

During a weekend of nice weather, I decided to break out my Xenit (courtesy of the fine folks at FD) and get to work:



7 hrs of work for both case halves. Yikes... please someone tell me that the other parts are easier to clean

Mike J

That looks great - you also flush out all the oil passages, etc?

Cheers,

Mike

ReinerFink

Not yet...

I have not order the plugs and the factory manual says its only necessary for a spun bearing or the like. The same thinking goes for the oil spray tubes in the cam housing -- I could order the Al plug, drill/tap/remove the pressed in sheet metal, just to get to the tube and clean it when it should be fine.

On the other hand, I splurged for some 0W-40 synthetic oil for my 20min break-in period. I wanted something that will exit the car so quick that it will drag any crud with it.

Im open to expert opinions on the issue (I know you did do yours Milke, then again, you have a Parts Washer and all I have is hands with no fingerprints right now...)

p.s. What air pressure did you need to blow the brake clean out the piston squirters?

-reiner