Hello,

I need to have my crankshaft machined and am curious if it's thought that it should be re-hardened? The shop doing the work said that Porsche's crankshafts didn't require it because their hardening is fairly deep compared to other makes. Any opinions on this out there?

Thanks!

Rick

 

cranks ain't the problem.

it's the uber snarky German engineering, petulant engine, lousy oiling, no starts, running hot and sharded belts that KILL you.

 

Are you suggesting we drive electric?

 

I think the general consensus is that you can get away without hardening if you only take .010 off it.

 

That's why I'm going to run two oil pumps and spring-loaded valves to get around those issues

 

I'm sure that if you want to do more to the crank after machining, you can.I'm sure that your machine shop has access to cryo stress relieving vendors. After that, if you wish you could get it re-hardened by getting it to a re-nitriding vendor..just costs $$...You might also want to check with a local gun shop..They use these procedures too.

 

Personally, I'd have it nitride hardened if you are machining it. It's cheap and you'll never get a second chance. Maybe the better question is why wouldn't you do it?

 

I hope I'm confusing the description of hardening process they're using, because I wouldn't call it cheap. To get the crank turned will be $250.00, and the hardening process is $500.00. I've already got ~$600.00 for cross drilling the #2&3 rod journals.

 

I think you need to find a different shop- the expensive,pro shop I use charges less than half that for grinding and nitriding.

 

I didn't have my crankshaft nitride treated after I had the rod bearings turned and cross drilled. Porsche 944 crankshafts are just about the hardest crankshaft in the world. If you offset ground the rod journals for a longer stricken using Mitsubishi eagle rods like some have some then I would recommend the nitride process.

I can't believe this guy. Totally forgot about the fuel lines cracking and catching the car on fire. If your going to hate at least get the top killers in there.

 

Geebus, i'm slipping.

that's no joke. we lost one of the nicest cars on the forum to the above scenario.

 

I'm in the S.F.Bay area, and choices are extremely limited thanks to ever stricter environmental regulations that have chased away so many machine shops. For the cross drilling, I had to crate up my crank and send it to Lindsey's because no one here would do that at all. There is ONE shop to get the crank turned at, so they get to name their price. They in turn send out the crank to a 3rd party for nitride hardening, which again is a case of 'this is the cost, take it or leave it'.

Right now I'm thinking I'll err on the conservative side and have it done.

 

Why do you need your crankshaft machined? If its bad why don't you just use another good crank?

 

My crank as is with standard bearings was going to have clearances between .003" and .004". That's within service limits, but who's interested in putting together an engine that will be in well-well worn condition from the beginning? I'm shooting for .0015". And then I'll probably get the bearings coated, which will tighten it up another .0003".

I was going to run the crank as it is, but then the loose clearances began to bother me...AFTER I spent all that money on getting it cross drilled. In the end it'll just keep pushing back the date of completion, which has no deadline anyway. It could be in 2016, or 2017...

 

Odurandina will show chebby v8 down your throat if you don't complete it next week.

If you need good crank, I have at least 3 good 2.5 cranks and will give you one for cheap.