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Wed Jul 16, 2014 9:21 am

I have an older case that is in need of annealing does any one out there know the specifics on what the temp, for how long and what needs to be done after it has been removed from the heat? Other then the machining. If you know of a link please send it my way.

Thanks

Erik

Wed Jul 16, 2014 9:30 am

http://www.geneberg.com/cat.php?cPath=22_505

Case Reconditioning

We are often asked about line boring a case, be clear that line boring does not recondition the case, it only patches it up to go a few more miles. Every line bored case we tested suffered from low oil pressure when hot (with the stock pump), often within as little as 1000 miles. That is the reason people sell huge oversize oil pumps, booster springs and longer relief valves. If the case was properly reconditioned it could use the stock VW pump, relief valves, springs and have normal oil pressure at idle when hot just like it did when new.
When VW reconditioned cases (up until 1968) they did far more than just line bore. To properly recondition a case today consists of; cleaning the case, bolting it together with an alignment bar in the crank and cam tunnel, torquing to stress relief specifications. Have the case stress relieved for 3-1/2 hours and let cool in the oven. When cool, take it out of the oven and re-torque to stress relief specifications and again stress relief for 3-1/2 hours. When cool remove from the oven and disassemble, remove all of the studs and alignment pins, machine both halves of the case flat and reinstall all of the studs and pins and torque to running torque specifications. Now, line bore the crank, and cam tunnel, often back to standard, bore the oil pump, pulley, flywheel seal holes and the cam seal groove. Lastly, the brass drive gear must be cut smaller on the OD the same amount that the 3 and 4 side of the case was machined.
After all this work and expense (far more than a new case costs) you have a case that will only provide 70% to 80% of the life that a new one will (and that's when used for stock applications). The life would be far less with a performance engine. Obviously, VW stopped reconditioning cases in 1968 due to the cost in relationship to the cost of a new case, plus now being assured of 100% of the engine's life, especially if used for higher performance applications. VW could melt the old case, cast a new case and machine it in the new automatic machinery far cheaper.

Wed Jul 16, 2014 9:45 am

Berg wrote that right after aquiring a boat load of engine cases he wanted to sell. He also preached 6.6:1 compression. Don't believe everything that is written. Also why would you want to aneal a case?

Wed Jul 16, 2014 9:56 am

I have a 64 bug and want it to be correct. It may not be sooo hard finding a good used case but they are getting harder to find. The case I do have has been warped a bit and we do have a mechanics that does anneal cases here in Sonoma County. But I was wondering if its possible to anneal it your self. As well as I am just curious about the process. My mechanic will not indulge my curiosity except he makes it hot. I know a great deal about the VW engines, my father knew Gene Burg back in the 60s and 70s this is just one part in I assume many areas that I would like to learn more about.

Wed Jul 16, 2014 10:16 am

When you say "annealing the case' do you really mean to "line bore" the case?

Wed Jul 16, 2014 11:29 am

No, Annealing is heating the case up to a specific temp and a certain amount of time where the molecules return to there original position, this will take a large portion of the warp out of the case, getting it ready for machining. In many cases from what I have been told this can eliminate the machining in rare instances. This has nothing to do with machining.

erik

Wed Jul 16, 2014 12:31 pm

I don't think you will take any of the warp out of the case by annealing. And no, the molecules do not return to their original position. Annealing changes the crystal structure of the material in much the same way quenching does. Quenching cools the material quickly so large crystals do not have the time to form. Smaller crystals result in a harder and stiffer material. When cooled quickly, materials also have a great deal of internal stress that has the effect of hardening and stiffening things up as well. Annealing on the other hand cools the material slowly so that larger chrysalis can form resulting in a softer material. Cooling the material slowly also allows for more movement between the grain boundaries of the crystals as they form resulting in lower internal stress.

Personally, I wouldn't put time into annealing a magnesium case. Sure it it is possible to return the case to its original properties, but the time and money into it wouldn't be worth it. Besides, I would expect a good deal of warpage to take place during the process. The machining to true up the case halves and align bore the bearings is a hidden cost in the annealing process.

When it is all said and done, you could have probably just gotten another case.

Wed Jul 16, 2014 12:52 pm

"Annealing" does not fix warped cases if anything it warps them more. The cost to heat treat the case, remachine the halves , remachine all tunnels etc etc would far exceed the cost of getting another case.

Wed Jul 16, 2014 1:01 pm

I think its just to "stress relief the case"

followed by align boring.

Wed Jul 16, 2014 5:17 pm

vwbugnut wrote: No, Annealing is heating the case up to a specific temp and a certain amount of time where the molecules return to there original position, this will take a large portion of the warp out of the case, getting it ready for machining. In many cases from what I have been told this can eliminate the machining in rare instances. This has nothing to do with machining.

erik

That's called "heat straightening"

Useful to do in some instances.

how far is it warped? and what shape is it warped into?

Wed Jul 16, 2014 8:11 pm

I have personally done this to dozens and dozens of warped case's then line boring the mains and cam saddles but never machining the case halves. It works about 50% of the time but I do not condone it. I did it as a standard procedure in a major VW shop in New Mexico in the 70's when I was working as a machinist for them, I never liked it but it was part of the job I was told to do and arguing against it was pointless. In the years I worked there I never saw one come back but that doesn't mean heating them up to 500 deg didn't permanently cause structure changes as I am sure it did. This shop brought in hundreds and hundreds of cores from over sea's so I guess the owners didn't care to much about them making it 50k. I do not condone doing this unless you are desperate and poor as dirt.

Thu Jul 17, 2014 8:28 am

a bonfire might do a nice job of it.......no dont try it.I personaly think that thinking is flawed. it warps to where it wants to be...so lets warp it back...so it can do it allover again...like bending a wire back&forth....not to good unless you want extra parts. let it take set then machine it straight.fix everything that needs to be fixed then fix the parts that need updating&mods,dont be stupid and think a tiny oil pump will work just fine in the long run just to try to prove a point,thats possiably why the case is afu now.more flow more cooling.let it bypass all it wants it's still cooling as it bypasses the pressure relief. do it right do it once be done and forget about it so you can have fun.

Thu Jul 17, 2014 5:58 pm

Mr.Duncan wrote: http://www.geneberg.com/cat.php?cPath=22_505

Case Reconditioning

line boring does not recondition the case, it only patches it up Every line bored case we tested suffered from low oil pressure when hot (with the stock pump), often within as little as 1000 miles. The life would be far less with a performance engine. r.

Mr Duncan, that is hilarious! Even funnier... some people still believe it!

Thu Jul 17, 2014 6:39 pm

mark tucker wrote: it warps to where it wants to be...so lets warp it back...so it can do it allover again...like bending a wire back&forth....not to good unless you want extra parts. That is exactly what will happen. Aging is all about letting the material decide where it should be - and then machine it straight. Running it as a stocker for a few decades is the trick.

Fri Jul 18, 2014 12:11 pm

thermol cycling is good for almost everything,but the range is importaint . it's amazing how much longer valve spring last when properly heat cycled.

Fri Jul 18, 2014 1:29 pm

VWCOOL wrote: Mr.Duncan wrote: http://www.geneberg.com/cat.php?cPath=22_505

Case Reconditioning

line boring does not recondition the case, it only patches it up Every line bored case we tested suffered from low oil pressure when hot (with the stock pump), often within as little as 1000 miles. The life would be far less with a performance engine. r.

Mr Duncan, that is hilarious! Even funnier... some people still believe it!

Think I would have adjusted the boring bar? Low OP in a thousand miles- Had that happen when a set of internet main bearings had a .020 under center main and the rest were .010. So ya :oops: :oops: now I check EVERYTHING.

Fri Jul 18, 2014 4:11 pm

Automotive machine shops are NOT equipped to 'anneal' anything. They can heat things up to facilitate straightenting but that is not annealing. You would need a serious heat-treating oven for that w/ all the gauges and whistles. That is only found in foundries or machinetool and/or parts productions.

I weld bandsaw blades and the weld area has to be annealed to 'soften' it a bit as it is very brittle after welding. For steels, as soon as it starts to turn hint of 'red' it is done. I turn the lights out when I am annealing the blade as you can overcook it too and take out the hardness on the teeth.

There are plenty of good used cases out there for that early engine. We do not usually keep those cases...so they are dime a dozen. People go after the later cases w/ larger ports and dual-reliefs usually.

Fri Jul 18, 2014 5:23 pm

Erik

Which place here in town does this work?

Fri Jul 18, 2014 6:12 pm

Just off of yolanda Sorens is the guy who does it. here is a links to his contact info https://www.google.com/search?q=Soren+Andersen+Aut...channel=sb

Tell him Erik Paul sent you

erik

Sun Nov 02, 2025 9:14 am

bumping because its interesting