Dougs951S

The shop called me today to let me know the head would be ready this friday...54 days after discovering the crack. I did end up getting a new head gasket/cam tower/head nuts and washers set from the shop, and the the new head paid for and rebuilt for free. It's been a huge pain in my side, but at least the shop owner is standing by his work and doing the right thing. Here's to no more delays, I hope..

elanman

If the machine shop you use can't monitor force as they are pushing out guides don't use them. Its simple you exceed the allowable stress(300 MPa) in the Alu it will break,It is probable less bearing in mind fatigue of cyl head Alu .Can't remember the KN load allowable but if interested I could find it or work it . If load looks close to limit drill out until thin wall and collapse.The rest is all detailed in the Porsche manual you can't make a mistake
Right down the instructions and measure yourself,give the machine shop your measurements .Modern digital instruments are use (rem fractions on a vernier!)
Don't let them near your head most of them are useless!

Dougs951S

question for yall. the shop wants to reuse the guides that I previously purchased, the ones that caused my old head to crack. they have 0 miles on them and the shop says they can get them out with no damage and reuse them. Shoud I allow this or press for new guides installed (again!). I dont see an issue with reusing them personally since they're brand new.

968workaholic

If they were pressed in hard enough to crack the aluminium casting, I wouldn't trust their integrity. Your this far already, why take a chance now

Tiger03447

No telling how they might have been distorted during the pressing..After they press the guide, I thought that they had to be reamed to eliminate any distortion that may have been incurred during the pressing. Please suggest that they chill the guides a bunch prior to pressing or heat the head (or both) to eliminate further problems...just.02 cents..and BTW, talk with the shop owner for their procedure of installs..maybe their machinist(?) didn't follow proper rules to start with. If you still feel that something might be wrong with the guides, use new ones..to eliminate any doubts. Hope this might help some.

elanman

New guides everytime. If they are Porsche guides they are made of cheese but it allows the valves to be reused ,Make sure you polish the valve stems if you are re using the valves
Machine shop you are using are jokers Don't let them near any auto engine stuff maybe a train diesel engine