Stud/bolt preload is a wonderful thing! Iirc, as a rough rule of thumb, 5T/d for dry, 10T/d for lubed (really depends on the friction coefficient, mu). It’s all about the clamp-up! 😀
Nice step by step non-rushed reassembly. I can't wait till you get it back in the car an fired up for the first time! Seeing your videos makes me want to drive my 85 911, but it's winter here and she stays safe in the garage until spring. Keep up the great videos!
There is a worthwhile and cheap upgrade you can do, you probably have already heard of it. Its a fitting on the outside of the engine if i remember correctly its on the return oil line from the head. It actually restricts the flow of oil returning to the crankcase reducing oil frothing and increasing lubrication of the valve gear. You will also see a significant increase in oil pressure displayed by the gauge.
Yes, I'm familiar with the oil line restrictor. It replaces the fitting that I connected my garden hose to. Garden hose pressure is about 40 psi and I was amazed how much water came out of those squirters. It went over 6 feet high. Oil pressure is higher than 60 psi although the viscosity is much higher. I think it is a good idea to reduce the oil flow here for the frothing reasons you mentioned. I will install these.
Surprised the studs are not titanium or some other exotic metal. Without head gaskets, taking up any gaps, surely could be unpleasant. Are those the stock cams?
Porsche did design an exotic stud called Dilivar. Most of them are broken by now. It was an effort to match the thermal expansion to the aluminum cylinders. Yes, those are stock cams
Loving this head rebuild project Tom. Especially the details/assembly height checks to ensure the cam doesn’t bind. Maybe I missed it but how did you determine that your cylinders are Alusil (vs Nikasil)? I’ve read that the number of fins can be used to differentiate. Is that an accurate method? Also just want to confirm that you only used copper gasket sealer between the cylinder / casing seal surface. Trying to learn and absorb as much knowledge as possible before I perform this same process. Thanks.
Thanks! Let me guess your engine has bad valve guides too? My cylinders are stamped KS which is the manufacturer that only uses Alusil. Mahle is Nikasil I used the spray gasket sealant on the base gasket. Sealant here is optional. Some people use Curil T2 on the cylinder base which is also good, but my god that stuff is for gaping gaps. See you on the next one
Tom: One question. I was taught compressed air has moisture in it. Is that a concern, particular when using it for the final clean? Thanks for all the videos, excellent information.
Thank you. Yes compressed air has water in even though I have water traps/filters on my air hose lines. I don't think it matters. For gasket surfaces you can wipe with isopropyl alcohol if you want to clear moisture off. Engines create water when they run as a normal byproduct of combustion. No big deal if you ask me. I'd rather clear any debris or lint that might get left in the engine. Very high pressure is pretty effective at cleaning.
I only removed one cylinder for inspection. To me it's easier to clean them on the engine with cylinders so they don't flop around. If it's a full teardown, then it would be easier to have them vapor blasted after removed from the rods. Good question and I'm sure there are a dozen ways to do it. My opinion is that most shops only do full rebuilds because this type of cleaning is a time sink on a partially assembled engine.
20 Tons per side on the head studs! Is it only me who ponders this stuff?
Stud/bolt preload is a wonderful thing! Iirc, as a rough rule of thumb, 5T/d for dry, 10T/d for lubed (really depends on the friction coefficient, mu). It’s all about the clamp-up! 😀
Really appreciate the long format "how to", keep up the good work!
The level of craftmanship and information is impressive, thank You.
Nice step by step non-rushed reassembly. I can't wait till you get it back in the car an fired up for the first time! Seeing your videos makes me want to drive my 85 911, but it's winter here and she stays safe in the garage until spring. Keep up the great videos!
Thanks, I hope you can enjoy your 85 soon! I can't wait to start this up. I'm not sure if I will start it on the engine test stand or in the car?
Satisfying indeed. Impressive to watch your meticulous approach to reassembly. Thanks for sharing with us!
Love the water feature @12:20! Seriously, really enjoyed your attention to detail on the assembly. 😀👍👍
Almost got my neighbors wet!
There is a worthwhile and cheap upgrade you can do, you probably have already heard of it. Its a fitting on the outside of the engine if i remember correctly its on the return oil line from the head. It actually restricts the flow of oil returning to the crankcase reducing oil frothing and increasing lubrication of the valve gear. You will also see a significant increase in oil pressure displayed by the gauge.
Yes, I'm familiar with the oil line restrictor. It replaces the fitting that I connected my garden hose to.
Garden hose pressure is about 40 psi and I was amazed how much water came out of those squirters. It went over 6 feet high.
Oil pressure is higher than 60 psi although the viscosity is much higher.
I think it is a good idea to reduce the oil flow here for the frothing reasons you mentioned. I will install these.
This is awesome!!! you are a wizard, my friend!
Great work as usual. Love your attention to detail.
Great video Tom... it's amazing how similar it is to the 993 generation of flat sixes. Looking forward to the next one!
Good video. I really appreciate the detail that you put into your videos. I'm looking forward to part 7.
Thanks, these engine videos are very informative and enjoyable to watch!
Very good info, thanks for taking the time and doing careful work!
Yes you got that right
Thank u
Acetone crosses the blood-brain barrier, so do not let it touch your skin. time to glove up! I really enjoy your videos, thanks
Thank you for the reminder! Acetone is strong
Thanks for the tip, I like my brain just the way it is!
Great work, very thoughtful. BTW, Dilavar, not Divalar.
Thanks, I always get that Dila-dud thing backwards, ha ha.
Surprised the studs are not titanium or some other exotic metal. Without head gaskets, taking up any gaps, surely could be unpleasant. Are those the stock cams?
Porsche did design an exotic stud called Dilivar. Most of them are broken by now. It was an effort to match the thermal expansion to the aluminum cylinders.
Yes, those are stock cams
Loving this head rebuild project Tom. Especially the details/assembly height checks to ensure the cam doesn’t bind. Maybe I missed it but how did you determine that your cylinders are Alusil (vs Nikasil)? I’ve read that the number of fins can be used to differentiate. Is that an accurate method? Also just want to confirm that you only used copper gasket sealer between the cylinder / casing seal surface. Trying to learn and absorb as much knowledge as possible before I perform this same process. Thanks.
Thanks! Let me guess your engine has bad valve guides too?
My cylinders are stamped KS which is the manufacturer that only uses Alusil.
Mahle is Nikasil
I used the spray gasket sealant on the base gasket. Sealant here is optional. Some people use Curil T2 on the cylinder base which is also good, but my god that stuff is for gaping gaps.
See you on the next one
Tom: One question. I was taught compressed air has moisture in it. Is that a concern, particular when using it for the final clean?
Thanks for all the videos, excellent information.
Thank you.
Yes compressed air has water in even though I have water traps/filters on my air hose lines.
I don't think it matters. For gasket surfaces you can wipe with isopropyl alcohol if you want to clear moisture off.
Engines create water when they run as a normal byproduct of combustion. No big deal if you ask me. I'd rather clear any debris or lint that might get left in the engine. Very high pressure is pretty effective at cleaning.
Nice job. Safe some old toothbrushes for that type cleaning they work wonders.
For sure, especially in the nooks and crannies of the cam tower.
Would it not be a good idea to clean the piston crowns before fitting them to the cylinders?
I only removed one cylinder for inspection.
To me it's easier to clean them on the engine with cylinders so they don't flop around.
If it's a full teardown, then it would be easier to have them vapor blasted after removed from the rods.
Good question and I'm sure there are a dozen ways to do it.
My opinion is that most shops only do full rebuilds because this type of cleaning is a time sink on a partially assembled engine.
Tom did you have the mike off during the jug installation cause of all the cursing?
Ha ha, I don't talk as much when I'm concentrating. That ring compressor barely worked. I ordered the right size, but it didn't arrive in time
Don't they sell small head shims to get you to specific height desired for spec?
They sell base gaskets that come in .010" increments to change deck height. That's miles bigger than the .001" that I'm sorting through.
@@GarageTimeAutoResto yah. I had to go back and rewatch the bit where you measured the different heads. I thought you were fighting more variance.
Yeah, they were all machined pretty close.
I was just playing with small tolerances to improve the fit