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Unlocking Peak Performance: Porsche Valve Job Results Part 4
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- เผยแพร่เมื่อ 26 ก.ค. 2024
- My Porsche 911 cylinder heads are back from the machine shop and the valve job results are impressive. They resurfaced the valves with a 5 angle seat cut to provide maximum flow and performance. S-Tec also resurfaced the head sealing surface to be in factory spec. Thank you to S-Tec for executing a flawless performance valve job on my 3.2L engine heads.
If you haven't already watched parts 1-3 of my Carrera engine fix project please watch these too:
Part 1 Engine removal: • How To Remove And Diag...
Part 2 Engine Teardown: • Suspenseful Porsche 91...
Part 3 Cleanup Engine Bay: • You Might As Well Clea...
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Straight Edge: amzn.to/48imO50
#porschevalvejob #topendrebuild
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00:00 Introduction Porsche Valve Job
01:21 Measure Head Combusion Chamber Volume
08:11 Measure Machined Cylinder Head Heights
12:03 Remove and Inspect Valves and Seats
14:37 5 angle valve job explained
15:49 Measure valve guide clearance
17:07 Measure Installed Valve Height
21:30 Remove Carbon From Piston Domes
24:04 Checking Porsche Cylinder Heights
25:42 Freshly painted and plated engine parts
![[ไฮไลต์] ฟุตบอลชาย ฝรั่งเศส vs อเมริกา รอบแบ่งกลุ่ม | โอลิมปิก 2024](http://i.ytimg.com/vi/oZ9aSS0NEEg/mqdefault.jpg)
Thanks to S-Tec for doing a great valve job on these heads. Assembly next week!
Kudos to the machine shop for a great job on those heads. I am surprised at the low rev limiter setting. Curiously odd piston dome shapes.
9.5:1 USA pistons.
Yeah the rev limiter is kind of a bummer. I think Steve Wong chips can increase the limit. I feel the rev limiter in Mac all the time.
Blueprint level measurements and assembly. Thanks for taking all the time needed to explain the how’s and why’s of 911 top end precision.
Thanks, I always overkill things that are new to me. The nice thing about doing this for myself is that I can overindulge on the details.
From the vantage point of a camera, it appears they did an outstanding job on the valves and heads. Kudo's to you as well, for taking the time to measure everything to insure it goes back together, not only according to factory specs, but as accurately as you can do it!
Thanks, I'm happy with the work that S-tec did. I know it's not easy, because I've done some valve seat grinding and seat installation before on my 912 heads and it's tricky.
I like to think my careful planning and measurements will allow this engine to run happy for a long time.
The heads and yellow zinc plating look great. Can’t wait to hear and see it run.
You and me both!
Looks like the machine shop did a great job, looking forward to the assembly.
Great video, looking forward to the rest of the series
Once again, a great video, Tom. Are you able to post where you took your parts to be yellow/zinc plated?
Another great vid thanks.
Just saw the comment reply below. Thanks.
For some things we use Mitutoyo inside mikes that measure to four places in some places and Mitutoyo digital calipers that measure to 5/10,000. Looks to me we would be better using analog dial mikes. My fantasy is to have a 12-inch Starrett dial Mike. Don’t need it, just want it.
I had to rotate the head and my head just to read the numbers ha ha.
This would have been better and easier to do on a surface table with a nice height gauge.
That's on my wish list
I'm impressed that these don't use head gaskets.
Correct, no head gaskets. One of the reasons for all the tight tolerances.
Only since you said 5angle like a ton of times, you ought to have looked at Dave Vizards Cylinder Porting head guide. Proof is in the numbers that while 5 angle jobs have their niche and sound fancy, they’re arguably the worst for say your streeter here. An earnest piece of advice….
Thanks, I'll look into his work a bit more. He seems to be a v8 guy with and dealing with shrouded combustion chambers. 911 heads are hemispherical.
I don't understand how softening the edges of a three angle valve is bad for a street engine. It's not that fancy, it's just easier to do now with single point cutters.
Why not get more flow if it doesn't cost more.
Nice work, Tom. I've a 616/36 912 engine to be reconditioned for my 356. I'm wondering if you would you also consider S-tec a capable machine shop for Porsche push rod motors, both case and heads?
Yes, they do machine work for many of the local 356/912 shops near here. I would recommend them. Contact Sheldon and talk with him.
Interesting tool to measure the volume. I'd never seen that done before. Great work. Where did you have the anodizing done?
Yellow zinc chromate by Cadillac plating. They do all my engine test stand rings too.
@@GarageTimeAutoResto good to know. Lots I need to have redone.
Let me know if you want to tag on to my regular parts lot. It saves money to combine and meet the minimum lot charge
@@GarageTimeAutoResto thanks.
Hey Tom, do you need to use different metal gaskets between the cam towers and the head to account for the difference caused by machining?
No gaskets are used between the heads and the cam tower. I'm not aware of any gasket that is .0004" thick. Paper is .003"
The best we can do is measure and sort the parts for the best fit. After that the parts will mush together and be one happy engine I hope.
Metal definitely moves.
@@GarageTimeAutoResto bah, yes! Sorry, I meant the heads and the cylinders.
@MH-ev3wr oh, no gaskets there either on my engine. There are base gaskets that go between the cylinder and the case.
What valve springs do you use.
These are stock Porsche springs. My other 3.2L engine in MAC uses AAsco springs and titanium retainers.
I didn't understand the word for the solvent for removing of the carbon because I am German. Please tell me.
I think he referred to Berryman’s Chem dip. It is a brand name carburetor cleaner.
Correct, Berryman's. It's safe for all metals, but it does eat carbon. Sorry I don't know the active chemical that makes it work, but it's been around forever. I hope you can find something similar in Germany.
Did you inspect all 6 x each port?
Inspect all 12 valve guides? No
Thanks - Looking forward to assembly@@GarageTimeAutoResto
Is there a reason why you didn't rebuild your heads instead sending them out. It seems like a simple procedure. Would you recommend a novice that has never rebuilt a head and does not have the tools yet DIY? Which is cheaper?
I did this for fun and as a challenge to keep my build under $10k.
It's better to take it to a machine shop that does these all day long. Are you in socal? I can recommend a few
@@GarageTimeAutoResto I'm in Alabama.
@bwj1158 I don't know anyone there. Probably best to send out to the West coast
Never assume unless you want to be an a**
Didn't do a three angle valve job