The dreaded dilivar head studs?
 

My 83 SC snapped a few head studs last month and I was quoted $4,500 to make things right again. I thought I'd give it a shot myself even though I'd never removed an engine before - that's the kind of optimist I am. Working alone, the engine came out in 6 hours using Wayne's nice step by step guide...a helper would have been nice on the lowering part, but sometimes a man has to work alone ;) I stripped the engine down in about 4 more hours until the 19mm bolt on the cam shaft stopped me cold. Ronnie's.930, who lives just on the other side of the lake from me, was kind enough to loan me his P237 tool and I was able to remove the cams, rockers and cylinders in 2 hours. I decided to save the dreaded head studs for a fresh new day...today. I went to Lowes to arm myself for the battle - oxy/mapp torch, 2' leverage pipe, 10" pipe wrench. It turns out I was over prepared since all 12 dilivar studs came out without heat or leverage. I just used the little 10" pipe wrench and spun them out almost effortlessly. I guess, when it comes to head studs, it really is a lottery, but by the time I extracted the last six studs, I had it down to one per minute. I did use my grinder to flatten a half inch section of the threads so my pipe wrench could get a sure bite, but even with the grinding, the whole process took about 15 minutes.

I'm not trying to gloat over my luck or brag about my mechanical prowess (since I'm an average shade-tree mech at best)...I just wanted to share one non-nightmarish head stud experience to help balance out all the doom and gloom posts that almost scared me away from the job.

The moral of this story is that one guy with no experience and limited tools, but with Wayne's guide can remove and disassemble an SC's engine and remove the head studs...by himself. Now, if that guy can reassemble and reinstall said engine remains to be seen. I'm planning to get on that by the weekend if Pelican ships my new studs, rings, gaskets etc. by then. Wish me luck.

Luck!

Keep us posted.

I have some new studs if you need them at a good price

Great.

Hopefully you have a pics time line and posting some pics would be good.

Now is the time to get the valve job done.
Bruce

You were lucky to have enough remaining broken stud existing to remove with the pipe wrench. Good luck with your re assemble.

Thor

Agreed...I was fortunate. All three were broken at about the same place (about two inches down from the barrel nut). Two on cylinder 4 and one on cylinder 3.

This whole thing started out as a valve job ;) It'll be much easier with the engine out in the open. I'll be doing the cam timing before that...this is quite the education.

I had my GoPro HD cam taking pics every 60 seconds, but I've had difficulties uploading to this forum - it's obviously more complicated than headstud removal ;)

PM sent

Thanks...will do.

Dirty, naked Porsche engine porn
 

For those who are interested in photos of this project, the following link will take you to more than you want.


Free Cloud Storage - MediaFirehttp://forums.pelicanparts.com/uploa...1340764014.jpg

How my SC looks on better days (i.e. with its motor installed).
 

Links to many more pics:
Free Cloud Storage - MediaFirehttp://forums.pelicanparts.com/uploa...1340764568.jpg


Free Cloud Storage - MediaFire

Great looking car!

PM sent.

Thor

Do you have Alusils? If yes did you rering them?

Use Supertec Studs.

I went with the OEM stainless from our host...the car has 85K on it so, when it's time for the topend rebuild in a few years, I may revisit the studs along with some performance upgrades, but right now, I'm more interested in getting the car back on the road.

Yes, they are Alusils...
 

and no, I'm going to follow Wayne's advice and stay with my original rings (with the exception of the oil ring on cylinder 1 which was found to be broken). I would have liked to have left the pistons in the cylinders, but just couldn't manage to make it work out that way.

Plain steel OEM studs are plenty good for a std street engine build. They never seem to break.

For future reference, you shouldn't have to grind flats on the studs to get them off with the pipe wrench. A pipe wrench is specifically designed to bite into round surfaces. I know the stud is small in diameter. But if you get the pipe wrench closed down as tightly as possible on the stud, it'll bite. The harder you pull on a pipe wrench, the harder it grips.

Looking at the pictures, make sure to take a look at the input shaft seal on the transmission (behind the shaft tube). That trans housing is very wet looking.

Engine looks like it was really dirty as evidenced by all the dirt on the cam towers behind the valve covers. In hindsight it would have been good to wash the engine before you disassembled too much of it. As it sits now, you have to be very careful about avoiding dirt & crud from getting into places you don't want it.

There's a ton of dirt on top of the case and the heads and towers really need a good cleaning. Doing so will help the engine run cooler. The 911 needs every bit of air cooling you can give it and dirt does a great job of insulating the engine instead of allowing the alloy surface area to do it's job- release heat to the atmosphere.

Nice BMW 540? I had a E39 M5 for a while. Fun car. Way more horsepower than anybody really needs........

All good tips...thank you.

When I tried to remove the studs with the pipe wrench, it was very slow going since it would only bite once out of every 20 or so attempts...so, I bought a smaller pipe wrench thinking smaller jaws would provide better bite, but same result. 10 seconds with a cutting wheel and the stud had a nice flat spot to bite and the job was done in minutes. I was going to toss the 29 year old corroded dilivar studs anyway, so I didn't care about rendering them useless.

The original plan had been to remove the engine and take it to a mech to have the studs removed, but once I got it out, I just kept working on it. I should have taken a break to clean it, but it was apart before I knew it.

Oh yes, it's a 540is in the background...my favorite of the BMW's I've owned. I'll probably keep it until the wheels fall off ;)

Stock steel head studs never break but in turn they rarely seal properly with a Nikasil cylinder.
They don't offer a consistent clamping pressure adequate to prevent head movement under load conditions at all temperatures
Without doubt, the Supertec head stud offers the best/most stable platform for all types of air cooled 911 engines.

The engine below was built (by someone else) with steel studs 23000 ago. No studs were loose during disassemble and you can clearly see the head movement.

http://forums.pelicanparts.com/uploa...1340919438.jpg
http://forums.pelicanparts.com/uploa...1340919532.jpghttp://forums.pelicanparts.com/uploa...1340919647.jpg

Good job!!!!
 

You did pretty well dropping the engine by yourself considering this was your very first attempt. Any particular reason why you removed the engine without the transmission? Putting it back would be a challenge doing it solo. One thing I noticed after looking at those pictures was the absence of an engine holder/stand. I'll give you A+ for your effort and determination. Keep us posted.

Tony

Thanks. The shop I wanted to use had more than a month long waiting list to take the whole car, but said they could take the pulled engine right away (they only take as many cars as they can shelter indoors - which I like, actually). So, I figured that was all the excuse I needed to tackle a job that's tantamount to a rite of passage for an older 911 owner. The guide I followed suggested an engine only removal and that made sense to me given my objective...and I figured, since I'd be working alone, a lighter load to manage would be preferable. I just moved to a new neighborhood and don't have the sort of neighbors (or relationship with them) that would allow me to ask for a hand, my friends from work aren't the sort to get their hands dirty and the rest of the people I know are all girls (which is fine for everything except engine removal - no offense to any females).

I didn't get an engine stand since the plan was simply to remove the engine and take it to the shop, but my ambition outpaced my planning and before I knew it, I had it down to the block...and now, I'd like to see it through. I recognize that proper assembly is the more nuanced and important phase of the project and have been appreciating all the feedback, tips and advice this forum has provided.

I'm expecting rocker reassembly and cam timing to be the most challenging parts and if, at any time I feel the requirements exceed my abilities and that moving forward on my own might compromise the quality of the build, the shop option is always open to me.

I expect remounting to be really challenging and am working on a more stable way of supporting the engine than the 2x4 and floor jack method that I used for the extraction.

You've done the most difficult part.........
 

Ducatist,

You have done the most difficult part of engine rebuilding!!!! That's taking the engine off the car by yourself and doing it with the transmission left behind. You have removed the broken dilavar studs, the rest are easy. If you have the time and interest to do the engine rebuild, I'll strongly suggest you do it. You have demonstrated your ability to do work and the determination to overcome a difficult task. So why deprive yourself the joy and satisfaction of engine rebuilding?

The rest of the engine rebuilding could be done almost sitting down while enjoying your favorite beer during the process. Get a few reference manuals like Bentley and Wayne's Engine rebuild book, some metric tools, etc. and you are on your way to your first engine rebuild project. In case of doubt, simply post a question in this forum and you'll have the answers in your finger tips.

There is really nothing difficult about it if you use care and prudent judgement. The most hardest part is overcoming the fear and anxiety of the unknown territory (engine rebuilding). Once you have decided to do it and take that extra step forward, the rest of the way would be smooth sailing. Think about it before you bring the engine to your mechanic. I will personally assist you in my limited capacity that you succeed doing the project. Keep us posted.

Tony

+1, when time comes I'm looking forward to it.

All

Please note that no matter what book you have always check for corrections. Here is the link for Waynes one: How to Rebuild and Modify your Porsche 911 Engine: Corrections & Updates

Thanks for showing the in-service performance example of the steel studs Henry. Good to know for future service on my engine.

Engine update
 

Almost all of the parts are in from our host...should be able to start the reassembly later this week. I damaged a piston during disassembly and had to order a matching replacement (rookie mistake), but otherwise, it's going well. New SS head studs are installed and the rest of my time has been spent cleaning stuff. That carbon buildup on the pistons is a real pain...finally used some POR15 caliper cleaner and wished I'd been using it all along - melted the stuff off quickly.

http://forums.pelicanparts.com/uploa...1341288888.jpg

Considering the age of this engine I think it would be folly not to split the case and do a minor refresh. Your going to be real mad if the pick-up tube seal fails next week and you lock the motor up.

I would worry about the o-ring that seals the # 8 main bearing.
With time they get hard and leak, especially after an engine R&R. This leak requires a case split and o-ring replacement to properly repair the leak.

Thanks again Henry. I appreciated all the time you spent with me on the phone yesterday...your insight and advice were very helpful.

I am in about the same spot. Waiting for an intermediate shaft timing chain gear from our host to glue the case together. I also had a damaged piston, (1). Had to go off board to procure that. Does your passenger side oil tray in your chain box have a groove cut in it from the chain? That is why I am rebuilding. Tensioner failure. Aluminum in the engine. Good luck. Mike.

This may sound dumb but i don't see what you mean by the "movement" from using the steel studs. Please explain!

Not really... And I'm also like to hear the details

As illustrated in post 22, the steel studs offer inadequate clamping pressure to keep the heads from moving excessively. This constant movement results in poor if not horrible head to cylinder sealing. Dilivar head studs show the same type of sealing anomalies under high stress situations.

Speed Buggy,

Mine had three broken headstuds, but everything else looked and ran fine. My tensioners have the saver collars from our host which are supposed to prevent the kind of damage from tensioner failure that it sounds like your engine suffered.

Where did you end up finding your piston? I've been working with the guys at EBS Racing since last Friday and they told me they're sure they have one that matches mine, but they still haven't managed to actually pull it from stock. I guess the holiday put them behind or something. Hopefully, they'll turn up the piston soon since it's really holding me up. I have the Alusil pistons that some of the builders just throw away rather than reuse, but the guys at Parts Heaven charge $150 per (EBS is only $50) and like I said, some builders just sell them as aluminum scrap. Apparently, my damaged piston is a little uncommon based upon the dome markings.

http://forums.pelicanparts.com/uploa...1341517066.jpg

Darn. I was planning on spending my money on a set of steel studs, but i guess after reading this I'll have to go with the more expensive high performance studs instead.. I don't wanna risk having problems down the road.

I got mine at Parts Heaven. Couldn't find anywhere else. I had a couple of maybe's but they fell through. My machine shop recommended P.H.

Still having no luck finding a matching piston
 

So far, none of the places I've searched (EBS Racing, Parts Heaven and Henry Schmidt) has a replacement piston to match my damaged one. Buying a whole set seems like overkill and I'm told the difference between a "1" and a "3" piston is less than .001"...so, I'm pondering buying a "2" since no "3's" appear to be available. Either way, I'm stuck until I find a solution.

Here are pics of my piston and cylinder markings...any advice would be welcome.

http://forums.pelicanparts.com/uploa...1341959772.jpg
http://forums.pelicanparts.com/uploa...1341959787.jpg
http://forums.pelicanparts.com/uploa...1341959820.jpg
http://forums.pelicanparts.com/uploa...1341959841.jpghttp://forums.pelicanparts.com/uploa...1341959921.jpg

One thing I would suggest is for you to create new threads, here, in the 911, and in the parts for sale & wanted forums requesting the piston you need. I remember a while back someone needing a piston and a member, maybe MBurns, said he had a wide variety of them . . .