Broken head stud. Feeling sort of sick right now...

[juanbenae]

Originally Posted by sugarwood

Man, I would kill to be able to watch an engine rebuild.
I wished I lived near people who knew how to do this stuff.

I watched and assisted in my motor being rebuilt in my garage by a trusted Porsche tech a few years back. the most valuable thing I learned was that there certain parts of the rebuild I could not be sure I could repeat as best as it could be done... I could physically do all of the work, but much like skills ive acquired over the years in my career they can't be repeated after sharing the experience once. waynes book is a great tool, but I don't think it's as simple as say monopoly instructions before you start the game to follow along with...

I know the satisfaction in completing a project you weren't sure you could do when planned. but a motor rebuild requires a knack, experience from the way you attach the rods & mains to crank & case, to how you most effectively brush the case seal on before you seal it back up. cam timing? liked to have my worked checked.

I paid around 10% of the parts cost for my motor rebuild, got to do a ton of the work myself, but was glad I had the oversight an experienced hand provided.

reading a book or a thread does not make some an engine rebuilder, it makes most of a fool. I salute those that can do the work by reading a book as they go. I do, that's just not me.

[sugarwood]

I totally agree.
I think you have to partly insane to attempt an engine rebuild alone with zero experience and no supervision.
I salute those people, but I don't have the right stuff for that.

It's unfortunate that certain aspects of this hobby are beyond the reach of most people.
Then again, people are attempting to do in their weekend garage what a professional does for a living for decades.
Can you imagine someone trying to do your job by reading a few internet posts with 5 or 6 photos? LOL

[MARISOL78sc]

I agree with sugarwoods sentiments. Good on You if you have the knowledge and time to wrench, I bought my SC knowing a trans build was in the future. 5K including new clutch and incidentals. My question was longevity another 100K was the answer. Im handy somewhat technically savvy but id rather pay the pros I know who offer fair prices than to be laid up for year with a Project car sitting. Im a busy man, fixem by pros and enjoy. .

[Reiver]

As in most complex endeavors the first go is a steep learning curve and practice.
The 'oh, I get it now' is usually after the fact.

[VFR750]

It is unfortunate you found this so early in your ownership. I worried about finding a loose head for many years. Starting in 2003 before I even bought a 911 I purchased Wayne's rebuilding book. It part of the reason why I chose a SC.

I studied that book for years, and in 2010 I started buying tools and parts for a full rebuild.

In 2014 after a track day I started hearing the sound of a blown head gasket. Since I already fixed a loose head nut in 2013, it was inevitable.

To do it yourself is possible, but the forum really helps. Also having access to a shop which can handle the harder stuff like inspections. I used "Toms Rennshop" here in Connecticut.

As for DIY, having the right tools is critical to not mucking up surfaces and threads.

There is a lot of cleaning. Especially on a 32 year old engine.

Inspection and determining if it is reuse, repair or replacement is the most stressful. Partially because it adds cost. Ignore costs. If it should be replaced, do it. You will sleep better. Plus the engine will be more reliable and valuable.

As a first time engine rebuild for me, it was intimidating. But, going slowly, taking tons of pictures, bagging and tagging everything, reduces the fear of losing parts.

Going back together took a lot of time, following Wayne's book and the various sealant threads on the bbs. I and I still made mistakes. 100+ hours easily. Probably closer to 200 hours of real labor. (This is excludes reading, planning, staring at a pile of loose parts)

I did the whole enigine once followed by two more topends.

I pulled and installed the engine four times.

I can say pulling the engine by yourself can be done in about 2 hours as long as you have a good plan and check list.

I can say planning your rebuild with little bags of specific parts and exact quantities makes it seems a little less overwhelming.

Make a budget, and double it. Sounds like a cliche. But I can show you financial proof that what you expected to do, and what pops up along the way can be disheartening. But you can't cut corners on a 911 engine. Or any engine really. So you might as well mentally prepare yourself for a large bill, and be very happy if it comes out less.

I feel for you. I know what's ahead if you decide to do it yourself. It's a hobby at that point. No rush....

If you decide to have a shop do it that would be a very reasonable choice, too.

[Jameel]

Thanks again for all the encouragement. I just drained the oil this morning in preparation for the drop. I'm not afraid of the process. In fact, I am looking forward to it. I've got experienced people to help along the way, plus the good knowledgeable people on this forum. I should say I'm feeling pretty confident after having come off my first wrenching experience ever: building my 1776. Yeah, VW engine, not a 911, but I did my homework and was extremely fastidious about all the details. My dad's retired 911 mechanic (Tom Bruch) recently drove the beetle and gave the engine a thumbs up. That was a great drive! (here's a video of the motor in the car https://www.youtube.com/watch?v=zyhckZcZNF)

[yelcab1]

Well, from Feeling kinda sick, to Looking forward to the experience, is a big change. Congrats. Damn the torpedo, dive dive dive..

[Jameel]

Thanks VFR750. Wise words.

I found myself spending the early morning on Thanksgiving prepping the engine for the drop. Between checking on the bird and the various manuals, my brother and I managed to have it out by 3pm. This will be a memorable day for sure!

I've been reading ravenously about which path to take. After taking the CIS off, I wanted to throw that mess in the trash. The thing scares me. And learning about it just turns my stomach. But there are downsides to carbs too, not to mention cost. Rebuilding to stock is one thing, getting more performance is going to really add to the cost. Right now I'm leaning heavily towards this option: Porsche 911 Extracting Power from CIS 911's | 911 (1965-89) - 930 Turbo (1975-89) | Pelican Parts DIY Maintenance Article

[JackMan]

Unless you want to fall down the slippery slope, stick to CIS. Otherwise, pawn your children because the sky is the limit once you crack the case.

[VFR750]

isn't it satisfying when the engine is out? 😀 Did you get the customary picture standing in the empty engine bay?

When you see it ready to go back in, you will be a different person. Right now, you can only see the outside. When you are done, it will be like x-ray vision. You'll see all the parts you touched. So much more knowledgeable. It will be worth it.

[HarryD]

Originally Posted by Jameel

Thanks VFR750. Wise words.

I found myself spending the early morning on Thanksgiving prepping the engine for the drop. Between checking on the bird and the various manuals, my brother and I managed to have it out by 3pm. This will be a memorable day for sure!

I've been reading ravenously about which path to take. After taking the CIS off, I wanted to throw that mess in the trash. The thing scares me. And learning about it just turns my stomach. But there are downsides to carbs too, not to mention cost. Rebuilding to stock is one thing, getting more performance is going to really add to the cost. Right now I'm leaning heavily towards this option: Porsche 911 Extracting Power from CIS 911's | 911 (1965-89) - 930 Turbo (1975-89) | Pelican Parts DIY Maintenance Article

Looks like fun. Before you commit to the upgrades verify everything else in your car is up to the task. A few that leap to mind: oil cooling (do you already have an external cooling), brakes, suspension. Steve Weiner posts here regularly, he is a great resource.

Are you doing just top end our are you splitting the case and then enduring the related machine work to get your case ready for another 200k?

[Jameel]

Originally Posted by HarryD

Looks like fun. Before you commit to the upgrades verify everything else in your car is up to the task. A few that leap to mind: oil cooling (do you already have an external cooling), brakes, suspension. Steve Weiner posts here regularly, he is a great resource.

Are you doing just top end our are you splitting the case and then enduring the related machine work to get your case ready for another 200k?

I haven't decided yet on whether to crack open the case. I just have the trombone cooler, and stock everything else. Brakes are great. Unless I'm way off, adding a little punch with SSI's and maybe a cam shouldn't require a bunch of racy upgrades. I'm not going nuts here...

[HarryD]

Originally Posted by Jameel

I haven't decided yet on whether to crack open the case. I just have the trombone cooler, and stock everything else. Brakes are great. Unless I'm way off, adding a little punch with SSI's and maybe a cam shouldn't require a bunch of racy upgrades. I'm not going nuts here...

Sounds like you have the"bones". Cooling is s big deal and you have the basics in place to do some upgrades.

[Jameel]

So we got the long block torn down this week. Here's the carnage.

We'll focus on cylinder #4 since this was the one with the broken stud. When we got a socket on the stud adjacent to the busted one, it turned with little effort, then after we pulled the head off, the stud pretty much folded over. So, two broken head studs. They are Dilavar. We found the head gasket had cracked, and in the spot where it cracked the mating surfaces of the head and cylinder had a little damage to the outside of the gasket. Hopefully these areas can be cleaned up on the mill.

So here's pics of #4, head and cylinder. I should add that all the heads were dry around the edge except for #4 on the bottom. It was dark and oily. Yellow arrow points to funky area where the gasket failed.











And here's a pic of my cams, found two small areas of pitting.






But the most curious thing we found was this. Looks like a headless wood screw decided to shoot the rapids and go for a little ride inside #1. He left his mark too. Ironically enough, #1 had good leakdown and compression. I probably won't be using this piston again, but what about the head? I'm not sure I want to leave that witness mark in there. Can it be filled with weld and smoothed out?

[HarryD]

Originally Posted by Jameel

So we got the long block torn down this week. Here's the carnage.

We'll focus on cylinder #4 since this was the one with the broken stud. When we got a socket on the stud adjacent to the busted one, it turned with little effort, then after we pulled the head off, the stud pretty much folded over. So, two broken head studs. They are Dilavar. We found the head gasket had cracked, and in the spot where it cracked the mating surfaces of the head and cylinder had a little damage to the outside of the gasket. Hopefully these areas can be cleaned up on the mill.

So here's pics of #4, head and cylinder. I should add that all the heads were dry around the edge except for #4 on the bottom. It was dark and oily. Yellow arrow points to funky area where the gasket failed.











And here's a pic of my cams, found two small areas of pitting.






But the most curious thing we found was this. Looks like a headless wood screw decided to shoot the rapids and go for a little ride inside #1. He left his mark too. Ironically enough, #1 had good leakdown and compression. I probably won't be using this piston again, but what about the head? I'm not sure I want to leave that witness mark in there. Can it be filled with weld and smoothed out?

Looks like your motor had some hard times. Before you throw anything away, consult with your machine shop. They may be able to save the cam, both heads and the piston for less than the replacement costs.

[bigel]

Originally Posted by Jameel

But the most curious thing we found was this. Looks like a headless wood screw decided to shoot the rapids and go for a little ride inside #1. He left his mark too. Ironically enough, #1 had good leakdown and compression. I probably won't be using this piston again, but what about the head? I'm not sure I want to leave that witness mark in there. Can it be filled with weld and smoothed out?

No, not a wood screw...that is the remnants of your piston (oil ring expander, or 'oiler') ring that seems to have disintegrated some time ago.



Wow!

Well, it'll be good when you're finished with the rebuild.

Good luck.

[Jameel]

I took apart the oil control ring on that piston and found the spring to be completely intact. Looks like that cylinder had problems before, got reringed, and put back together. Must have done a good job because it was making 185 lbs of compression at 6.5% leakage.

[HarryD]

Sounds like you may have dodged an expensive bullet.

['76 911S 3.0]

I would wager that the one of the screws that holds the spider fuel manifold in the intake backed out and made its way into the cylinder...had the exact same indentations on mine during a tear down. Opened up the intake manifold, found one of the screws holding the spider manifold had backed out and was missing.

[Jameel]

Excellent info. Now that I think about it more, I think the oil ring spring would have been crushed in one shot by the piston and not made those impressions, since its rather light and hollow. The impressions on both our pistons aren't just ridges from the spring, but also the shaft of the screw. I'm going to check my spider today for that missing screw.