CentralLine

Well, I am in the process of doing a tune up with spark plug change, and found this stuck in the spark plug bank of the passenger side, front-most, upper bank. That is of course the hardest plug to get to.

The sheared bolt came out with some fancy fingerwork, but the stud looking thing required a special flexi-grabber. At first I thought the "stud" was a socket that someone gave up on from a previous plug change. It was sitting on the plug after I pulled out the plug wire. The plug actually looked ok, once I got it out.

Did this just fall in there (I hope)? Or did the assembly shear off from somewhere else and end up there.

Looking for good news, but fearing the worst.....

Wachuko

Ohhh the memories...

When I purchased my car the first thing I did was preventive maintenance… oil hoses, belts, filters, sparkplugs, etc… I also decided to check the valve adjustment just for peace of mind…

I remove the valve covers from the passenger side of the engine… move to the other side to do the same and I hear this loud THUNK!!!… come back to the other side and see something like what you have in your hands…

Broken head stud... get ready to replace all 24 with ARP...

Wachuko

You will need to remove the valve covers to confirm where it came from... but I doubt someone left it there for kicks...

Here you go... 964 C4 Head bolts replacement update...

Total for the repair came to around US$6K... (engine sealed, clutch, 2 tires, alignment... it is all in the post).

CentralLine

Looks like fun things are ahead.

I am a DIY'r and am willing to tackle about anything. My (unfortunately now deceased) brother and I put in a centerforce clutch about 2 years ago when he owned the car... but of course he was the former Porsche mechanic.

Is this a repair I could reasonably do myself? Can I replace the valve guides at the same time if they need it? Is there a post somewhere that would instruct me on doing the repair myself?

Many thanks.

Colin 90 C2

Take a look at the DIY forum. Anthony has an excellent writeup on rebuilding an engine. I believe that you can get away with just replacing the broken stud instead of replacing them all. That is probably what the dealer would do.

Good luck,

Bill Gregory

One very good book resource is Wayne Dempsey's "How to rebuild and modify 911 engines". Although it's describes 89 and earlier engines, much is applicable to our 964 engines. It would help to have the Factory Manual available too. Bruce Anderson's "Porsche 911 Handbook" is another useful resource.

CentralLine

Is there any way to just replace the one broken stud, or am I doomed to have to do a full rebuilt? I have looked at some of the threads, and there is nothing small about this project. I think I might be getting cold feet.

To make matters worse, it is an '89 C4, which means no cylinder gaskets. I would have to get the cylinders machined... way beyond my ability level. (Of note, the car has 78,000 miles on it).

I wish this hadn't been by brother's car, because I have a hard time letting it go. I can hear him saying "dump it" however. It's just a car, and I can't keep it forever. He had grown tired of it and had moved on to motorcycles, when I started to buy it off him, so maybe I shouldn't feel so nostalgic. The main reason I bought it, however, is that we had done some nice modifications on it together, including Koni adjustable coilovers, the centerforce clutch, etc. So it drives wonderfully. Rock solid at 150.

What is it with Ruf saying he likes the 964 best? I will be in a position to buy a new 997 in the next year, if I choose to (I was never a fan of the 996's), or perhaps an OBDII era 993. This car is worth $25K on a good day. Is it worth keeping given the extent of the repairs? (I would guess $5000+ for a good rebuilt, which won't happen in Tucson... Phoenix maybe?)

You can tell I am struggling. Any input would be appreciated.

Thanks.

Colin 90 C2

There is no reason that you can't replace just one stud, or even just refresh the one side of the engine.
For cost effectiveness, most would say that while you're in there, just redo them all.
I think that with your current mileage, I would just do the one broken stud. I have 145,000 on mine and the only things that I've changed is the leaking seals.

Once you drop the engine, you're home free. I think that is a lot of the cost of the rebuild. For reference, I dropped mine in about 3 hours by myself with a lift.

Wachuko

My car had around 32k miles when this happened... in my case I decided to replace all of them... along with all the seals in the car, etc... I was to new to these cars at the time and scare sh*less to touch the internals... and at the time that was the suggestions I got from the folks here.

If you decide to tackle this yourself I recommend doing at least all four in the cylinder affected. You will have to retorque them to specs when you replace them so it would be best for all four to be new... imho of course.

I would not worry about not having the udpated heads. If there is no apparent head/cylinder leaks you should be fine. And with 78k miles that baby is still new

Again, this is IF you decide to tackle it yourself and minimize the expenses. Since I had the Porsche shop do my work I decided to replace everything while in there for some peace of mind.

As far as keeping the car... I would... it has sentimental value, it is one of the best 911 made, you will not get what is worth, and it will nice to alternate with a 997 (you will be able to go back and forth between Porsche history )

Let us know what you decide and keep us posted on the progress. Best of luck!!

axl911

How many miles do you have on the car?

Wachuko

Heirsh

The older I get the more sentimentality matters to me. I would keep it if I were in your shoes.

Good luck with your decision.

springer3

If you go one-at-a-time, you can replace all the head studs without any engine disassembly. The problem is getting the broken stud out. I don't know how to do that, but I'll bet it can be drilled out and helicoiled without pulling the cylinder head. I don't see any way around removing the engine to get access. It is too bad the stud broke. If it had pulled out, you could replace it with a self-tapping stud, with no need to remove the engine.