SC Head Bolts Symptoms

[Yorkie]

My neighbor has just bought an '80 SC and it makes a loud farting noise under hard acceleration. He was wondering if it could be broken head bolts. Other than simply opening up the lower valve covers, are there any other symptoms he can check for broken head bolts? Would he see oil leaks, knocking, loss of power?
Thanks,
Kevin

[pa911]

hmm loud farting noise never heard that one before.maybe one of the experts will chime in.

[David]

Sounds more like an exhaust leak, but it wouldn't hurt to check. You should be able to see the bottom of the stud where the cylinder meets the case under the engine. If there's any question after that you can pull the lower valve covers and check.

[Groesbeck Hurricane]

I'd start by checking the 12 exhaust studs and the pipe connections. If these were all fine I'd start looking at the headstuds.

[Yorkie]

We went underneath the car and tightened up the nuts and allen screws just to see if that was the cause but they were all OK. Somebody suggested to me that it could be airbox resonance at full throttle.
Kevin

[sammyg2]

Usually an exhaust leak will make a ticking noise even at idle, if this car only makes the noise under full throttle then I would suspect head studs. If it is leaking bad enough to make noise I would expect an oil residue at and around the gasket mating surface.

It doesn't take very long to pull the lower valve covers and check, just make sure he either drains the oil or jacks up the side he's working on real high to keep the oil from running out.

[Yorkie]

So if they are some busted head studs what are we looking at $$$$$$ to replace them?

Kevin

[sammyg2]

Depends on certain factors:
If there is no damage to the heads or cylinders, and if the cylinders and pictons are in great shape and nothing else needs to be fixed, you can do it for under $1000.
If the cylinders are toast, and the heads need to be rebuilt, and while you're in there you might as well do the bearings, and a cam upgrade, if you have a shop do it, etc well it can get realllll expensive.
So anywhere from $1000 to $10,000 is my best guestimate.

[walt]

My broken head stud sounded like metal to metal "pinging" under heavy acceleration. Not sure I am describing that correctly. Very simple to pull off the lower valve covers and check for broken ones. If all looks good you may want to continue with a valve adjust.

[Joe Bob]

My broken stud(s) sounded like a playing card stuck in moving bicycle spokes....

[bagpiper47]

With a $10,000 top estimate wouldn't it be cheaper to swap the engine for a rebuilt? I see those in the panorama magazine going for $3500. Wouldn't that be more economical, or am I missing something? Even $1500 to ship and install sounds better than $10k. Is there something wrong with the rebuilt engine's??
Just curios.

[sammyg2]

What company's add in panorama are you refering to?
Please take the company's name and do a search here before writing the check.
If you believe that a company can offer a complete 911 engine overhaul for $3500, I have a bridge and some swamp land for sale.

No reputable company, let me repeat that, no reputable company can promise a complete quality $3500 911 engine rebuild and actually deliver. The labor to do a quality rebuilt will be almost that amount.
Nothing worse that getting a quote, watching the quote amount double, then triple, then ending up with a POS used engine.
Too many horror stories here.
Shame on pano for being sooo greedy as to continue running those adds.

My engine had one broken stud and didn't make any noise at all or leak at all, I spent just over $1000 (did it myself) and did not have to replace very much at all. Studs, gaskets, rings and a few odds and ends.

The $10,000 estimate would be for a situation where you pay to have an expert go through the engine and make everything perfect, or a situation where a great deal of upgrades are done.

figure around $6500 to $7500 unless you do it yourself. Even then it could go higher depending on condition.