Broken head studs, now what?

[MichiganMat]

Gents,

Found out my SC motor has some broken head studs. I've torn down the top-end and found that studs on #2 and #3 have broken. Also, on #3, the stud barrel nut backed out and compromised the P&C gasket. This was on a track day and the exhaust gases melted the gasket ring and damaged the side of the cylinder. So now I have a few questions for you:

- 2 broken studs on my engine. Is it typical to replace them all at this point?
- Stock studs, 993, or ARP?
- Is a used P&C ok as a replacement my damaged one? Do builders "always buy new"?
- P&Cs typically come in pairs (used, at least), but can I use any port-matched head?
- The head has some sign of wear from the gasket blowing out, Im not sure if I should reuse it or not. any general advice? could it be machined?
- My cam has a bit of pitting on one lobe, but the rocker is in good shape. Is pitting typical? Should I replace the cam too?

I guess Im really wondering how deeply I should go into this project. All studs, or just the broken ones? Im leaning towards all, but wanted to get the Pelican take on it first.

Many thanks,
Mat

[al lkosmal]

Mat,
The last few 3.0 engines I've rebuilt all had broken head studs on the exhaust side..more than one...like yours. Although there are a few options.............I'd replace the all of the bottom studs with steel. The top studs are steel and seem to be fine...the bottoms are dilivar and after 30-40 years are prone to failure.

regards,
al

PS: Do you have Alusil or Nikasil P&Cs? Small or large port heads?

[Catorce]

Why would you not do a full rebuild at this stage? Is this a car you are getting rid of, or ???

[MichiganMat]

Originally Posted by Catorce

Why would you not do a full rebuild at this stage? Is this a car you are getting rid of, or ???

Not sure I have the stomach or the bank account for a split-the-case full rebuild.

No plans to sell the car any time soon, just want to get it back on the road.

[mikedsilva]

Originally Posted by Catorce

Why would you not do a full rebuild at this stage? Is this a car you are getting rid of, or ???

slightly off topic, but can you also reproduce cases for older motors?
like the dreaded 2.7?

[Mark Henry]

Originally Posted by MichiganMat

Not sure I have the stomach or the bank account for a split-the-case full rebuild.

No plans to sell the car any time soon, just want to get it back on the road.

A full rebuild is cheaper than a top end job, then having to do it all over because you should have done a full rebuild.

I'd at least remove the rods and then make the call.

[Catorce]

Originally Posted by mikedsilva

slightly off topic, but can you also reproduce cases for older motors?
like the dreaded 2.7?

Yes, we are doing an aluminum case 2.7 as part of the tooling package for the 3.6

[Catorce]

Originally Posted by Mark Henry

A full rebuild is cheaper than a top end job, then having to do it all over because you should have done a full rebuild.

I'd at least remove the rods and then make the call.

Exactly what I was hinting at. The words "false economy" come to mind, and it's easy to spend the same money twice on a 911 motor build because you went half assed the first time.

[MichiganMat]

Originally Posted by al lkosmal

Mat,
The last few 3.0 engines I've rebuilt all had broken head studs on the exhaust side..more than one...like yours. Although there are a few options.............I'd replace the all of the bottom studs with steel. The top studs are steel and seem to be fine...the bottoms are dilivar and after 30-40 years are prone to failure.

regards,
al

PS: Do you have Alusil or Nikasil P&Cs? Small or large port heads?

Im thinking to do all the studs at this point, but Im not sure. At the very least, all the bottom studs need replacing, but Im concerned about reusing that top row. Supertech?

Heads are small-port. Engine is an end-of-year '83 SC. Its got the later 3.2 case. Not sure about the P&Cs.

Id like to build it up for track abuse, but I've built a new car to do that... so as much I as Id like to pump $ into this to trick it out for hard work, its probably going to become more of a street / occasional AX car. So Im trying to find that balance of upgrades to repairs. Im open to opinions.

[john walker's workshop]

Tops are steel, so go stock steel on the lowers. The cylinder obviously needs replaced, used is fine if it mics out and is the same height as the others. Then have the heads flycut.