writtmeyer

While adjusting valves I checked the head stud torque [studs replaced several years ago] on my '77 2.7 [with 75k miles] and found 2 which appear broken, one upper and one lower. Questions/opinions:[list]
is it a problem to continue driving?[*]can the 2 studs be replaced without removing the engine?[*]am I better to either rebuild myself/have it rebuilt- or consider replacing with a rebuilt engine as offered in Excellence and elsewhere?[*]opinions on rebuilt engine sources and advisability of replacing with 3.0 or 3.2 SC etc.

Car is in great shape otherwise and used as weekend fun car, not a daily driver or any track use..

thanks.

Alan Herod

from my experience it certainly depends on whether the broken head studs are on the same cylinder. The problem cannot get any better driving it with broken head studs and many resort to rebuilding the engine the moment they discover the broken head stud. My SC engine has a broken head stud and that cylinder has 3% leakdown. That problem has existed for over three years and many track days. I performed periodic leakdown on the engine over the years and never encountered the slightest degradation on that cylinder. With over 170K miles another cylinder on on the opposite bank began showing degraded leak down numbers. I am contemplating rebuilding that engine when I get around to it. The car received a magical cure which also did away with the ancient CIS. First get some baseline numbers -- and if the leakdown and compression is good keep driving. Remember that you can do lots of repairable damage driving it. If you have 5-7K lying around and you don't want any more power -- fix it now. You might already have damage that will result in the 10K rebuild. This might be the time to call Instant-G, depending on what you want to do with the car and how long you want to keep it.

Steve Weiner-Rennsport Systems

Hi:

You'll likely get varied opinions on this but I'd offer mine.

Given how few people/shops/Dealers can properly rebuild the 2.7 and how expensive that whole thing is, my very best advice would be to recommend that you aquire a 3.0 SC motor and either install as-is (with new studs, of course) or rebuild the 3.0 so you have a reliable, durable and fast car.

I'd strongly recommend that you budget for the purchase and installation of a front oil cooler kit, too as thats the real key for a long-lasting air-cooled 911 engine.

pjc

Steve's probably right unless you want to stay 'original' - I've just had my 2.7 engine restored and even getting relatively cheap major components from the USA it still cost around $18,000 - OK the car is as close to original as I can get it with a body restoration two years ago.

For what its worth, just because an engine is giving good leakdown and pressure readings doesn't mean all is well. My engine had factory readings all round but when taken apart almost every wearing part was on the end off it's tolerance, hence new barrel/piston set (originals were Alusil!!), camshafts, rockers, regrind crank, shufle pinning, time-certs, line hone, oil mod, decking etc. The crankcase on the 2.7's sure need some work.

My concern about running with a broken stud is that I believe it can potentially cause terminal damage to the head in the long term if gas is escaping.

PJC