911 SC Broken Head Stud
 

I have an '81 SC with a broken head std. It has ~140K on it. I discovered the broken stud while adjusting the valves and it appears to be only one of the lower studs. Up until this point I had been trying to solve over heating when driving in traffic. On the open road its fine. Could the broken stud or possibly studs have yet to really get in there to look cause over heating? Any thoughts on how long I can nurse it along like this?

Anyone have shop recommendations in the Miami area? Currently I'm living in Ecuador and commuting to Miami for work and I don't have access to garage space or tools to do the repair myself.

Nick

Nick,

As you already know, broken OEM head studs are not uncommon with the SC's and you should not drive it until its repaired otherwise the bill will be a lot higher to fix the loose head(s) beating up & down on the cylinders.

Your overheating is another issue and I'd need LOT more details to offer anything constructive. Outside air temps, distributor issues, lean AFR's, obstructed engine-mounted coolers, loose fan belts, and failing oil thermostats all play a role in engine operating temperatures.

Here are things that have been done to try and deal with over heating plus recent maintenance in the last 5K

Elephant Racing grooved Oil lines
Elephant Racing Fender Mount Cooler
New Oil Thermostat
New Fan Belt
New Plug Wires
New Plugs
New Fuel Filter
New WUR to correct fuel pressure issues. Now Cold Pressure Warm Pressure are correct. It holds Pressure with key off and system pressure is correct
Updated AC system all new components from Retro Air and RennAire
New Alt. Visually nothing blocking airflow on top of motor

Over heats in City traffic anything over 85. AC on it over heats faster than AC off

My old engine had a broken spring which may have been causing the overheating. I also had the elephant lines and cooler - timing, afrs, fuel pressures were all in spec.

However, I also had some clogged injectors. This meant that some cylinders were running way lean. There was no noticeable running problem either. Just way hot.

meaning you're seeing the oil temp needle horizontal +

I installed a CHT to monitor the near future of oil temps. The CHT reacts immediately giving me time to adjust driving to keep oil temps down. It takes a few minutes for the oil temps to react higher and a very long time to bring it down


and with my carbs I may experience a fully clogged jet allowing no combustion and a cold cylinder head or a partially clogged jet allowing seemingly over 1500F EGT /very hot combustion and CHT rising about 25F degrees while nursing the engine.

just my routine on a street engine

I had this dual CHT gauge and spark plug probes installed on #2 & #5 awhile ago




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