Headstud quandry
Thread Starter
Track Day
Joined: Dec 2001
Posts: 21
Likes: 0
From: Seattle, WA
Headstud quandry
I took my '78 911SC--182K miles on the odometer-- in to my usual mechanic for a valve adjustment and received unhappy news that I had a broken headstud. M-1 claimed that he found that the headnut came off and was lodged in the plug recess when they tried to put the plugs back in. Does this even sound possible?
I took the car to a second mechanic, and asked for a complete pre-sale inspection, with specific emphasis on checking the head studs. M-2 said the compression was good (4@160, 2@155) and that the headstuds were in good shape. He also mentioned that headstud cracking usually only showed up on the lower studs. True? Or did he only pull the bottom valve cover for a quick look?
Here's my quandry: M-1, whom I've known for just 2 years, is trying to sell me on a complete engine rebuild. M-2 used to service the car for the previous owner for over 20 years. Who is likely giving me the best info?
I took the car to a second mechanic, and asked for a complete pre-sale inspection, with specific emphasis on checking the head studs. M-2 said the compression was good (4@160, 2@155) and that the headstuds were in good shape. He also mentioned that headstud cracking usually only showed up on the lower studs. True? Or did he only pull the bottom valve cover for a quick look?
Here's my quandry: M-1, whom I've known for just 2 years, is trying to sell me on a complete engine rebuild. M-2 used to service the car for the previous owner for over 20 years. Who is likely giving me the best info?
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
Greger:
Its easy to tell if a head stud has snapped,....all the mechanic has to do is pull all 4 valve covers and gently torque them to spec. The broken one(s)will spin freely, of course.
Some of these engines broke both top & bottom ones and its not real consistent. Personally, I'd be inclined to listen to the folks who know the car best.
I know most of the Seattle area shops if you'd like to e-mail me offline with more details.
Its easy to tell if a head stud has snapped,....all the mechanic has to do is pull all 4 valve covers and gently torque them to spec. The broken one(s)will spin freely, of course.
Some of these engines broke both top & bottom ones and its not real consistent. Personally, I'd be inclined to listen to the folks who know the car best.
I know most of the Seattle area shops if you'd like to e-mail me offline with more details.
Racer
Joined: May 2001
Posts: 265
Likes: 1
From: seattle,wa.
the 930s, with dilivar studs broke both top and bottom studs because they were all dilivar. SCs had dilivar on the bottom row and steel on the top. i've never seen a steel stud break in the 28 years i've been servicing 911s.
