Head Stud Question/Concern - 1986 Coupe
 

I have gotten mixed reactions on my situation and wanted to ask here.


I have my daily driver with 200,000 miles on it and and after readjusting the valves found another head stud broke...so that is 2 broken head studs - leaking bad, etc...so it will be parked for a bit.

I also have my other 86' (65,000 miles) (that was written off) sitting in storage. The car was a one owner, before me, and was very well maintained.

So...I am going to drop this engine with the bad head studs and install the low mileage engine...my question is: Should I just install new head studs in the 'new' engine now and get that out of the way or let it be and questionably wait for the day when they break?



Head studs, embarrassingly, were not on my radar until now...that being said it has been quite the rabbit hole and late nights reading up on failures, fixes, etc...



Some locally say "don't mess with what ain't broke" and others say "do it now and never worry again" between motorcycles and old Land Rovers I have done so much preventative "what if" and "just in case" work I am just wanting to swap engines, after a good inspection and drive again.


Appreciate your thoughts...thanks!



Erik

I would

1) Remove the lower valve covers of your spare engine and account for all of the head studs on that engine. If all are there,

2) Swap out the engines and enjoy driving your car. Fix the engine that was in your car, especially if it is the original engine to that car, in your own time, and

3) If your own time runs out, let someone else deal with it.

What he said. "If it ain't broke, don't fix it." I'd take off the valve covers and check the head studs, and do a valve clearance adjustment. DO NOT preemptively replace the head studs. Otherwise you will start down the slippery slope of "while I'm in there" which inexorably leads to "engine rebuild." Trust me, many of us have slipped down that slope. Don't go there.

If you do have a broken or loose head stud, then only take the engine apart far enough to replace the lower studs. Keep the current engine as a spare core. I wouldn't even rebuild it until/unless you find something wrong with the replacement engine. Only then, rebuild and swap them.

I've seen 8 studs broken from just sitting for years, on a 6K miles otherwise pristine car. YMMV.

There must be more to that story. But, if that's the case, then replace the studs. Otherwise, down the slippery slope you go!

Reading trough threads the last few days the phrase "while you are in there" comes up more than a few times. Lower studs are what, dilivar (?) so I see the merit of others who are just replacing the lowers. I am mixed on what side of the fence to be on: replace them all! or...replace the 12 or...check them and let them be.





I was just on another forum and this comes up a lot. Unused or not used seems to equate to this problem.

Agree with YMMV, some had 50,000 miles others had 140,000 miles...I got lucky at 200,000...




Might just put down the wrenches and let my head wrap around things a little more.


Appreciate the input.




Erik

I'd just run the low mileage one if the studs are good.
Replacing the top steel studs with new steel studs seems like a waste of effort, unless you're using an aftermarket set of 24, like supertec or the like.

8 broken studs on an engine that sat around for years? God must not have loved that car.

To the OP, I would drop the 200K engine, fix it now, and put it back and drive it. It's not rocket science, you know. 6 weeks, tops.

I have a single broken one I found last fall. I will be replacing only the lowers on both sides. If I'm lucky, I can get the rest out without disturbing the P&C. I could just do the one side, but I'll do both for good measure and know that I won't have to get in there for a long time.

Yes, the Dilivar head studs is another one of those "What were they thinking??" questions. It seems they will break eventually. This isn't a highly researched answer, but I'm pretty sure that it has more to do with the corrosion conditions the car was in. Salty roads or ocean air leads to more corrosion and more cracking and breaking.

Google environmental induced stress corrosion cracking...... If the spare engine sat in a dry environment the studs might be in good shape. Humidity and time are not friendly to these parts.

Swap and drive! Do check your studs first to be sure

Dilivar...ugh. I've replaced them, torqued them up, went to lunch, and came back to a broken stud and nut lying on the floor. Ask anyone who replaced them back in the day. It wasn't uncommon for the brand new studs to break. Corrosion (external) had nothing to do with it, it was a metallurgy problem. Specifically "intergranular corrosion" during manufacturing of the studs themselves.

swap engines and you are on the road the next day ....

as mentioned fix the broken studs in your own time and have a repaired engine ready to put back in if you need to . ( which you likely wont in your lifetime )

Thanks everyone for the input. I kind of feel lucky I have two engines at this point, albeit one non functioning. The bones are good as they say.


SO, to get things straight, when I open the low mileage engine up and find no broken head studs, it's best to not mess with them physically at this point and just visually inspect?

Main question is: If not broken, but old and corroded let's say, these have enough in them to keep things in place and it's only when they literally break is when things start going south? I have seen/read some will torque them to check...but...I am not sure I want to explore that "option".


Between Pelican and Rennlist (and European) forums it has become a bit of a rabbit hole. Loads of different takes and opinions...



*** In the end it seems the best thing to do is swap engines, which will be my first engine drop if I can be honest, and plan, for piece of mind, to either do it myself, and/or have my shop replace the lower studs in the next few years - just to take that out of the equation, and since I will own until I can't drive anymore -seems logical.


Again, thanks everyone -

Erik

You have a spare engine. Given prices recently, that's like money in the bank, and pays better interest.

As long as it's not SVB.

We had a 3.2 in the shop. Owner only wanted to replace broken head studs and nothing else. We replaced the studs. The next day, there were broken studs on the floor. While looking at the engine, I heard a pop and personally witnessed a stud with its nut still attached, fly up about a foot and fall to the floor. Since then, our motto has been - all or nothing. If we do a top end on a 3.2, it gets new studs. We don’t ever “re-tourque” studs. Either replace or leave everything alone. And let the customer know that divlar may break at any time without warning.

My thought is if you have the engine out of the car it's a GREAT time to do certain projects...as opposed to doing them with the engine IN the car.

Wise words.

Just be careful of the "while you're in there" syndrome!