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[bikerboy53]

It seems like a few years ago there was some talk about NOT using the SE cylinder studs because they could/would cause pulled threads in the crankcase. Can anyone confirm whether that is/was true? I did a search of the site, but couldn't come up with anything.

My bike recently blew the front head gasket, and when they got it part way apart, one of the head bolts had backed off about half an inch! Once they got the cylinders off, they found that the stud has some aluminum threads coming out around where it goes into the crankcase. Looks like it may have pulled the threads... I had to leave before they could take the stud out, but it doesn't look good!

The motor currently has the SE cylinder studs in it. When we did the build, the MOCO was recommending the use of the SE studs for 10:1 compression and higher. The motor has 10:1 pistons in it, but I'm wondering if the "standard" cylinder studs might be a better choice?

Can anyone help me figure this out? I don't want to put the SE studs back in if it's going to happen again.

[GMR-PERFORMANCE]

The stock stud is by far strong enough for 99% of the builds out there. The thing with the SE stud was that it had a thread locker applied to the threads. However when install many times the stud really was not tight and could be move very easy by hand. The se stud has not shoulder to lock down on the case. We would strip off the Se thread locker, clean the holes in the case apply one to two drops or read to the threads install them to correct height , and let the red dry. If its cold or you are i a hurry you can use a heat gun to warm the case and that will activate the thread locker much faster. 

Maybe one of the threads started to work itself loose over time with the heat and cooling cycle.  A steel insert back into the case would be the best repair. Heli coil if that is all that the shop is up for.


Re install stock studs once your repair is complete.

[bikerboy53]

GMR,
Thanks for the help. Sounds like after we fix the threads, it's time to go back to the stock studs with the shoulders.

Can the threads be repaired without disassembling the rest of the motor? I'm kinda nervous about getting any metal particles from the repair down into the crankcase, so I'm thinking it's time to pull what's left of the motor and split the cases at this point.

Thanks again for the help!

[Snakebyte]

Could heli-coil it, but I guess it all depends on how close the spigot is to the stud.

[prodrag1320]

a heli-coil,if installed correctly will be fine.there a lot easier to do with the motor together,in the frame.if the motor is apart,ide do a insert using a mill to install it.which ever you use,make sure its straight,just a bit off and it`ll be way off at the top of the stud

[johnsachs]

I'm nervous about using Heli-coils for case stud hole repair.
Kirby's right, an insert, installed straight, is the best way to repair the deal. I made a small jig to tap the hole  correctly, with the motor in the frame, so the stud has NO off angle.
Studs at an angle = major PMS/Problems. 
John

[Twolanerider]

I know there are people who dislike heli-coils for reasons that are their own.  I've never had any particular issue with them and have used them to save the proverbial bacon many many times over the years.  However.....  A Harley cylinder stud's hole is perhaps the only place where I'll use a TimeSert threaded insert rather than a heli-coil insert. 

[HD Street Performance]

In your opinion why is the Time-Sert a better option?
I have used both with equal success, maybe there is something I need to learn about this.

[FlaHeatWave]

'In my experience with a lot of Helicoils, properly installed, they are much better than the parent alloy.

[Twolanerider]

In your opinion why is the Time-Sert a better option?
I have used both with equal success, maybe there is something I need to learn about this.

I've used both also.  Not really worried about either one relative to the other.  HeliCoils are certainly far more common and I've never understood the distaste that some seem to have for their use.  A product can't be around as long as they have and been used as widely and really be much of a problem.  

Speaking specifically to the cylinder studs my experience is limited but what I can offer isn't anecdotal.  It is my own experience.  Even with a properly set red loctite had an incident of a coiled insert later walking after a removal then during the subsequent reinstallation.  The top shoulder on the TimeSerts keep that happening.  The inboard walk is a rare issue with helicoils.  Not something I'd worry about on other than very critical and difficult to reach installations.  But on those installs the top shoulder on the TimeSert is an added insurance.  

There is (or at least used to be) a TimeSert kit specifically for Harley cylinder stud holes for cases where a coil insert install had failed.  Found that once when someone else's coil insert had failed.  Don't know why with any certainty.  The appearance was of degradation (for whatever reason) around the coil.  Coil both then couldn't stay as tight and could expand.  The one piece inserts can't do that either.

It's just a couple of instances; I know.  But it's a couple out of a total experience of at most six installs that I've either done or been in after first hand.  HeliCoils are fine.  I use them and don't worry about them.  But out of an abundance of caution I'll go the other way on cylinder studs in these aluminum motors.  

I don't remember the tap sizes for each type of insert off the top of my head.  Have a (perhaps mistaken?) recollection that the tap to install the TimeSert insert is just slightly smaller than the tap for the coil inserts also.  If that recollection is correct that would also suggest another small reason to lead one way or the other.

[bikerboy53]

Everyone,

Thanks for your valuable feedback! After weighing the options I think I'll ask my local shop to see about the TimeSerts or similar solid repair insert. (I've used Keenserts at work -they are a solid insert and use special anti-rotation locking keys that are driven into place after the insert is screwed in.) I'll ask my shop to look for a kit specific to HD cylinder studs, and also to use a jig or other alignment tool to get it put in straight.

I was thinking that they may be able to clean the cylinder spigot bores in the crankcase, and seal the openings with heavy (duct?) tape so that the cases don't have to be split. Maybe they can complete the repair with the motor still in the bike, and keep from getting shavings in the crankcase. I hope...

[johnsachs]

Everyone,

Thanks for your valuable feedback! After weighing the options I think I'll ask my local shop to see about the TimeSerts or similar solid repair insert. (I've used Keenserts at work -they are a solid insert and use special anti-rotation locking keys that are driven into place after the insert is screwed in.) I'll ask my shop to look for a kit specific to HD cylinder studs, and also to use a jig or other alignment tool to get it put in straight.

IIRC, Ram, Timesert, and/or others offered a kit for stud repair with timeserts.
John

[HD Street Performance]

Twolane
Thanks so much for taking the time with a detailed explanation. I see your points and they are good ones.

[rbabos]

It's been said many times the SE studs are too stiff. You want the stud to have stretch so it allows for expansion , retaining the original torque value rather than torque increasing from cyl and head expansion. Too stiff,  the expansion transfers too much into the aluminum threads. Over time of repeated cycles the threads can yeild.  As for helicoils or inserts, go with the one with the longest thread section.
Ron

[GMR-PERFORMANCE]

There is a self taping style  thread insert. You would not have to remove engine for this. I have used them on other things never a case stud but they have worked very well.  With extreme care you can install a time sert without taking the engine out of the frame.  A plate attached tot he case with sleeve to keep drill inline..

http://www.carrlane.com/Catalog/index.cfm/27825071F0B221118070C1C513E111D081B0006280B1713050245221E0107070F1A3C3B285356445B