HarleyTechTalk

Technical Forums => Twin Cam => Topic started by: Jim Bronson on January 08, 2020, 07:54:22 AM

Title: Reusing Cylinder Studs
Post by: Jim Bronson on January 08, 2020, 07:54:22 AM
I'm having my base o-rings replaced due to a serious oil leak. The tech called yesterday and mentioned that he does not like to torque the studs more than twice and suggested that I have them replaced. Does this sound right? This would be the third time they would be torqued (once at the factory and once when the 110 kit was installed). The dealer isn't doing the work but rather a respected indy shop. Thanks.
Title: Re: Reusing Cylinder Studs
Post by: kd on January 08, 2020, 07:58:06 AM
The cost is coffee money.  I would change them.
Title: Re: Reusing Cylinder Studs
Post by: jls 64 on January 08, 2020, 08:04:48 AM
Quote from: kd on January 08, 2020, 07:58:06 AM
The cost is coffee money.  I would change them.
:agree: change them.
Title: Re: Reusing Cylinder Studs
Post by: koko3052 on January 08, 2020, 08:39:58 AM
#3 here....& I would not use SE studs.
Title: Re: Reusing Cylinder Studs
Post by: Jim Bronson on January 08, 2020, 08:44:00 AM
Quote from: koko3052 on January 08, 2020, 08:39:58 AM
#3 here....& I would not use SE studs.
There were no replacement studs included in the SE 110 kit, so they reused the factory stock studs at the time of the kit installation. Anyway, I'll have them replaced this time. Many thanks.
Title: Re: Reusing Cylinder Studs
Post by: 1workinman on January 08, 2020, 04:39:03 PM
Quote from: kd on January 08, 2020, 07:58:06 AM
The cost is coffee money.  I would change them.
More of a curiosity here but say on a 124 the base gasket leaks do you recommend replacing the studs 
Title: Re: Reusing Cylinder Studs
Post by: jam65 on January 08, 2020, 05:49:42 PM
Why not since you would have your engine pulled down this far. Cheap as coffee.
Title: Re: Reusing Cylinder Studs
Post by: kd on January 08, 2020, 06:00:19 PM
Quote from: 1workinman on January 08, 2020, 04:39:03 PM
Quote from: kd on January 08, 2020, 07:58:06 AM
The cost is coffee money.  I would change them.
More of a curiosity here but say on a 124 the base gasket leaks do you recommend replacing the studs


IMO I think I would consider a few things. High compression, engine temp, rpm and throttle position (the amount of air you force the pistons to compress) will effect the overall cylinder growth. Cylinders are torqued cold into the stretch zone of the steel studs.  I have never measured the total growth of the cylinder and head assembly but general consensus seems to be .050 to .060 on a stock engine so that will be designed into the yield limit of the steel studs.  If the aforementioned factors (heat, compression etc) cause further growth and work load it may be pushing the engineering factor of the studs.  I also feel there is a risk of case damaged aluminum threads by winding them in and out too often that may risk effecting case life.

I think I would be very careful when cracking the nuts loose and try to get a sense if there still is stretch in the stud holding down. If a nut released immediately I would be suspicious that it may have been overworked and is no longer providing the original stretch.  If it rotated slightly before turning loose I may see that as still providing stretch effect and had not worn out the resilience in the steel.  I do know you can feel this if you do a cold torque on a new stud and then slowly wind it back to loose on an engine that has not been run.  If a hot rod engine that had been run as intended (hard  :teeth: ) and it didn't have this feel I may suspect the reason for the base gasket leak could be related to stud fatigue and change them to be safe.  I don't like doing repeat performances of that type.   :crook:  Like Jam said, they are chump change.  Just make sure you have clean threads and are careful not to cause any damage that will ruin your day.
Title: Re: Reusing Cylinder Studs
Post by: itsafatboy on January 08, 2020, 07:36:23 PM
I like the ARP studs they have the collar like stock , fueling sells them but im sure you can find a better price
Title: Re: Reusing Cylinder Studs
Post by: Jim Bronson on January 08, 2020, 09:46:51 PM
I'm not sure where they're getting them, but they did say they ordered a set. They are a long-established performance shop that builds engines and hot rod bikes, so I'm trusting they know what they're doing.
Title: Re: Reusing Cylinder Studs
Post by: Pete_Vit on January 09, 2020, 08:14:05 AM
Said this before...I didn't replace the studs on the Sporty rebuild and no issues, when I did the Springer and 2 of the studs came out of the case with the head bolts, I replaced them all just in case, my piece of mind  :up: and as KD said "coffee money I would change them."   
Title: Re: Reusing Cylinder Studs
Post by: nosjunkie on January 09, 2020, 05:04:35 PM
Before you break a stud it will pull the thread out of the case... I used to try to cheat the torque up into the 50ft lb area and more... it was always the case that failed...  that said I used the ARP studs in my builds... and sometimes Bigcerts in the case..
Title: Re: Reusing Cylinder Studs
Post by: SP33DY on January 10, 2020, 07:29:05 AM
This may be mentioned elsewhere on this forum:

When I change the studs, I double nut them and use a box end wrench on the lower nut. With one hand keeping light tension on the wrench, I use a torch to heat the stud near the case. When he heat softens the loctite, the wrench turns pretty easy. When the studs are out and things have cooled down I run a greased chaser through the holes to remove any remaining loctite. This way the threads in the case are protected from damage that can occur when breaking the studs loose cold.

If the cases still have flywheels in them, I fish some masking tape sticky side up between the flywheel and the case to help keep loctite pieces from going ito the crankcase. You can stiffen the tape to make it easier to handle by flagging it to a small zip tie. Then blow the residual grease out with brake clean.
Title: Re: Reusing Cylinder Studs
Post by: CVOThunder on January 11, 2020, 03:49:08 AM
Was watching an old Model T engine rebuild video and the guy had a coiled element heat "gun" to heat up the stud so it would release from the rusted block. Probably don't need something that intense on an aluminum block but looked better than using a torch. Could have been an induction type thing.

I'm thinking that bigcerts are the same type of thing as case savers used on VW Beetle blocks?
Title: Re: Reusing Cylinder Studs
Post by: Hillside Motorcycle on January 13, 2020, 04:11:37 AM
No need to replace the cylinder studs in that application whatsoever, thus the reason for them being not included.
Not an opinion.
Title: Re: Reusing Cylinder Studs
Post by: No Cents on January 13, 2020, 09:47:44 AM
Quote from: Hillside Motorcycle on January 13, 2020, 04:11:37 AM
No need to replace the cylinder studs in that application whatsoever, thus the reason for them being not included.
Not an opinion.

    :agree:
cylinder studs...no.
head bolts...I would.
Title: Re: Reusing Cylinder Studs
Post by: JMHD on January 16, 2020, 04:13:27 PM
 
Quote from: Hillside Motorcycle on January 13, 2020, 04:11:37 AM
No need to replace the cylinder studs in that application whatsoever, thus the reason for them being not included.
Not an opinion.
:agree:
Title: Re: Reusing Cylinder Studs
Post by: sfmichael on January 19, 2020, 12:24:21 AM
replace the head bolts / nuts if you're concerned

studs are good to go for multiple uses unless a problem is noted