Threaded Rod as Head Stud replacement

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Wickedest1

Member
Oct 31, 2012
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I appreciate the input. As soon as I can scrape up a dollar ill go get some nuts. But to keep every ones mind at ease I measured how deep the acorn nuts go before they bottom out. I've made sure they didn't. Extra washers to even out the difference. And I'm sticking to inch pounds.
 

Wickedest1

Member
Oct 31, 2012
688
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Ok, 112 miles later, 62 of them in a single run and the head studs and bolts are great...still holding its initial torque of 125in lbs...I'm happy...seems to start easier...maybe its my imagination...but I can walk start my bike...cold start this way too...takes 2or3 tries, but no more downhill bump starts...
 

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
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People are now torquing stock studs to 25 ft/lbs? Holy Moly.

Threaded rod works fine, 18 ft/lbs is fine (never had mine come loose at 18). But retightening when cold after a couple heat cycles always helps.
 

Wickedest1

Member
Oct 31, 2012
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about 60 more miles on my flying horse with this threaded rod head studs...with the stock studs i was forced to check tight every 5 rides...ive put almost 200 miles on her since the replacement and i have to say that the torque rating is still the same...125in lbs...no feet...but seriously having proper torque on the head has made this thing scream...definitely starts easier and i find it has a better burn...by that i mean not nearly as much 2smoke as before...maybe its just the wind always working in my favor...except going uphill...then theres always a bunch of wind pushing against me....wee.
 

Wickedest1

Member
Oct 31, 2012
688
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ive hit the 350 mile mark with this threaded rod in place of studs...still at 125 inch pounds...

id say this stuff is perfect...

heres a link to the exact threaded rod ive used...

http://www.nutty.com/M8-x-125-x-1-mtr-B7-Thr-Rod-4140-Aloy-Steel_p_13641.html

i only needed one 3 foot section and wouldve had enough to do 7 total studs but i enstead got a 4 foot section directly from the store front...ive got enough for another complete set of studs...

doubtful ill ever need to change these studs out ever again on this engine...

hope this has been of some use for you...
 

Wickedest1

Member
Oct 31, 2012
688
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Gps says 1208.7 miles since the threaded rod went in...same torque, no blow by...im convinced...this, to me, seems a viable replacement...hope this helps someone
 

nightcruiser

New Member
Mar 25, 2011
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Gps says 1208.7 miles since the threaded rod went in...same torque, no blow by...im convinced...this, to me, seems a viable replacement...hope this helps someone
Yah, this is great info. It's nice to KNOW something has been tried and tested and worked well before you take a chance and go in that direction. Sourcing studs can be a PITA really, that's one reason I just sprung the few bucks for a kit from SBP, cause I got tired of trying to find the best source and the best studs that will work over the internet. Knowing this works I would be more likely to try it... thanks.
 

2door

Moderator
Staff member
Sep 15, 2008
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This is an old issue that has suddenly popped up again and this might be the place to revisit. There are engines out there with different threads in the case as opposed to the top end. Typically what I've seen are 8mm cylinder studs with a 1.25 thread on the top, or cylinder head end and a 1.0 thread on the case end.
I have an engine on my bench right now that was a warranty return to a vendor that the original purchaser had for whatever reason, taken the head and cylinder off. He then tried to reinstall them and got the studs in wrong. He forced the course threads into the case and stripped the threads in the aluminum then tried to force the acorn nuts onto the fine threads at the top of the studs. He ruined everything and sent the engine back saying the head gasket leaked.

In short, check the threads on the studs. Some have course threads top and bottom, some have fine threads in the case and course on the top end.

Want pictures to prove it? Just ask.

Tom
 

dumpstercrusher

New Member
May 20, 2013
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Glen Burnie, Maryland
how did u cut the studs? my buddies head stud ripped out when i put lil pressure and completely tore it out. This is how it came from factory. Are the studs u got just a bit bigger than the one u stripped the threads?
 

Wickedest1

Member
Oct 31, 2012
688
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You double up a set of nuts just past the cut point...and if you stripped tge block, putting a larger diameter threaded anything is going to destroy ther bottom end...when my stud stripped it was under the acorn nut, not in the block...please please please DO NOT buy threaded rod from home cheapo and expect it to work...if the stud hole is stripped you can drill it out and tap it larger, which isnt too difficult, or the helicoil...i have no idea about that...good luck to you both
 

Wickedest1

Member
Oct 31, 2012
688
7
18
41
connecticut
This is an old issue that has suddenly popped up again and this might be the place to revisit. There are engines out there with different threads in the case as opposed to the top end. Typically what I've seen are 8mm cylinder studs with a 1.25 thread on the top, or cylinder head end and a 1.0 thread on the case end.
I have an engine on my bench right now that was a warranty return to a vendor that the original purchaser had for whatever reason, taken the head and cylinder off. He then tried to reinstall them and got the studs in wrong. He forced the course threads into the case and stripped the threads in the aluminum then tried to force the acorn nuts onto the fine threads at the top of the studs. He ruined everything and sent the engine back saying the head gasket leaked.

In short, check the threads on the studs. Some have course threads top and bottom, some have fine threads in the case and course on the top end.

Want pictures to prove it? Just ask.

Tom
I agree 100%...so here's the way to bypass that, if you have coarse thread in the case use coarse threaded rod, fine thread...well you get the point...just buy some matching flanged hex bolts...
 

Huffydavidson

STREETRACER/MANUFACTURER
Jan 29, 2012
1,076
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st.louis,mo.
Ok guys, here the word I got. Back in 2011 Grubee, Powerking and some of other A grade manufactures changed over from 1.0 pitch to 1.25 pitch x 8mm thread . Healy coil kit cost about 30 bucks . however a perma coil kit on eBay is only 12 and its the same thing . I bought a bottom in from thatdax that had a bent c rod. I bought for parts. It had fine thread 1.0 pitch . so I decided I was going to have this Casey ready to build another race engine and I drilled out and put in thp earm coil.anyway if you call Dwayne and that stats he's got both studs dance1
 

thatsdax

Member
Feb 22, 2008
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I prefer 1.25 on the block as it is cast alloy and the extra meat makes for a solid connection. A good 1.25 cut is better than a poor 1.0 for sure.

Heli Coil works fantastic. When done to spec, it is stronger than the original threads. Enjoy the ride..