Advantages/disadvantages head bolts vs. head studs

[turbowrenchhead]

With the noss head that I run I have had some issues with the copper washers. I purchased vittos acorn nut kit. However they squish so much that they compress onto the studs. This makes for a very difficult head removal. Are there any disadvantages to running a head bolt with a flat flange? One can just use a lil silicone to seal the flange to the head to seal the coolant chamber. This would make a head removal much easier.

Edited May 21, 2014 by turbowrenchhead

[BUILDER]

The copper washers are really only there as a fail safe. As long as your O-Rings are all good there will be no water to leak out of the nuts. I have ran plenty of motors with no copper washers under the nuts. 

[Larry's Shee]

Studs don't wear threads out in alum cyls.

[turbowrenchhead]

I tried just acorn nuts without washers, they leaked. There are some studs that the o rings don't seal off.

[dirtydownunder]

i use a lil bit of sealant on the threads and copper washers. 

 

something is up if they keep leaking tho, they normally dont.

[turbowrenchhead]

I wonder if steel washers and a bit of silicone work.....

[dirtydownunder]

Copper is the perfect sealing washer as it's soft. Just look for fatter copper washers if yours are really thin.

[Dixie normus]

It blows using copper washers. I prefer the pro design/noss type that puts a o ring around each stud

Edited May 22, 2014 by Dixie normus

[m671054]

Studs clamping load would be at the cyl deck. Bolt clamping load would be under bolt head. Studs are a much better design. Find some better washers check mcmaster carr

[Dixie normus]

Studs FTW

[Abe]

I personally was curious why one needs the acorn nuts with NOSS style heads vs not needing them with a pro design even though both have pretty much the same design for orings around the studs. In my belief it's due to most people running the noss head use their oem studs which do not have a stepped up center section and have no more than a single thread edge or nothing contacting the oring to prevent the upward flow. the pro design studs and even the arp studs that I'm using have a longer and larger diameter center section that makes a seal against the oring to prevent upward flow of the coolant through the threads.

[registered user]

ive got various engines. some have studs and others have bolts. never had a problem with either one

[m671054]

ive got various engines. some have studs and others have bolts. never had a problem with either one

were they always bolts? Or was it designed with studs and you switched to bolts? As your aware bolt pattern/spacing and thread depth, along with head rigidity would all factor into your ability to maintain a good seal.

[registered user]

no i havent put bolts in where studs originally were. ive never had the need to do that. got couple honda which use studs in the cylinder and a nut holds down the head. got couple ktm's and they use bolts that screw into the cylinder. both methods have worked fine

Edited May 22, 2014 by registered user

[turbowrenchhead]

These cylinders I have now are at 66mm and they won't have a long life on the bike. I think I'm going to get some bolts today. My Noss head doesn't have seperate o rings for each stud. Just the main o rings for the head to seal it off from the dome and atmosphere. There are only two studs that are outside the main o ring that are not going through the coolant chamber.