Anyone use studs on the cyclinder (head)

[bign1514]

I've read some people doing it, but really have seen any feedback. I know when you have worn threads - you can use heli-coils and timeserts. I've used both and had luck with timeserts (or keyserts). Heli-coil had trouble with alot of torque (maybe not installed perfectly - but good with low torque). If you went the timesert route (but you have to drill out a bigger hole where the water seals at), its cheaper to do the studs and acorn nuts. I've looked up parts in mcmaster-carr (love this site) and I came up with part numbers:

www.McMaster.com

93275A030 - studs

94000A039 - Nuts


I've had a Kawasaki cylinder with these in the past and love the idea of the stud and nuts. It just feels better torquing them down, instead of - I hope the screw doesn't spend.

But again I am no engine expert - just learning as I go.

Does anyone have any feedback on this method or use on the yamaha engines? Is there a reason?

Any thoughts?

 

[augustaf]

Kawis have a diff. cyl. design. Unlike Yam they require studs to be installed for boring or honing. Back in the day when people still raced skis, requiring frequent dissassembly everyone used studs, kept the aluminum threads from getting tired and failing. Don't need to do that if you have properly installed helicoils. I prefer not to use solid inserts unless they are made of SS - rare like "unobtainium"

 

[WFO Speedracer]

I have seen a few Yami setups like that ,studs have more clamping force ,that is a known fact, its somewhere in the neighborhood of 30% more.

 

[WB800BLASTER]

i use them on all my boats.

 

[Matt_E]

I have seen a few Yami setups like that ,studs have more clamping force ,that is a known fact, its somewhere in the neighborhood of 30% more.

Explain please.
Are you saying that 30ftlbs on studs ain't the same as 30ftlbs on bolts?

 

[WFO Speedracer]

Explain please.
Are you saying that 30ftlbs on studs ain't the same as 30ftlbs on bolts?

The torque on the studs and the bolts is the same the clamping force is not,with a bolt you are clamping the head by forcing it from one direction,pulling on the threads in the process,with studs you are effectively sandwiching the head between to two surfaces and clamping from both sides,thus 30% more clamping force,see Matt you really can learn something new here every day.You will never see a pro drag car with head bolts,or main bolts,the extra clamping force of the studs is the reason for that.:bigok:

 

[SJ/XPBri]

Explain please.
Are you saying that 30ftlbs on studs ain't the same as 30ftlbs on bolts?

Matt this doesn't really address the 30% issue, but studs do hold more evenly.

"Bolts vs. Studs

One of the first questions many new racers will ask is, "Which should I use, bolts or studs?" Bolts make it easier to remove a cylinder head with the engine still in the car, but it is best to use head studs whenever possible.

The biggest reason for this is cylinder head studs simply provide better and more consistent cylinder head torque loading. That's a fancy way of saying there'll be fewer blown head gaskets. When installed, a bolt must be torqued into place. This creates two forces on the bolt: a twisting motion and a vertical clamping load. But a stud is threaded into place with no clamping load-that comes when the nut is tightened down. Ideally, you only thread the studs finger tight in a relaxed state, install the cylinder head, and torque the nuts into place to provide the clamping load. This removes the twisting force from the equation, and the stud will only stretch in a vertical axis instead of stretching and twisting, in the case of a bolt. This provides more accurate and even clamping forces across all the studs. This is also true, in the case of studs over bolts, when securing the main caps.

There are also secondary benefits to using studs. First, it makes it easier to properly align the head gasket. It is also easier on the threaded holes in the block because you aren't using the threads in the block to pull the stud into place. If you are using an older block or an aluminum block, this is definitely preferable."

 

[bad93blaster]

i run the kawi studs in my motors

 

[bign1514]

good information - thanks! i think for around 30 bucks it would be worth transferring over to studs......

i just hate the feeling every time I go to re-torque my head or take it off (for whatever reason) I just hope the threads dont break!!

 

[waxhead]

I use studs in my race engines as well
it spreads the load on the threads