head bolt toqure spec HELP

nastygramus

nastygramus

New Member
OK I finally got my Manic Mechanic head Ive read till my eyes started bleeding and couldn't find what to torque the head bolts @ can I PLEASE get a little help on this one ? Thanks
 
130 to 150 inch pounds, and throw the chrome acorn nuts in the trash and replace them with shouldered hex nuts. NO LOCTITE.
Check the torque after the engine has reached operating temperature a couple of times and tighten if necessary but do not exceed the 150 figure.

You'll also want to make sure the studs are tight in the case before torquing the head down.
Tom
 
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My eyes thank you ! This motor came with regular (non-acorn) nuts with 2 flat washers and a lock washer if I use a shouldered hex nut can I do away with the washers ? with all of them on there I don't like how much thread the nut can bite !
 
Yes, you can do without the washers, especially the lock washers. You always want at least two threads extending past the nut, on any assembly, not just your bike.

Tom
 
If we're talking about a china girl motor, I've come to the conclusion that 125 in lb is plenty. More than than that risks cylinder distortion. Just be advised, you'll need to retorque the head bolts about 4 or 5 times in the first few hundred miles, starting after the first heat cycle.

For a 50cc with 6 mm cylinder studs 120 in lb is good.
 
Also, a dab of anti-seize is a good thing one the studs. For my mind, every threaded fastener should have loctite, or anti-seize. A dry thread tends to either come loose when you want it to stay tight, or get stuck when you want it to come loose.
 
Hi, its adviseable 2 loctite the studs into the cases, but dont "bottom" them, take them to 1 or 2 threads from being bottomed. Its also adviseable 2 use 1 flat washer with the nuts. I always put a spot of loctite blue 2 prevent them vibrating loose, as I do with most things on the bike, even tho its relativly smooth running. Cheers.
 
I'm going to repeat what I've said here many times. There is no reason to rely on Loctite (thread locking compound) on engine fasteners. It is absolutely unnecessary as long as the proper torque is applied to the nuts and studs and they are re-torqued after a few heat/cool cycles. Thread locking compounds will only cause you problems down the road especially if the high strength variety (red) Loctite is used on engine fasteners.

Where this myth originated, I have no idea, but you only need to talk to those who have experienced a sheered fastener to know what you'll be up against with a thread locked stud or bolt.
Those who use/rely on it have obviously never attempted to disassemble the parts they have 'glued' together with a thread locking product.

Tom
 
I started using loctite after I got tired of picking up all the stuff that vibrated off the bike.

Well mostly. The muffler cap I brazed on - :)
 
Actually, I have undone fasteners that I have used loctite on, many, many, many times, without a problem & with little, if any more effort than if no loctite was used, which I have also done. If the correct amount of the right type of loctite is used for the particular application, u wont encounter this type of problem, with no need 2 retension or worry about it vibrating loose. No, its not absolutely nescessary, but it aint gunna cause sheered head studs folks, rest assured. Cheers
 
In the event that u run into a problem where some 1 has used the wrong grade of loctite on something (super retaining compound on ur cars wheel nuts) & it dont wanna undo, heat it with a propane torch, (no,, u dont need the gas axe) & then try. Heat should break the loctite down. Cheers
 
2door said:
130 to 150 inch pounds, and throw the chrome acorn nuts in the trash and replace them with shouldered hex nuts. NO LOCTITE.
Check the torque after the engine has reached operating temperature a couple of times and tighten if necessary but do not exceed the 150 figure.

You'll also want to make sure the studs are tight in the case before torquing the head down.
Tom
Click to expand...

What would it be in Foot pounds?
 
i agree about the loctite save the exaust bolts. unless you have it fastened to the frame which i dont loctite in those threads i highly reccomend, and throw away the god damn studs, they are all garbage!
.xx.
 
I used red locktite to secure the head studs into the threads in the base of the engine. Now they don't twist out when I remove the head nuts. Then I sort of made that hand motion that people do after throwing trash in a dumpster. You know what I mean, like proud of a job well done? Took care of THAT issue? (sorry, that bit of description added nothing..)

But....was this a bad idea? From reading this thread I'm thinking it was a bad idea..
 
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Re: Waterproofing a mag?

Hi, using loctite type products is a matter of personal preference, just use as directed & in correct amounts if u do. The way u used red loctite is wot its meant for, so the stud stays put when u undo the nut thats had blue loctite applied. If u used correctly u'll still b able to remove it when nescessary, as stated on the container. These products have been around for a long while & I imagine they did their R & D to get the formulation right. When fitting the studs into the cases it an idea to not quite bottom the studs due to different expansion rates. Cheers
 
Okay good tip. I did bottom them out, but not very hard. What you say makes good engineering sense. In future I will back off slightly after the bottom position.
 
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