torque on head bolts

will_start

Member
Joined
Jan 20, 2008
Messages
486
Hey Kerf,

Whats inexpensive to you living on a $50-100K income may be expensive
to a kid on a $500 a year income. Believe me I know, been there done that...

So my idea is centred around helping those with standard tools and no funds
to buy more. I have easily spent the cost of the motor on tools and spares
and ...

To answer your question for the chinese motor 12 ft/lb is the torque given by the online manual I used.

See below link.

http://www.zbox.com.au/instructions.htm

6. Head Bolts

Tighten all fasteners after each five hours of operation. It's most important to check cylinder head bolts: tighten in a X pattern to 12 ft/lb. using a torque wrench. A two piece cylinder and head design engine requires head bolts be kept tight. Important: Check head bolts before each and every ride, vibration can cause them to loosen and blow a head gasket. Caution: Do not over torque or head bolts may break off.

WS.
 


azbill

Active Member
Joined
Dec 15, 2006
Messages
3,697
personally, I hold my ratchet by the head (not the handle), and tighten
very little torque that way
it was a tip here a while ago, I can't remember who gave it
 
I

ibdennyak

Guest
Denny
Your buddy finger tight might be 12 ft lbs. Where mine, if the wind blows any harder the thing will unscrew:eek:I had to add my 1/2 cent you guys are doing good knocking it out on proper torque tech. better to use a torque wrench than not at lest your consistently wrong( I hope a little under torque instead of way over as in stripped or broke) instead of all over the place.
Norm

Very true. One thing I did discover after checking free hand tightening vs torque wrench tightening is that from about 3/8 and down, the gut reaction is to over tighten, and from 3/4 on up the tendency is to undertighten. If I remember right, the torque for a 1/4 inch grade 5 bolt is like 12 ft lbs. That is about two fingers on a box wrench. I also remember replacing a head gasket in a fiat allis crawler...425 ft lbs. That is both arms with a foot propped against the block and using a 3/4 wrench. (expensive sucker). Even a cheap one at least makes one aware of about what is needed. Now as for our metric friends.....they're on their own. :LOL:

Denny
 
A

Alaskavan

Guest
Hi Kerf. Those inexpensive TW's you linked to only go to 60 - 65 inch lbs. That's not enough.
 
K

kerf

Guest
I see that now. The point is there are reasonably priced inch pound wrenched available. I would advise against using a foot pound wrench at this low torque, something in 150 - 240 inch pounds would be about right. I use those other wrenches mostly for setting bedding screws on target rifles.
 
A

Alaskavan

Guest
I agree about not using a foot pound wrench. I wouldn't trust one much at such a low level of torque.
 

will_start

Member
Joined
Jan 20, 2008
Messages
486
OK,

I did a tighten of my head-bolts from a light finger tight position.
It was only 3/4 of a turn that got the torque wrench to stop turning.
I had to do it in 1/4 turns, but basically that was it.

Can anyone else do this test on their motor who has a torque wrench ?

I'd like to know that I'm doing the right thing here too.
As I don't know that I trust my torqueing skills.

CYA

WS.
 
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