torque on head bolts

B

blompod

Guest
I checked the head bolts on my 50cc in the process of breaking in and the head bolts all took a good half turn without any effort at all. I dont have a torque wrench and was wondering if nipping them up after every other ride is ok. Planning on getting a torque wrench down the track but they are not the cheapest of tools . Thankyou :D
sorry this should have been in technical :???:
 


G

Guest

Guest
I wouldn't waste your time on a torque wrench. Get some better nuts or double nut each headbolt. My bolts get loose often.
 
G

gone_fishin

Guest
blompod: warning! sometimes it's the BOLT and not the nut that has loosened.

ok, if you don't have the funds or other resources to change out headbolts or nuts, i strongly suggest next time you check the headbolts you make absolutely certain each one is fully screwed into the block before re-torqueing. otherwise, as the bolt loosens and you re-tighten the nut, you will eventually pull the bolt outta the block, stripping the hole in the process.

ps-any time anyone feels a topic would be better suited in another forum, simply
PM srdavo with the details and it's a done-deal 8)
 
B

bolton75

Guest
A beam type torque wrench does not cost much money (generally - some of them are dear but I'd just get one of the cheaper ones) and is perfect for use on bicycles. Simple and effective.

Generally the click type torque wrenches are the ones that will set you back quite a few $$$.

I've always found Parktool tools to be of good quality and they sell two different types of beam torque wrenches (TW-1 & TW-2). Check it out and decide for yourself.

http://www.parktool.com/repair/readhowto.asp?id=88
 
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F

fetor56

Guest
A beam type torque wrench does not cost much money (generally - some of them are dear but I'd just get one of the cheaper ones) and is perfect for use on bicycles. Simple and effective.

Generally the click type torque wrenches are the ones that will set you back quite a few $$$.
Those cheap beam type TR's arn't particularly accurate and since u don't need much pressure in the first place i would be concerned about using one.
I've found that a MODERATE pressure with a spanner or socket(regularly) is a good check for tightness.When checking only apply enough pressure to see if the head bolts move....in other words don't go tightness crazy. :)
 

will_start

Member
Joined
Jan 20, 2008
Messages
486
torque wrench idea for non torque wrench owners

Hi All,

Here's my Torque Wrench(TW) idea for those without one.
{ here's a link for those with no idea what a Torque Wrench is }
http://en.wikipedia.org/wiki/Torque_wrench

If we had people who had a torque wrench they could work out the number
of turns it takes to get the torque limit reached on their bikes

Get a few people to do it on Same size engines.
Then Average the figure.

Then we would have a torque setting for beg-giners
with no Torque wrench, but probably with a socket set.

The starting point would be when you can gently
turn the nut until it stops you tightening.
Or maybe until it hits metal would be the starting point?

Here's my experience:
I went and spent $45 on a micrometer torch wrench
that gives 1 inch pound increments.

here's a pic of one of similar type.

http://en.wikipedia.org/wiki/Image:Click-torque-wrench.jpg

The setting in a couple of the online manuals said use
12 foot pound, which I believe is 124 inch pound
(12 inches in a pound right, I mean foot :cool: )

I had a socket wrench, that initially, i used to tighten to varying
amounts. It was a guess.

If I had a number of turns in mind, at least that would
have helped determine how many turns was in the range of being right.

Like the Carbie screw setting of 4 and a half turns.
It may be 4 on some, may be 5 on others, but at least you have a figure
to aim for. That setting done by a newbie could be 3 or 7.

The manual says always tighten the head bolts, a friend told me not to
tighten too much or I'll blow the head. So I ended up buying the tool
to stop my fears of snapping the bolt, or it being the reason
my bike would never start.

So, with my TW, I am going to re-tighten my head bolts from a starting
point.

I'll report back how I started and how many turns for each head-bolt.
Probably later this week.

Some are bound to shoot down this idea,
some are bound to consider the idea.
As Homer says, so easy to criticise, so hard to create.

I think I just found my sig.

CYA

WILL START
 
A

Alaskavan

Guest
Will, I think 12' lbs = 144" lbs. Someone else has probably mentioned this, but what the heck. If you have a good fish weighing scale, hook it on a (breaker bar) wrench 12" from the center of the socket. Pull on the scale. When the scale reads 12 lbs, I think that would mean you've applied 12 ft. lbs of torque.
 
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I

ibdennyak

Guest
Hi All,

Here's my Torque Wrench(TW) idea for those without one.
{ here's a link for those with no idea what a Torque Wrench is }
http://en.wikipedia.org/wiki/Torque_wrench

If we had people who had a torque wrench they could work out the number
of turns it takes to get the torque limit reached on their bikes

Get a few people to do it on Same size engines.
Then Average the figure.

Then we would have a torque setting for beg-giners
with no Torque wrench, but probably with a socket set.

The starting point would be when you can gently
turn the nut until it stops you tightening.
Or maybe until it hits metal would be the starting point?

Here's my experience:
I went and spent $45 on a micrometer torch wrench
that gives 1 inch pound increments.

here's a pic of one of similar type.

http://en.wikipedia.org/wiki/Image:Click-torque-wrench.jpg

The setting in a couple of the online manuals said use
12 foot pound, which I believe is 124 inch pound
(12 inches in a pound right, I mean foot :cool: )

I had a socket wrench, that initially, i used to tighten to varying
amounts. It was a guess.

If I had a number of turns in mind, at least that would
have helped determine how many turns was in the range of being right.

Like the Carbie screw setting of 4 and a half turns.
It may be 4 on some, may be 5 on others, but at least you have a figure
to aim for. That setting done by a newbie could be 3 or 7.

The manual says always tighten the head bolts, a friend told me not to
tighten too much or I'll blow the head. So I ended up buying the tool
to stop my fears of snapping the bolt, or it being the reason
my bike would never start.

So, with my TW, I am going to re-tighten my head bolts from a starting
point.

I'll report back how I started and how many turns for each head-bolt.
Probably later this week.

Some are bound to shoot down this idea,
some are bound to consider the idea.
As Homer says, so easy to criticise, so hard to create.

I think I just found my sig.

CYA

WILL START
Interesting concept. Been wrenching on my equipment for quite a few years, and Snap-On learned to love me. . Not passing judgement, just adding information. What a torque wrench measures is the friction developed to put a given amount of tension on a fastener. So you are already using apples to measure oranges. (Ideally you would measure the straight line tension on the bolt.....not practical when you are laying under a Cat in the mud replacing bearings. :yuck:) Torque wrenches measure friction very accurately, but other factors like lubrication, tensile strength of the fastener determining stretch, etc. enter into it, and can cause discrepancies. Counting turns adds more error possibilities because of different gasket compositions etc. That being said, who knows, it might work. I kind of think you may be over complicating the issue, but it can't hurt. The big thing would probably be using a big enough amount of samples to get a good average. If it works, I have a friend in Wisconsin I would like to introduce you to. He always said he used the bulge of his bicep to determine torque on the head bolts of his diesel farm tractor. Unfortunately, he also spent more time looking at his bicep bulge, than using the tractor. Blew lots of head gaskets. :D Anyway, try it and see what shakes out. Oh, by the way...your starting point is called "finger tight". :D

Denny
 

will_start

Member
Joined
Jan 20, 2008
Messages
486
Hey All,
Alaskavan, thanks for correcting me.

I can't believe I got the torque setting wrong.
12 foot pound = 144 inch pound.
1 foot = 12 inches.
12 x 12 = 144 not 124. DUH!!

That said, I had an ex aeronautical engineer set it for me,
now thats a worry !!

Oh well, this is why I include as much detail in my posts as possible.
I left the start point open ended, as I may come up with a better way when
I do actually get the tools out.

I never know what I'm going to come up with each time I go out to play.

Denny, tell your Wisconsin friend to buy a TW, tractors don't come cheap.

Will.
 
K

kerf

Guest
Well heck, might as well dump my opinion in here too. Torque wrenches are inexpensive, aluminum strips easy, cylinders can be warped with incorrect torque procedures. The torque pattern on a 4 bolt head would be pretty hard to screw up. I always tighten to 1/3 torque all the way around then 2/3 etc.
Does anybody know the specified torque on these head bolts? Wrong torque can be bad. A 60 in. lbs. wrench would be about all I would trust at low settings in aluminum.
 
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