Logo
FULL SITE MENU

BF 130 head bolt torque Spec

V

Vinh

Regular Contributor
Does anyone know the head bold torque spec for a BF130? Also anyone know where can I get a head gasket for the same motor? I tried boats.net and they don't have it and they couldn't find it either. Thanks for any info.
Vinh
 
It is 12251-ZW5-023. It will work on all of the 130's. There are still about 11 in stock at Honda US.

As for the torque values. There are several different torque values depending on the size of the bolts...and there are two patterns when doing it.

Some of the bolts are torqued to a value then turned another 180 degrees in 90 degree steps.

I recommend getting a manual to see the sequences and identification of bolts and their torques. It seems too complicated from my feeble mind to explain it in only words. It may be misunderstood and you could do harm to the engine or yourself.


Mike
 
As Mike points out, there are 18 bolts total. 10 of them are "turn to torque" "flange" bolts and the sequence and pattern is pretty complicated for describing with the written word and no pictures. The remaining bolts use the nominal torque for their dimension but there are specific location and sequence for them as well.

Quantity...... Dimensions

10............ 12mm X 163mm

4 ............ 10mm X 90mm

2 .............. 8mm X 80mm

1 ............ 10mm X 70mm

1 ............. 8mm X 50mm

Do you know where each of these bolts is supposed to be located in the head? Again, as Mike said, if you get this wrong, much bad juju. Here's where a shop manual can save you an engine.
 
Last edited:
Guys,
Thanks for the replies. I got the head gasket. Yes I know where all the bolts go and the sequence. I just need the torque number for the 12MM head bolts. 1/4 and 1/2 turn after the torque spec is a lot. But this is all depends on the torque value that it printed in the manual. Can one of you give me the torque number for the 12mm bolts? Thanks
Vinh
 
Ok, here goes;

First, and this is important, coat all bolt threads and flanges with engine oil. It sounds like you've done this before so I hope you already know how important it is not to delete this step.


The 12mm X 163mm bolts are torqued initially to 33lb. ft.

The diagram I have shows them being tightened in an "outside-in" pattern. Working from the ends of the head and crisscrossing alternately in toward the center during this "initial" torque sequence. I find this somewhat unusual so let me know if this matches the information you have.

You then continue the process by marking the head at each bolt flange "I" mark and, using a conventional "inside/out/crisscross" pattern you turn each 12mm bolt an additional 90 degrees while also performing the first of two "step" torques to the 8 and 10mm bolts. The process is complete after repeating this step a second and final time.

The 8mm bolts are to have a final 20lb. ft.

The 10mm bolts are torqued to 29lb. ft.

DISCLAIMER:
While these specifications sound reasonable, they do not come from the HELM INC. manual so I hope they are accurate. I'm pretty sure this came from a Seloc repair manual copied to a CD. I do not and have not worked on this engine or used this procedure so I have no first hand knowledge of how effective it is. I offer this to you because you sound like you are stuck and need some direction. But, you will have to be the ultimate judge whether or not to use this or if it will meet your needs.

Good luck.
 
Careful of the Seloc manuals. The Helm manual says to torque clockwise from inside out. Initial torque value is 33 ft-lb in 2 to 3 steps. Then two additional turns of 90 degrees.

Mike
 
Jgmo,
Thank you very much for the info. That really help. I believe the sequence you described is for removing. Installing should start from the center and criss cross and work your way out. 33 ft/lbs seems low. I just check my car manual and the head bolt is 55ft/lbs. Let me double check with my honda motorcycle engine spec. It should be the same engine so the torque should be the same. I don't like the idea of turning the extra 90 or 180 degrees after you set it to the spec. Thank you again for the info
Vinh



jgmo said:
Ok, here goes;

First, and this is important, coat all bolt threads and flanges with engine oil. It sounds like you've done this before so I hope you already know how important it is not to delete this step.


The 12mm X 163mm bolts are torqued initially to 33lb. ft.

The diagram I have shows them being tightened in an "outside-in" pattern. Working from the ends of the head and crisscrossing alternately in toward the center during this "initial" torque sequence. I find this somewhat unusual so let me know if this matches the information you have.

You then continue the process by marking the head at each bolt flange "I" mark and, using a conventional "inside/out/crisscross" pattern you turn each 12mm bolt an additional 90 degrees while also performing the first of two "step" torques to the 8 and 10mm bolts. The process is complete after repeating this step a second and final time.

The 8mm bolts are to have a final 20lb. ft.

The 10mm bolts are torqued to 29lb. ft.

DISCLAIMER:
While these specifications sound reasonable, they do not come from the HELM INC. manual so I hope they are accurate. I'm pretty sure this came from a Seloc repair manual copied to a CD. I do not and have not worked on this engine or used this procedure so I have no first hand knowledge of how effective it is. I offer this to you because you sound like you are stuck and need some direction. But, you will have to be the ultimate judge whether or not to use this or if it will meet your needs.

Good luck.
Click to expand...
 
Funny how some folks do not like the correct information on tork values.--------My suggestion is to spend to money on the proper manual and see the instructions for tork in black and white !!
 
Hi guys,

I have the shop manual for bf130 and kind of confused on the rocker assembly install Page 9-10 where it says
"Be sure to tighten the 8x76mm flange bolts to specified torque and tighten the 6x40mm flange bolts to the standard torque."

What is the difference between specified torque and standard torque? Is it the same?

It does not say anything about 90 degrees increments such as the main 12x163mm cylinder head bolts which require the standard torque plus the 180 degrees in 90 degree increment.


jgmo said:
Ok, here goes;

First, and this is important, coat all bolt threads and flanges with engine oil. It sounds like you've done this before so I hope you already know how important it is not to delete this step.


The 12mm X 163mm bolts are torqued initially to 33lb. ft.

The diagram I have shows them being tightened in an "outside-in" pattern. Working from the ends of the head and crisscrossing alternately in toward the center during this "initial" torque sequence. I find this somewhat unusual so let me know if this matches the information you have.

You then continue the process by marking the head at each bolt flange "I" mark and, using a conventional "inside/out/crisscross" pattern you turn each 12mm bolt an additional 90 degrees while also performing the first of two "step" torques to the 8 and 10mm bolts. The process is complete after repeating this step a second and final time.

The 8mm bolts are to have a final 20lb. ft.

The 10mm bolts are torqued to 29lb. ft.

DISCLAIMER:
While these specifications sound reasonable, they do not come from the HELM INC. manual so I hope they are accurate. I'm pretty sure this came from a Seloc repair manual copied to a CD. I do not and have not worked on this engine or used this procedure so I have no first hand knowledge of how effective it is. I offer this to you because you sound like you are stuck and need some direction. But, you will have to be the ultimate judge whether or not to use this or if it will meet your needs.

Good luck.
Click to expand...
 
Hi,
"Standard" torque is used to specify the maximum amount a given diameter bolt can be placed in tension without becoming permanently distorted or stretched beyond it's elastic properties.

Bolts actually work by acting as a spring. As a bolt approaches maximum torque it is being elongated slightly. This elongation puts the joint in a state of tension. This spring like tension keeps the fasteners from working loose because of external forces. An "over-torqued" bolt can be stretched beyond it's ability to "spring back" to it's original length and is said to have "gone plastic". In extreme cases of over tightening, the bolt diameter can be seen to change and is called "necked down". If this occurs, the bolt can no longer be relied on to hold the joint in a permanent state of tension. Eventually, sometimes very quickly, the joint will loosen and fail.

American or S.A.E. grade bolts are marked with slash marks to indicate tensile strength. 3 slashes= grade 5 and 6 slashes = grade 8....the two most common grade bolts used in the American automotive industry.

The metric or ISO grading system uses numbers on the heads of bolts to indicate "hardness". You will find 8.8, 10.9 and 12.9 stamped on the heads of metric bolts but there are a few more being used.

So, getting back to the question of "standard torque" for a bolt it comes down primarily to the bolt's diameter and grade. The higher the grade of a given diameter bolt, the higher the torque required to put it in tension.

You can Google a bolt "standard torque" chart when standard torque is called for and use the diameter and grade rating to arrive at a reliable torque setting.

On the other hand....

Specified torque is something the equipment engineers have developed for putting a given bolt into maximum tension just below failure. This is arrived at through exhaustive measurement and testing. It takes the clamping ability of a bolt right out to the edge to achieve maximum clamping and holding during thermocycling, vibration and stress.

Most bolts used in this way are considered one time use only. This is often referred to as "torque to yield" (TTY) or "torque to fail" and is used extensively in engine assembly. Primarily head to cylinder block clamping. These types of bolts should not be reused.

It is also very important to follow directions given for torquing these fasteners. The tightening sequence s and patterns are important for achieving what the engineers intended. It is also very important not to deviate from the thread lubrication recommend.. If no lube is called for, don't use any.

Bolt joints calling for thread locker (Loc-Tite) will usually specify a higher torque than standard because thread lock is not a lubricant but will actually add a friction factor to the thread interface.

That's about it.
Hope I didn't bore you.
 
Last edited:
Great info jgmo!!

The other question I had was regarding the specified torque. Shop Manual does not give directions to inspect or replace these bolts on the head assembly since I need to remove old head parts and swap to new head. The only bolts that are to be checked or replaced is the torque to yield main bolts (10 of them) around the pistons on the head when re-installing.

If a specified torque is given for the rockers/cam assembly, based on what you said, it would be considered are TTY bolt... If this was the case, why doesn't the shop manual note to torque 90 degrees twice to give 180 degrees rotation similar to the main head bolts... If a specified torque is given with no 90 degrees re-torquing requirement, to me it seems that it won't stretch these bolts and they can be reused.

In the Engine re-assembly sections, I found 3 torques in bold,

Torque = this one appears only for the head main bolts and requires 180 degrees rotation with drawing w/ angles
Specified Torque - lbs with no degrees of rotation stated
Standard Torque (which I think) is nominal torque - lbs with no degrees of rotation

I just thought specified and standard torque was overlapped... and was the same.

jgmo said:
Hi,
"Standard" torque is used to specify the maximum amount a given diameter bolt can be placed in tension without becoming permanently distorted or stretched beyond it's elastic properties.

Bolts actually work by acting as a spring. As a bolt approaches maximum torque it is being elongated slightly. This elongation puts the joint in a state of tension. This spring like tension keeps the fasteners from working loose because of external forces. An "over-torqued" bolt can be stretched beyond it's ability to "spring back" to it's original length and is said to have "gone plastic". In extreme cases of over tightening, the bolt diameter can be seen to change and is called "necked down". If this occurs, the bolt can no longer be relied on to hold the joint in a permanent state of tension. Eventually, sometimes very quickly, the joint will loosen and fail.

American or S.A.E. grade bolts are marked with slash marks to indicate tensile strength. 3 slashes= grade 5 and 6 slashes = grade 8....the two most common grade bolts used in the American automotive industry.

The metric or ISO grading system uses numbers on the heads of bolts to indicate "hardness". You will find 8.8, 10.9 and 12.9 stamped on the heads of metric bolts but there are a few more being used.

So, getting back to the question of "standard torque" for a bolt it comes down primarily to the bolt's diameter and grade. The higher the grade of a given diameter bolt, the higher the torque required to put it in tension.

You can Google a bolt "standard torque" chart when standard torque is called for and use the diameter and grade rating to arrive at a reliable torque setting.

On the other hand....

Specified torque is something the equipment engineers have developed for putting a given bolt into maximum tension just below failure. This is arrived at through exhaustive measurement and testing. It takes the clamping ability of a bolt right out to the edge to achieve maximum clamping and holding during thermocycling, vibration and stress.

Most bolts used in this way are considered one time use only. This is often referred to as "torque to yield" (TTY) or "torque to fail" and is used extensively in engine assembly. Primarily head to cylinder block clamping. These types of bolts should not be reused.

It is also very important to follow directions given for torquing these fasteners. The tightening sequence s and patterns are important for achieving what the engineers intended. It is also very important not to deviate from the thread lubrication recommend.. If no lube is called for, don't use any.

Bolt joints calling for thread locker (Loc-Tite) will usually specify a higher torque than standard because thread lock is not a lubricant but will actually add a friction factor to the thread interface.

That's about it.
Hope I didn't bore you.
Click to expand...
 
Well, I can't account for the separation of "specified" as opposed to standard in those instructions. It could be that engineering determined that those particular bolts require a slightly different torque than "standard" as would be listed on a generic chart.

Or, it could be the manual writers simply conflated the two terms. It happens.

I didn't mean to imply that all specified torque bolts are to be considered torque to yield. My apologies if it seemed so.

Typically TTY bolts will always be called out as one use only no matter what the tightening process. And, it's not unusual for "specific torque specs" to be listed in a manual for reusable fasteners. Ad a matter of fact, my experience is that most bolts in an engine assembly have specified torque listed, the majority of which are NOT TTY. And, it is actually unusual for a mechanic to be directed to use standard torque settings. Although, most quality manuals will provide a standard torque chart for common bolts.

Hope this helps.
 
Thanks!

I will re-order the main tty bolts for the head assembly. The others I will check for warp and stretching. I think you nailed it with regards to specified as opposed to standard per instructions compared to the generic chart.

jgmo said:
Well, I can't account for the separation of "specified" as opposed to standard in those instructions. It could be that engineering determined that those particular bolts require a slightly different torque than "standard" as would be listed on a generic chart.

Or, it could be the manual writers simply conflated the two terms. It happens.

I didn't mean to imply that all specified torque bolts are to be considered torque to yield. My apologies if it seemed so.

Typically TTY bolts will always be called out as one use only no matter what the tightening process. And, it's not unusual for "specific torque specs" to be listed in a manual for reusable fasteners. Ad a matter of fact, my experience is that most bolts in an engine assembly have specified torque listed, the majority of which are NOT TTY. And, it is actually unusual for a mechanic to be directed to use standard torque settings. Although, most quality manuals will provide a standard torque chart for common bolts.

Hope this helps.
Click to expand...
 
Back
Top