Snapping head bolts

[wagoon 2,429]

Nice explanation Greg. From my understanding of steel and tools if the bar was twisting that far to effect the torque application that much it isnt steel. Especially drop forged tools as the grains of the steel in compressed quite tight that is why they are stronger. Now because they are stronger the are also more brittle compaired to mild steel. If the bar was made of mild steel I could imagine that it might twist but hard tool steel will generally just snap.

The next part is the force required to actually twist steel even mild steel. If your are twisting the bar you are applying WAY to much force. No matter how long the bar is it should not twist when doing up head bolts. Im guessing the bar would need to be several feet long to twist enough that you snap bolts but again a bar that long would most likely snap because the longer the bar the less twist it can take. Just to clearify I am assuming that all bars are the same diameter just to make it easier as you will notice that after a certain length the bars get larger in diameter to put up with the force.

Myself I like to use my apprentice mechanics friend's method that he learned at a very large engine reconditioner. They used rattle guns to do up bolts to torque because " you can feel the torque through the gun" and that is word for word.

[gerg 10,871]

I guess if you're screwing engines together all day, every day, you get a feel for it. Problem is, one gun might be brand new with nice and tight internals, another might be well-worn with heaps of blow-by, and that's even if they're the same brand. Even lubing one up makes a massive difference to the torque output. I do like using guns generally though, eliminates many clearance issues trying to swing a big bar around.

 

As for the extension bar twisting, well the best quality ones dont snap, but they do twist quite a lot. They're likely to be chrome-vanadium, not tool steel. Snapping can be very dangerous, as witnessed at work when a linesman had a hex adaptor (tool steel) shatter in his hand when using a hydraulic rattle gun, while working up a power pole. It tore straight through his work glove and made a big mess of his hand.

[wagoon 2,429]

Tool steels can be medium carbon steels as well as alloy steels like with chrome vanadium. I know they will twist some but if they twisted enough to allow snapping of a head bolt before it got to the required torque they would work harden and then would snap. I get where your coming from and yes tools steels are quite dangerous if used incorrectly. I was focusing on the amount of force required to snap a head bolt and the bar being blamed for twisting and causing the issue.

I do think you are onto something with how many steps used to properly tension the head down.

[Outback Jack 6,352]

Heya Johnanthony,

Next time try using a lil anti seize compound on ya bolts before they go in, gives you a more true torque reading. Use quality head bolts like ARP because some cheapies are shit steel. That is about all I got.

Nice discussion on torque flex too. I use a long socket, no flex.

 

Jack.

[Flatchat 4]

Had the same issue, brought a new set of bolts same as u and snapped 2 out of the packet, threw them in the bin and ordered studs, Havnt had an issue since, I thought I had been setting the torque wrong aswel but I just thought the quality of the bolts nowadays are crap

[hendrixhc 10,921]

Use ARP head bolts?

[Johnanthony 3]

Must say in my 20 years as a mechanic I've never broken a bolt by using an extension bar on a torque wrench. Torque is a rotational force, and your extension bar simply becomes a torsion spring. No big deal, as a spring just stores energy. You just have to move the torque wrench a bit further to get to your setting.I'll equate it to weight. Instead of a rotational force like torque, weight is a linear force as a result of gravity. If i put a set of scales on the floor and stand on them, i weigh 77 kg (on a good day). If i then put the scales on a bouncy latex pillow (ie a spring), i don't suddenly weigh more or less. I still weigh 77 kg but it takes a certain amount of compression in the "spring" to reach my weight.Your torque wrench is nothing more than a scale that clicks off at a certain force. What you have attached to it is immaterial.I must read more about this torque inertia thing.The only way i can see an extension bar being a problem with torquing bolts up is when you're using the "angle torque" method, as used with E-series engines. Even at that, it will be less torque, not more.A couple of questions: were the bolts of decent quality? Did you use lube on the threads and under the heads? Did you do the torque-up in stages? The more stages the better. I like 3-4 stages myself, starting at 1/3 of the max setting.

 

Little experiment master.

Stand on a set of scales and deduct your weight.

Now jump on the same set of scales and see if the readings will fluctuate. Determine the maximum reading.

Now put said pillow on the same set of scales and deduct your combined weight. (You should see an increase in maybe 100 grams)

Now jump on the pillow on the same set of scales. Determine the maximum reading.

The principles are the same agreed.

However if you report your findings we will see that even though the same amount of resistance is applied we can have very different readings when calculating force and inertia.

[Johnanthony 3]

That being said. I do have an E2 head. What is this angle torque you speak of master?

[slydog 7,873]

Tighten to spec then 1/4 turn more on ohc engines I think.

[Johnanthony 3]

So here was my method..

Solvent all surfaces

Fit gasket to block

Fit head over gasket using locating pins

Install all bolts to finger tight by hand, dipping the first 3rd of thread into clean motor oil then wiping bolt of any excess with an oily rag so as bolts are dry but oily to touch.

Using a king chrome click type torque wrench, 14mm socket, and extension bar,

I slowly turned bolts 1/4 turn at a time until tension was reached or until bolts snapped.

 

An E2 head is a tick ford thing I believe. It has nothing to do with OHC. We are still working on a xflow mate.

The Only difference to my E2 stamped head is the chamber is diamond shaped instead of circular. It looks cool, but I don't know how this would perform differently to standard versions.

[Johnanthony 3]

The first time I snapped the bolt was on the third pass pass. The durapro bolt snapped on the second. i want to reach maximum torque over 3 passes

[slydog 7,873]

I use assembly grease not oil as it affects the tensioning...if you read what arp say

[Johnanthony 3]

I guess if you're screwing engines together all day, every day, you get a feel for it. Problem is, one gun might be brand new with nice and tight internals, another might be well-worn with heaps of blow-by, and that's even if they're the same brand. Even lubing one up makes a massive difference to the torque output. I do like using guns generally though, eliminates many clearance issues trying to swing a big bar around.As for the extension bar twisting, well the best quality ones dont snap, but they do twist quite a lot. They're likely to be chrome-vanadium, not tool steel. Snapping can be very dangerous, as witnessed at work when a linesman had a hex adaptor (tool steel) shatter in his hand when using a hydraulic rattle gun, while working up a power pole. It tore straight through his work glove and made a big mess of his hand.

Ow.

[Johnanthony 3]

I use assembly grease not oil as it affects the tensioning...if you read what arp say

[Johnanthony 3]

This may be a contributing factor. I am still not 100/ sure why this has happened. I am not a master mechanic, I just love ford motor cars, and I am having a go like an Aussie battler.

[hendrixhc 10,921]

ARP only way to roll.

[matt_lamb_160 252]

"Torque Inertia" haha. Got to love made up dynamics thought up by people in their shed. There is no way an extension can give more torque unless it is attach to a torque multiplier. If you are jerking on the wrench you will have problems.

 

E2 is not a Tickford thing. It is just an EFI head.

 

If the bolts are breaking their is something wrong with them or you are doing the up too tight. It can happen with well lubed bolts as there is less friction and a greater proportion of the torque goes to bolt tension. I have heard of it before with people using ARP lube.

 

 

Very hard to tell why this is happening to you, other than the torque wrench is screwed.