Yes 3/8 BSF. there are 5 long and 5 short and 10 washers.(10 long bolts for an ally head) It's obvious where the long and short go. This page from Drags might help. I think it gives lengths.
https://draganfly.co.uk/product-category/bsa/sparesparts-for-bsa-a710-b3133-c101112-m202133/engine-gaskets-gearbox/cylinder-head-barrel/pre-unit-m-group-head/
Ron
email (option): ronpier@talk21.com
I'd recommend using class 3 'heavy' washers at least for the head bolts...I usually make up thicker ones for the job...
I also found that the stated bolt lengths aren't ideal (IMO)....I worked out the lengths to give the most thread engagement with the barrel...Also remember that in a perfect world the bolt that secures the head steady should have a little extra length...
Finally, I've bought zinc plated bolt sets in the past that snap at the end of the thread with little force applied..It may be that they have become more brittle after plating. Fasteners of this type should be 'debrittlised' after plating.....Make sure you are buying high tensile fasteners....
Tap out all the holes before fitting new fasteners and apply a little light machine oil only when torqueing down...Fasten to the tightening sequence in the manual and torque down to 28-30 ft. lbs.
I'd also recommend a solid copper head gasket if you don't already have one...Modern composite gaskets are pretty unreliable.....Ian
email (option): ian@wright52.plus.com
Thread Insert Deathmatch! Helicoil vs TimeSert vs key locking insert vs BigSert
Interesting watch.
https://www.youtube.com/watch?v=LpDduCVUy6w
We made these a while back if it's any help.
https://pesltd.uk/?product=02-0861&ptno=02-0861
Does anyone think that if the head bolts had a longer hex section it would be less likely to damage the fins?
These are a bit long as they were for another job, but it gives you an idea.
https://pesltd.uk/?product=24-0381&ptno=24-0381
email (option): pes.sales@btconnect.com
I've made these in the past and used a deeper head depth...I did mine at 7/16" from memory....Saying that though, I don't know for a fact my bikes ever had standard head bolts during my ownership so I'm unsure what originals actually measured up at...Ian
email (option): ian@wright52.plus.com
Interesting watch.
https://www.youtube.com/watch?v=LpDduCVUy6w
The material pulls when the shear strenth of the cylinder at the OD root is exceeded \
So it is a property on the material not the insert
That is why the "Big Cert" could break the bolt because as the od was lot larger the surface area of the cylinder at the thread / parent maerial is bigger.
Now what affects this
1) actual profile of the tap
A very round rooted tap will have a lot more material and of course no sharp stress raisers
2) the fit of the inset into the hole
If you cut through an insert with a bolt in it you will see that the insert does not extend to the very end of the thread.
The closer it is to the end of the thread the stronger the insert will be
This is the same as the fit of a bolt
As you go from hardwear ( garden gate galvanised ) grade which are quite sloppy up to aerospace grade they get tighter and substantially more expensive.
So all his video really shws is all of the inserts were stronger than the parent metal
No big surprise there
What is important is pressure tightness, in particular for spark plug inserts
Pull out ( as in unwinding ) resistance
And vibration resistance
or holes that go right through the crankcase like the 4 sump bolrts and plug holes then it is solid inserts
Everything else gets a wire insert .
Thanks WM. I was wondering what type of inserts people have used in their various repairs.
Hence I posted the video out of interest.
What works and what does not work as well....
I have one spare barrel that has one stuffed bolt hole.
Was wondering if a heli-coil would suffice.
cheers
Either using timeserts wire thread inserts or Anita specials, we try to rigid tap in a cnc mill. The results are far superior to any other method. Even tapping heads.
The down side of making custom fasteners, is the lack of control over the platers. Anything that's left in for too long can be a nightmare.
Though not a fan, this is one of the reasons we started making oil fittings in stainless.
email (option): pes.sales@btconnect.com
In my case not having to deal with any platers is a major motivator for the use of stainless in many applications, as well as avoiding the repetition that comes along as the plated surface finish fails...Zinc plating IMO is a complete waste of time if the bike is ever to be used on a saltly road (or beach in Normandy) and it looks less like Cadmium than blasted stainless steel does...Frankly, I think the dislike of stainless is a little irrational, as alternative plated finishes to those originally used aren't 'standard' either, but each to their own I guess...
I've used some tin plate (with a copper base) for some fittings lately...The finish is a fair match for cadmium visually but only time will tell how durable it is...
I've done this only where replication in stainless is problematical, for example the various parts of the filler cap mechanisms...Ian
email (option): ian@wright52.plus.com
Not quite sure, but I think someone here in Israel once used Land Rover bolts.
I do not remember of course from which part, but they suited him exactly.
email (option): michasteinmann@gmail.com
The two main problems with stainless steel alloys is that it's more prone to fracture that high tensile steel alloys.
It's bad enough that most machine shop don't understand the properties of steels let alone Stainless grade steel alloys.
Another problem that is often overlooked is the galvanic corrosion between mild steel and and stainless steel.
It's a big problem with older busses and coaches. It seemed like a good idea skinning them in stainless with a mild steel frame. Once you get some mud and water in the interface area the magic starts. A few years later and the coach looks sound, but is rotten behind it's skin.
Things do change though, I remember when motocross wheels built with stainless spokes collapsed. They seem to work ok now.
email (option): pes.sales@btconnect.com
I've used stainless fasteners for decades and can't honestly say galvanic corrosion (or the results of it) have been an issue...There are grades for most applications. In my last job (a pharmaceutical manufacturer) we had production machinery and pumps etc. produced entirely in stainless steel, rotors, shafts, fasteners etc. etc....Ian
email (option): ian@wright52.plus.com
I have bought these in the past to use as head bolts: https://www.ebay.co.uk/itm/185058276439?ViewItem=&item=185058276439
Regards,
Bastiaan
email (option): wdmotorcycles@gmail.com
Well the take away from that & just bout eery other monkey with a tension wrench video is just about all of them are as strong or stronger than the bolt
I am not a fan of helicoils in BSF as the wire is no longer the correct diamond shape it once was so they tend to strip the threads off the bolts if overtightened.
I run some shadows as hire cars and it was interesting when I first took a spannar to one and noticed every hole in the alloy was helicoiled, including the plug holes
Fail to put some lube on the plug threads and you can forget about changing plugs
The mobile thread repaired ftted bronze ones and that was the last time We ever had a frozen plug
WM for sure.... there is more than just bench testing to see how these things really compare or perform in real applications.
I posted the video to see what experienced people who have worked with such repairs have found.
Thanks for the info.