I’m running a micro squirt setup on a 1800 Type 4 in my 72 Bus and am loving it except I had an issue I wanted to see if anyone else has had this. I’m running Mario’s T4 trigger wheel. Was driving on the highway and engine sputtered out on me. Had it towed home and found out the fan bolt had broken so no spark due to loss of crank trigger signal. Fortunately was able to extract the broken bolt with an easy out and I’m back in business. Does anyone have any ideas why the bolt might have broken and any steps to prevent it from happening again? BTW I’m using OEM fan bolts I got from Heritage Parts in England since they were about the only ones I found that has them.
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Type4 Issue
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Bruce.m
- Posts: 1000
- Joined: Sun Aug 11, 2013 1:44 pm
Re: Type4 Issue
Over torque?
Out of balance fan causing vibration?
Out of balance fan causing vibration?
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Ol'fogasaurus
- Posts: 17881
- Joined: Mon Nov 13, 2006 10:17 pm
Re: Type4 Issue
While you/we don't usually see it, there is a "cycle limitation" on fasteners. A "cycle" is the fastener being tightened/torqued (stretched) then loosened back up).
Some fasteners are good for only one cycle (torqued in place, then removed) while others have many more cycles before they start to weaken and need to be replaced (the material is stretched the unstretched aka a cycle). The threads and how they are made (cut or rolled) also makes a difference in the strength of the fastener (grade). Also, beside the stretching of the fastener there is the material wear to it due to the tightening and loosening of the assembly.
Every country has its own set of specs/rules on fasteners (et al). The materials and their mix also has to do with the "grade rating" of the fastener. (see the URL below for an example). The fastener design limitations are usually due to the materials mixed in the mix of the materials fasteners. Also, how they are mixed, stretched during the forming of the material (for grain adjustment for example) and other instructions in the making of the fasteners. A lot of specialy fasteners have coding involved in the part number (the longest part number I remember being 17 or 18 digits long.
It's been a long time since I was directly involved with this so maybe this might help some. The US has several such as ISO, ANISI, and several others while other countries have their own specs and instructions to come up with fastener design. Fastener companies also have their own specs which may or may not match other standards.
https://engineeringlibrary.org/referenc ... ign-manual.
I didn't read all of this, but I would suspect that everything that is involved isn't talked about here either. Fastener design is very complicated as you have to have the limitations needed for the fastener's design which includes the materials, their mix (amount for example) and other things. Very complicated!
Again, for what it is worth.
Lee
Some fasteners are good for only one cycle (torqued in place, then removed) while others have many more cycles before they start to weaken and need to be replaced (the material is stretched the unstretched aka a cycle). The threads and how they are made (cut or rolled) also makes a difference in the strength of the fastener (grade). Also, beside the stretching of the fastener there is the material wear to it due to the tightening and loosening of the assembly.
Every country has its own set of specs/rules on fasteners (et al). The materials and their mix also has to do with the "grade rating" of the fastener. (see the URL below for an example). The fastener design limitations are usually due to the materials mixed in the mix of the materials fasteners. Also, how they are mixed, stretched during the forming of the material (for grain adjustment for example) and other instructions in the making of the fasteners. A lot of specialy fasteners have coding involved in the part number (the longest part number I remember being 17 or 18 digits long.
It's been a long time since I was directly involved with this so maybe this might help some. The US has several such as ISO, ANISI, and several others while other countries have their own specs and instructions to come up with fastener design. Fastener companies also have their own specs which may or may not match other standards.
https://engineeringlibrary.org/referenc ... ign-manual.
I didn't read all of this, but I would suspect that everything that is involved isn't talked about here either. Fastener design is very complicated as you have to have the limitations needed for the fastener's design which includes the materials, their mix (amount for example) and other things. Very complicated!
Again, for what it is worth.
Lee
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Bruce.m
- Posts: 1000
- Joined: Sun Aug 11, 2013 1:44 pm
Type4 Issue
Was it the single centre bolt that holds the hub to the crank? The hub is a tight fit on the crank nose & even after the bolt is removed you need a puller or a copy of the VW tool to remove it.
Obviously there are the bolts that hold the fan to the hub but since you say “bolt” I guess it’s the central item.
If there is a burr or ding on either the crank nose or the hub mating face, the hub may not seat cleanly on the crank. In use I can see this causing vibration & putting a lot of stress on the small bolt.
Obviously there are the bolts that hold the fan to the hub but since you say “bolt” I guess it’s the central item.
If there is a burr or ding on either the crank nose or the hub mating face, the hub may not seat cleanly on the crank. In use I can see this causing vibration & putting a lot of stress on the small bolt.
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Ol'fogasaurus
- Posts: 17881
- Joined: Mon Nov 13, 2006 10:17 pm
Re: Type4 Issue
I agree Bruce. One has to consider not only "cause and effect" but "cause and affect also. You do something here to fix something but what affect does it have here or somewhere else.
If one looks up the term "nut certs" you get one thing that is fairly common to see now days but (many years ago) there was a different type of fully threaded "tube type" of was installed in the (engine block for example) block to cover the softer material from the harder material fastener/stud. I don't know if it is still done as it was "old stuff" back in the 50 and 60s when fixing older stuff. There were certain car manufacturers that had problems with the threads being over tightened (or the block had aged) and the threads would be distorted or pulled out from overtightening or too many insert rounds ("rounds" being where the fasteners had been put in and torqued then removed then reinserted and torqued/over-torqued) of the bolts or head studs.
It's funny but having discussions by different types of engineers having discussions and giving information in mass that I learned to write (print) upside down and backwards (this is when I was standing on the other side of my 7' long desk while others were either around me or on both sides yapping away. If I knew in advance, I would get a "check print" made of my 12' long drawing so they wouldn't be writing on the original (about $1800 as I was told). The funny thing was that my doing that ended up distracting some of the people having the needed discussion
.
Lee
If one looks up the term "nut certs" you get one thing that is fairly common to see now days but (many years ago) there was a different type of fully threaded "tube type" of was installed in the (engine block for example) block to cover the softer material from the harder material fastener/stud. I don't know if it is still done as it was "old stuff" back in the 50 and 60s when fixing older stuff. There were certain car manufacturers that had problems with the threads being over tightened (or the block had aged) and the threads would be distorted or pulled out from overtightening or too many insert rounds ("rounds" being where the fasteners had been put in and torqued then removed then reinserted and torqued/over-torqued) of the bolts or head studs.
It's funny but having discussions by different types of engineers having discussions and giving information in mass that I learned to write (print) upside down and backwards (this is when I was standing on the other side of my 7' long desk while others were either around me or on both sides yapping away. If I knew in advance, I would get a "check print" made of my 12' long drawing so they wouldn't be writing on the original (about $1800 as I was told). The funny thing was that my doing that ended up distracting some of the people having the needed discussion
.Lee