Is it imperial???
Discussion
Annoyingly the bolt that holds the pipe bracket to the offside side rocker cover appears to have come completely loose ... I just pulled it out with my fingers!
It doesn't even seem to be "biting" so it may have been loose for a long time and I may have to clean up the thread in the head but I tried screwing it back in using a 5mm hex driver and that seemed too big, I then tried a 4mm which was too small - I don't have a 4.5mm to try and 4.5mm drivers seem a bit thin on the ground (in Salisbury it looks like I'll have to order one).
Anyone know for certain what size head that bolt has?
(Other alternative is to replace the bolt itself I guess...)
It doesn't even seem to be "biting" so it may have been loose for a long time and I may have to clean up the thread in the head but I tried screwing it back in using a 5mm hex driver and that seemed too big, I then tried a 4mm which was too small - I don't have a 4.5mm to try and 4.5mm drivers seem a bit thin on the ground (in Salisbury it looks like I'll have to order one).
Anyone know for certain what size head that bolt has?
(Other alternative is to replace the bolt itself I guess...)
Might be one of these :
http://en.wikipedia.org/wiki/Torx
Or even :
http://en.wikipedia.org/wiki/Spline_drive#Spline
I had something on the driveshaft of my 944 that was a bit grubby and turned out to be Spline headed bolts.
HTH
http://en.wikipedia.org/wiki/Torx
Or even :
http://en.wikipedia.org/wiki/Spline_drive#Spline
I had something on the driveshaft of my 944 that was a bit grubby and turned out to be Spline headed bolts.
HTH
like most things TVR It will be a good chance its a fine thread but could be metric fine or imperial fine probably BSF 55 deg thread angle, UNF thread 60 angle. I very much doubt it will be metric course, measure the outside diameter of the stud and pitch if poss to confirm this. My torque screws that were in my rocker covers were not in very tight, too much to loosen by my fingers, but a set of pliers clamped loosly easily removed them, as the torque setting for tightening them up I believe is very low I think about 10 N/M. I replaced them with the Hex head ones and are much better .
Mark
Mark
portzi said:
like most things TVR It will be a good chance its a fine thread but could be metric fine or imperial fine probably BSF 55 deg thread angle, UNF thread 60 angle. I very much doubt it will be metric course, measure the outside diameter of the stud and pitch if poss to confirm this. My torque screws that were in my rocker covers were not in very tight, too much to loosen by my fingers, but a set of pliers clamped loosly easily removed them, as the torque setting for tightening them up I believe is very low I think about 10 N/M. I replaced them with the Hex head ones and are much better .
Mark
It's 1/4" UNC coarse thread!Mark
That doesn't help when OP can't describe whether its a socket cap, hex, or 12pt head though.
None of them are torx, the originals are just 12pt heads ~ so a 5/16AF ring spanner or 12pt socket is the designated size (many just seem to use 8mm as the nearest metric equivalent). Many owners replace them with socket cap screws (allen bolts) to make things easier ~ I prefer studs & long bolts personally.
spend said:
It's 1/4" UNC coarse thread!
That doesn't help when OP can't describe whether its a socket cap, hex, or 12pt head though.
None of them are torx, the originals are just 12pt heads ~ so a 5/16AF ring spanner or 12pt socket is the designated size (many just seem to use 8mm as the nearest metric equivalent). Many owners replace them with socket cap screws (allen bolts) to make things easier ~ I prefer studs & long bolts personally.
I stand corrected thanks Spend, That doesn't help when OP can't describe whether its a socket cap, hex, or 12pt head though.
None of them are torx, the originals are just 12pt heads ~ so a 5/16AF ring spanner or 12pt socket is the designated size (many just seem to use 8mm as the nearest metric equivalent). Many owners replace them with socket cap screws (allen bolts) to make things easier ~ I prefer studs & long bolts personally.
I grabbed the offending bolt out of the car just now and it's *DEFINITELY* not a 12 point head ... it's just a plain old boring stainless steel socket cap hex head that looks like it's just a normal M6 thread.
The *ORIGINALS* may have been a 12 point head but I guess these ones must have been changed.
Now I just need to work out whether the reason that it's completely out is because it wasn't tightened down originally or because it doesn't fit the thread. If the thread itself is damaged then that gonna be a pain as I'm going to have to remove the rocker cover to get access to the hole to run a tap down it to clean the threads.
The *ORIGINALS* may have been a 12 point head but I guess these ones must have been changed.
Now I just need to work out whether the reason that it's completely out is because it wasn't tightened down originally or because it doesn't fit the thread. If the thread itself is damaged then that gonna be a pain as I'm going to have to remove the rocker cover to get access to the hole to run a tap down it to clean the threads.
spend said:
It's 1/4" UNC coarse thread!
That could be a worry...spend said:
That doesn't help when OP can't describe whether its a socket cap, hex, or 12pt head though.
Well I did say that I'd tried a 5mm hex key and a 4mm hex key so as far as I was concerned it was definitely a socket headed bolt of some type (as opposed to a splined / 12 point head or a hex head bolt) and it certainly appears to be so.Whether it has the right thread for the hole is more of a worry - not so much for this one as it's loose and won't even go in but the other bolt looks the same and appears to be fully driven home so if someone's forced in an M6 or tried to retap a 1/4" thread with an M6 then it could be a bit nasty!
spend said:
None of them are torx, the originals are just 12pt heads ~ so a 5/16AF ring spanner or 12pt socket is the designated size (many just seem to use 8mm as the nearest metric equivalent). Many owners replace them with socket cap screws (allen bolts) to make things easier ~ I prefer studs & long bolts personally.
None of then *SHOULD BE* TORX. 
It seems that very few of these cars are really as standard as they might appear to be and after spending a number of years fighting with socket head fastners at work then my *PREFERENCE* would always be for TORX headed fasteners - certainly in the smaller sizes) as they aren't prone to the bits / tools becoming wedged in the heads in the same way that hex keys do.
Bassfiend said:
...Whether it has the right thread for the hole is more of a worry - not so much for this one as it's loose and won't even go in but the other bolt looks the same and appears to be fully driven home so if someone's forced in an M6 or tried to retap a 1/4" thread with an M6 then it could be a bit nasty!
That shouldn't be a problem, 1/4UNC is bigger than m6 (m6=6mm 1/4"UNC=6.35mm).Bassfiend said:
This is the offending bolt ... and yes, I know it's not much use without any kind of reference but I'll try to size it tomorrow, it is however about 6mm / 1/4" across the threads (I need to find my calipers to measure it accurately)...
That's the one that fits on the inside, the outside one needs to be longer... Looks like 'someone' might just have measured the short inside bolts & got 4 the same (you need 2 x 1.25" long and 2 x 1.5" long OTOMH) when replacing the original 12 point bolts with socket caps.spend said:
That's the one that fits on the inside, the outside one needs to be longer... Looks like 'someone' might just have measured the short inside bolts & got 4 the same (you need 2 x 1.25" long and 2 x 1.5" long OTOMH) when replacing the original 12 point bolts with socket caps.
Fantastic! That's the useful info that I didn't know that I needed... I just ordered some same length screws and I'll order some longer ones now... Thanks fella!
Gassing Station | Chimaera | Top of Page | What's New | My Stuff