Length of "extra" Lightweight head bolt
- clanger9
- Posts: 1165
- Joined: Sat Jun 20, 2015 9:38 am
- Location: Chester, UK
Length of "extra" Lightweight head bolt
Please can anyone tell me the length of part number 042196? It's the "extra" cylinder head bolt on a Lightweight and is described in the parts list as "Bolt, cylinder head, 5/16 in. by 22 TPI"
Unfortunately the part isn't available from club spares, so I'm hoping I can find an alternative...
I can't seem to find it among the parts for my engine rebuild. It's possible either that I've lost it, or it wasn't fitted to my engine in the first place. I don't recall it being there when I dismantled it.Unfortunately the part isn't available from club spares, so I'm hoping I can find an alternative...
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1989 Moto Morini Dart 350
1993 Ducati 750SS
1993 Ducati 750SS
- Ozmadman
- Posts: 2651
- Joined: Wed Dec 14, 2011 1:02 am
- Location: ESSEX UK
Re: Length of "extra" Lightweight head bolt
Yes 5/16ths BSF that wil be the problem. I would get a length of silver steel and make a stud up using a BSF die and use a nut at the top. I had a serious issue with mine where the thread in the barrel had been stripped, helicoiled and then stripped again by the P.O I presume. I couldn't drill it any deeper as it would show through the fins so I had to drill it out larger and the best way to make sure it would hold was to go to 10mm coarse thread which I did. Then I made a 10mm stud which I loctited into the barrel as even at 10mm the thread wasn't brilliant due to the size of the original hole. I then had to drill out the hole in the head to that size to accommodate the new size stud. Finally enlarge the hole in the gasket. Could still just about fit the head over the stud with the engine in the frame and all worked fine and actually it's more secure with a larger stud and nut in that position. Tightening the smaller bolt always seems a bit dodgy to me just don't tighten it up to the same torque as the studs!! Just needs nipping up. Will post a few pictures of my efforts when I get home later as the pictures are on my pc
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
-
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Re: Length of "extra" Lightweight head bolt
Hi
Sorry if this sounds flippant, but isn't it fairly straightforward just to measure the depth and subtract a clearance?
Edited to add, in the light of Ozmadman's comment - Namrick have a fair selection of 5/16" BSF bolts available.
Regards Mick
Sorry if this sounds flippant, but isn't it fairly straightforward just to measure the depth and subtract a clearance?
Edited to add, in the light of Ozmadman's comment - Namrick have a fair selection of 5/16" BSF bolts available.
Regards Mick
- clanger9
- Posts: 1165
- Joined: Sat Jun 20, 2015 9:38 am
- Location: Chester, UK
Re: Length of "extra" Lightweight head bolt
Not at all - I can certainly figure it out by measuring the depth, etc. 5/16" BSF x 3" seems "about right".
I could do with the dimensions of an original so I know how deep the bolt is supposed to go into the block. My guess is (as Paul says) that it doesn't need to be especially tight and it's just there to keep the oil feed to the head leak-free.
I could do with the dimensions of an original so I know how deep the bolt is supposed to go into the block. My guess is (as Paul says) that it doesn't need to be especially tight and it's just there to keep the oil feed to the head leak-free.
1989 Moto Morini Dart 350
1993 Ducati 750SS
1993 Ducati 750SS
- Rob Harknett
- Member
- Posts: 11236
- Joined: Mon Jan 01, 1990 12:00 am
- Location: ESSEX UK
Re: Length of "extra" Lightweight head bolt
Are there no other such bolts that can be made to the correct length???
-
- Posts: 2886
- Joined: Mon Mar 24, 2014 5:44 pm
- Location: Aberdeenshire
Re: Length of "extra" Lightweight head bolt
Hi
See here for a 3" bolt - others listed
http://www.namrick.co.uk/acatalog/Home_ ... lts_4.html
Regards Mick
See here for a 3" bolt - others listed
http://www.namrick.co.uk/acatalog/Home_ ... lts_4.html
Regards Mick
- clanger9
- Posts: 1165
- Joined: Sat Jun 20, 2015 9:38 am
- Location: Chester, UK
Re: Length of "extra" Lightweight head bolt
Thanks for the pointers, all! I'll try a standard 5/16" x 3" BSF bolt and report back...
1989 Moto Morini Dart 350
1993 Ducati 750SS
1993 Ducati 750SS
- Rob Harknett
- Member
- Posts: 11236
- Joined: Mon Jan 01, 1990 12:00 am
- Location: ESSEX UK
Re: Length of "extra" Lightweight head bolt
Always check holes for muck, which could stop a bolt tightening up. Too much effort trying to tighten could strip a thread.
-
- Member
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Re: Length of "extra" Lightweight head bolt
My rule of thumb for minimum thread engagement............... diameter of thread x 2 for aluminium, casting or plastic and x 1.5 for steel.
only dead fish go with the flow
- Janet
- Member
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Re: Length of "extra" Lightweight head bolt
If you can wait until tomorrow afternoon, I'll take mine out and measure it for you as long as you don't need it to be accurate to a thou.clanger9 wrote:Not at all - I can certainly figure it out by measuring the depth, etc. 5/16" BSF x 3" seems "about right".
I could do with the dimensions of an original so I know how deep the bolt is supposed to go into the block.