Many thanks to Mr Comnoz for the idea to waist the head bolts so making them able to stretch with the head when it warms up. I did this to a set of new standard head bolts to replace the rusty examples that were in current use on my MK3. Along with the live loading disc spring washers under the 5/16" nuts at the front i have banished the oil weep from the head gasket when i replaced it a couple of weeks ago.
The last time i renewed the head gasket i torqued the head down as acurately as i could with the equipment i had available. Easy when you have just put the cylinder head back on. The problem is the retorqueing being a bit hit and miss because of the need to remove the petrol tank, carbureter, exhausts, coil bracket, head steady etc to use the correct torque wrench. Its too easy just to use a spanner and heave away thinking that will do.
The answer is to make the task simple and easy.
I already had a 3/8" square drive dial torque wrench (reads up the 20ftlbs) and along with a Britool 1/4 x 5/16 whitworth obstruction spanner and some custom made attachments i can check and accurately retorque the cylinder head in less than five minutes without removing anything from the bike.
You can see the three home made attachments (3/16"whit flat socket spanner, 1/4w to 3/8" square drive adaptor and 5/16"W with internal 3/8" square drive socket) alongside the torque wrench, obstruction spanner, short extension and 1/4 whit socket
arranged like this for the central bolt (number one) and 9 & 10 (the 5/16" nuts) 18 ftlb reading for 30 ftlb actual, 12 ftlb reading for 20 ftlb actual
This configuration to tighten the rear underneath nut (No2) 18 ftlb reading for 30 ftlb actual
Side bolts (3,4,5 & 6) 18 ftlb reading for 30 ftlb actual
Front sleeve nuts (7 & 8) 13 ftlb reading for 30 ftlb actual
Because of the extension in leverage i can easily acheive 30 ftlbs torque using a 20 ftlb wrench. To make sure that i knew what torque i was applying i used my 1/2" drive torque wrench to calibrate the various configurations of attachments. i then photographed them and printed them out, writing on the picture what torque values to use for each bolt or nut.
The only downside is that i have to use a mirror (or lay on the floor) to see the dial when tightening the underneath nuts.
Happy torquing!
regards
Peter
The last time i renewed the head gasket i torqued the head down as acurately as i could with the equipment i had available. Easy when you have just put the cylinder head back on. The problem is the retorqueing being a bit hit and miss because of the need to remove the petrol tank, carbureter, exhausts, coil bracket, head steady etc to use the correct torque wrench. Its too easy just to use a spanner and heave away thinking that will do.
The answer is to make the task simple and easy.
I already had a 3/8" square drive dial torque wrench (reads up the 20ftlbs) and along with a Britool 1/4 x 5/16 whitworth obstruction spanner and some custom made attachments i can check and accurately retorque the cylinder head in less than five minutes without removing anything from the bike.
You can see the three home made attachments (3/16"whit flat socket spanner, 1/4w to 3/8" square drive adaptor and 5/16"W with internal 3/8" square drive socket) alongside the torque wrench, obstruction spanner, short extension and 1/4 whit socket
arranged like this for the central bolt (number one) and 9 & 10 (the 5/16" nuts) 18 ftlb reading for 30 ftlb actual, 12 ftlb reading for 20 ftlb actual
This configuration to tighten the rear underneath nut (No2) 18 ftlb reading for 30 ftlb actual
Side bolts (3,4,5 & 6) 18 ftlb reading for 30 ftlb actual
Front sleeve nuts (7 & 8) 13 ftlb reading for 30 ftlb actual
Because of the extension in leverage i can easily acheive 30 ftlbs torque using a 20 ftlb wrench. To make sure that i knew what torque i was applying i used my 1/2" drive torque wrench to calibrate the various configurations of attachments. i then photographed them and printed them out, writing on the picture what torque values to use for each bolt or nut.
The only downside is that i have to use a mirror (or lay on the floor) to see the dial when tightening the underneath nuts.
Happy torquing!
regards
Peter
