Headbolts
- Thread starter Flathead
- Start date
That all depends on your experience with fasteners. "Snug" to you might mean one thing and something different to someone else. As I've said here many times, over tightening fasteners has caused more problems than any other one thing with these kits. In the case of the cylinder head too loose or too tight can cause you further problems.
Trying to 'guess' about proper torque is not a good idea. I'd check around and try to find someone who will either loan you a torque wrench or tighten the fasteners for you. The problem with having someone do it for you is you'll need to go back to them after a few heat/cool cycles and have the torque 'checked' a couple of times after the initial tightening.
Save a few bucks and buy a torque wrench. It'll be cheaper than the repairs you might have to make by not using one.
Tom
Trying to 'guess' about proper torque is not a good idea. I'd check around and try to find someone who will either loan you a torque wrench or tighten the fasteners for you. The problem with having someone do it for you is you'll need to go back to them after a few heat/cool cycles and have the torque 'checked' a couple of times after the initial tightening.
Save a few bucks and buy a torque wrench. It'll be cheaper than the repairs you might have to make by not using one.
Tom
allen standley
Well-Known Member
I concur. Harbor Freight 10 bucks.
http://www.harborfreight.com/catalogsearch/result?q=tourque+wrench
http://www.harborfreight.com/catalogsearch/result?q=tourque+wrench
crassius
Well-Known Member
failure in the head studs most often is caused by the acorn nut binding on the threads - if you are using open nuts, then you will be a bit safer if you can't get a torque wrench to do it right
less common, is the threads of the stud pulling out of the cylinder, I always loosen the studs a bit & reseat them to be sure the threads seem to be performing correctly and weren't left loose or cross threaded at the factory
less common, is the threads of the stud pulling out of the cylinder, I always loosen the studs a bit & reseat them to be sure the threads seem to be performing correctly and weren't left loose or cross threaded at the factory
crassius
Well-Known Member
haven't done it on HTs, but always used to drill large to put in brass bolt - cut it flat to the surface & file area smooth - drill it to take proper size threads
was successful on motorcycle cases, heads, & cylinders all thru the 50s & 60s, as brass has very similar expansion to aluminum
amount of hand work makes replacement cheaper tho if you're paying for that labor
was successful on motorcycle cases, heads, & cylinders all thru the 50s & 60s, as brass has very similar expansion to aluminum
amount of hand work makes replacement cheaper tho if you're paying for that labor
mogollonmonster
Member
Either 12-14mm, I believe the Dax motor I'm running is 14mm. Standard sockets are deep enough, although an extension might be necessary to clear the cooling fins. I always use 1/4 inch drive, to keep me from being over zealous. I don't own a torque wrench, but I'm one of them who can "feel" torque, I've been turning wrenches a long time, and I'm familiar with the sensations of steel preparing to give. There is no fastener on these engines that needs to be that tight. I do not always torque wrench, but when I do, I use the needle type.
Buy one, it'll save your bacon. Most of my repairs are done on the roadside, well away from anyone and anything, crosslegged on the shoulder of some lonely highway. Those situations are rarely conducive to proper equipment usage. After making a head gasket out of a bud lite can with a razor knife, just get the thing tight and get it home. That is not the proper way of things, buy a torque wrench.
Buy one, it'll save your bacon. Most of my repairs are done on the roadside, well away from anyone and anything, crosslegged on the shoulder of some lonely highway. Those situations are rarely conducive to proper equipment usage. After making a head gasket out of a bud lite can with a razor knife, just get the thing tight and get it home. That is not the proper way of things, buy a torque wrench.
sbest
Member
Compression firing never strips the threads on these engines. It is always human error. If it was running well while you had it, it wasn't likely the previous owner. The case metal on these is not so bad either, but some of the owners....
If you have a 48cc motor with M6 studs, you can always drill and tap them out to M8. Room for the nuts will be a bit tight but 12mm x M8 nuts are available. If you have the 66cc with the M8 studs I don't think you are going to get M10 in there. Not a lot of metal around the stud for an insert nut. Pretty much gotta use a helicoil.
As for what tool to use, the M6 nuts are pretty much always 10mm and due to the depth you have to use a socket. The M8 studs have 12, 13 and 14 nuts available. 13mm is ISO standard, 12mm is Japan standard and my Grubee came with 14mm, go figure. I carry a short "tube wrench" for on the road repairs:
Stripped threads on these motors are pretty much always operator error. You have to use a torque wrench at least for the first 5 years of your motor mechanic existence. I use one in all the critical areas still.
Steve
mogollonmonster
Member
Compression stripping at less than 180psi... Nope. Operator error. It might be aluminum but it ain't a pie tin. Blame the dog, but not compression.