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Head coming loose

4K views 11 replies 5 participants last post by  Phill 
#1 ·
Hi Guys
The head and exhaust on my 30cc HY keep coming loose even though I've used red loctite and anti shake washers.
Any ideas on how I can keep em tight?
Thanks
Phill
 
#2 ·
How much torque are you putting on the screws when you tighten them up?
Are you using a torque wrench or just guessing?
I have been searching for the torque settings for you but have come up empty.
 
#5 ·
I would have thought one of the large scalers would have chimed in by now.

I'm guessing the head bolts would need to be as tight as most trimmer engines. You might find some torque settings for a Zenoa or Homelight engines with a quick search.
As for the exhaust bolts, that will be bolt torque related also after reading your reply.
 
#6 ·
think FT was referring to fu(k3n tight revo not finger tight. i will see if i can figure out some torque settings being a 6mm bolt into alloy (head bolts) i would say somewhere from 30nm to 45nm but may be way off.
loctite would be useless in this application as it melts with heat. i would think that they are coming loose either due to lack of tention or if the threads in the bottom end are worn as the motor heats the holes would also get bigger causing the bolt to become even loser in the threads. maybe try a slightly longer bolt also so you can see a couple of threads protruding out the bottom of the holes (if possible) that way you know that the bolts are holding as much thread on the case as possible.
 
#7 ·
The Briggs and Stratton single barrel engines run 140 to 185 inch pounds which is 15.8nm to 20.9nm..

Ted (Fast Eddy) the owner of Darksoul doesnt use a torque wrench to tighten these bolts up, he just uses the snug it up method...he does use a spring washer on the bolts.

If the bolts are coming loose, check the threads for damage and wear, and ensure the bolt holes are clean and clear of oily residue....apply red loctite and allow 24 hours to dry completely before running the engine

If the bolt holes look damaged it may be necessary to Heli-coil the holes or replace the bottom end casings
 
#10 ·
I have read some people drill holes in the bolt heads on the exhaust and threading wire through them to tie them off, it stops them from getting loose and dropping out.
 
#11 ·
Through drilling has been around for many years...very common for use in the front ends of cars and on brakes, so I imagine it will work fine on the exhaust bolts

There is a bolt alignment gauge set up available through one of the 5th scale mobs that looks much like the ones used on truck wheels, don't know anyone that has used them, but they work well on trucks so I reckon they may also be pretty good on the exhaust

see pickie...



http://www.davesmotors.com/fd106stage8fastenerssmall.jpg

Spring washers for the head bolts are definitely the pick of the bunch
 
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