alansh

I run the engine for about 45 seconds , just above idle and the six bolts sheared off . This was the first that it had run, the holes in the prop were drilled with proper 58 gx prop jig . I put the washer with holes on first then the spinner back plate then the other washer with holes ,and they were then tightened right up ,then the shaft bolt was put on very tight . Has this happened to anyone else ,I now have to try and drill the stubb ends to try and get them out . I would be gratefull for any advice.

pe reivers

1) With a spinner back plate, do not put one of the washers between spinner and prop hub.
2) I suppose you used a wooden prop? In that case, the tightening sequence is not right. The wood will crush, and leave the 6xM4 bolts with insufficient tension after you tighten the central nut.

The central bolt keeps the prop assemby on the crankshaft, so after you tighten the 6 M4 screws, lightly tighten the central bolt. Then LIGHTLY TIGHTEN THE 6XM4 BOLTS AGAIN? go back to the central bolt, and then to the M4 bolts again!
Take care not to crush the prop wood.
I found, that in the 58cc engine, a wooden prop that was light ("blond wood") compressed too much. The wood quality must be hard enough to stand the proper bolt torqueing. IF the wood relaxes and sets, the procedure has to be repeated, or the bolts will shear. There is no maybe about that!

rc bugman

My Feedback: (30)

Hi,

If the bolts are not bottomed out, take a dremel cutting wheel and cut a groove each bolt. You may have to cut a groove in the hub. Then take a flat blade screwdriver and back out the prop bolts. Much better than drilling out the bolts. Don't ask how I know.

Elson

RC Extreme power

My Feedback: (24)

I have seen this happen to most all brand engines that use 5mm bolts to hold the prop, The first thing is if they come with the silver light weight bolts change them to the black case hardened bolts and do as Pe siad for tightening them.

One thing that works some times when trying to remove the broken bolts is to use a reverse drill bit, As you drill it will back out the screws.

Milton

alansh

Thank you all for your help, i will leave one washer off next time . I have got 5 of the studds out no trouble there is one stubborn one left. What noticed with ends that came out was they were only 6mm long so they had not gone very far into the hubb, would this also have been the cause for them to shear

RC Extreme power

My Feedback: (24)

I don't think that would matter, That would only make you strip out the threads when trying to tightening them. That is why I send two sets of prop bolts with our engine, One set for thin props and another set for thick props.

Good luck on the repair, Looks like you just about got it. Pick up some longer 5mm black case hardened bolts for it and might solve your problem.

Milton

jack1933

My Feedback: (2)

Hello, May I refer you to a thresd on Flying Giants that covers this problem in detail? Its titled broken prop bolts on Da 150, on the thread Gas engines and power, dated 7-22 2007. I think this will solve your problem.
Regards
Jack

jack1933

My Feedback: (2)

Also refer to a thread on Flying Giants 3W broken prop bolts, and there are a few more threads about this subject.

jack1933

My Feedback: (2)

hello all Don't know why the other site is blanked on this site, but you can figure out which it is. Maybe if I miss spell it, it will give you a clue Try Fluing Gients.

pe reivers

You mean fluing Gyants?
RCU sucks on this subject. I hate this kind of facism.
RCU moderators, please note. You are on the wrong track!