[imported_gremlin_390]

hey everyone.

i need to know the symptoms of over revving a nitro engine (specifically the HPI S-25). My crank snapped and HPI wont replace it for me under warrenty. i dont ever remember over revving that engine, but thats bescides the point. What do you think would malfunction first from over revving... the crank shaft journal, or the connecting rod ? from this question, i can argue whether they are right or not.
Need feedback ASAP please !!!

Thanks.

[imported_nitrocan]

too lean perhaps!

[tekno]

probably when you ran it, it was to cold and too lean thus causing it to break. allways try to run your engine rich and drive don't let it stay in one spot and rev.(you probably know this but stating my help)

[Doc]

My brother had the crank shaft in his HPI F4.1 break at the connecting rod journal spot.

He returned it to HPI for warranty service. At first, HPI claimed that they would not cover it because the motor was being run too lean. He successfully argued it with them for a while and they caved and eventually replaced the motor. The motor was not being run too lean, there was an abvious defect in the metal/design that caused this. The HPI rep did eventually admit that they were haveing a lot of broken cranks coming back.

When dealing with HPI warranty, I have two bits of advice:

1) Always rejet the motor back to stock before returning it for a warranty repair.

2) Do not accept an initial refusal. Be polite, but argue your point with them and start asking for supervisors if they still refuse. Thier customer service people have a bit a latitude in making decisions, but will always start on the conservative side. They can be swayed.

[imported_gremlin_390]

thanks guys. and thanks alot doc, very helpful. fortunately, before i returned the engine, i cleaned it the best i could, put new gaskets on the carb and put the needles back to stock. But what i didnt mention in this thread is that the whole side of the connecting rod was ground down when the journal broke (im cluless to how). so what im thinking is that i usually see con rods give way before cranks, and if my shaved down con rod didnt break, then the crank has to be faulty in some way. So #1 ("stock" the carb.) has been done, and #2 (refuse politely) has been done by my dad when the tech guy called when i was out. The supervisor was suppose to call us last night but never did, so i guess we wait for them to call back, because they need my input as to what the final descision will be.