K5.9 Tear Down

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Bill_G

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Hi, just registered yesterday. Great forum.

I just picked up a used 5.9 engine. I'm tryin to tear it down, but can't get the piston/rod out. Got the sleeve out of the block no problem. When I try to slide the rod off the crank it seems like there isn't enough space. The rod only moves enough to see the oil hole then stops and binds. I've read some threads about people moddin these engines, but nobody says about having trouble with disassembly. Is there something different about this engine than any other? Any trick to gettin that thing out? I've taken a lot of engines apart and never had a problem like this.

Thanks for any help.
 
i don't have alot of knowledge tearing down or rebuilding nitro engines but wanted to take the time to welcome you to the HPISF family!!
 
Welcome to the forum!

I have only experienced this problem on brand new engines. Once they loosened up I have not had a problem getting the piston out. I would not try to force it to come out and risk internal damage. I am sure one of the engine experts may be able to help you out soon.
 
Thanks for the welcome.
I thought the same thing about it being new because it isn't that used. Make sense? You can still see the cross hatch in the sleeve. So, I tried heating, but didn't help.
 
did you remove the backing plate? Its alot easier once you remove the roto start and owb.
 
Hey Bill ... first off welcome to the show !!!

Ok so assuming you have the mill disassembled, take a couple of zip ties (cut the then tips off) put them in thru the exhaust port and slowly turn the engine over so as the piston goes up, the zip ties will pus the sleeve up and out of the block . If you need clarification on what I a saying ...give me a ring ... I will PM my number over to you...


Gregg
 
The sleeve is already out, no problem there. I know the back plate must be removed first to allow the rod to slide off the crank. The rod only slides about half way then runs out of "wiggle room". Makes me wonder how the engine was assemble in the first place.
 
mount a flywheel so you can twist the crank ever so slightly back and forth, then wrap a zip ty around the rod and pull as close to the bottom as possible (piston at TDC). Then pull and rotate at the same time, it should pop right off. For assembly, round off the sharp inside corner of the crank pin, put a drop of oil on it and push the rod back on while rotating ever so slightly until it pops on. Bushing damage may occur if this is not done right, when they are that tight. Maybe run it for a while, after a few tanks it should just slip right off.
 
Last edited by a moderator:
the man in the above post "purenitro" is the one to speak to with your engine questions.........
 
I think he drinks to much Nitro ! Is he reliable ?????
He knows his stuff Bill.

** I was able to get the piston / sleeve in and out without shaving the crank ... wiggle-wiggle-wiggle ... flywheel on the crank help alot.


Gregg
 
Thanks for all your interest and help guys. I did manage to get it out finally. Here's what I was thinking. The motor is slightly used. The motor has been apart or at least opened up already. So I was thinking what if the inner bearing, some how, wasn't completely seated. If this was the case this would give more room to slide the rod off the crank pin. So I went with that idea and started to heat the block with heat gun. Got her warmed up and then used a brass punch through the center of the crank and gave a few light taps. Then I was able to pull the rod off. It was still a pretty close fit. I don't know for sure if the bearing wasn't seated completely or if heating it up again is what did the trick, but heating the first time didn't seem to help.
It's one of things where you don't know the true history and gotta take all variables into account.

The main reason I wanted to get this tore down was so I could clean it. When I removed the back plate and saw all the black poop inside there was no way I was gonna run it like that. All components do look in good shape.

Purenitro, are you suggesting I should chamfer the crank pin? I had thought the same thing to help get it back together more easily so the bushing wouldn't get damaged. I could probably chuck the crank in the lathe to get a nice even chamfer on it.

Now I'm gettin mixed feelings that this is a good engine based on what I've been reading here. Should have came to this forum sooner. I've always heard the HPI motors were decent. Either way I'm gonna run it and see how it performs.
 
I have a 1.5oz shot of 30% on ice for a night cap and a mix 50/50 of 20% and orange juice on my cheerios, it's a castor/synthetic blend...... same effect as fiber :)

Welcome Bill.
 
Just take a polishing bit and take the sharp edge on the crank pin 180* on the inside edge, and round it off. Next to nothing for material removal but that edge is usualy very sharp and will dig into the bushing, taking a sliver of material out. Don't touch the running face of the pin, just a fraction on the very end.
 
most here will tell you the other hpi engines are ok but i've just heard alot of people dissapointed with the 5.9 as it was hyped up to be insane and fell a bit short!!!
 
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