Bent rod
#1
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Bent rod
One of several Norvel 074's that I own just didn't perform as well as the others. I thought to check the crank fit as per CP's advice. As soon as I got the backplate off I found the problem. This was my first 074 that I bought about 6 or 7 years ago. I've no idea how long the rod has been bent, but it sure explains being down on power. I'm pretty sure it's never been hydraulic-locked. Is there another way to bend a rod or did I just not notice my mistake. The engine only has about 3 Qts. through it, all with an APC 7-3 prop. Thanks in advance.
#2
RE: Bent rod
An electric starter can probably do that on an overprimed engine without you feeling a hydrolock.
Running the engine too lean and/or without castor in the fuel could possibly do the same damaged before it is properly run in.
Running the engine too lean and/or without castor in the fuel could possibly do the same damaged before it is properly run in.
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RE: Bent rod
Pretty easy to wad up a norvel rod. Most common, as Mr Cox... stated, is the use of an electric starter. Also, easy to "lock-up" the engine during the first couple of runs if done in cold weather. Piston gets warm & expands, & cold air shrinks the sleeve. With this condition, if you're lucky, the prop just gets spit off, with no damage. If that big 7x3 prop stays tight to the crank, the flywheel effect will help bend the rod during "lock-up". ................ George K.
#4
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RE: Bent rod
Thanks for the info, guys. Yes, I use an electric starter. I use one of the original red Norvel starters Sig used to sell. I swear, the motor slows down when it starts. That is one HIGH rpm starter. I ordered a new rod last night, and today received more parts I ordered last week. Quick service. Sure is nice knowing parts are available again.
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RE: Bent rod
And if you had not been able to get the new rod I'll bet there was a chance you could have straightened it. The same softness that allowed it to bend might allow it to be straightened.
#7
RE: Bent rod
You can also bend them throwing a prop.
Yes it is nice having parts available again. Just replaced a rod on an 061 last week. So much cheaper than replacing engines.
Yes it is nice having parts available again. Just replaced a rod on an 061 last week. So much cheaper than replacing engines.
#8
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RE: Bent rod
Funny you should mention that. While I've never had one of my Norvels throw a prop, I've sure seen it happen. One guy not only lost the prop and screw, he also lost the thrust washer and drive washer as well. We never found anything but the prop. I ended up with the rest of the motor after he died a few years ago, thinking of it as a "parts-motor". Now, thanks to NV engines, it's complete again. Very quick service from NV, by the way. No sooner did the parts arrive for that motor than I discovered the bent rod. Ordered the rod and it's on it's way. Gotta love it.
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RE: Bent rod
I had the same thing happen with my 061 with that same Norvel red electric starter. Funny, Ive continued to use it with my Surestarts with no problem but am afraid to use it on my Norvels!
#10
RE: Bent rod
There is really no need to use an electric starter on these engines, a springstarter from Norvel is all you need. It gives a little quicker flip than one gets by just hand flipping.
The springstarters fits most other engines too (apart from the TT07GP). The AP wasp even has the little hole in the crank case. On other engines, like the TD for instance, one can make a hole in the engine mount instead.
The springstarters fits most other engines too (apart from the TT07GP). The AP wasp even has the little hole in the crank case. On other engines, like the TD for instance, one can make a hole in the engine mount instead.
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RE: Bent rod
I prefer not to use the spring starters as they tend to either cause unnecessary drag on the hub or vibrate, contributing to a slight loss of power. I agree though that they don't bend rods.
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RE: Bent rod
I find them easy to hand start. Full throttle, two drops of fuel on the screen, flip three times, attach the driver, flip and it's running. That's with 5% nitro 20% oil.
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RE: Bent rod
Not doubting you but I've been running Norvels since day one and when the Revlites came out, I found hand starting quite difficult. The culprit, to my mind, is the unusually high taper to the cylinder. This certainly contributes to power but the relatively slow speed of the hand flip appears to allow too much blow-by for hand starting. Maybe you're referring to the early, AAN engines ?
In any case, the early .074 rods were visibly too thin, later versions were thicker in the stem.
In any case, the early .074 rods were visibly too thin, later versions were thicker in the stem.
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RE: Bent rod
Ran both a .061 and .074 on the test stand. Soaked them both in caster and followed the breakin recommended in the instructions. The first time starting them took a few minutes to get to know them, after that no problem. I'll have to post on you tube.
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RE: Bent rod
That would be useful, thanks. I've never used Norvel's break in procedure, preferring the usual heat cycling method that's worked so well for me for years. But Revlites are unique. That only proves once again, when all else fails, read the instructions.