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| Engines Discuss engines |
Topic Review (Newest First)
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| 09-17-2016 09:42 AM | ||
| RAMJET |
Re: I have a Saito 300 twin on nitro Joe the black oil is normal for a gas running engine it's mostly carbon. but opinions will vary LOL . why would a rod cause black oil just because it was to weak .It would have worked fine until it failed . I could see if the bushing was undersized and spinning in the rod but you can see the bushing was a tight fit because there is no wear on the outside of the bushing . if it was a weak rod .it was weak rod . but like I said above this a good example of the type of damage you can expect from incorrectly setting up a gas engine (I guess you can add over machining the rod/ moron factor). I think it was a very good assumption, the engine was without question pushed beyond what it was NOW designed, if you redesign the engine to only take 3000rpm you better respect those limits .Without knowing the owner had been deliberate in weakening the rod, it was the most likely cause. Anyway the statements I made are fact and will apply to any engine. I was not trying to diagnose the picture only use it for a example.cheers Roger Quote:
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| 09-16-2016 06:04 PM | ||
| JoeT |
Re: I have a Saito 300 twin on nitro Quote:
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| 09-16-2016 05:41 PM | ||
| plowboy |
Re: I have a Saito 300 twin on nitro Hey JoeT, if your MAAC number makes you almost ancient What does that do to me............... 5515L................. Al |
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| 09-16-2016 05:38 PM | ||
| plowboy |
Re: I have a Saito 300 twin on nitro Thanks for all the input, I have sen a leter to CH in Florida and I will await their answer . The I will see what I am ging to do with it. Thanks again, Al |
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| 09-13-2016 11:30 AM | ||
| JoeT |
Re: I have a Saito 300 twin on nitro Not a good assumption. The broken rod above was from a maching job gone bad, the bushing inserted was a bit oversized and left too little material on the king rods. FYI, the FG86's I believe (search google) came with Aluminum bushings aka No bushings out of the factory. You can see by all the blackness in the oil that there was fatiguing happening and if you look closely, the actual broken piece on the king rod looks too smooth for a quick fracture. |
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| 09-13-2016 11:16 AM | ||
| RAMJET |
Re: I have a Saito 300 twin on nitro Yeah Joe, gas does have some advantages besides economy, not having to worry about the bearing getting rusted from the glow fuel or the engine getting gummed up from sitting . but damage from detonation or preignition is also more likely on gas if you get the compression / timing or mix wrong. the picture shown looks like it might just be detonation or preignition inspired damage LOL. doubtful it was rpm alone because glow engines rev much higher and they stay together just fine. preingition is when pressure /heat or something hot in the chamber(carbon) lights the mixture before the plug fires. Detonation is when the mixture lights correctly with the plug ,the burn is going well and pushing the piston down until the pressure and heat surpasses the fuels ability to resist exploding (detonation). in both cases forces well in excess of the engine design will be reached. hence the picture above . cheers Roger |
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| 09-13-2016 09:30 AM | ||
| JoeT |
Re: I have a Saito 300 twin on nitro Quote:
Master Rod for FG63 Master Rod: Broken, but it does show the bushing on the FG84: |
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| 09-13-2016 09:11 AM | ||
| kip51035 |
Re: I have a Saito 300 twin on nitro Lack of oil will take out the big end of the conrod. As much as 20% good quality 2S oil may be required. |
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| 09-11-2016 08:12 PM | ||
| RAMJET |
Re: I have a Saito 300 twin on nitro The fact that it has a bushed rod and is going to run much hotter than glow are also factors . the power loss will be significant ,I'm guessing 15-25% because we are using pump gas , alcohol will stand neck and neck with top racing fuel and produce even more torque . we are not switching to racing fuel so the losses will be quite large. engine longevity will also take a hit on gas . Quote:
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| 09-11-2016 07:45 PM | ||
| OLD PRAIRIE RED NECK |
Re: I have a Saito 300 twin on nitro I love the fuel economy of my FG11, 30 minutes on 5 oz but I worry about the fact that that is only 1/4 of an oz of oil for 30 minutes running. Not much lube for an engine that would normally get at more than double that in the same amount of run time! |
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