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Seidel 7-70 radial: Help me decide!

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Seidel 7-70 radial: Help me decide!

Old 12-26-2015, 01:17 PM
  #1001  
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Yeah, what Doc said (without all the typing!).

John.
Old 12-26-2015, 01:38 PM
  #1002  
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No fair John! You know someone had to do it though. Don's a great builder and a college professor but internal combustion engines are a mystery to him. There aren't any secrets but if you haven't been exposed to the mechanical side of things you just plain don't know or understand what makes em work. As I love to say "it aint rockit science" (sp) I rebuilt my first lawnmower at ten, small block Chevy at 15. Oh what fun. Mom said she'd kill me if that lawnmower didn't run, I'm still here. lol
Doc
Old 12-27-2015, 04:33 AM
  #1003  
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Seems like I should be able to check the rocker movement while still on the stand. (I'm not sure if it means anything but they rockers do ALL move.) In terms of clearing any "gunk" can I just keep it on the stand, essentially flood the engine, remove all the plugs, and then motor it with the starter? Figuring out a way to affix it to the workbench sounds like a lot of work (and you're right that the plugs would be angled downward as would the hole...so gravity would let the fuel flow out).
Old 12-27-2015, 10:52 AM
  #1004  
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Rocker movement is only part of it they have to have lash (gap) at the right time for compression to occur, compression is required for combustion, especially in a glow engine. The combination of compression residual heat and the reaction od the methanol with the platinum coating on the glow plug coil is what makes it light. Four stroke glow engines are even harder to make run due to the extra cooling during the extra rotational cycle that two strokes don't have.
Old 12-27-2015, 12:26 PM
  #1005  
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Don, why not pack up your engine and send it to Doc. I have no doubt he could get it running great! Just a thought .
Old 12-28-2015, 05:48 PM
  #1006  
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I would remove all the plugs, pick a cylinder and put your finger over the glowplug hole, and feel for the compression. You should feel it through the prop and the plug hole. Two rotations and you should feel the compression when you see both the rockers even. When they are even with the piston at the top, the lash should be checked. When piston is going up on the compression stroke, you will feel air try to escape; turned backwards should feel suction through the plug hole when rockers are even. If they are not even, keep turning the prop till they are. With a new engine, valves may close up faster while the seats seat. Repeat 6 more times. I like using denatured alcohol, also called methylated spirits, to free up engines as it desolves the gunk. You will need to oil the engine with some after run oil if you are going not run it very soon after cleaning it. Cant hurt no matter.
Also engines breaking in tend to destroy glowplugs from the small metal particles that come from the break-in. That stinks with 7 expensive ones. They may look good but can be bad. I would put each one in a single cylinder engine and make sure it runs flawless.
Old 12-28-2015, 07:22 PM
  #1007  
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Yesterday, I talked on the phone with a guy from a company in Osaka that can do maintenance on the engine. And, luckily, the guy even spoke English and was quite helpful. We went through all the things I had already tried and he made many of the same suggestions given here. He seemed eager to help me get the engine going WITHOUT sending it in. So all of that is good news. We'll talk again after the New Year celebration, which is a really big deal in Japan.

TFF, I have felt both the compression and the suck at the plug hole (though not for all cylinders). What is "lash" and how would I check it? And what would I do about "non-standard lash?"

Bob, I'm sure Doc could get it running. But getting the whole kit-and-caboodle to his new place in Tennessee would probably be harder than shipping it back to India!

Last edited by abufletcher; 12-28-2015 at 07:25 PM.
Old 12-28-2015, 08:35 PM
  #1008  
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Lash is the "slack" in the valve train system to handle expansion from heat of various parts. There is a very small gap between the valve stem top and the rocker arm when the valve is fully closed. If the lash closes up, heat caused expansion can hold a valve open, leaking compression; too loose and the valves dont flow the best amount of air/fuel or exhaust. The set screws on top of the rockers are how it is adjusted with a feeler gauge as measurement.
Old 12-28-2015, 09:06 PM
  #1009  
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Don.. you Got the thing from India! lol.Doc would do a better job!
Old 12-29-2015, 03:40 AM
  #1010  
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Lash is the same as "gap" its the measurement you do with the feeler gauge between the top of the valve stem and the rocker arm. Thanks for the vote Bob but not knowing how long I'm going to be anywhere just now makes sending it to me rather impractical. Heaven knows when I'll have a proper shop again. TFFs suggestion of metholated spirits is s good one, but like he said lubricate with after run oil afterward unless you get it running somewhat quickly after flushing. As for after run oil there's various ones you can choose, I like Marvel Mystery oil, especially their air tool oil, it has extra rust inhibitors, get it on Amazon.
Old 12-29-2015, 03:57 AM
  #1011  
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Yeah, I can just see the postman chasing Doc from Texas all the way to "rural" Tennessee! Regarding after-run oil, can't I just use the Klotz synthetic oil that I mix with the methanol?
Old 12-29-2015, 07:13 AM
  #1012  
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I don't know what sort of rust inhibitors it has, it may be fine. The reason we use after run oil in glow engines is that methanol is hydro something or other (technical term, hydroscopic maybe) and attracts moisture that causes bearings to rust and your favorite bearing supply company to smile. If you run an engine say weekly you'd prolly never need to run after run oil through it but let one sit up for a month or two without it and you may not feel the roughness but tiny pits begin to develop in the ball bearings six months and you will feel the roughness is noticeable, a year and the engine may be hard to turn over or not do so. The stuff is cheap insurance and easier to apply than new bearings. Two strokes aren't too bad but four strokes are a PITA don't ask how I know so much about this.
Old 12-31-2015, 06:47 AM
  #1013  
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New to forums. Help with asp selection?
Old 12-31-2015, 07:05 AM
  #1014  
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Need more data
Old 01-09-2016, 05:18 AM
  #1015  
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No progress on my UMS 770. My best hope is the guy in Osaka (importer for Evolution engines).

In the meantime, over the holidays, I pulled my Sopwith Snipe out of mothballs, re-did the rigging (16 wires on each side), and today ran its Saito 72 for the first time in months. It started right up but still needs some tuning. It has been a long time since the Snipe was in the air.
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Old 01-09-2016, 05:35 AM
  #1016  
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You always take such great pix, those are stunning Don.
Doc
Old 01-09-2016, 06:52 AM
  #1017  
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Thanks. I enjoy photographing the models almost as much as building and flying them. (Maybe even more than flying them. ) Here's a color version.
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Old 01-09-2016, 09:24 AM
  #1018  
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That's real nice but the B&W are so much more period.
Doc
Old 03-07-2016, 04:59 PM
  #1019  
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The engine is on its way back to UMS in India. After confirming things with a Mr. Ramaraj at UMS, I shipped it yesterday and it should arrive within a week. They will examine it and do any necessary repairs.
Old 05-27-2016, 07:17 AM
  #1020  
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It's been a slow process. But I accepted that long ago. The engine is still in India. It spent a couple of weeks in Indian customs (and I'm being told that I have to pay the duty on this engine that was being shipped for repair and re-export). Then a week ago I was informed that their mechanics recommended that ALL THE PART ON ALL THE CYLINDERS (virtually everything except for the crankcase) should to be replaced, for a cost of $500 (parts and labor). I responded back that that was absolutely crazy since surely not all those parts were damaged.

Yesterday I got another email explaining that there are been a mix-up, that the repair recommendations I received were actually for some other customer who had requested that his 770 be upgraded to the 777. That evaluation was sent to me by mistake. I'm told that they should have the recommendations for the repair of my 770 in a few days.

We'll see. I know from 12 years of experience in the Middle East that things happen in their own time...and getting upset about the situation won't make things go any faster.

Last edited by abufletcher; 05-28-2016 at 05:14 PM.
Old 05-28-2016, 05:22 PM
  #1021  
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Another email, this time with photos of the problems with MY engine. The email states that when the mechanics disassembled my engine it was found in "rustic" condition. Honestly, I'm not too surprised at this given the weather in Japan and my general lack of understanding of how to properly maintain engines. The following items will need to be replaced, if they cannot be salvaged with some careful polishing. All of this explains why the engine had no compression whatsoever.

1) Piston Ring - 7 nos
2) O ring inlet - 7 nos
3) O ring (top cover c case ) - 2nos
4) Piston pin & connecting rod pin
5) Bearing - 3nos ( Top cover front end bearing , Cam gear bearing and top cover rear end bearing)

(*Note for anyone wondering: "nos" is British English for "number of parts.")

I have written back asking for an estimate for this work. Honestly, if it's going to cost almost as much as the upgrade to the 777 ($500) then maybe that would be the best thing to do.
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Last edited by abufletcher; 05-28-2016 at 05:24 PM.
Old 05-28-2016, 08:09 PM
  #1022  
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That is really a bum deal that it needs so much work Abu, I had hoped it would have been something trivial and cheap...
Old 05-28-2016, 09:48 PM
  #1023  
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Mostly I blame myself.
Old 05-29-2016, 07:37 AM
  #1024  
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Wow. I guess you will have to fill the crank case with oil to store just to save the investment. Fly it every weekend to keep new oil in it
Old 05-29-2016, 07:44 AM
  #1025  
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Yes, sorry to see the damage to the engine.

Just to help the rest of us avoid similar problems, can you share what type of fuel you were using that might have caused the corrosion ? I'm not thinking specific brand; rather was it glo fuel and if so, was the oil component synthetic or castor ? Did Seidel include any advice in their instructions regarding types of fuel or precautions when storing the engine ?

Dick

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