Author Topic: OS VF 40 won't run right (Read 5514 times)

Gerald Arana · « **on:** June 06, 2015, 12:49:01 PM »

Here's the deal: OSVF 40, new bearings, recently rechromed, .323 venture with a ST type NVA. (.010 I'm guessing.)
Has very poor compression and doesn't seem to want to draw fuel. All gaskets appear to be in good condition.
Has only been run on the bench a few times. Took it to the field and it would not start period!

Put in on the bench and got it started but it would only turn my stunt prop (CF 3 blade) around 2500-3000. In other words an idle no matter what I did to it.

Put the RC carb on it (Has humongus hole) and it still wouldn't run on the 3 blade. Got pi$$#@ and put a 10 X 6 two blade wood (Zinger) on it and Voila! Runs like a champ.

Today I got the idea to drill out the venture to approx. the size of the RC carb. Same old crap..........nothing above an idle with the 3 blade. Put the 10 X 6 back on and it ran a steady 11,430 RPM.

Anybody know what gives with this engine?

Thanks, Jerry

PS: Pipe is set at 17-3/4"

RandySmith · « **Reply #1 on:** June 06, 2015, 04:53:34 PM »

Quote from: Gerald Arana on June 06, 2015, 12:49:01 PM

Here's the deal: OSVF 40, new bearings, recently rechromed, .323 venture with a ST type NVA. (.010 I'm guessing.)
Has very poor compression and doesn't seem to want to draw fuel. All gaskets appear to be in good condition.
Has only been run on the bench a few times. Took it to the field and it would not start period!

Put in on the bench and got it started but it would only turn my stunt prop (CF 3 blade) around 2500-3000. In other words an idle no matter what I did to it.

Put the RC carb on it (Has humongus hole) and it still wouldn't run on the 3 blade. Got pi$$#@ and put a 10 X 6 two blade wood (Zinger) on it and Voila! Runs like a champ.

Today I got the idea to drill out the venture to approx. the size of the RC carb. Same old crap..........nothing above an idle with the 3 blade. Put the 10 X 6 back on and it ran a steady 11,430 RPM.

Anybody know what gives with this engine?

Thanks, Jerry

PS: Pipe is set at 17-3/4"

323 is way too big, should be closer to 275 venturie
does it have good compression? and is it abnormally tight ?
no leaks at the gaskets?
head seal?

Randy

Gerald Arana · « **Reply #2 on:** June 06, 2015, 09:29:27 PM »

Randy,

Compression is poor at best AFAIC. All gaskets are good.

Yes, I thought .323 was a tad large too. But it wouldn't run until I hogged it out.

IMO, the sleeve has too much taper. It's loose (real loose) at the bottom and snug (sort of) at the top. As soon as it gets hot the compression all but disappears.

I'm thinking about using it for a fishing weight! (not really, I have to much $$$ in it)

Jerry

Tim Wescott · « **Reply #3 on:** June 06, 2015, 10:15:30 PM »

Just had a horrible thought -- you did put the sleeve back in the correct orientation, yes? Boost on the exhaust side and exhaust on the boost side would cause some of the symptoms you're seeing, although the fit you describe sounds like an issue in and of itself.

Howard Rush · « **Reply #4 on:** June 06, 2015, 11:19:36 PM »

I would show it to Larry Fernandez. Not that he'd be able to fix it, but he would most enjoy whatever awful is wrong with it.

Hope this helps.

Gerald Arana · « **Reply #5 on:** June 07, 2015, 02:54:13 PM »

Hi Howard,

Well, if that Larry would ever show up at the field I'd be happy to give him a good laugh! But alas, he's to busy painting his car. (At least I hope that is what he's doing! LOL!)

And yes, the sleeve in in correctly since it's pinned......

Cheers, Jerry

RandySmith · « **Reply #6 on:** June 07, 2015, 10:04:24 PM »

Quote from: Gerald Arana on June 06, 2015, 09:29:27 PM

Randy,

Compression is poor at best AFAIC. All gaskets are good.

Yes, I thought .323 was a tad large too. But it wouldn't run until I hogged it out.

IMO, the sleeve has too much taper. It's loose (real loose) at the bottom and snug (sort of) at the top. As soon as it gets hot the compression all but disappears.

I'm thinking about using it for a fishing weight! (not really, I have to much $$$ in it)

Jerry

The poor compression is why it doesn't draw fuel well or make much power, can you get it rechromed? or a new P/S for it? you will need a 275 or so venturie if you want to use it for stunt, and you will need a good fit on a P/S

Randy

bob whitney · « **Reply #7 on:** June 07, 2015, 10:05:15 PM »

who cromed the sleeve and where did the ring come from

Howard Rush · « **Reply #8 on:** June 07, 2015, 11:01:33 PM »

Rechromed? Reminds me of the guy who won an Olympic gold medal and was so proud of it he had it bronzed.

Gerald Arana · « **Reply #9 on:** June 08, 2015, 10:02:19 AM »

Quote from: bob whitney on June 07, 2015, 10:05:15 PM

who chromed the sleeve and where did the ring come from

Bob, sent you a personal message. It is a lapped piston engine.

Howard; LMAO!

Randy, its been rechromed. I think that's the problem. Do you have a P/L for it?

Jerry

Brett Buck · « **Reply #10 on:** June 08, 2015, 03:15:29 PM »

Quote from: bob whitney on June 07, 2015, 10:05:15 PM

who cromed the sleeve and where did the ring come from

There's no ring, its ABC. I could make a pretty good guess about who did it based on the description, but it wouldn't serve any useful purpose at this point.

Unfortunately there are so many people gassing on endlessly about "cheap nickel plating" that getting them chromed is not terribly uncommon. Never mind the results and the astonishing durability of the original nickel and the fact that no one can reliably get the "better chrome" versions to work properly.

Jerry got the thing as it came, but for God's sake, if you have a stock 40VF (or any other OS ABC engine) that still has enough compression to start, LEAVE IT ALONE! The 40VF is still the Gold standard of stunt engines, literally, the basis for comparison for all the others, IT DOESN'T NEED FIXING.

Brett

Gerald Arana · « **Reply #11 on:** June 09, 2015, 07:45:37 PM »

Quote from: Brett Buck on June 08, 2015, 03:15:29 PM

There's no ring, its ABC. I could make a pretty good guess about who did it based on the description, but it wouldn't serve any useful purpose at this point.

Unfortunately there are so many people gassing on endlessly about "cheap nickel plating" that getting them chromed is not terribly uncommon. Never mind the results and the astonishing durability of the original nickel and the fact that no one can reliably get the "better chrome" versions to work properly.

Jerry got the thing as it came, but for God's sake, if you have a stock 40VF (or any other OS ABC engine) that still has enough compression to start, LEAVE IT ALONE! The 40VF is still the Gold standard of stunt engines, literally, the basis for comparison for all the others, IT DOESN'T NEED FIXING.

Brett

Brett, Are you going to Woodland the 27-28 TH? I'm planning on being there on the 27 TH but have to come home, so I won't be there on the 28 TH. I'll bring it along for your inspection. (and tell you who rechromed it)

Jerry

Brett Buck · « **Reply #12 on:** June 11, 2015, 09:57:03 PM »

Quote from: Gerald Arana on June 09, 2015, 07:45:37 PM

Brett, Are you going to Woodland the 27-28 TH? I'm planning on being there on the 27 TH but have to come home, so I won't be there on the 28 TH. I'll bring it along for your inspection. (and tell you who rechromed it)

As far as I know, yes, I will be there. I can take a pretty good guess on the chroming, but sure, we can confirm it.

Brett

Gerald Arana · « **Reply #13 on:** June 18, 2015, 03:55:44 PM »

Well since nobody guessed right and I just discovered it myself, The piston was in backwards!

But the compression still stinks......

Just got done running it and it turned the CF 3 blade (12 X4 ?) .. Can't tell you the RPM's because I had it on two (2) blade and not three (3) blade. When it cools down (and gets some compression) I'll run it again and tach it.

Con't...........

EddyR · « **Reply #14 on:** June 18, 2015, 04:42:35 PM »

If it is a flat top piston what difference would it make. Is the liner in backwards?

Brett Buck · « **Reply #15 on:** June 19, 2015, 09:59:00 AM »

Quote from: EddyR on June 18, 2015, 04:42:35 PM

If it is a flat top piston what difference would it make. Is the liner in backwards?

It matters because there is a cutaway in the piston to permit flow into the bypass.

Brett

Brett Buck · « **Reply #16 on:** June 19, 2015, 10:01:34 AM »

Quote from: Gerald Arana on June 18, 2015, 03:55:44 PM

Well since nobody guessed right and I just discovered it myself, The piston was in backwards!

That's not the first time that has happened! In fact you will not be the only one at Pete C.'s contest who has done that. But he flies electric now.

Brett

EddyR · « **Reply #17 on:** June 19, 2015, 05:55:22 PM »

I thought it might be something like that as I have never seen one of those motors.
Ed

RandySmith · « **Reply #18 on:** June 21, 2015, 10:40:20 AM »

Quote from: EddyR on June 18, 2015, 04:42:35 PM

If it is a flat top piston what difference would it make. Is the liner in backwards?

It has a large cut away on the front side of the piston, but that should have been very easy to see, and should have been a big clue about the poor fuel suction. It would also fill the engine with hot exhaust.. this and the poor piston fit would render the motor useless

Randy

Brett Buck · « **Reply #19 on:** June 21, 2015, 01:39:06 PM »

Quote from: RandySmith on June 21, 2015, 10:40:20 AM

It has a large cut away on the front side of the piston, but that should have been very easy to see, and should have been a big clue about the poor fuel suction. It would also fill the engine with hot exhaust.. this and the poor piston fit would render the motor useless

I am going to see the engine next weekend, but the rechrome job sounds very familiar to me. It does run very hot and slow, just like you put the liner in backwards on a baffle-piston engine (which I have also seen MANY times).

BTW, the way I noticed my first example of backwards piston was that the chamfer on the big end of the conrod was visible from the back. Lots of people take the engine apart but not that many ever take the wristpin out.

Brett

Gerald Arana · « **Reply #20 on:** June 21, 2015, 02:54:04 PM »

Quote from: Gerald Arana on June 18, 2015, 03:55:44 PM

Well since nobody guessed right and I just discovered it myself, The piston was in backwards!

But the compression still stinks......

Just got done running it and it turned the CF 3 blade (12 X4 ?) .. Can't tell you the RPM's because I had it on two (2) blade and not three (3) blade. When it cools down (and gets some compression) I'll run it again and tach it.

Con't...........

Ok, engine turned 9800 at best and slowly went to nothing as it heated up....I guess. It acted like it had seized but in fact was VERY loose. (read no compression)

Anybody want to buy a fishing weight?

Jerry

Bill Little · « **Reply #21 on:** June 21, 2015, 03:34:27 PM »

I could be way off base, but I think someone told me a .46VF piston and liner would work in a .40VF. Anyone know for sure? Seems like it made a .42VF. If so, you might can find someone who got some of Randy's AAC set ups and has the stock ones in a drawer!

Anybody?

BIG Bear
RNMM/AMM

RandySmith · « **Reply #22 on:** June 22, 2015, 03:17:59 PM »

Quote from: Bill Little on June 21, 2015, 03:34:27 PM

I could be way off base, but I think someone told me a .46VF piston and liner would work in a .40VF. Anyone know for sure? Seems like it made a .42VF. If so, you might can find someone who got some of Randy's AAC set ups and has the stock ones in a drawer!

Anybody?

BIG Bear
RNMM/AMM

You need the head, piston sleeve, and crankshaft, to convert to a 46, a 40 head nor crank will work

Randy