Notices
Everything Diesel Discuss R/C Diesel engines here.

mvvs 2.5dfs/r sort of success

Old 04-23-2014, 07:12 AM
  #1  
telmore
Senior Member
Thread Starter
 
Join Date: Nov 2003
Location: Bucks, UNITED KINGDOM
Posts: 165
Likes: 0
Received 0 Likes on 0 Posts
Default mvvs 2.5dfs/r sort of success

Just had my MVVS 2.5 diesel sort of running.


Seemed to only want to start with tons of compression but once I'd had a few pops out of it at that compression I could slacken off the comp a bit - it would start but only run for about a minute - judging by the smoke it was well rich.


Lots of black exhaust residue.


It seemed very tight when I bought it new - I was chatting to someone at the Nats a few years back who had one and he said they're not easy to run in....


Still quite successful.

Annette
Old 04-23-2014, 04:38 PM
  #2  
123Cat
 
Join Date: Oct 2005
Location: ACTAustralia, AUSTRALIA
Posts: 393
Likes: 0
Received 0 Likes on 0 Posts
Default

What sort of model are you going to put it in
Old 04-24-2014, 12:00 AM
  #3  
telmore
Senior Member
Thread Starter
 
Join Date: Nov 2003
Location: Bucks, UNITED KINGDOM
Posts: 165
Likes: 0
Received 0 Likes on 0 Posts
Default

A Modelhob Smousen..
Old 04-24-2014, 03:46 PM
  #4  
controlliner
 
controlliner's Avatar
 
Join Date: Mar 2009
Location: Ontario, Canada
Posts: 1,238
Likes: 0
Received 1 Like on 1 Post
Default

Your fuel may be low on ether. If the oil in the exhaust is really black, you may be running it over compressed. Low ether fuel will need a lot of compression to stay running when cold. Your exhaust residue should range from a honey colour to light brown.
Old 04-24-2014, 08:22 PM
  #5  
telmore
Senior Member
Thread Starter
 
Join Date: Nov 2003
Location: Bucks, UNITED KINGDOM
Posts: 165
Likes: 0
Received 0 Likes on 0 Posts
Default

Using Model Technics D1000 which is 25/72/3.

Annette
Old 04-25-2014, 06:13 AM
  #6  
controlliner
 
controlliner's Avatar
 
Join Date: Mar 2009
Location: Ontario, Canada
Posts: 1,238
Likes: 0
Received 1 Like on 1 Post
Default

D1000 is good. If it is fresh, one would assume the ether has not gone off. In that case you may be running over compressed. I would get it running and once it is warmed up, I would back off on the "tommy bar" until the engine falters a bit and then lean it out until the engine runs smooth. If the engine is new, do not over prop it.
Old 04-25-2014, 03:59 PM
  #7  
Warren B
 
Join Date: Feb 2010
Location: Melbourne, AUSTRALIA
Posts: 68
Likes: 0
Received 0 Likes on 0 Posts
Default

My MVVS DFS/R runs a rather black exhaust most of the time, I think it might be normal for this engine as it shows no sign of distress or over compression.
Mine is running with throttle an tuned exhaust in a rather quick rc pattern plane.- very nice indeed.
Old 04-25-2014, 04:17 PM
  #8  
AMB
 
Join Date: Jun 2003
Location: winter park, FL
Posts: 6,748
Likes: 0
Received 2 Likes on 2 Posts
Default

Warren what prop are you running and aprox rpms?? sounds like a no issue situation with the set up martin
Old 04-26-2014, 03:05 AM
  #9  
Warren B
 
Join Date: Feb 2010
Location: Melbourne, AUSTRALIA
Posts: 68
Likes: 0
Received 0 Likes on 0 Posts
Default

I'm running an APC 8x5.
it just gets on the pipe with a shallow dive then says on the pipe after that.
If I want to be on the pipe from launch it needs to be an 8x4 or 7x5, but I have found these a bit noisy and quick for relaxed flying.
Not sure of the rpm but I don't think the pipe works below 15,000.
Old 04-29-2014, 04:48 PM
  #10  
AMB
 
Join Date: Jun 2003
Location: winter park, FL
Posts: 6,748
Likes: 0
Received 2 Likes on 2 Posts
Default

Just rechecked mine today sitting in an old J 3 cub ( Nitroplanes??} span 50 inchs wt 48 oz 4 oz tank fitted with a wood zinger 9 x 5 8800-9000 idle about 3300 good transisition muffler stock MVVS 3225 conventional not tuned exhaust carried to back\
exits at rear KS alum tubing easy flyer no speed demon compression seems low but still a finger flip 10-15 after a choke martin

oh blue smoke of course oil out the stack dark honey color fuel davis ABC

Last edited by AMB; 04-29-2014 at 04:53 PM.
Old 08-08-2015, 08:43 PM
  #11  
BrightGarden
 
BrightGarden's Avatar
 
Join Date: Jun 2014
Location: Hudson Valley. New York. USA
Posts: 283
Likes: 0
Received 2 Likes on 2 Posts
Default

I had heaps of trouble with an MVVS D7 today and came across this thread. In fact I took one of the comments and tried boosting the ether in the fuel but to no avail.
If anyone catches this update and has any advice, I'd appreciate hearing what you know.
This is supposed to be an easy-starting engine and I got Charlie Bupkus today after fiddling for four hours on it.
My arm feels like I pitched 9 innings today!

Here's a vid at the end of my efforts: https://www.youtube.com/watch?v=J0LBEtSOm1Q
Shows a bit of a bite but it never really catches.
Old 08-09-2015, 12:49 AM
  #12  
Mr Cox
 
Mr Cox's Avatar
 
Join Date: Jul 2007
Location: Karlstad, SWEDEN
Posts: 3,791
Likes: 0
Received 2 Likes on 2 Posts
Default

It is hard to tell from just a short movie but to me it looked like is was over compressed. It fires but only rocks back and forth between two TDC points.

The large venturi can give a low suction but that would be something that you can check for with the engine running. In your rig the fuel level is well above the venturi and fuel will flow due to gravity alone. In fact that might also deliver too much fuel while trying to start the engine. I would suggest to not put any fuel in the tank at all until you learn how to start the engine. The easiest is to prime the side of the piston only, that should fire each time when the compression ratio is set right. Second option is to prime a little directly into the venturi that will give you a long enough run to get the hang of the starting and compression ratio. Once the engine starts easily and runs out the prime you can put fuel into the tank and tune the needle.
Old 08-09-2015, 01:48 AM
  #13  
qazimoto
My Feedback: (1)
 
Join Date: Sep 2005
Location: Central Coast NSW, AUSTRALIA
Posts: 1,448
Received 8 Likes on 8 Posts
Default

Is that synthetic oil in your fuel? If so it's a no-no with that engine. You might try some castor oil in the fuel, about 25% to start with.
Old 08-09-2015, 04:57 AM
  #14  
BrightGarden
 
BrightGarden's Avatar
 
Join Date: Jun 2014
Location: Hudson Valley. New York. USA
Posts: 283
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by Mr Cox
It is hard to tell from just a short movie but to me it looked like is was over compressed. It fires but only rocks back and forth between two TDC points.

The large venturi can give a low suction but that would be something that you can check for with the engine running. In your rig the fuel level is well above the venturi and fuel will flow due to gravity alone. In fact that might also deliver too much fuel while trying to start the engine. I would suggest to not put any fuel in the tank at all until you learn how to start the engine. The easiest is to prime the side of the piston only, that should fire each time when the compression ratio is set right. Second option is to prime a little directly into the venturi that will give you a long enough run to get the hang of the starting and compression ratio. Once the engine starts easily and runs out the prime you can put fuel into the tank and tune the needle.
Thanks for giving this some thought. The tank in the video does look like it is higher than the venturi but it isn't. Early on I determined putting the fuel higher than the venturi would flood the engine.
I exhaustively tested this engine. I did the other thing you suggest numerous times - started from a closed NV, got it to purr a bit either thru priming through the exhaust port or the venturi or both, then gradually open the NV - to no avail. I pretty much exhausted pemutations. I added a screen at the end of the video that I am inserting here.
Don't know, first place to look is if anything is fishy with the NV when I get it out.
Cheers, Peter

Attached Thumbnails Click image for larger version

Name:	Outro.jpg
Views:	256
Size:	245.0 KB
ID:	2113510  
Old 08-09-2015, 05:02 AM
  #15  
BrightGarden
 
BrightGarden's Avatar
 
Join Date: Jun 2014
Location: Hudson Valley. New York. USA
Posts: 283
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by qazimoto
Is that synthetic oil in your fuel? If so it's a no-no with that engine. You might try some castor oil in the fuel, about 25% to start with.
Hi Q, thanks for getting back. I am using the ubiquitous Davis Diesel fuel. What you see in the photo is John Deere starting fluid = either, and is what people mix their own fuel with, here.
I have run other engines in the last two weeks on this (fresh) Davis Diesel fuel, and I just tried boosting the ether content of the fuel a bit to see if that would have an effect..
There were notes online that some MVVS engines needed an unnatural deal of compression or higher ether - tried that with no positive outcome.
Cheers - Peter
Old 08-09-2015, 09:05 AM
  #16  
Mr Cox
 
Mr Cox's Avatar
 
Join Date: Jul 2007
Location: Karlstad, SWEDEN
Posts: 3,791
Likes: 0
Received 2 Likes on 2 Posts
Default

As it does fire I think it is just a matter of finding the right settings. Is the engine new or used?
If it is a used engine you might want to check that the liner is in a correct position, I don't think there is any alignment pin and someone may well have put the cylinder the wrong way around.

On new engines I've found that a large plastic prop helps for the first starts. Not sure what you have on there now, but you can easily put on a plastic 9x4 or 9x5. Perhaps even a 10x4 just to get it running. A too large prop isn't any problem on diesels, they will just run cooler as the optimum compression setting is lower.
Old 08-09-2015, 02:05 PM
  #17  
BrightGarden
 
BrightGarden's Avatar
 
Join Date: Jun 2014
Location: Hudson Valley. New York. USA
Posts: 283
Likes: 0
Received 2 Likes on 2 Posts
Default

Hi Mr Cox - This is a used engine, via a seller another RC site.
I will definitely check the liner.
The props is a Zinger 9-6 and I believe I have a larger prop.
I'll try those tests/changes and let you know the results - thanks for the help.
Old 08-09-2015, 06:45 PM
  #18  
BrightGarden
 
BrightGarden's Avatar
 
Join Date: Jun 2014
Location: Hudson Valley. New York. USA
Posts: 283
Likes: 0
Received 2 Likes on 2 Posts
Default Update on MVVS 2.49 D7 Diesel

Update - I disassembled the engine tonight and the 6 head screws weren't even finger-tight. So, that's a big problem solved, I hope. Another question is whether the liner was inserted correctly. Pic below and if anybody has original paperwork for the engine with assembly diagram, that would be great.

Thanks! Poughkeepsie Pete

Attached Thumbnails Click image for larger version

Name:	MVVS 2.49 CL Diesel Finicky (1 of 1) notated.jpg
Views:	308
Size:	572.6 KB
ID:	2113631  
Old 08-09-2015, 08:45 PM
  #19  
qazimoto
My Feedback: (1)
 
Join Date: Sep 2005
Location: Central Coast NSW, AUSTRALIA
Posts: 1,448
Received 8 Likes on 8 Posts
Default

Originally Posted by BrightGarden
Update - I disassembled the engine tonight and the 6 head screws weren't even finger-tight. So, that's a big problem solved, I hope. Another question is whether the liner was inserted correctly. Pic below and if anybody has original paperwork for the engine with assembly diagram, that would be great.

Thanks! Poughkeepsie Pete

Looks like the exhaust port is 180degrees out. The highest port will be the exhaust. It's also the one with the dark sooty deposits. That's almost certainly your problem. Many people store engines with the screws only finger tight. It partly eliminates the possibility of a "stuck" motor years ahead in the future.

Also it's worth checking that the piston/rod is facing the right direction. Once again the exhaust deposits on the piston top will be the clue. Also check the rod "big end" for the recess to match the crankpin.

Last edited by qazimoto; 08-10-2015 at 11:23 PM.
Old 08-09-2015, 09:09 PM
  #20  
Mr Cox
 
Mr Cox's Avatar
 
Join Date: Jul 2007
Location: Karlstad, SWEDEN
Posts: 3,791
Likes: 0
Received 2 Likes on 2 Posts
Default

Well, that's likely the problem. As said above it is off by about 180....
Old 08-09-2015, 09:13 PM
  #21  
BrightGarden
 
BrightGarden's Avatar
 
Join Date: Jun 2014
Location: Hudson Valley. New York. USA
Posts: 283
Likes: 0
Received 2 Likes on 2 Posts
Default

Thank you all. Nice to get a definitive and easily solvable answer. I am looking forward to checking it out tomorrow - would do it now but I have neighbors, ha.

You're right about storing the engine with loose screws, that would work nicely. Should have checked when I was having all the problem. But now I know 4 hours worth of how not to run a diesel.
Well, I certainly learned a few things here, and will let you know how it goes.
Best,
Peter
Old 08-09-2015, 10:31 PM
  #22  
wnewbury
 
Join Date: Dec 2004
Location: Durant OK
Posts: 159
Received 4 Likes on 4 Posts
Default

My MVVS 2.5 starts easily and runs well. I think you will be happy with yours after the liner is rotated 180 degrees. Too bad the seller temporarily ruined the engine.
Old 08-09-2015, 11:24 PM
  #23  
gerryndennis
 
Join Date: Jun 2008
Location: Christchurch, NEW ZEALAND
Posts: 345
Likes: 0
Received 0 Likes on 0 Posts
Default

Hi Pete,

Thanks for for all your recent diesel videos, I could watch Diesel engines for hours (I know, sad right?).

You seem to have things pretty well sorted out and I'm sure you've now solved the MVVS's issues. I hope you don't mind a couple of suggestions though?

Firstly the position of your propellor. Diesels start best with a really snappy flick (it can almost look like a hit),known as the diesel flick. Most people tighten the prop so that one blade is at about the 2 O'clock position when the engine is just coming on to the compression stroke. This lets you get a really good flick as you bring your hand across the top. I might be wrong but it looks like you're prop is at about 12 and you end up pushing down rather than flicking across. It seems to work fine, so don't worry if this is easier for you, but you might get better results from flicking across.

Secondly, I noticed in one of your videos you left your fuel can open for a long time while you filled the syringe tank, emptied the tank, cleaned something out of the tank, then filled it again. You would have been better to fill then cap the can to reduce the ether loss (it evaporates really quickly) Even better would be to transfer enough fuel for a days flying to a plastic squeezy bottle with a cap and use that. That way you only have to uncap your can once. Plastic bottles are no good for long term storage but are OK for a flying or running session (some might disagree). Dr Diesel sells 'Valve Spout' bottles for this. These bottles are really good and probably worth the price if you are going to be doing a bit of Dieselling.

Hey, minor things and I only mention it because I only learned when I was told by someone else.

I'm looking forward to the video of your MVVS singing.

Dave H
Old 08-10-2015, 03:05 AM
  #24  
BrightGarden
 
BrightGarden's Avatar
 
Join Date: Jun 2014
Location: Hudson Valley. New York. USA
Posts: 283
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by wnewbury
My MVVS 2.5 starts easily and runs well. I think you will be happy with yours after the liner is rotated 180 degrees. Too bad the seller temporarily ruined the engine.
Thanks wnewbury - I look at things like this as I either learn now - or later. This internet community sure is a help. I have gotten to know the engine quite a bit more than before I got a lot of great help here. I have a feeling this was a pass-thru from the gent I bought it from - he does a lot of online sales and I had bought other things from him.
Cheers!




Originally Posted by gerryndennis
Hi Pete,

Thanks for for all your recent diesel videos, I could watch Diesel engines for hours (I know, sad right?).

You seem to have things pretty well sorted out and I'm sure you've now solved the MVVS's issues. I hope you don't mind a couple of suggestions though?

Firstly the position of your propellor. Diesels start best with a really snappy flick (it can almost look like a hit),known as the diesel flick. Most people tighten the prop so that one blade is at about the 2 O'clock position when the engine is just coming on to the compression stroke. This lets you get a really good flick as you bring your hand across the top. I might be wrong but it looks like you're prop is at about 12 and you end up pushing down rather than flicking across. It seems to work fine, so don't worry if this is easier for you, but you might get better results from flicking across.

Secondly, I noticed in one of your videos you left your fuel can open for a long time while you filled the syringe tank, emptied the tank, cleaned something out of the tank, then filled it again. You would have been better to fill then cap the can to reduce the ether loss (it evaporates really quickly) Even better would be to transfer enough fuel for a days flying to a plastic squeezy bottle with a cap and use that. That way you only have to uncap your can once. Plastic bottles are no good for long term storage but are OK for a flying or running session (some might disagree). Dr Diesel sells 'Valve Spout' bottles for this. These bottles are really good and probably worth the price if you are going to be doing a bit of Dieselling.

Hey, minor things and I only mention it because I only learned when I was told by someone else.

I'm looking forward to the video of your MVVS singing.

Dave H
Dave - I very much appreciate your comments especially since I don't know how long it would take me to meet the right guys at the club I recently joined who know anything about diesels, especially this one.
I have to get one of those Valvespout bottles on order with Dr Diesel over here - Eric Clutton. He imports them and I see them in a lot of videos. I now understand how volatile the ether is in the fuel from what you say - you have to really protect it. I have the raw model diesel ingredients sitting here so I can boost the fuel I have left in that first can of Davis Diesel I am running.

You are correct about the placement of my prop - I was shooting for a down swing which I can now correct. TDC was about 11'is o'clock. All the while I was flicking the prop I was wondering what beating a frail plane would have been taking if I were trying this while it was installed in a plane rather than a test stand. I could see the landing gear squashing under the effort of starting the engine - ha.

I'm glad you watched my videos - I want to get on to showing the engines in actual airplanes actually flying! Maybe showing my early efforts will be helpful to other newbies, too.

Thanks for the share, very much appreciated.
Old 08-10-2015, 01:25 PM
  #25  
gerryndennis
 
Join Date: Jun 2008
Location: Christchurch, NEW ZEALAND
Posts: 345
Likes: 0
Received 0 Likes on 0 Posts
Default

The way you're going Pete, you'll be the club Diesel expert.

Dave H

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.