Diesel Conversions

Kim wrote:Plus, I still don't have the whole mixture/compression relationship figured out, but intend to keep trying!

Later ! Diesel Kim

When you get that lined out, please let me know. More compression, less compression, leaner, richer --- what to do, where to go? KEEP me informed.

andrew

Ivanhoe wrote:Can I ask for people's opinions on the various diesel conversions available for the .049?

I have a couple of SureStarts lying around and I am considering fitting a diesel conversion and heavier crankshaft to at least one of them, since a true diesel .8cc is, as far as my finances go, totally out of the question!
I know very little about the conversions, do they have a true contra-piston, and if so, how do you get a close enough fit in the cylinder for them to work? How easy to start is the engine thus equipped?
I've read Kim's message here about his conversion, and note that he had trouble starting it, having to resort to an electric starter(!) and that it then stopped "of it's own accord", which has me wondering.

Any advice would be much appreciated

Wilf

Wilf the heads arr essentially glow heads that have been drilled out and the element replaced with a threaded whole for the comp screw then the contra is a disk.
Thts how all the heads on the Market go.
But the heads that are sold by Davis and Bernie use a coined gasket in between the glow head gasket and head I HATE these so I make them out of aluminium from cans.
Or there is the mecoa type that use an "O" ring around the contra thus eliminating the need for a countergasket (both are use to get a sela bit the Teflon gaskets are prone to rupturing)
Then there is the Norvel branded heads that use neither just a well fitting brass contra piston that expands so it has a tight fit.
I have tried "O" rings and counter gaskets and I can say the former is the better.
Or make your own!
I need to get my act together and write a "How to make a diesel conversion" thread
Indra.

andrew wrote:

Kim wrote:Plus, I still don't have the whole mixture/compression relationship figured out, but intend to keep trying!

Later ! Diesel Kim

When you get that lined out, please let me know. More compression, less compression, leaner, richer --- what to do, where to go? KEEP me informed.

andrew

Hi Andrew, virtually all of what I call my "Previous Modelling Life" that is before the 40-odd year gap until I returned to the fold, was spent cranking diesels, the "compression/mixture" thing is something that really only comes with experience, I always start by opening the needle to roughly the right setting, backing the compression right off, then advancing it steadily while I flick the prop, you can feel when the engine is about to fire,(or hydraulic!) so a little bit more compression and away it should go. If you can't get an even run by altering the compression you change the needle exactly as you would a glow, but then you have to compensate with the compression setting. With a good diesel you normally never need to touch the needle again once it's set, all starting is done with the compression. A word of warning about "Hydraulicing" flood a diesel and it will lock up solid, this, as many others have said, can damage a small engine, but, in my experience the worst part it that when the prop locks, your finger slides up a usually quite sharp bit of plastic! Sand the edges off those props, I still have scars to this day!

Wilf

Ivanhoe wrote:

andrew wrote:

Kim wrote:Plus, I still don't have the whole mixture/compression relationship figured out, but intend to keep trying!

Later ! Diesel Kim

When you get that lined out, please let me know. More compression, less compression, leaner, richer --- what to do, where to go? KEEP me informed.

andrew

Hi Andrew, virtually all of what I call my "Previous Modelling Life" that is before the 40-odd year gap until I returned to the fold, was spent cranking diesels, the "compression/mixture" thing is something that really only comes with experience, I always start by opening the needle to roughly the right setting, backing the compression right off, then advancing it steadily while I flick the prop, you can feel when the engine is about to fire,(or hydraulic!) so a little bit more compression and away it should go. If you can't get an even run by altering the compression you change the needle exactly as you would a glow, but then you have to compensate with the compression setting. With a good diesel you normally never need to touch the needle again once it's set, all starting is done with the compression. A word of warning about "Hydraulicing" flood a diesel and it will lock up solid, this, as many others have said, can damage a small engine, but, in my experience the worst part it that when the prop locks, your finger slides up a usually quite sharp bit of plastic! Sand the edges off those props, I still have scars to this day!

Wilf

Yep IMO the two worst props (sharp edges) are tha APC props and the ones that the bambi came with.

Wilf the heads arr essentially glow heads that have been drilled out and the element replaced with a threaded whole for the comp screw then the contra is a disk.
Thts how all the heads on the Market go.
But the heads that are sold by Davis and Bernie use a coined gasket in between the glow head gasket and head I HATE these so I make them out of aluminium from cans.
Or there is the mecoa type that use an "O" ring around the contra thus eliminating the need for a countergasket (both are use to get a sela bit the Teflon gaskets are prone to rupturing)
Then there is the Norvel branded heads that use neither just a well fitting brass contra piston that expands so it has a tight fit.
I have tried "O" rings and counter gaskets and I can say the former is the better.
Or make your own!
I need to get my act together and write a "How to make a diesel conversion" thread
Indra.[/quote]

Thanks for the info, Indra, it's the whole contra piston thing that was foxing me, yes I'm sure that, with access to a precision lathe, and the necessary skill, making a diesel conversion would be easy enough, unfortunately I have neither!
Norvel sounds the nearest to a "true" diesel, and no doubt costs the proverbial arm and leg!
I may have to re-think this whole idea!

Wilf

Well it appears Norvel do not give prices,
http://www.nvengines.com/index.php?option=com_content&view=article&id=82:diesel&catid=41:roknewspager-showcase

The price for the NORVEL head is buried on the parts section: $24.95


By the way, APC stands for: Awfully Painful Cut

nitroairplane wrote:Well it appears Norvel do not give prices,
http://www.nvengines.com/index.php?option=com_content&view=article&id=82:diesel&catid=41:roknewspager-showcase

I was about to say what Andrew has above, the Norvel is $24.95, I've sent them a message to ask if it will fit a Cox, waiting on reply now

Wilf

"I need to get my act together and write a "How to make a diesel conversion" thread
Indra."


YES YOU DO !!!!!!!!!!!!!!!!!!!!

andrew wrote:The price for the NORVEL head is buried on the parts section: $24.95


By the way, APC stands for: Awfully Painful Cut

++++++++++++++ Right ON !!!! Testify Brother !!!! +++++++++++++

Ivanhoe wrote:

nitroairplane wrote:Well it appears Norvel do not give prices,
http://www.nvengines.com/index.php?option=com_content&view=article&id=82:diesel&catid=41:roknewspager-showcase

I was about to say what Andrew has above, the Norvel is $24.95, I've sent them a message to ask if it will fit a Cox, waiting on reply now

Wilf

Just heard back from Norvel, they assure me that their head does fit the Cox 049, I must admit it looks the best engineered of those I've seen so far, a lot will depend on how much they want to ship it here!

Wilf

Ivanhoe wrote:

Ivanhoe wrote:

nitroairplane wrote:Well it appears Norvel do not give prices,
http://www.nvengines.com/index.php?option=com_content&view=article&id=82:diesel&catid=41:roknewspager-showcase

I was about to say what Andrew has above, the Norvel is $24.95, I've sent them a message to ask if it will fit a Cox, waiting on reply now

Wilf

Just heard back from Norvel, they assure me that their head does fit the Cox 049, I must admit it looks the best engineered of those I've seen so far, a lot will depend on how much they want to ship it here!

Wilf

Well i doubt it will be too much, they are based in easter europe, and how much does a head weigh?

nitroairplane wrote:

Ivanhoe wrote:

Ivanhoe wrote:

nitroairplane wrote:Well it appears Norvel do not give prices,
http://www.nvengines.com/index.php?option=com_content&view=article&id=82:diesel&catid=41:roknewspager-showcase

I was about to say what Andrew has above, the Norvel is $24.95, I've sent them a message to ask if it will fit a Cox, waiting on reply now

Wilf

Just heard back from Norvel, they assure me that their head does fit the Cox 049, I must admit it looks the best engineered of those I've seen so far, a lot will depend on how much they want to ship it here!

Wilf

Well i doubt it will be too much, they are based in easter europe, and how much does a head weigh?

Hey Nitro!

When you do start your Conversion Info Page, maybe consider cutting and pasting your update and responses as an "Edit" to your original post? Don't know if it's practical, and will be a little more work, but this would keep the new information in one up front spot for review.

Looking forward to your ideas! Also, you have used an aluminum disc to replace the teflon one in the Davis conversion ?

"Well i doubt it will be too much, they are based in easter europe, and how much does a head weigh?"



Yes, I see they are Russian, with everything priced in US$! don't they trust the Ruble?
They want $9.99 shipping to here, which I suppose isn't too bad, although, as you say, how much does a head weigh, and how much packing does it need? they'll probably just throw it in a Jiffy bag!
Of course I also have to take into account an upgraded crank, again plus shipping, so all in all it had better piggin' work!

Wilf

Kim:Yes i use aluminium.
Wilf I ran my .049 conversion on the stock crank with no problems.

If you want to run a Diesel, then buy a Diesel. I love Cox engines and would never convert one to Diesel. Buy conversion parts etc plus the engine itself. I bought a PAW .061 B/R and its made to run and powerful little engine. They sell it RC or UC. It is new bought from a dealer on ebay at $76.00+ 10.00 postage. It has ball bearing and it will hold up for mucho amount of time. By all means do what you like but just an idea. Larry Renger is big Cox expert and his Diesels are PAW. Made in UK so Euro's should not have problem getting them.
Now to die-hard Cox Diesel's users if they work thats fine. Some modified head with teflon disk sounds bogus to me. Diesel's have true conta-piston that is fitted to engine. Not a converted glow plug head.
Dan

dankar04 wrote:If you want to run a Diesel, then buy a Diesel. I love Cox engines and would never convert one to Diesel. Buy conversion parts etc plus the engine itself. I bought a PAW .061 B/R and its made to run and powerful little engine. They sell it RC or UC. It is new bought from a dealer on ebay at $76.00+ 10.00 postage. It has ball bearing and it will hold up for mucho amount of time. By all means do what you like but just an idea. Larry Renger is big Cox expert and his Diesels are PAW. Made in UK so Euro's should not have problem getting them.
Now to die-hard Cox Diesel's users if they work thats fine. Some modified head with teflon disk sounds bogus to me. Diesel's have true conta-piston that is fitted to engine. Not a converted glow plug head.
Dan

I beg to differ.
Converted cox engines are great for most high wing scale applications and vintage FF models.
Also just making these things run on a different fuel is interesting.
I run converted engines and meant to be diesels.
The pee wee .020 is the most succesful one yet.
I am currently trying to get a tee dee .010 to run as a diesel and am waiting for a response from RON Valentine about cranks.

dankar04 wrote: Some modified head with teflon disk sounds bogus to me. Diesel's have true conta-piston that is fitted to engine. Not a converted glow plug head.
Dan

Ah, but the Norvel conversion I'm going to use DOES have a proper contra-piston, no Teflon disks, O-rings or anything else.
The point is, if I do a conversion I already HAVE most of the engine, Norvel's conversion is $24.95, and for those of us on a strictly limited hobby budget that makes it affordable, I'd much rather get a "real" .8cc (.049) diesel, but I can't justify the cost.
All of my early aeromodelling years were spent using diesels, glows took a long time to catch on over here, and I would LOVE to get hold of an old Frog 80 to re-live my youth, but the last I saw on EBay went for getting on for $100 and it wasn't a very good example!

Wilf

Ivanhoe wrote:

dankar04 wrote: Some modified head with teflon disk sounds bogus to me. Diesel's have true conta-piston that is fitted to engine. Not a converted glow plug head.
Dan

Ah, but the Norvel conversion I'm going to use DOES have a proper contra-piston, no Teflon disks, O-rings or anything else.
The point is, if I do a conversion I already HAVE most of the engine, Norvel's conversion is $24.95, and for those of us on a strictly limited hobby budget that makes it affordable, I'd much rather get a "real" .8cc (.049) diesel, but I can't justify the cost.
All of my early aeromodelling years were spent using diesels, glows took a long time to catch on over here, and I would LOVE to get hold of an old Frog 80 to re-live my youth, but the last I saw on EBay went for getting on for $100 and it wasn't a very good example!

Wilf

WIlf I will keep my eye out for .8cc diesels.
What is you max price?
I think I may be able to find one for you.