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[BJ]

Two questions for you all.........
1.) Does anyone know if the Zen conversion part supplied by Prestwich to replace the pull start (see http://www.ebay.co.uk/itm/STARTER-PULLEY-ZENOAH-rc-model-boat-gas-CNC-C1-/150635498434?pt=UK_ToysGames_RadioControlled_JN&hash=item2312934bc2) will fit a CRRCPro GW26 engine (http://www.crrcpro.com/product_show.asp?id=222)?

2.) Also what is the preferred two stroke oil for these CRRCPro engines - part synthetic or mineral oil plus the recommended %age of oil?

[glennb2006]

I don't think the starter pulley fits straight on, the CRRC has as a funny starter ratchet systemn which I think is part of the flywheel, not like a Zen where you unscrew a nut.

If you do want an electric start option you might want to look at the combined collet / starter pully type which fit onto the taper end.

As to oil, the motor is not a high performance engine so any old general purpose 2 stroke oil will do you.

Glenn

[bulldog1966]

i have a pro the book you get with it says 40ml to 4lts of petrol

[cobramax]

Hi BJ ,I had one of those engines ,the older type where you had to throw away the black spark coil that came with it and replace it with the red Zenoah one,the crank was the same ,so a standard pullstart should work fine..as for oil content ,I think the book allowance is probably a missprint as you should be looking at around 290-312ml per 5lts, go for a caster based for longevity - "King Cobra Venom " -   is the best IMO  hope this helps .JOJO            

[BJ]

The question was " Does anyone know if the Zen conversion part supplied by Prestwich to replace the pull start (see http://www.ebay.co.uk/itm/STARTER-PULLEY-ZENOAH-rc-model-boat-gas-CNC-C1-/150635498434?pt=UK_ToysGames_RadioControlled_JN&hash=item2312934bc2) will fit a CRRCPro GW26 engine (http://www.crrcpro.com/product_show.asp?id=222)?"

Well, the answer to the question is that the Zen design uses a FINE thread (M8 x 1p) whereas the CrrCPro design uses  COARSE (M8 x 1.25P) thread. The Prestwich part can be converted to the coarse thread by re-tapping BUT do make sure that you tap from the CORRECT side to ensure that you have the most undamaged thread. That is the side of the boss that adjacent to the piston.
Now in http://www.modelboatmayhem.co.uk/forum/index.php?topic=16442.0 there is a reference to the metal starter dogs by Martno1fan - well the answer here is that they are not so good showing signs of a lot of wear with little use.
If the driveN dog (the one on the pull start side) does not move out when pulled over try tightening the Phillips headed screw shown in picture GW261.jpg in Patternmakers post.
For me, I hope that the best solution will be the modified Prestwich part... 24V on big Sullivan work fine every time so far

[glennb2006]

The question was " Does anyone know if the Zen conversion part supplied by Prestwich to replace the pull start (see http://www.ebay.co.uk/itm/STARTER-PULLEY-ZENOAH-rc-model-boat-gas-CNC-C1-/150635498434?pt=UK_ToysGames_RadioControlled_JN&hash=item2312934bc2) will fit a CRRCPro GW26 engine (http://www.crrcpro.com/product_show.asp?id=222)?"

Well, the answer to the question is that the Zen design uses a FINE thread (M8 x 1p) whereas the CrrCPro design uses  COARSE (M8 x 1.25P) thread. The Prestwich part can be converted to the coarse thread by re-tapping BUT do make sure that you tap from the CORRECT side to ensure that you have the most undamaged thread. That is the side of the boss that adjacent to the piston.
Now in http://www.modelboatmayhem.co.uk/forum/index.php?topic=16442.0 there is a reference to the metal starter dogs by Martno1fan - well the answer here is that they are not so good showing signs of a lot of wear with little use.
If the driveN dog (the one on the pull start side) does not move out when pulled over try tightening the Phillips headed screw shown in picture GW261.jpg in Patternmakers post.
For me, I hope that the best solution will be the modified Prestwich part... 24V on big Sullivan work fine every time so far

I'm thinking if you have simply run a tap down the threads then you might have taken too much metal out for the pulley to stand the torque of starting the motor, but only one way to find out.

If that is the case and it comes off, you have two choices, try and use a combined collet / pulley type which goes onto the drive end of the motor, fits onto the taper, or ring Dave Marles and ask him to supply you a pulley drilled but not tapped so that you can put your own thread in to it.

Glenn

[cobramax]

BJ,,,YOU ASKED TWO QUESTIONS   

[zooma]

Two questions for you all.........
1.) Does anyone know if the Zen conversion part supplied by Prestwich to replace the pull start (see http://www.ebay.co.uk/itm/STARTER-PULLEY-ZENOAH-rc-model-boat-gas-CNC-C1-/150635498434?pt=UK_ToysGames_RadioControlled_JN&hash=item2312934bc2) will fit a CRRCPro GW26 engine (http://www.crrcpro.com/product_show.asp?id=222)?

2.) Also what is the preferred two stroke oil for these CRRCPro engines - part synthetic or mineral oil plus the recommended %age of oil?

We always found that the CRRCpro engine's ran best on an oil that is blended for large scale model car racing by Rock Oil - it is called Racing Venom and although it is a semi-synthetic oil it does contain a small element of castor oil that not only suites these engines well but also has the bonus of smelling like the old Castol TT oil when he boat goes past.


Unlike ordinary castor based oil this one runs smokeless after starting from cold and gives good performance and protection for the engine.


This oil is available from www.kingcobra.co.uk but as they also supply the model trade it can also be bought from many good model shops here in the UK and some overseas as well.


It is not an expensive oil and it has been around for many years now so it is well tested

[martno1fan]

You do realize your replying to a 6 yr old thread ?  lol

[TomHugill]

You do realize your replying to a 6 yr old thread ?  lol

I found some utility in his reply old thread or not.




Unlike yours "lol".

[zooma]

You do realize your replying to a 6 yr old thread ?  lol

Helpful information can be timeless 


I only read this thread for the first time yesterday as it still had the "new" badge on it but I still found it interesting and thought I had something helpful to contribute to others that may also read it for the first time.... or even revisit it.


I have worked with CRRCpro since they first started to manufacture model engines and also worked with Zenoah for over 40 years and have found the oil used when running these engines can make quite a difference to the performance and longevity of these engines.


Over the years I have come across many Zenoah, CY, CRRCpro and other types of small two stroke engine owners who have been told that "any oil will do" -  and it is true that any oil is better than no oil at all. Having said that, an oil that has been developed for use in a small capacity air cooled unit will work better.


Many two stroke oils sold on garage forecourts for example for motorcycle use had their formula changed or modified to accommodate the injection method of oiling the engines (previously everything was "pre-mixed") and others were changed to accommodate the different temperatures seen on water cooled engines.


Racing and using these types of engines since the 60's has provided a lot of experience and working with them on a daily basis also helped me to see what wear and tear the components parts suffer when using different types of oils in them.


Looking at the results of many thousands of engines over this time period has helped to build a reliable data base to refer to and the use of a good oil such as Racing Venom is a small investment that can helps to give good performance and prevent excess wear and tear on the engine.

[martno1fan]

No doubt a good quality oil is better havent tried your suggested oil but ive been using good quality 2 stroke oils made for bikes for years and never had a single issue with any engine , i only ever use fully synthetic oils and they work very well for me .Ive tried quite a few oils over the years some cheaper than others and to be totally honest ive never noticed much difference , i always run high oil ratio in my engines 14-1 sometimes 16-1 depends on the power of the motor . More oil = more power and better protection in my opinion .Ive seen so many guys running 25-1 ratios and thats fine in your lawn mower but not in an rc boat engine 16-1 minimum would be my suggestion .

[zooma]

No doubt a good quality oil is better havent tried your suggested oil but ive been using good quality 2 stroke oils made for bikes for years and never had a single issue with any engine , i only ever use fully synthetic oils and they work very well for me .Ive tried quite a few oils over the years some cheaper than others and to be totally honest ive never noticed much difference , i always run high oil ratio in my engines 14-1 sometimes 16-1 depends on the power of the motor . More oil = more power and better protection in my opinion .Ive seen so many guys running 25-1 ratios and thats fine in your lawn mower but not in an rc boat engine 16-1 minimum would be my suggestion .

That's a lot of oil! 


Depending on the type of oil you use you may feel safer using a really "thick" (high viscosity) mix like that and if it works for you then that is OK - but that is a LOT of oil !


I have never run anything with that much oil as it stifles the engines power and I have always wanted to run my engines at their most efficient.  Bogging them down with with such a high oil to petrol ratio never worked for me and over-oiling a two stroke engine will usually cause faster carbon deposits in the engine and the exhaust system that will need to be cleaned to keep the engine running well.


24-1 is universally considered to be a fairly "rich" mix but is ultimately also a very "safe" mix with just about any type of genuine two stroke oil,  but most run with a thinner mixing ratio (depending on the type of engine, the type of oil, and what the engine is being used for).


The oil manufacturer often offers a suggested mixing ration on the product label and is a good place to start and good manufacturers will have a technical department that can advise on any particular or unusual application their oil is being used for - but ultimately will not have the "hands-on" experience of a model engine specialist who will have years of practical experience to call upon.


Racing engines in large scale r/c cars, skateboards, helicopters, aircraft and boats is something I have seen plenty of over the last half a century of working with these engines every day of my life and I have even helped those that race chainsaws !!!! (ultimate fast log cutting) but thick oil mixes have never figured in any of them.


I also rode two stroke trial bikes and a 50-1 mixing ration is not uncommon (and is the mix recommended with every new Montessa I ever bought)..................but if using "general purpose" or lower quality oils then a thin mix could be a bit risky - but the way I see it is why have an expensive engine and feed it "any old oil" when the best is so inexpensive?


A good two stroke oil is one of the least expensive things you will buy for your boat so I would always buy the best that I could find to get the best performance out of the engine whilst offering the most protection and anti-carbonizing qualities.

[martno1fan]

16-1 ratio is whats recommended by almost every rc boat engine builder i know worldwide . Actually some recommend 14-1 for highly modified motors .
 Engines in boats work far harder than they do in bikes or cars  .
 16-1 is the mix all the Americans use its what my friend runs in his race boats over in Trinidad and hes 3 times Champion racing one of my Arrow hulls,his motors scream .
Most American racers run 6 oz to the gallon which equates to around 16-1,  many of these guys are top racers and some holding world speed records. Ive seen where some guys did some dyno tests showing that the power actually goes up when using 6- 8 oz per gallon .
Dave Marles recommended to one of my customers who i built a hull for a ratio of 13-1 for one of his modified engines,if its good enough for Dave ill stick to what im doing  .

[martno1fan]

I think also if you check back above Cobra Max also recommends 312 ml in 5ltr of fuel thats a ratio of 16-1.
Here's a handy chart for guys not sure of the maths .

http://hyderacing.com/instructions/gas_oil_ratio.htm

[zooma]

If you ask anyone about two stroke oils and their usage you tend to get a tremendous variety of answers so what works for you is the way to go, but being aware of what also works for others may sometimes be helpful to you and worth considering for testing if the opportunity arises.

[martno1fan]

Heres one of my Arrow hulls racing over in Trinidad using a 30 cc Quickdraw pioneer engine pretty sure its 16-1 oil ratio but ill ask . Paul the owner has had her clocked at over 60 mph, not bad for a 57" boat in the sea . Seems to be revving out pretty well to me  .

https://www.youtube.com/watch?v=P8CABrvYHH4&feature=youtu.be

[zooma]

Heres one of my Arrow hulls racing over in Trinidad using a 30 cc Quickdraw pioneer engine pretty sure its 16-1 oil ratio but ill ask . Paul the owner has had her clocked at over 60 mph, not bad for a 57" boat in the sea . Seems to be revving out pretty well to me  .

https://www.youtube.com/watch?v=P8CABrvYHH4&feature=youtu.be

Thanks for the link.  Not sure which was the Arrow hull that you built but they were all going well!  I used to race off-shore many years ago and did the British off-shore in the late 60's - one of the first I am guessing - wouldn't mind building a current spec boat for fun - but it would have to be Zenoah powered.

Have you any idea what engines the other guys were using - were they all Zenoah tuned derivatives?

Do you mould these Arrow glass fibre hulls yourself in Blackpool and if so do you have a web page where I could get some more info about them?

I have no problems getting Zenoah engines but wouldn't mind finding a competitive hull to have another go.............. perhaps?

[martno1fan]

Hi sorry the Arrow was the one winning the race orange and yellow hull,yes i make them here,i dont have a website but you can check them out on my facebook group if you wish .Currently i make 3 gas size hulls the 57" Arrow and a 58" Apache and a 50" cat .
All those boats are running in fully modified class and all run Quickdraw Pioneers,the zenoahs run in a dif class,they cant keep up with these .

https://www.facebook.com/groups/347874658563715/

[martno1fan]

Pioneer  27 or 30 cc are the ones they have a full circle crank that will not twist ,betttr than the zenoah crank.
http://www.quickdrawengines.com/Page_263.html

[martno1fan]

Arrow 57,Apache 58.

[zooma]

Pioneer  27 or 30 cc are the ones they have a full circle crank that will not twist ,betttr than the zenoah crank.
http://www.quickdrawengines.com/Page_263.html

The CY crank has been very popular with car race engine tuners for years - it's amazing that Zenoah have not made one yet !