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nheather

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Posts posted by nheather

    Sealing Decals

    in General - Nitro

    Posted

    I have a new body for my son's Hyper 7. When you apply the stickers do you seal it with a varnish?

    If so what do you use - do you just use a generic polyurethane varnish spray or something specific.

    Cheers,

    Nigel

    Carb Factory Settings - Whatdoes this mean?

    in General - Nitro

    Posted

    keep it at 1mm mate other wise the engine will cut out as soon as the thottle is released

    Yes I appreciate that. My question was whether the STNV should be set with the 1mm gap or whether I should temporariliy remove it (since it was siad that the adjustment should be done with throttle closed).

    Cheers,

    Nigel

    Carb Factory Settings - Whatdoes this mean?

    in General - Nitro

    Posted

    I've just finished sealing a troublesome Mach 28 and want to put the carb back to factor settings.

    For the Sub Throttle Needle Valve the manual says this

    Withe adjustment screw in place, close off the throttle body against the screw. Very gently screw in the needle valve until it closes off the supply fuel nozzle and is prevented fomr re-openingby the entry of the needle valve in the centre hole of the fuel nozzle (work with great care with this one - we are looking for minimal frictional contact between both parts). RE-OPEN VALVE 2.5 TURNS

    My immediate question is what does 'close off the throttle body against the screw' actually mean.

    Cheers,

    Nigel

    Engine Sealing Question

    in General - Nitro

    Posted

    I have been following this excellent guide

    http://www.msuk-forum.co.uk/index.php?showtopic=70981

    I have done my backplate and the blanking screw for the booster bottle.

    Just the carb left to do, but I have a question first.

    In the photographs, it shows the part of the carb that slides into the engine without an O-Ring.

    Mine has an O-Ring.

    So is this deliberate - you will acheive a better seal with the gasket than with the O-Ring.

    Should I remove the O-Ring and use sealent or should I keep the O-Ring aswell as the sealent?

    Cheers,

    Nigel

    Motor prices

    in General - Nitro

    Posted · Edited by nheather

    2 years ago £1 = $2.00

    Then at £140, the engine cost $280

    Now £1 = $1.50

    So now, at £190, the engine costs $285

    So the price of the engine has stayed pretty much the same for the last 2 years.

    Cheers,

    Nigel

    Screw Below the Carb - Couple of Questions

    in General - Nitro

    Posted · Edited by nheather

    My engine has a screw just below the carb. It doesn't fix anything, just fills a hole. So a couple of questions

    1 - What is it for. The only thing I can think of is a lubrication hole for the crankshaft - but you can do that by squirting oil down the carb throat.

    2 - I'm ready to seal my engine. None of the tutorials mention this. The screw has a fibre washer - is that sufficient or should I add copper gasket material. If I do then should I keep the fibre washer in place or remove it?

    Many thanks for the help.

    Cheers,

    Nigel

    Head Gaskets ?

    in General - Nitro

    Posted

    No not stuck on top of liner or on old button - that was the first place I checked.

    The problem is not which ones to buy but which ones to fit. As you say, they are cheap and I actually have the full range

    Brass 0.1mm

    Copper 0.1mm

    Copper 0.2mm

    Aluminium 0.3mm

    I have the copper ones because at the time there were none to be had in the UK at all so I ordered from the US. They supply the Dynamite parts. WHilst they were in transit the UK stock became available so I also have the Hobao parts.

    The problem is that I don't know which ones to fit?

    The dynamite exploded diagram shows 0.1mm and 0.2mm copper

    The hobao exploded diagram shows 0.1mm brass and 0.3 mm aluminium

    What neither of them show is whether they should both be fitted or just one. And if just one, which one under which conditions.

    Cheers,

    Nigel

    Head Gaskets ?

    in General - Nitro

    Posted

    Many thanks,

    It doesnt need one seperating the button from the heatsink.

    Agree, that isn't where it shows. The manual shows

    Heatsink (Cylinder Head)

    Button

    0.3mm aluminium gasket (shim)

    0.1mm brass gasket (shim)

    Cylinder lining

    But it doesn't make it clear whether both should be fitted or just one.

    I've been researching a bit more and found that you should put an extra shim in if you are using >25% or sometimes when breaking the engine in.

    So if I need only one, should it be the 0.3mm or the 0.1mm ?

    Cheers,

    Nigel

    Head Gaskets ?

    in General - Nitro

    Posted

    A question about head gaskets. I have a Hobao\Mach 28 but I guess this question is quite generic.

    When I got my 2nd hand car, the previous own had cross-threaded a glow plug (he told me about this up front). So I got a new head button, but when I removed the old one, I found that there were no head gaskets fitted.

    I found the Hobao Mach 28 instructions and this shows two gaskets

    a brass 0.1mm which goes next to the button.

    an aluminium 0.3mm which goes on top of the liner

    so liner > 0.3mm alum > 0.1mm brass > button

    Also when googling I found the Dynamite Mach 28 instructions and this also shows two gaskets but these are

    0.1mm copper

    0.2mm copper

    Now my question as a newbie is "Should I fit both gaskets or just one?"

    I was wondering whether you just fit one depending on what power fuel you intend to use?

    If just one, which should I fit for 20%

    Can anyone advise please.?

    Cheers,

    Nigel

    Some Advice Please - What Would You Do?

    in General - Nitro

    Posted

    Many thanks that is great.

    Few more questions

    1 - what is the slime they talk about for the needles.

    2 - Do you ever both sealing the head or do you assume that the brass\aluminimum gaskets will be good enough.

    3 - Is the high temp sealent specific to model cars or do you just use stuff from Halfords

    Cheers,

    Nigel

    Some Advice Please - What Would You Do?

    in General - Nitro

    Posted

    Many thanks for the support. Here is what I've decided to do with your advice

    1 - Return the evilbay engine for refund

    2 - Work on the Mach 28, especially looking at the sealing

    3 - If no luck then buy a new engine - probably a Picco - I see they do one with a rotostart backplate, although out of stock at the moment.

    Big Question though.

    I've looked through the Pinned Threads and done a search for 'engine sealing' but I can't find any of the threads that the replies have suggested I look at. So I would really appreciate it if someone could provide an actual link\links to the thread\s I should be looking at.

    Many thanks,

    Nigel

    Some Advice Please - What Would You Do?

    in General - Nitro

    Posted · Edited by nheather

    one more thing.

    snapback.pngnheather, on 03 April 2010 - 04:51 PM, said:

    But needs to be on a budget becuase this is really only a toy.

    Tesco sell toy RC cars, these are hobby grade.

    Yes, I didn't mean it quite like that. I fly nitro helicopters so I know full well that you get what you pay for. What I meant is that my son just uses it to mess around in the park or common ground - he isn't into racing so he doesn't need the best and it won't be heavily used.

    So I was looking for a good quality 2nd hand engine rather than paying £100+ for a new one.

    Cheers,

    Nigel

    Some Advice Please - What Would You Do?

    in General - Nitro

    Posted

    mach 28 fantastic engine , main causes of not holding tune are air leaks, bottom of cooling head, back plate and carb neck where its bolted to engine all really simple to seal

    Must admit that air leaks were my first thought and I changed all the fuel pipes and the o-rings.

    Is there a way for checking for air leaks?

    If I do find one, how do you go about selaing it?

    Cheers,

    Nigel

    Some Advice Please - What Would You Do?

    in General - Nitro

    Posted

    Thanks for my replies - you have pretty much echoed my feelings anyway.

    Next question - where to go next.

    Do I keep perservering with the Mach 28?

    OR

    Do I go for something else?

    If something else then do I go new or old?

    And if I want to reuse my RotoStart does this mean I have to stick with Hobao\Mach or are all backplates pretty much standard. The rotostart I have is this one

    http://www.modelsport.co.uk/?CallFunction=ShowSpecification&ItemID=25032

    Cheers,

    Nigel

    Some Advice Please - What Would You Do?

    in General - Nitro

    Posted

    Last year I bought my son a used Hyper 28 from this forum - great package but the Mach 28 engine is very tempremental - well tuned it runs well but takes a lot of attention between each run as it doesn't hold tune well. Tried everything to resolve this but no go and researching, this seems to be a common feature of Mach 28 engines. It's frustrating enough if I'm with my son but it would be too much for him to do on his own.

    Anyway, I decided to replace it with a 21 (which I have read are a lot better) and decided it must be a Hobao because I have a Rotostart with a Hobao back plate (I assume different makes would require different backplates - is this true?).

    But needs to be on a budget becuase this is really only a toy.

    After looking here with no joy I bought a Hyper 21 Pro 8 port from evilbay.

    It was advertised as good performance, runs well, good compression, only 2 gallons.

    What I received has done way more that 2 gallons. The pullstart (although I don't need it) is showing loads of wear, scuffing, ingrained dirt. The carb is also showing a load of wear with scuff on the intake and the blacking on the barrel has been warn away - also the needle screw heads show some chewing. When I removed the pullstart, I noticed that the screw threads in the backplate are warn (perhaps has ssen several pullstarts)

    Not sure about the body, it's reasonably clean but I would need to take apart to inspect piston and liner which I'm not prepared to do.

    I have tried running it - it took quite a bit to start initially because the settings were way off 20% or factory default. When I did get it started it seems to run okay.

    I have raised these issues with the seller. At first he stuck to his story, but gradually he admited that he had bought the engine from a friend and that the engine could have seen a lot more action than advertised.

    Now the seller is a decent chap and has offered to accept the return and refund the purcahse price and postage costs.

    So what would you do - it runs, it was reasonably cheap (

    When Should the Clutch Engage

    in General - Nitro

    Posted · Edited by nheather

    Clutch bell spins freely - that right isn't it?

    I double checked the install direction and it matches the manual.

    You may have misread - the clutch isn't engaging until the revs get very high - throttle barrel open over 50%.

    Like thye spings are so strong they are stopping the arms from flinging out - but I've looked at the videos and I have the spings installed correctly.

    What size springs are fitted to the clutch 0.9mm or 1.2mm etc. As thicker springs need more rpm normaly used to stop engine bog.

    No idea what size - they are the ones that come with the Hyper 7.

    Cheers,

    Nigel

    When Should the Clutch Engage

    in General - Nitro

    Posted

    May be a little rich but it is reving very high when clutch engages.

    Clutch is little used so not wear.

    This leaves, fitted wrong, which I'm more than happy to beleive, though I've had a look at the instructions and can't see that I've down anything wrong.

    I fly Nitro Helicopters and the clutch bell on those has a lining. The clutch bell on the hyper 7 is just metal - is that right?

    Cheers,

    Nigel

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