OS Engines

[Jon Dell]

following a chat with Richard, thought i would start a thread on OS Engines. as most of you will know Jon Hazlewood runs OS engines and will again be doing so in 2008. Jon's engine set up will be as follows:-

OS speed VZB 21 off road engine
Byron 30% fuel
Hong Nor 2047 pipe (subject to rules at EFRA meetings)
OS P3 plugs

if any of you have any questions (OS related), please fire away.

oh and Merry Christmas

regards

Jon Dell

[MR Piraterc]

Welcome to the forum Jon how do you find the new os speed compares to the recab and would you have any running in / tuning tips to share

[Jon Dell]

OS in their wisdom, decided to copy and improve on the recab. performace wise you would struggle to notice anything between them. the only plus over the recab is that you are not buying from ripmax.

i wrote the following for racer a few years back. this is my prefered way to run in engines.

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In being asked to write about how to run-in engines, I found myself with a bit of a problem, there are quite a few different opinions on how best to do it. In the end the answer was with the Editor, he wanted to know how I did it and was there any advice I could pass on to the readers.

Over the past 3 years, I have been mechanicing for Jon Hazlewood and between us, we have had a high degree of success with our racing. One of the key aspects of our set up is to have a reliable engine. I have always believed that IC racing is about endurance and not necessarily about being the fastest. At the end of the day, an engine which does not continue to run all the way through a final is not going to win you many prizes.

Running-in an engine can effect how reliable an engine is throughout its life span. Choosing the right ingredients for your engine package will also affect the life span of the engine, but hopefully you would have chosen them by now. If not, then try to stick with the manufactures recommendations or ask other drivers at your club that are using the same engine of your choice.

When I need to run-in an engine I do try to plan ahead and not run it first time at a big race meeting. This isn’t always the case and is a difficult thing to control and unfortunately I have been seen to run-in an engine the night before a big race. End result is that the engine needs to be perfect for the practice so that effective car set up can take place. The best situation is to run-in the engine before you get to the track and have that first run at a club meeting or even a practice day. 

My method is a well tried and tested and learnt in the main from other racers that I have had the pleasure to have met at race tracks. Successful running-in can be made easier well before you put the car on the starter box. Removing the engine from the box I will bolt on the engine mounts, fit a flywheel that has a good knurling on its edge. This is important as the engine is going to be tight at its top dead centre (the point where the piston gets stuck in the liner) and the starter wheel will need to grip on to the flywheel in order to rotate it. The knurling can be refreshed with a triangle shaped file. Just re cut the edges into the flywheel, takes some time to do, but save money and running-in frustration.

Fit the clutch system and ensure the clutch bearings are in good condition. New exhaust gaskets/joiners, fuel pipe, and air filter should be fitted to ensure leakages don’t occur and that everything is clean, free from dirt. It might be worth cleaning out the fuel filter and flushing out the fuel tank as well. It’s possible you are running-in an engine because your old engine failed for some reason. That reason could be something outside of the engine components, such as the items I have mentioned, so check them with care.

Bolt the engine into the car and set up the throttle linkages. I always set up my linkages so that the horn is north to south of the servo, and the carb is always full shut with a 1mm or gap before the servo can open the carb (see picture). Failure to do this may mean that the engine could stop when applying the brakes as the idle would fall to low as the carb fully shuts.

Yet another important issue is does the starter wheel actually turn the engine flywheel. You can check this with the starter box unplugged. Push down on the car, so that the flywheel touches the starter wheel. Check to see if the starter wheel is touching the chassis. If it does this will slow down the starter wheel and it may not transfer its energy to the flywheel. You can file the underneath of the chassis to allow for more access for the starter wheel to flywheel.

Now fully charge the starter box and the glowstart and go find a nice spot to run in your engine. With all the prep work done this is now going to be easy. Here are the bullet action points on running it in:-
•   Put a few drops of after run oil down the plug hole, just before you attempt to bump the engine. This will add lubrication and help turn it over.
•   Prime the fuel into the engine by blowing down the exhaust pressure fuel line. If you open the carb as well, carb will fill up with fuel again adding lubrication where it’s needed.
•   Turn the main (top end) needle out by one full turn, this will ensure the engine will at least run rich first time.
•   Open the carb fully by moving the servo by hand. Running in using the radio ties up your hands and makes it harder.
•   Clip the glow start on and leave for 5 seconds to full warm plug.
•   Now dump the engine down onto the starter wheel. If your lucky the engine cranks, fuel pumps through and hopefully fires. If not the engine locks. This seems brutal, but you now need to take a screw driver and leaver the flywheel around from underneath the chassis.
•   On the engine firing, close the carb, but not fully. The goal is to have the carb fully open but running dead rich, the wheels should be turning but not fast, the engine tone should sound very flat, smoke and lots of oil should be coming out of the exhaust. This is achieved by now opening the carb and turning the main (top end) needle out. If you go too far and the engine is starting to stall, quickly pinch the fuel line to the carb. This will lean the engine out so you can quickly adjust the settings.
•   There is a balance between running the engine rich enough and hot enough. To be honest this balance can’t be taught, but learnt by doing it.
•   Run 6 tanks through the engine on this rich setting. Before opening the tank lid to re fill, shut the carb, and quickly fill. Then slowly open the carb. You may have to pinch the fuel line again to ensure the engine does not stall.

Sometimes you will find as the fuel goes down in the tank, the engine gets leaner. This it sometimes due to air leaks in the tanks that aren’t noticed during normal running. As it gets leaner, the revs will increase. Adjust the settings to keep the engine running rich at all times.

After 6 tanks, the initial running in is complete. Now wind in the main (top end) needle back to around where it was out of the box. Tuning is another issue, but for now run the car up and down a tarmac strip or dry track. Different engines may require more than one tank to fully run in, but for the engines I use one extra tank on a flat bit of ground is enough. The car should accelerate smoothly with plenty of smoke from the exhaust. Monitor the engine temperature, making sure that it’s not too hot.

To finish off I would run the engine for a race meeting with a rich setting. This is not so rich it doesn’t perform, but rich enough so that it does not run hot. After using the engine always add after run oil down the plug hole to avoid rusting of internal parts.

[megacrash]

Hi John

I a big os fan - Ive found it to be the most reliable motor ive run and its replaced the ninja brand which i ran for a year and a half.

there is a few things im not certain on though ive heard everyone moan about the lifespan,conrod issues etc..  ive put nearly 3.5-4 gallons through my v spec now and im wondering if it would be worthwhile replacing the conrod.  Ive not got any running problems with it, holds a tune perfect doesnt overheat and ive only used 2 plugs in the 3.5 gallons ive run it. so im just weighing up if its worth doing  as i dont know the price for an os conrod

Next my last raceday i found my carb was sticking open a few times i asked brennan rails and he mentioned that if my carb isnt straight then this could be causing it. My carb was at an angle so i left it at that as i didnt want to nag brennan all day.  Is there anything else that could cause this  the carb is perfectly smooth when i open and close it

Cheers for your time

Brian

[length]

wow thats top info jon iv been told several different ways on how to run them in, most times its just to run them as rich as you can without them stalling and after 5-6 tanks start winding back in to origanal settings, im lucky iv just bought a special edition RB S7 with a turbo head so i got the joys of running that in but again thanks for the info its just good to hear it from someone whos been there and done it just a few times before

[Jon Dell]

Brian,

if your OS is a standard V-spec, you do need to keep an eye on the crankpin and the conrod. when we first ran the v-spec in 2004 we found that after 7 hours these 2 items would have worn. the type of wear i am talking about is not the type where the engine does not work or starts cutting, but its the type of wear that is measured against new and is quite small. once the conrod starts to wear slop will increase and the crankpin will start to wear. changing the conrod on a regular basis will keep the crankpin running longer. about 5 to 7 hours per conrod should be expected.

this is why we started to use the recab modded OS because it had a special coated crankpin. in 2 years of running we are yet to see a coated crankpin wear and as such conrods are not replaced on such a regular basis. if anything the piston / liner is now the soft spot. 15 to 20 hours ideally, which at 1 hour per race meeting, is half a season for a week in week out racer.

the OS speed also has the coating and additionally they have coated the area that the clutch bearings run on. again this increases the life of the crankshaft which is the heart of the engine. rebuilding the engine with bearing / conrods / pistons makes sense, but once the crankshaft is gone, the engine is now beyond a cost effective point.

as for the carb.... are you running a Losi? if so the angle required for the carb can make it stick when you pull it yourself. however the load point and the way the servo pulls the carb open is slightly different than how you pull it open by hand, and in most cases i have found under normal running conditions the sticking does not occur. if its not that, it could be that the carb barrel has some damage. this can come from trying to turn the ball end without undoing the grub screw or from contact with the centre diff mount (this happens when the chassis flexes). 

[megacrash]

thanks for the reply john excellent read,

i might just run the v spec till it dies then consider either the recab or speed, although i will change the conrod on this to get some extra life out of it.

As for the carb its on a mugen mbx5r,  ill pull it apart and have a closer look cheers

[Neil McRae]

Didn't notice this thread!

Jon tuned my OS Speed at the Truggy Nats round 1. I haven't touched it since and its never cut out since, once a hard landing caught the flywheel but thats it. Helped me beat Dan during the nats and many other races

With the carb, if you look at the OS vspec the carb is more angled when you rotate it and for quite a few trucks/buggies if you have a heavy landing you can pinch the the carb, check where the boot is and you might see some damage. On the CRT I have to angle it slightly to avoid the diff, just make sure you adjust the linkage, use a longer servo horn (hanger do one) if needed.

I found these:

http://www.amainhobbies.com/product_info.php/manufacturers_id/75/products_id/7118

the 7mm version helps with run times but doesn't sacrafice top end like the OS 7mm one does.

Regards,
Neil.

[slow coach]

Hi Jon when you say rich/temp do you temp engine while running in and what temps you looking for also how do you achieve this balance by mixture or just something simple like covering head with rag or foil etc, i have seen this kind of run in practise from Josh cyrul also and did wonder as not seen it from anyone else, i also run the std Vspec and apart from a rear bearing failure which i have replaced with a TKO ceramic plus new conrod the engine is running really well last meeting i forgot to start my pit timer and came in a shade before 10mins just made it, as race was 20 minutes just carried on and backed off a little as i had a slight lead but brill engine, i run the smaller insert and restrict carb opening to about 70-80% of full opening always use the os P3 plug with os 2060 pipe, i favour economy rather than speed as track is anything but smooth and theres not many places you can actually run flat out and having to fuel your own car saves a load of time by doing one stop rather than 2.

cheers

[Jon Dell]

hiya,

sorry i dont know the temp during warm up, but it would be warm to touch. a rag or something over the head would help. if its a cold day i use a winter thermal glove as a rag can get caught up in the wheels/drive train.

Now a bit into the season the OS Speed is still romping along. i have seen a few issues with air leaks, and recommend pushing hard down on the carb when securing the bolt and ty wrapping the rubber carb boot. The new Byron Gen 2 fuel is providing excellent run time and bottom end power.

Jon

[slow coach]

anyone else tried this technique for running in motors yet mine arrived today and wondering if anyone else has tried and if they found it easy enough to do.

[Bren]

anyone else tried this technique for running in motors yet mine arrived today and wondering if anyone else has tried and if they found it easy enough to do.

I run OS & use this engine run in method all the time its quick & easy.

Bren

[megacrash]

I think ill give this method a try,

sounds easy enough and it has to be quicker than the painful old method i still go by