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Old 08-20-2006, 07:15 PM   #1
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Default OS - TP(Z) P5 (Piston problem)

Hi,

I purchased the motor from a hobby shop in Hong Kong, when I returned to Sydney, 1 month later, I was going to break in the motor when I realised the following

- The flywheel wasnt turning on my starter box
- I was able to move the flywheel half a turn but was getting stuck
- I had to use tremendous force to get it to do a full cycle. At one stage I had to use plyers to turn the flywheel (Im thinking this isnt good because if Im using this much force how can the starter box turn it!!)

After opening up the brand new motor I realised the following:
- When I remove the piston sleeve the piston and conrod/crankshaft rotate nicely
- When I insert the piston sleeve half way the piston does a full cycle OK
- When I insert the piston sleeve all the way in the piston is getting stuck 3/4 up the sleeve and doesnt move, when you try to turn the piston is pushing the piston sleeve out of the casing. I guess the reason why I had to use so much force originally was the piston sleeve pushing up against the head. I probabley did some damage as well trying to crank it a few times with such force cause it didnt sound too good

I also realised that when the piston is getting stuck it seems to be moving to one side - what could the problem be?
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Old 08-21-2006, 03:34 AM   #2
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Quote:
Originally Posted by KyoshoKid
Hi,

I purchased the motor from a hobby shop in Hong Kong, when I returned to Sydney, 1 month later, I was going to break in the motor when I realised the following

- The flywheel wasnt turning on my starter box
- I was able to move the flywheel half a turn but was getting stuck
- I had to use tremendous force to get it to do a full cycle. At one stage I had to use plyers to turn the flywheel (Im thinking this isnt good because if Im using this much force how can the starter box turn it!!)

After opening up the brand new motor I realised the following:
- When I remove the piston sleeve the piston and conrod/crankshaft rotate nicely
- When I insert the piston sleeve half way the piston does a full cycle OK
- When I insert the piston sleeve all the way in the piston is getting stuck 3/4 up the sleeve and doesnt move, when you try to turn the piston is pushing the piston sleeve out of the casing. I guess the reason why I had to use so much force originally was the piston sleeve pushing up against the head. I probabley did some damage as well trying to crank it a few times with such force cause it didnt sound too good

I also realised that when the piston is getting stuck it seems to be moving to one side - what could the problem be?
The std pinch on an new TZ engine is guite great. You will need to use a heat gun to bring the crankcase to temp (and possibly lossen the glow plug slightly) to get started the first few times during break in (remember to retighten it as soon as the engine fires up each time!). This is normal with this engine. Once you have 5-6 tanks of fuel through it it should lossen up considerably. Also let it cool completely between tanks during break in and ensure the piston is at BDC during cool down. I also recommend that you take it easy on break in and take your time. Otherwise some conrod damage can result from to quick of break in.
Just remember, it is very important to get the engine temp to at least 200 deg f. prior to starting on break in, and until it is loosened up.

I doubt you did any damage to the engine by rotating it through its cycle with the pliers. Heat the block with the heat gun and all should be fine.

BK
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Old 08-21-2006, 07:33 AM   #3
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All the O.S. engines come with a tight fit and you have to heat them up before starting them the first few tanks.
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Old 08-21-2006, 02:38 PM   #4
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and then they blowup LOL
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Old 08-21-2006, 04:51 PM   #5
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WOW.... After break-in, I find them to run great and last forever.
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Old 08-21-2006, 05:50 PM   #6
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Quote:
Originally Posted by mxwrench
The std pinch on an new TZ engine is guite great. You will need to use a heat gun to bring the crankcase to temp (and possibly lossen the glow plug slightly) to get started the first few times during break in (remember to retighten it as soon as the engine fires up each time!). This is normal with this engine. Once you have 5-6 tanks of fuel through it it should lossen up considerably. Also let it cool completely between tanks during break in and ensure the piston is at BDC during cool down. I also recommend that you take it easy on break in and take your time. Otherwise some conrod damage can result from to quick of break in.
Just remember, it is very important to get the engine temp to at least 200 deg f. prior to starting on break in, and until it is loosened up.

I doubt you did any damage to the engine by rotating it through its cycle with the pliers. Heat the block with the heat gun and all should be fine.

BK
WOW!!! the last motor I broke in was a stock standard GS15 on the V One S!!!
I know motors are suppose to have a lot of compression when they are brand new but would have thought you can at least turn it without getting stuck, the OS was impossible.
Well I guess 3 people have advised the same so it must be true
Any reason why they make it so tight?
Do other high end brands of motors have the same issue?
I dont have a heat gun, can I use my wife's hairdryer??

While we're on the topic of breaking in, I was advised to break in the motor with the same fuel I would be using for racing - so I got 16% Nitro with 10% oil (its not synthetic, I cannot remember off the top of my head the exact percentage of caster/synthetic). I was told this will break in the motor harder but will limit the life of it but will run faster/harder - this is OK for me. So run about 5-6 tank fulls?
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Old 08-21-2006, 08:41 PM   #7
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there not matched so if your lucky it will work or it will blow up novas,jp,max,sirio,mega, are more matched
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Old 08-21-2006, 08:46 PM   #8
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you should only use a hair dryer not a heat gun, you can use a heat gun but you have to be careful.
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Old 08-21-2006, 10:47 PM   #9
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Normal on all highend engines, RB, MAX, Novarossi, etc.

Use a hairdryer, heat it up, put some after run oil down the glowplug and repeat for the first couple tanks.

Make sure you break it in at 195-220F so the engines internals get to expand and make sure the piston cools at bottom dead center after each tank completly.

Do this for 9-10 tanks and your ready to run.
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Old 08-21-2006, 11:34 PM   #10
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Quote:
Originally Posted by Fsturbo15
Normal on all highend engines, RB, MAX, Novarossi, etc.

Use a hairdryer, heat it up, put some after run oil down the glowplug and repeat for the first couple tanks.

Make sure you break it in at 195-220F so the engines internals get to expand and make sure the piston cools at bottom dead center after each tank completly.

Do this for 9-10 tanks and your ready to run.
- Where do I point the hairdryer? Downwards towards the glowplug or on the side of the motor (near the head or crankcase)?
- Do I remove the glowplug while heating it up then once its up to temp put in the after run oil and glow plug?
- Do I need to remove the glowplug when checking for BDC or is close enough is good enough by feeling?
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Old 08-21-2006, 11:38 PM   #11
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PS - I have a temp gauge, the one where a wire wraps around the crankcase (Venom, I think), this is OK to test the temp before breaking in the motor? So the temp needs to get 195F-220F before breaking in the motor?
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Old 08-22-2006, 12:01 AM   #12
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-Point the heatgun on the engine head and crankcase, try not to heat up the carb.
-You don't have to remove the glowplug while heating the engine.
-I usually remove the exuast and check beforehand, then mark my flywheel, don't mark it where it touches the starterbox or your mark will fade. You can also just keep checking by removing the exuast after each tank.

The temp doesn't need to get to 195-220 before starting it , just try to heat it up enough so the engine will turn over easier.

I would make sure it is at 195-220 once it's running and warmed up.

Quote:
From the very 1st time you start your engine, plop the car on the ground & begin running it in a parking lot in 2-3 minute intervals, tuned only *slightly rich* getting the temps up in the 200F range on a normal day. Every 2-3 minutes, shut the engine down & let it cool completely with the piston at BDC, and then fire it back up; continue this cycle until you've run 15 min or so, and then bump up to 3-4 minute intervals. Vary the RPM and don't be afraid to get the temps in the 200's. What you want is heat cycling of the components without the incredible stress that comes with breaking an engine in when it's overly rich & cold. After cycling the engine in this mannerfor about 20-25 total minutes, it'll be ready for the track and race tuning. I realize this method goes against the old-school "idle on the box" routine, but you'll be amazed once you've completed this break-in routine, your OS will still have amazing pinch w/out sticking at the top AND your OS's compression will last far longer than it will with the "old school" method.
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Old 08-22-2006, 03:48 PM   #13
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You are on the right track. I use my lady's haridryer at the hottest setting, point the blower to the crankcase and not the carb, you can try to rest the hair drier on top of the chassis and it only takes 3 minutes to heat it up enough to get it to crank on the box. Leave the glow igniter on for sometime after you get the engine to start so that you do not stall. Also ensure that you have set the idle screw correctly. Some people forget to check the idle screw when first cranking their engines and blame it on it being too new etc.

I just broke in my EB Modded tz 3 and I had to heat it up for the first 4 tanks of break in. If you cannot get the temps up high enough on the first tank, leave the hair drier on the crank for 1/3 of the tank once the engine is ignited.

I used the Cyrul's WOT method to break mine in but you use what you feel more comfortable with.
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Old 08-22-2006, 05:41 PM   #14
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Quote:
Originally Posted by SasonRC
You are on the right track. I use my lady's haridryer at the hottest setting, point the blower to the crankcase and not the carb, you can try to rest the hair drier on top of the chassis and it only takes 3 minutes to heat it up enough to get it to crank on the box. Leave the glow igniter on for sometime after you get the engine to start so that you do not stall. Also ensure that you have set the idle screw correctly. Some people forget to check the idle screw when first cranking their engines and blame it on it being too new etc.

I just broke in my EB Modded tz 3 and I had to heat it up for the first 4 tanks of break in. If you cannot get the temps up high enough on the first tank, leave the hair drier on the crank for 1/3 of the tank once the engine is ignited.

I used the Cyrul's WOT method to break mine in but you use what you feel more comfortable with.
Thanks for all the advise!!! Hopefully I can break in the motor this weekend. Will keep you posted...

While the motor is in pieces:
- Would I need to apply threadlock to the 4 screws that hold the backplate or header?
- I read somewhere once where they said its necessary to put some silicon around the carb area to prevent air leaks, this true?
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Old 08-23-2006, 07:20 AM   #15
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Although not neccessary, I do seal all my engines. You learn from experience. Air leaks are a pain to deal with so why bother, just eliminate the problem from the get go.

Use Copper RTV oxygen safe sealant. I use it for a lot of things, so spending the seven bucks on a tube is not a big deal.

I use it to seal the backplate on all my engines. In some others I use it to seal the carb joints. Although on the TZ I did not do that since it has the plastic seal already. Don't go too crazy with the threadlock on the backplate screws but do use it.

Don't forget to shim the head if you are using 30% fuel or more.
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