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Old 09-09-2006, 09:22 PM   #61
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Quote:
Originally Posted by V1-RRR-WC
Hi Guys,

Ok, here's my problem.....

My O.S. Speed Tuned started giving me hard start problems. I would have to enguage the start box and keep it there for no less than about 20 - 30 secs straight (sometimes more) before the engine would come to life.

Once running, it would perform great. But, once it's off again, problems to start back. Even from a cold start.

This is a pretty new engine. I am rather concerned however, that even after about 15 - 20 tanks the piston is still very tight and I would sometimes need to use an allen driver to remove it off TDC. (Top dead center)

The temps are within safety limits and I replaced fuel lines.

What else could this be???

I am in the process of taking down the engine and would like to know what to look for?

Thanks for any help.


--------------------

Edited

I just took the engine apart. Here are some photos of the piston and head.

Does this not look like it's pitted? What could be the cause?

I use Byron 25% and a P7 plug.

Thanks
oh my god, bro wat have u done to your engine? i would say that its gone. totally gone for an engine like that. i guess the problem might be caused by overheating for prolonged time, or there are some dirt or particles that somehow went into ur engine, thus causing all those scratches and marks. i am not trying to be cocky here, but its really the 1st time i have seen such engine. when u change the glow plug, do u take caution by turning ur car upside down, so that the dirt can't get into the engine? would there be any compression now? my advise is stop running the engine. get a new turbo head, new set of OS TZ piston and sleeve, then pop into this speed. or if possible, get some1 to mod the sleeve to that of speed. also can a new con rod. else u gonna regret later by running this engine. also make sure the spacer / washer at the turbo head is 2 pcs. and when installing engine, make sure the heat sink is securely fasterned. just my advise.
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Old 09-10-2006, 05:51 AM   #62
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Hi Guy I have a question. Has anyone got any information about about the os T3 and the os T5. the specs i have is that the OS T3 comes out as a slide carb, blue turbo head and silver crank case. The T5 comes out as a slide carb, silver turbo head and black crank case.

Is this correct

P.S. Has anyone ever come across a T3 with silver head and black Crank Case

thanks Will
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Old 09-10-2006, 05:58 AM   #63
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Quote:
Originally Posted by Rody
Foampervert:
The 2 different crankshafts are to fit the rules of different governing bodies. One Fits EFRA, and the other crankshaft fits ROAR/IFMAR/FEMCA

V One RRR-WC
These engines are shimmed for 16%, and not 25%. To run 25%, you need to raise your head clearance. This is why detonation has occured!

Hi Rody,

Thanks for your input.

I suspect I may have found the problem. Let me know what you think......

When loosening the head bolts, they all came off with no real force at all. So, I suspect that exhaust gases were leaking, but not enough to see oil coming off the side. (Not to mention Byron's oil content is somewhat low)

You know, I did notice that the heat sink was abit discolored at the base, but being black it was hard to determine what was the cause.

I know it would have caused the hard starting and coming to think of it, it makes sense. This is why the engine needed to run for such a long time before it started. It needed to get hot for the metals to expand, thus reducing the leakage.

Do you think this could have caused the detonation however?

As for the shims, there were two. One is thicker than the other. The user manual also ok's the use of 20%.

I have a 5P TZ runing on 25% for about 8 months. Not a single worry...

Let me know what you think.
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Old 09-10-2006, 06:11 AM   #64
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Quote:
Originally Posted by uniquexme
oh my god, bro wat have u done to your engine? i would say that its gone. totally gone for an engine like that. i guess the problem might be caused by overheating for prolonged time, or there are some dirt or particles that somehow went into ur engine, thus causing all those scratches and marks. i am not trying to be cocky here, but its really the 1st time i have seen such engine. when u change the glow plug, do u take caution by turning ur car upside down, so that the dirt can't get into the engine? would there be any compression now? my advise is stop running the engine. get a new turbo head, new set of OS TZ piston and sleeve, then pop into this speed. or if possible, get some1 to mod the sleeve to that of speed. also can a new con rod. else u gonna regret later by running this engine. also make sure the spacer / washer at the turbo head is 2 pcs. and when installing engine, make sure the heat sink is securely fasterned. just my advise.
Hi Uniquexme,

Thanks for your input as well.

I considered this theory, but my cars are always kept extremely clean. After each heat or race I clean them down, so the chance of dirt getting in is rather minimal.

Not only that, the piston sleeve and piston skirt is perfect. If it were dirt, these would have been scratched. The pitted marks are ONLY on the piston crown and head, which confirms detonation.

As mentioned in my post to Rody, I suspect head gases were leaking and hope that simply tightening this would solve the problem.

I also, cleaned up the head and piston crown. It does not look as bad now.

My question now is, do you think I should go down to 20% instead?
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Old 09-10-2006, 09:47 AM   #65
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Quote:
Originally Posted by V1-RRR-WC
Hi Guys,

Ok, here's my problem.....

My O.S. Speed Tuned started giving me hard start problems. I would have to enguage the start box and keep it there for no less than about 20 - 30 secs straight (sometimes more) before the engine would come to life.

Once running, it would perform great. But, once it's off again, problems to start back. Even from a cold start.

This is a pretty new engine. I am rather concerned however, that even after about 15 - 20 tanks the piston is still very tight and I would sometimes need to use an allen driver to remove it off TDC. (Top dead center)

The temps are within safety limits and I replaced fuel lines.

What else could this be???

I am in the process of taking down the engine and would like to know what to look for?

Thanks for any help.


--------------------

Edited

I just took the engine apart. Here are some photos of the piston and head.

Does this not look like it's pitted? What could be the cause?

I use Byron 25% and a P7 plug.

Thanks
Is the piston able to come up through the sleeve like is shown in the photo or did you set it there for picture's sake? If it can come up through then the piston / sleeve is toast. This is quite possibly the reason for the hard starting. As for the detonation and loose head bolts and head discoloring...The detonation is caused by too low of head clearance for the nitro being used and too lean of mixture settings. The loose head bolts I suspect are from severe overheating and thermal expansion that actually stretched the head bolts (causing them to be loose)(this is indicated by the discoloring of the cooling head unit itself).

My recommendation would be to: Replace the head button, head bolts, piston/sleeve, conrod, piston pin, clips, and after measuring carefully, possibly the crankshaft if the crankpin shows out of round or under spec. Also, you may want to consider replacing the crank bearings also. Better yet, it looks like you should can this engine and start over with a fresh one, as the sum of the replacement parts will surely exceed the cost of a new engine.

Next time, take care not to overheat the engine and keep an eye on the combustion chamber regularly (I always check after each heat or practice run) to catch early signs of detonation and also to help with your carb settings. Take a look in this months Xtreme RC Mag, there is a good article showing what to look for when viewing your head button/plug assy.(I know cause I wrote it!) This should help when tuning your engine for top performance, and hopefuly allow you to avoid the same mistakes next time.

Sorry for your loss, this engine is a very good performer when tuned properly and is well taken care of.

Good luck!

BK
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Old 09-10-2006, 06:38 PM   #66
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yeah i also reckon that it might most probably be long time of overheating and running too lean. so i think wat u can do now is like i said before :

- replace the turbo head
- replace the piston and sleeve
- replace the con rod and the pin
- check the crankshaft carefully to see if there is any damages.

it would be really a waste to dispose off the whole OS Speed, as the most important thing that cannot be self mod would be the crankshaft and the body (heavily modded).

another option is to get a OS TZ 5port, then u use its parts, get someone to mod the piston sleeve for u, and wola, u have a new OS Speed. keep the rest of the parts for spares later on.

hope it helps, really sorry to hear that u cocked up this engine. so try to becareful next time, get a temperature gun to measure the temperature everytime when u go to the track after 2 runs. we always make sure it falls within the range of 110-120 (with body shell on). if it gets too hot, try to open the high speed needle a bit, as for the rest of the needles, after u have break in the engine, shdn't touch it too much.

btw, i have a OS TZ 5port used for only 1 month, everything is in perfect condition. no scratches on the piston sleeve. see if u need it, i am currently planning to sell it. thanks.
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Old 09-10-2006, 07:09 PM   #67
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Quote:
Originally Posted by foampervert
Howdie Doki_doki,

thanks for the info; actually, i have been to the os website but it really doesn't state if it has a full cut crankshaft or the efra cut one.

Cos efra cranshafts are naturally ifmar legal as well.

The japanese osspeed website shows 2 different crankshafts... how strange.

In singapore, its totally unregulated except during invitational races (but then, there is no teching anyways, so this point is moot) so everyone runs pretty much 5 porters, modded to hell, 6-7mm type pipes and so on...

If anyone can just confirm that the os speed TZ comes with a full cut crankshaft, that will be really cool...

Thanks again.

-alexander
hi...from what i have seen from my engine, the crankshaft looks uncut similar to the picture shown on the www.osengines.com website and on the first picture of the crankshaft shown on the www.osspeed.com website. as for our races here in the philippines, it's all outlaw class but i have seen 3ports beat the hell out of 5 ports engines
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Old 09-10-2006, 08:54 PM   #68
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i wonder why OS Speed doesn't want to sell replacement piston, sleeve and crankshaft.
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Old 09-10-2006, 09:34 PM   #69
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holy detonation batman!!!!!!!!
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Old 09-10-2006, 10:07 PM   #70
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Quote:
Originally Posted by mxwrench
Is the piston able to come up through the sleeve like is shown in the photo or did you set it there for picture's sake? If it can come up through then the piston / sleeve is toast. This is quite possibly the reason for the hard starting. As for the detonation and loose head bolts and head discoloring...The detonation is caused by too low of head clearance for the nitro being used and too lean of mixture settings. The loose head bolts I suspect are from severe overheating and thermal expansion that actually stretched the head bolts (causing them to be loose)(this is indicated by the discoloring of the cooling head unit itself).

My recommendation would be to: Replace the head button, head bolts, piston/sleeve, conrod, piston pin, clips, and after measuring carefully, possibly the crankshaft if the crankpin shows out of round or under spec. Also, you may want to consider replacing the crank bearings also. Better yet, it looks like you should can this engine and start over with a fresh one, as the sum of the replacement parts will surely exceed the cost of a new engine.

Next time, take care not to overheat the engine and keep an eye on the combustion chamber regularly (I always check after each heat or practice run) to catch early signs of detonation and also to help with your carb settings. Take a look in this months Xtreme RC Mag, there is a good article showing what to look for when viewing your head button/plug assy.(I know cause I wrote it!) This should help when tuning your engine for top performance, and hopefuly allow you to avoid the same mistakes next time.

Sorry for your loss, this engine is a very good performer when tuned properly and is well taken care of.

Good luck!

BK

Hi Mxwrench,

The piston was simply placed there for the photo. As noted in my first post, to date the piston is still very tight at TDC, so I do not think I am loosing compression.

As for the loose head bolts, I suspect that the engine was opened and examined before it got into my hand, since it was among the very first to hit the US. I think it simply was not tightened properly after and neglegence on my part not to double check it.

The pitted marks is clearly detonation, but I do not think it is from a lean needle setting. I suspect the loose head bolts was causing the engine to suck air, which then leaned it out.

As suggested by several of you, I examined the engine today very closely. The conrod is perfect, crank and bearings. This engine has only raced twice, (when it worked, for no more than 5-6 mins each time) so I doubt major damage was done.

Anyway, I cleaned the piston crown, and head button. Re-assembled and started it this afternoon. It starts in one bounce and runs flawlessly.

I then tried to "break in" the engine again on the starter box with a cooling fan and a very rich mixture setting to get rid of that annoying sticking at TDC. It seems to have worked!

I will keep a close eye on the temps knowing the damage already done inside. I do think however, I should got alot more life out of this engine.

Thanks to everyone for all the info. I am alot wiser tonight.
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Old 09-10-2006, 11:45 PM   #71
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no worries bro, glad that u learn. hope u can recover back your engine.
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Old 09-11-2006, 11:03 AM   #72
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hello everyone,
I just put my new tz speed in my mugen and the engine has such strong compression my stasrter box won't turn it over! help I want to break this puppy in. I have a new mugen starter box with 2 7.2 stick packs, so it should turn it over.
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Old 09-11-2006, 11:13 AM   #73
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Quote:
the engine has such strong compression my stasrter box won't turn it over
you need to use a heat gun or hair dryer to heat up the head.Once the temperature reaches about 82deg C/ 180deg F, it should turn over. (still with some effort).

You need to do this to get the sleeve to expand to allow the piston to move up and down.
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Old 09-11-2006, 12:10 PM   #74
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ProE,
That worked like a charm!!! My girl migght be wondering why her hairt dryer smells like after run oil though.

lol
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Old 09-11-2006, 12:20 PM   #75
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My wife had the same problem . After looking for her hair dryer (for a second time), she just went out and bought herself a new one.

Now shes happy, and I'm happy.
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