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Old 08-01-2008, 12:18 PM   #1
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Default os VSPEC will not IDLE/tune, please help ( PISTON WAS IN BACKWARDS)

I just had two OS VSPEC motors taken apart then had the piston/ sleeve pinched at my LHS.

I reasebled the motors and wanted to break them in.

Both will not tune or idle.

The high end will clear out and run great while putting out nice smoke. but when i try to let it idle they just die out.

In order to keep them running i have to keep the carb open by over 1/8"( and raw fuel is sputtering from the carb. The idle needle will not even screw in far enough to keep it running

I have tried the factory settings on all needles, and also tried tunning them for performance. I am exsperianced and know a little but i can not get either of my motors to idle or have a nice bottom end to even idle.

I have replace the fuel line and checked my tank to make sure its holding pressure, and glow plugs burn nice and both are fine.

can anyone please help and give me some advice on what to do. Thanks in advance, Patrick



UPDATE: Problem Solved

Quote:
Originally Posted by wingracer View Post
The rod is long enough on an OS to put the piston in backwards and still run. Real easy to check. Just look through the exhaust port and turn the motor over by hand. If you can see under the piston and see the rod at top dead center, it's backwards. If all you see is the piston skirt, it's fine.
Well after reading about the piston , i went out to the garage, took the pipe off and looked right into the exhaust port to see if i could see the con rod. there it was plain as day. then it was all clear to me. The reason it was spitting fuel and acting weird is because the exausts and such were all backwards. and yes it will still run

I emediatly dissasmbled the motor and reinstalled the piston (which to my amazement wasn't damaged at all) the correct way this time. Set all my needles to factory settings, and threw it on the starter box. Primed the lines and AHHHHHHHHHHHH It fired right up and idle like a charm. took it outside and it runs awsome

Thanks to everyones input and help in this. I am so pleased to have both these motors back to like new again. Thanks again guys.

Last edited by patrick21x; 08-03-2008 at 12:05 PM. Reason: updated
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Old 08-01-2008, 12:38 PM   #2
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1. Did you replace the rods?

2. Did you try leaning the low speed needle?
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Old 08-01-2008, 12:42 PM   #3
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rods were not reoved from the piston and the seem to bee in good shape with no play in them.

I tried leaning the low speed but it has little to no effect ?

It seems like the carb has to be open way to much to get it to idle, and the top end is fine, just low end cant get to idle or tune at all
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Old 08-01-2008, 03:10 PM   #4
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WOW!!!!!!!!!!! I've got the same problem. I have a O.S. VSPEC EB MOD, I put a OS SPEED crank and rod because my buddy told me it will smooth out the power band even more so I spent $150 putting those two parts in my motor just for this thing not to idle or take a tune unless I open up the carb 1/8 ''. I hope some see this and help us out.....ASAP
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Old 08-01-2008, 03:19 PM   #5
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My Dad and I had this problem earlier in the season, Our settings were way off but my question is when you say you messed with the LSN exactly how much did you turn it and not notice a difference? We got so frustrated we started turning it 5 hours at a time till we got it better. I am not an expert at this stuff but to me it seems that you should try turning the LSN in more. If an engine is that out of tune changing it one hour probably wont help.
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Old 08-01-2008, 03:27 PM   #6
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I'm no expert but here is my thought. Start with the HSN at 2 turns open. And adjust the idle to ware it should be. Then try to get the car up to temp, (I know it will be frustrating) then do the fuel line pinch test. If you pinch it and it takes several seconds to go up in RPM (Witch is what I think it will do) Keep leaning it until it only takes a second to go up in RPM before it trys to shut off. If it doesn't go up in RPM at all before it shuts off, then it's too lean. (although I don't think this is the issue).
Hope this helps
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Old 08-01-2008, 03:49 PM   #7
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i tried the pinch test and it seamed that it would die out after a couple secounds which is ok or maybe a tad lean. Ican get it to idle fine as long as i hold the carb open at least 1/8". I tried to turn the low speed in 1/4 a time untill it was almost 4 turns in from flush. still that did not help. I just can not figure out why the idle has to be so far open to get it to run. Its like it doesnt get enough fuel at low speed but you can see raw fuel sputting out the top of the carb when i hold the throttle open. Any more help would be greaty appreciated.
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Old 08-01-2008, 04:21 PM   #8
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Quote:
Originally Posted by patrick21x View Post
i tried the pinch test and it seamed that it would die out after a couple secounds which is ok or maybe a tad lean.
Just the oppisite, It should go up in RPM in just less or at one second. Sounds like your rich to me.
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Old 08-01-2008, 04:27 PM   #9
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I just counted my LSN. it is 3 3/4 open from fully closed. Ware is yours?
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Old 08-01-2008, 04:57 PM   #10
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low speed is about 1/4 turn in from flush with the body.

would an air leak cause it not to idle or cause it to need allot more fuel, is that why the carb needs to be open so much
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Old 08-01-2008, 05:05 PM   #11
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Quote:
Originally Posted by patrick21x View Post
low speed is about 1/4 turn in from flush with the body.

would an air leak cause it not to idle or cause it to need allot more fuel, is that why the carb needs to be open so much
I counted from closed to give you my exact point. Air leaks generaly couse it to be lean, but you never know. At this point I would also see if the pinching was done wrong (possibly with a pipe clamp and not a proper tool) and caused the sleave to be out of round and then getting blow by. (Just a thought)
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Old 08-02-2008, 03:52 AM   #12
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Sounds to me like the piston/rod assembly was installed backwards !! There is a front and back to the piston !! If you put it in backwards it will still run but only at a higher speed, hence the raw fule issue, the skirt of the piston is not sealing the exaust port so the crank pressure is pushing the fuel into the pipe that is needed to keep the engine running at low speed. take a look into your exaust port and watch the piston as you rotate it to the top if you see into the bore after it has reached the top then you have an issue.
The rod and piston onthe OS may not let you see inside because of the length of the piston ,pull off the back cover and look in at the piston.
If the long skirt is on the carb side ,it's in wrong.
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Old 08-02-2008, 04:17 AM   #13
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Quote:
Originally Posted by patrick21x View Post
I just had two OS VSPEC motors taken apart then had the piston/ sleeve pinched at my LHS.

I reasebled the motors and wanted to break them in.

Both will not tune or idle.

The high end will clear out and run great while putting out nice smoke. but when i try to let it idle they just die out.

In order to keep them running i have to keep the carb open by over 1/8"( and raw fuel is sputtering from the carb. The idle needle will not even screw in far enough to keep it running

I have tried the factory settings on all needles, and also tried tunning them for performance. I am exsperianced and know a little but i can not get either of my motors to idle or have a nice bottom end to even idle.

I have replace the fuel line and checked my tank to make sure its holding pressure, and glow plugs burn nice and both are fine.

can anyone please help and give me some advice on what to do. Thanks in advance, Patrick
LHS doesnt know what they were doing! They put the Piston in Backwards!
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Old 08-02-2008, 04:44 AM   #14
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Quote:
Originally Posted by mremtr View Post
Sounds to me like the piston/rod assembly was installed backwards !! There is a front and back to the piston !! If you put it in backwards it will still run but only at a higher speed, hence the raw fule issue, the skirt of the piston is not sealing the exaust port so the crank pressure is pushing the fuel into the pipe that is needed to keep the engine running at low speed. take a look into your exaust port and watch the piston as you rotate it to the top if you see into the bore after it has reached the top then you have an issue.
The rod and piston onthe OS may not let you see inside because of the length of the piston ,pull off the back cover and look in at the piston.
If the long skirt is on the carb side ,it's in wrong.
Hi, may I know the piston skirt area must facing to carb or exhaust side? Thnaks.
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Old 08-02-2008, 09:11 AM   #15
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Check the engine for leaks, and cracks.. The V spec cases have been known to crack on the bottom. If you have no leaks or cracks.. Reset all the needles to.. HSN: Flush
LSN: Flush
Idle : Back the screw out while pushing the slide in with your finger, when the slide is JUST FULLY CLOSED STOP>, now go in 1-1/2 turn.

Now re tune your engine without touching the IDLE.
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