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Old 09-08-2010, 04:49 PM   #1
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Default OS V-Spec acting up!

Hi,
I was at the track today and my V-Spec was acting up a bit, actually ive been noticing over the last 1 1/2 gallons probably that its been needing to run hotter for equal performance.
Basically I need to have it at 115-120-125(C of course, at the limit) to get good performance. By this I mean a smooth powerband and maximum revs with good power on bottom.
The motor has about 5 gallons on it now and is a year and a half old. I used to run it around 110 and get the same power I now get at 124, I guess this should be normal as an engine gets older?
A mistake I made while tuning this engine a while back was a very lean LSN, to get it to perform it had to be HOT, around 115, and it was a mess, very erratic powerband. I caught on to my mistake, richened LSN up and it was fine, I just took a while to realize my mistake.
Im pretty sure this is not the case now since any small (1-2 hour adjustments) on the HSN cause pretty big results, as if the optimal tuning window is now smaller than before. If I slightly richen my HSN to get temps down a little I immediately notice the engine not fully reving. As for the LSN it seems spot on, Ive tried richening to see if Im making my famous mistake and it just gets veeeeery slow off the line and basically doesnt rev up so Im pretty sure its not a lean LSN.
All this said there may be a very simple answer, my engine is kind of old and getting along. Is my engine dying?
Any other comments/suggestions?

Thanks!!
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Old 09-08-2010, 05:07 PM   #2
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Sounds like the piston and sleeve may need repinched. Expecially if it has been getting worse over time. As the engine loses compression it loses power and you have to lean it out to get the performance, but if you lean it out too much the engine won't get the oil it needs to perform and it'll seize up. Best thing to do is get it repinched, theres a few folks on here that'll do it for about $30 shipped and that'll get you a few more gallons of fuel. Eventually you'll need to replace the piston and sleeve but that'll last you alot longer than repinching it.
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Old 09-08-2010, 05:10 PM   #3
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It sound like it is getting tired, When engines start to lose compression it effects, power, and stability of the tune. You will have to lean it out more to get it to run decent. Check out our website and if you decide to rebuild it let us know. It is a lot cheaper to resize it and possibly replace bearings than buying a new engine.

Hope this helps,

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Old 09-08-2010, 05:10 PM   #4
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Pinch it and replace the rod. Check the crank pin. If the crank pin is out of round then the motor is junk but if it is still round with a replacement of the rod and pinch of the sleeve it should be good as new. Take a look at the rear bearing to see if its smooth or notchy. If its not smooth that also may be your problem. If you go the pinch route I would suggest RcRenew.com I just had my V-spec speed done by him (medium pinch) and after 3 gallons the motor is still running just like a top! Not to mention I sent him the piston/sleeve monday and had it back by friday so I could race that weekend!!
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Old 09-08-2010, 05:11 PM   #5
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LOL I had no idea Lance would be posting at the same time I was
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Old 09-08-2010, 05:12 PM   #6
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Quote:
Originally Posted by jwm2 View Post
Sounds like the piston and sleeve may need repinched. Expecially if it has been getting worse over time. As the engine loses compression it loses power and you have to lean it out to get the performance, but if you lean it out too much the engine won't get the oil it needs to perform and it'll seize up. Best thing to do is get it repinched, theres a few folks on here that'll do it for about $30 shipped and that'll get you a few more gallons of fuel. Eventually you'll need to replace the piston and sleeve but that'll last you alot longer than repinching it.
+1, also any play on the rod/crank will make it very hard to tune.
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Old 09-08-2010, 05:26 PM   #7
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Originally Posted by awdcameolsx View Post
LOL I had no idea Lance would be posting at the same time I was
lol.... we must have been on the same wavelength..lol Thanks !Glad your happy with out service

Feel free to send in the whole engine and we can inspect it for you if you wish and check all the tolerances and let you know the condition of the internals and which options you have to get it back up and ripping again!

Thanks,
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Old 09-08-2010, 05:31 PM   #8
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lol.... we must have been on the same wavelength..lol Thanks !Glad your happy with out service

Feel free to send in the whole engine and we can inspect it for you if you wish and check all the tolerances and let you know the condition of the internals and which options you have to get it back up and ripping again!

Thanks,
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do you guys do all makes and models? or just stick to OS engines?
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Old 09-08-2010, 05:38 PM   #9
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do you guys do all makes and models? or just stick to OS engines?
Any .21 engine on or off road. we have a one day turnaround on resizing and we ship 2 times per day!

Thanks,
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Old 09-08-2010, 05:41 PM   #10
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Any .21 engine on or off road. we have a one day turnaround on resizing and we ship 2 times per day!

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could you pm me a price list? thanks lance!
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Old 09-09-2010, 08:44 AM   #11
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Cool! PM inbound Lance!
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Old 09-09-2010, 01:54 PM   #12
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I tore the engine down today, crank pin is fine and round, there is NO play between the rod and the piston and my bearings are very smooth. If anything the front one may be a little unsmooth but not sandy or gritty or anything. Just not as smooth as the rear bearing! But both seem fine!
So I guess the solution would be a repinch? Is my unresponsive tune due to loss of compression then?
Thanks guys!
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Old 09-09-2010, 02:54 PM   #13
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You can test the pinch by rotating the flywheel by hand. If theres little resistance at tdc then yeah it needs to be repinched.
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Old 09-09-2010, 02:56 PM   #14
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Could probably use a new front bearing as well. Any resistance at all will really hamper the power output of your engine as its spinning 10k-40k rpms.
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