500 hp Valve Spring Broke with 6 hours on it?
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11-13-2007, 05:38 PM
#12
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Spring
Ok we pulled it apart today and looks like just the valve spring. Cylinder has 150 lbs of pressure and valve moves fine. Looks like we got lucky. I showed the spring to Anthony from Wazzup racing and he thinks from all of the idling it may have broke from not enough oil up top and just heated up. We will see. Had to order new springs from Summit and will put it back together tomorrow.
11-13-2007, 06:15 PM
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gfs,
Just curious which springs you had used ? Last week I assembled 4 brand new heads with all new parts for a pair of 500 EFI's and on the advice of the guys at Crane we stepped the springs up from the original 500 EFI ones (99895) to the 99896 spring. Apparently this is the updated spring that Mercruiser is using also.
The idling can also cause problems as Anthony said. Initial startup is also an issue. I have been trying to get my customers to oil the springs down real good right before initial startup to make sure they are lubricated real well. Friction can cause a mess of heat in new springs. I know that at least one of the cam manufacturers is telling guys to just run the engine 10 minutes or so then let the springs cool down before starting it again. This is mostly on real high pressure mechanical roller springs.
Pleasant boating !
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
Just curious which springs you had used ? Last week I assembled 4 brand new heads with all new parts for a pair of 500 EFI's and on the advice of the guys at Crane we stepped the springs up from the original 500 EFI ones (99895) to the 99896 spring. Apparently this is the updated spring that Mercruiser is using also.
The idling can also cause problems as Anthony said. Initial startup is also an issue. I have been trying to get my customers to oil the springs down real good right before initial startup to make sure they are lubricated real well. Friction can cause a mess of heat in new springs. I know that at least one of the cam manufacturers is telling guys to just run the engine 10 minutes or so then let the springs cool down before starting it again. This is mostly on real high pressure mechanical roller springs.
Pleasant boating !
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
11-14-2007, 10:50 AM
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Bill K
The spring that broke was an Isky but I do not know the number. The ones that Anthony orderd to replace them where the Cranes from Summit. Waiting for him now to come check to make sure we put it in right and give final adjust.
11-14-2007, 10:57 AM
#16
Geronimo36
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Who was it that did your machine work?
11-14-2007, 11:04 AM
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I always soak the springs real good also before start up. The dampner spring between your inner and ouer rubs and can cause the springsto get a little hot before they have a chance to lube up.
Who really knows though? Congrats on getting by without serious damage.
Good luck with everything else.
Who really knows though? Congrats on getting by without serious damage.
Good luck with everything else.
11-15-2007, 07:13 AM
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Ran across this last night- on another site
We talked to Ron Iskedarian about spring breakage on counterwound springs and he told us that the counterwound springs set up strange harmonics that break them when they are run for periods of time under 8000 rpm's. He said they really need to be run above 8000 rpm if they are to be run for extended periods of time. He say's that if they are run in an engine that never see's 8000 rpm, they will break. This is the first we have heard of this, I'm just passing along what Isky told us. He said that non-counterwound springs, or springs with dampers in them hold up better for use under 8000 rpm.
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11-15-2007, 09:29 AM
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Isky Springs
Wow I can not believe they would not recomend these springs for under 8000 rpms? What the hell do they think we are running. Thanks for the heads up.
