Another valve spring question....
#11
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Re: Another valve spring question....
Originally Posted by HOTTZU98
yOUR dONZI MUST BE A ROCKETSHIP WITH A 500 IN IT SOUNDS LIKE A BLAST!!!
I have hit 78.2 gps (Garmin eTrex handheld) so far.
Bravo 1 drive 1.5 gears, stock Bravo 28p prop, a little over 5000 rpm, maybe 5100. Hard to tell when you are going fast.
The 80mph speedo is almost buried, showing maybe 85. I have Gaffrig II gauges..
It's a handful above 75! I'm working on that. It needs 'something'...
I want to try to fix the handling before I play with props.
I have already installed a single ram full hydraulic steering (from the helm back), from XS Marine.
I am planning on some LOONNNGGG tabs at this point to try to help the handling.
We'll see....
#12
MarineKinetics
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Re: Another valve spring question....
Ctadams21
It would be difficult to determine the origin of your current springs unless they have external markings. You could check O.D./I.D, damper, or the rate on a Rimac. However if the springs have begun to sag that would be inconclusive. It is correct, there were some problems with a run of springs used in the 500 series of engines (due to improper heat treat) that have since been resolved Here are some options from a previous post of mine regarding springs.
Valve springs are a “read” component, similar to a spark plug, in that they contain a great deal of information relating to the operating condition of your engine. Not only are they responsible for returning the valves to their seats, they need to keep them there; a difficult task compounded by aggressive ramping and (in some cases) forced induction. In the process they are required to dampen and stabilize the harmonics created by the valve train and dissipate the resulting thermal buildup. Spring life has so many variables it’s difficult to put a cycle value on them. Because they are affected by heat, RPM (one “zing” can kill a spring), wire quality/heat treat, and camshaft profile, the degradation curve is not linear and varies greatly from application to application. Heat is generated in the spring from multiple sources. First by cycling the spring through compression and extension. Secondly the friction between the coils generates heat. Third is heat absorption.
I would suggest that you check your springs for current values at seat load and open load, compare that to spec and see if you are within tolerance. These figures will give you baseline references for future fatigue evaluation and alert you to other potential valve train problems. Many cam/lifter failures originate with the springs inability to maintain dynamic stability. Check springs for discoloration and/or cracks regularly. If you do find a break that is jagged, that is due to harmonic resonance. A clean break is a sign of improper heat treat. Monitoring your springs for degradation is cheap insurance. Below are links to on head spring test tools of various prices.
http://www.power-t.com/spring/pt-700.html
http://www.intercomp-racing.com/fr_springtorque.htm
http://www.intercomp-racing.com/detail.cfm?ItemID=121
http://www.jegs.com/cgi-bin/ncommerc...52&prmenbr=361
http://www.moroso.com/catalog/catego...?catcode=27105
http://www.lsmproducts.com/p3.htm
Bob
It would be difficult to determine the origin of your current springs unless they have external markings. You could check O.D./I.D, damper, or the rate on a Rimac. However if the springs have begun to sag that would be inconclusive. It is correct, there were some problems with a run of springs used in the 500 series of engines (due to improper heat treat) that have since been resolved Here are some options from a previous post of mine regarding springs.
Valve springs are a “read” component, similar to a spark plug, in that they contain a great deal of information relating to the operating condition of your engine. Not only are they responsible for returning the valves to their seats, they need to keep them there; a difficult task compounded by aggressive ramping and (in some cases) forced induction. In the process they are required to dampen and stabilize the harmonics created by the valve train and dissipate the resulting thermal buildup. Spring life has so many variables it’s difficult to put a cycle value on them. Because they are affected by heat, RPM (one “zing” can kill a spring), wire quality/heat treat, and camshaft profile, the degradation curve is not linear and varies greatly from application to application. Heat is generated in the spring from multiple sources. First by cycling the spring through compression and extension. Secondly the friction between the coils generates heat. Third is heat absorption.
I would suggest that you check your springs for current values at seat load and open load, compare that to spec and see if you are within tolerance. These figures will give you baseline references for future fatigue evaluation and alert you to other potential valve train problems. Many cam/lifter failures originate with the springs inability to maintain dynamic stability. Check springs for discoloration and/or cracks regularly. If you do find a break that is jagged, that is due to harmonic resonance. A clean break is a sign of improper heat treat. Monitoring your springs for degradation is cheap insurance. Below are links to on head spring test tools of various prices.
http://www.power-t.com/spring/pt-700.html
http://www.intercomp-racing.com/fr_springtorque.htm
http://www.intercomp-racing.com/detail.cfm?ItemID=121
http://www.jegs.com/cgi-bin/ncommerc...52&prmenbr=361
http://www.moroso.com/catalog/catego...?catcode=27105
http://www.lsmproducts.com/p3.htm
Bob
#13
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Re: Another valve spring question....
If it were me and I was unsure I would change them. I could get ugly if some break at 5000 RPM. Our boating season is short enough with out having a break down in mid season.