Blaker888 Posted October 14, 2006 Author Report Share Posted October 14, 2006 NICE!!!!!! I love those wheel are they as heavy as the stock ones? I was also wondering what spring u went with on ur cam I thought about getting 921 because they are good up to 650 of lift! I feel like Im asking u a million ?!! I'm guessing the 918s would be a better fit; I'm thinking the 921s have way more seat pressure than that lobe needs. Valve seat life is less with stiffer springs (seat recession etc) not to mention they do not last as long. It is not uncommon with more agressive lobe designs that need 921 springs to require valvespring replacement every 50K-miles. Contact the cam company/designer and get the pressures required (both on the seat and over the nose) and add 10% to it to account for valvespring break-in. Mr. P. <{POST_SNAPBACK}> What does this mean steve!!!(both on the seat and over the nose) and add 10% to it to account for valvespring break-in.) I understan brakin but not the rest (over the nose and seat) what is that?!!!! Quote Link to comment Share on other sites More sharing options...
misterp Posted October 15, 2006 Report Share Posted October 15, 2006 Valvespring 101 - stiffer valvesprings will pound your valve seats into oblivion sooner; don't get valve springs stiffer than what the cam needs. When a camshaft lobe is designed and tested the engineers will write-up notes as to operating engine RPM range and the amount of valve spring pressure required to keep the lifter from being violently flung off the lobe as the cam is spinning. You get these number from the cam designer/maker. You then need to find springs that match those requirements. You can always buy springs that are harder/stiffer than called for, and they will work fine but the valves will be closed with much more force than necessary and you will have increased valve seat wear. All valvesprings will soften with age; this is a valvespring fact of life. For that reason a good rule-of-thumb is to have valve springs which are 10% stiffer than what is called for, because during the first few engine cycles the springs will break-in and settle. Stiffer springs made from harder steel alloys will soften even faster than usual during their lifetime, they just don't keep the tension very well. A little-mentioned fact about the Comp 921 springs is that in the real world they loose enough pressure at 50K-miles that they should be replaced. These two facts make the difference between needing a valve job at 100K-miles (heads with normal factory springs) or 50K-miles (heads with comp 921 springs). If you are going to buy a radical cam that needs radical valvesprings then you will also have to commit to pulling/servicing your engine heads a lot more frequently. The cam that you mention does not at all look radical enough to require the comp 921 springs, but you will have to call the cam maker to be sure because some cam grinds are deceiving - a good example of this are the Crower cams, they have brutal lobe ramps and usually need much stiffer valvesprings than cams from other companies measuring the same duration. Mr. P. Quote Link to comment Share on other sites More sharing options...
Blaker888 Posted October 15, 2006 Author Report Share Posted October 15, 2006 Valvespring 101 - stiffer valvesprings will pound your valve seats into oblivion sooner; don't get valve springs stiffer than what the cam needs. When a camshaft lobe is designed and tested the engineers will write-up notes as to operating engine RPM range and the amount of valve spring pressure required to keep the lifter from being violently flung off the lobe as the cam is spinning. You get these number from the cam designer/maker. You then need to find springs that match those requirements. You can always buy springs that are harder/stiffer than called for, and they will work fine but the valves will be closed with much more force than necessary and you will have increased valve seat wear. All valvesprings will soften with age; this is a valvespring fact of life. For that reason a good rule-of-thumb is to have valve springs which are 10% stiffer than what is called for, because during the first few engine cycles the springs will break-in and settle. Stiffer springs made from harder steel alloys will soften even faster than usual during their lifetime, they just don't keep the tension very well. A little-mentioned fact about the Comp 921 springs is that in the real world they loose enough pressure at 50K-miles that they should be replaced. These two facts make the difference between needing a valve job at 100K-miles (heads with normal factory springs) or 50K-miles (heads with comp 921 springs). If you are going to buy a radical cam that needs radical valvesprings then you will also have to commit to pulling/servicing your engine heads a lot more frequently. The cam that you mention does not at all look radical enough to require the comp 921 springs, but you will have to call the cam maker to be sure because some cam grinds are deceiving - a good example of this are the Crower cams, they have brutal lobe ramps and usually need much stiffer valvesprings than cams from other companies measuring the same duration. Mr. P. <{POST_SNAPBACK}> Thank u once again my Friend! Quote Link to comment Share on other sites More sharing options...
RevolutionRaceWorks Posted October 15, 2006 Report Share Posted October 15, 2006 Sorry for the slow response I had a mini roadtrip yesterday/ today I actually am running the Dart Pro-1 heads so They came with the 918's installed. Break in time on mine was fairly minimal. I acutally broke the truck before the cam had 1500 miles on it haha. The key thing to remember.. if you go to a head cam combo like I have is fuel. I am running the marine 8.1's that come with the maggies and I am at about 80% duty cycle on them right now on the stock pump. Before I swapped injectors I was having fueling problems above 5500 but once we did the swap that saved all the bitching. Shortly there after I turned her to 7200 and the fuel pump coughed.. and I broke a ring land. Fortunately zippy was able to get my short block warrantied and I have had nothing but smooth sailing since then. If you are going cam only and springs that should be able to get off okay with the stock injectors but I defintely would suggest you throw a wideband on it. Any questions I can answer I will feel free to ask anytime. As for the wheels they do weigh the same as the factory VHO wheels I traded mine for those. I really like these better. Just a personal thing. Quote Link to comment Share on other sites More sharing options...
detjoe Posted October 15, 2006 Report Share Posted October 15, 2006 Sorry for the slow response I had a mini roadtrip yesterday/ today I actually am running the Dart Pro-1 heads so They came with the 918's installed. Break in time on mine was fairly minimal. I acutally broke the truck before the cam had 1500 miles on it haha. The key thing to remember.. if you go to a head cam combo like I have is fuel. I am running the marine 8.1's that come with the maggies and I am at about 80% duty cycle on them right now on the stock pump. Before I swapped injectors I was having fueling problems above 5500 but once we did the swap that saved all the bitching. Shortly there after I turned her to 7200 and the fuel pump coughed.. and I broke a ring land. Fortunately zippy was able to get my short block warrantied and I have had nothing but smooth sailing since then. If you are going cam only and springs that should be able to get off okay with the stock injectors but I defintely would suggest you throw a wideband on it. Any questions I can answer I will feel free to ask anytime. As for the wheels they do weigh the same as the factory VHO wheels I traded mine for those. I really like these better. Just a personal thing. <{POST_SNAPBACK}> is your old short block at Gage? or did they rebuild it? did he offer to sell the short block back to you???still looking for a good 6.0L core... Frank has a very sharp color combo Quote Link to comment Share on other sites More sharing options...
vmax2fast Posted October 16, 2006 Report Share Posted October 16, 2006 Ask and you shall receive http://www.revolutionraceworks.com/gallery/05-Silverado-VHO <{POST_SNAPBACK}> Is that 6.0 high output badge/stripe stock? I've been looking for something like that to point out the fact! Quote Link to comment Share on other sites More sharing options...
RevolutionRaceWorks Posted October 16, 2006 Report Share Posted October 16, 2006 Joe they rebuilt my shortblock and threw it back in Vmax Pm CraigW Quote Link to comment Share on other sites More sharing options...
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