| Author | Message | ||
     Whitelightning222 |
Need some advice from you engine build guys. I own a S1W and have run N9 cams for several years. I've since learnt more of Buell engines and that N9 cams are too race orientated with too much overlap. I intend to install 536 cams + roller rockers. The head has been flowed by a guy called Dick O'Brien, with 175lbs springs and bigger valves. Will the 536 cams still need clearance machining? Will I still have to check for valve to valve clearence? Is this work best left to an experienced mechanic (I've done base / head gasket changes)? Any advice will be appreciated, John U.K. | ||
| Oldog |
check the cam chest lifter bosses for clearence on the lobes. check the rocker arms to boxes for clearence. do i understand that the cams are "milder" for better street use.. (Message edited by oldog on August 23, 2009) | ||
| Brinnutz |
IIRC N9 grind is .551 " lift... So if you're going to less max lift cams, if you don't have issues now, you should't...right? I'm no expert and don't claim to know wtf I'm talking about in this arena, but I'm just sayin... | ||
| Blake |
I'm a strong believer in always checking the valve to valve clearance. It's too easy not too. But like Binnutz and Oldog advise, if you are replacing a set of N9's with the 536 cams then you should be good to go. | ||
| Phelan |
If the N9s are similar to the SE .551 cams, yes they have more lift but they have smaller base circles than the SE .536 cams, so do check the cam chest for clearance. Besides that, make sure you have plenty of clearance in the rockerboxes for the rockerarms because I believe roller rockers are taller than stock, which will cause more clearance issues. Make sure to get adjustable pushrods too so that you can adjust them to the proper length for the roller rockers. (Message edited by Phelan on August 23, 2009) | ||
| Buellistic |
Any body ever weight adjustable push rods against solid push rods to see just how much HEAVIER the adjustable ones are ??? | ||
| Blake |
If my reckoning is correct off the top of my head, the rocker arms greatly diminish the effect of the pushrods. The rocker ratio cuts the speed of travel of the rods relative to the valves and then cuts the inertial force transmitted to the valves/springs relative to the rods, so the mass on the pushrod side is factored down in effect by the rocker arm ratio squared (compared to the valve side, the speed of travel of the rod and thus its inertial forces there are reduced by the rocker ratio plus that inertial force is reduced by the rocker ratio as it is transmitted to the spring). It's the same as having a fat kid scootch up on one side of the see-saw. So if the rocker arm ratio is 1.6, the mass on the pushrod side relative to the valve side can be 1.6*1.6=2.56 times that on the valve side and be no more a contributor to valve float. If my late night, off the top of my head figuring is correct that is.  | ||
| Whitelightning222 |
Thanks for the information. The rocker covers have already been reworked for clearance, as have the valve springs. Is it absolutely necessary to use adjustable rods? | ||
| Buellistic |
Blake: That is why "i" put 1.75 to 1 rocker arms in my engine and kept the OEM solid(non-adjustable push rods) !!! The rocker arms are ROLLER TIPED ... (Message edited by buellistic on August 24, 2009) | ||
| Phelan |
I would venture to say that most who use .536 cams do not use roller rockers. You can, however, get stock ratio non-rollers from S&S that have a larger load surface area to reduce pressure and wear without the clearance issues of rollers. Roller rockers use different length pushrods, so to use non-adjustables, you'd have to use adjustables to find the length, take them out, and have fixed length ones made for that length. I don't think there is a specific length that works for the rollers (IIRC it varies with brand, tolerances, etc.) which is why you have to use the adjustables. I could be wrong though. | ||
| Jstfrfun |
I put 555 Andrews cams in mine for a stronger mid-range pull, no problems with anything! |
