| Author | Message | ||
     Brinnutz |
As many of you know, I've aacquired a good set of XB12 heads... So, someone mentioned that XB cams are .551" lift. What are the max lift cams I can use with stock XB heads then when I do the swap? Do I need new pushrods? Can I swap out rockers or get XB rockers? XB rocker covers are a must I know. Basicaly, what all should I swap out when I do the head swap? | ||
| Ratbuell |
XB cams are good, not sure what you have to use valvetrain wise though. IIRC you can use X1 cams with good results as well. You also have to change the pinion gear if you're using XB cams - they have a different gear pitch. I don't remember if the OP drive gear changed...I don't think it did, but I know the XB cams have finer pitch on the gears than tuber cams. (Message edited by ratbuell on April 22, 2009) | ||
| Brinnutz |
Well, don't know how I missed this posted by Hurricaneleah: "The screaming eagle 0.550 lift high output cam is essentially an XB cam with the correct timing marks for sportster rotation. They will bolt right in as long as you have the right pinion. Just my 0.02,but i prefer the X1 cam or .536 lift screaming eagle grind over the xb lobe in a tuber streetbike. The XBcams have a hit at 4000 that is noticeable on the heavier tubers/sportsters. The X1 and 536 lift cams make good torque from 2000 up and make for a nicer street ride." Ok, the question is, which will be the best performing with XB heads? .551, or the .536??? Then with those cams, what mods would I need to do to the heads/pushrods/rockers??!? I don't think I'm going to attempt changing over to the XB valvetrain since it's pretty much totally different LOL. | ||
| Pkforbes87 |
Look at the nrhs website and the tech read on cams. I asked this question a while ago and decided that when I change cams it will be to 536. I believe even the 551 cams that will fit a tuber still require clearancing either in the cam cover or rocker box cover. Personally ill be going with roller rockers simply to keep the valvetrain as reliable as possible while beefing it up. Someone who's actually done this should verify, but the research I've done tells me that 536 cams will work with stock pushrods and stock ratio rockers. (Roller rockers can be obtained with the stock ratio which I believe is 1:1 - ratio just means how much is the pushrod lifting on one side compared to how much the valve is dropping on the other side) | ||
| Phelan |
If using XB heads, go with .536 cams. Also, you should clearance the stock rockerboxes or get XB ones when going with anything over .500 lift. Sometimes you don't have to, depending on the particular motor's tolerance levels, but no reason not to when IRS all apart anyway. Somewhere on XLForum.net Aaron posted the proper areas to recess in the stock covers. I did it on my sportster's covers before I sold off all my parts. | ||
| Brinnutz |
Well, do I need to clearance them if the XB's stock lift is .551 and I only go .536? I'm going to have XB heads, and XB rockers obviously. | ||
| The_italian_job |
I have a question: on an S1WL with Thunderstorm heads, would I fell benefits changing them with XB heads? | ||
| Phelan |
You don't have to clearance the XB covers, just the stock covers. Because of the casting techniques, sometimes the stock covers clear .536 cams and sometimes they don't. A leaking rocket gasket is a symptom of this, but obviously other things. could cause that too. Another thing to consider is that many builds by NRHS have noticed more valvetrain noise from .551 cams too than .536's. As previously hit on, the .551 cams were made for other performance characteristics, considering they were released after the .536's, but I have yet to see amy benefits with them over .536's in pre-rubber sportsters and tuber Buells. | ||
| Phelan |
Edoardo, what other changes do you plan? What kind of shape are your current heads in? Financially speaking, you should get the XB heads and .040" under pushrods to be safe (I almost forgot about that Brinnutz), then have them cut with a 15* squish to use the thunderstorm type pistons. Then you could sell the Tstorms. You should gain about 5 RWHP with the heads stock otherwise. |
