Thanks in advance I have the opportunity to buy some series 2 billet cams to suit the Z but I need to know exactly what i'm up for in advance. The person running these cams had problems with power dropping at high revs due to "lifter pump up", is this a rare case or is it quite likely with these cams? specs they are 9.5mm lift, 265 deg advertised duration, 221 @ .05", 114 deg lobe separation Min flat follower dia is 1.1527 IN, 1.1617 EX non VVT and can't easily be converted to VVT I realise the head will have to be clearanced but will I have to run solid lifters? apart from noise what are the drawbacks of solid lifters? Pretty good cams when chasing 4-500rwkw?
Nope 9.5mm lift will suit hydraulic lifters just fine. These look to be similar to JUN mild cams. What cams are they? Can't tell you if the head will need to be relieved without knowing the brand as JWT and JUN/Tomei style are different. Noise and maintenance. Not bad if the price is right. Should be just fine for 400rwkw with the right turbos etc. What is "lifter pump"?? And when you say series 2 billet do you mean they are new cams as in ground on new blanks? Also no such thing as a non VVT cam but you will need to either fit JWT cam adapter OR use series 2 cam gears. Either way I would be looking at getting the VVT cam gears rebuilt by Brett Dempsey.
They are tighe cams, ground from new series 2 billets Lifter pump up is where the lifters can open and close the valves fully, leaving them partly open and causing a loss of compression. I could have the terms wrong In regards to the VCT I was told
OK don't know much about tighe cams but unless they have reduced the base circle radius you will need to relieve heads to fit larger lobes. Not a big deal when everything is in bits for a rebuild anyway. Whoever told you about this may be thinking of the bandaid JWT upgraded VTC springs that sit in the front of the gear. The Brett Dempsey gears are completely rebuilt and strengthened internally and come with lifetime warranty. You can use them with the factory VTC springs and they will never fail.
that sounds great, so if I get the BDE cam gears I can retain the VCT? I was a bit annoyed about the posibility of loosing it. Anyone else have anything to add? Seems like these cams with bigger springs and rebuilt VCT gears are all I need
Depends on the design of the cam... It may be missing the oil passages up the guts of it to run the VVT.
You won't see/feel the benefits of VTC all that much. It helps in the low semi mid range but not to a point where its like a night and day difference. I for one suggest if you plan to run a solid lifter setup is to do away with VTC as adopting adjustable cam gears will ultimately give you a far better approach at cam phasing and timing adjustment.
The tighe billets very likely don't have the oil passages like chrispy said. I would say the pump up issues were related to incorrectly matched valve spring seat pressure than physical cam size. Running solid lifters will change the cam operating characteristics if they are intended for hydraulic lifters. Some engines respond better to solid lifter'd hydraulic cams, others do not. Very dependent on cam profile. Also for a street driven engine, keep the VTC if the cams allow it and use adjustable S2 gears, there are zero benefits to getting rid of it on an engine that will predominentley be driven in the low to mid range of its power delivery. The BDE gears fix any over roation or rattles experienced with reasonable sized cams.
Cheers Eric, I'm out of "thanks" for today but I owe you a few Did you see my PM? So how would I work out what springs I need? should I go heavier or softer than the ones that were used? I'll definately retain VCT if given the option, even though it's not my daily and will hopefully spend about 1/3 of it's life at the track
They are my cams, the problem with selling them is they pumped up the hydraulic lifters on my VG and I don't want to mislead any potential buyer. I now have a copy of the cam sheet so it seems best if that is posted up so Anton can get informed advice. Don't let me stifle comment, I'm interested in what the experts think too because I don't know
Well I've bought them, can anyone recommend springs to go for or avoid based on the specs of the cams?
far out. those cams are going to be a downgrade from stocks!!! 220 duration is TINY.... stock is 240/ 248 on auto TT's and 248/248 manual TT's you want 2 be increasing the lift and the duration ie to hold the valve open longer to aid the combustion process. by decreasing duration and increasing lift your really not going to get any gain at all stock cam spec For reference, stock cams are 248 duration 8.5mm lift 400+ CAM SET: 264 deg, 0.375" lift, +4 deg adv on EX L.C. R5 CAM SET: 272 deg, 0.385" lift, +4 deg adv on EX LC.
