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WhitleyTune

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  1. You should degree them, it is really best practice. The cam grinder has the decision to either grind the cam advanced with a smaller base circle diameter, or grind the cam for best fit i.e. largest base circle possible on the required lobe separation. So it's not uncommon to get a cam that the grinder gave base circle priority over ground in advance (as they probably should).
  2. The 1GZ is more like a V12 1UZ than two 1JZ's. It has slave drive cams, horrible intake manifold made for refinement etc. If it were me I would go with a Mercedes M120 V12. It is cheaper, better design & larger capacity, more power & torque, lots more potential if you want to go silly (Look at Zonda) etc.
  3. Just did a quick measure from the photos and looks like the seat diameter is around 42mm so yeah needs new seats. Heaps of meat in there though so should be a good thing. Yeah I am in Christchurch. I don't have a flowbench myself but have access to one. Would like to see a couple pieces! No stress though, only if you can be bothered sending them.
  4. Cool, thanks for that. Looks to be plenty wall thickness for the larger valves. Will you have to put new seat inserts in or are they large enough to fit the L28 valve sizes? Knock wise you will be fine at 10.5:1 with a mild cam on our 95/98 pump gas. The chambers on the 05L have a decent amount of squish so you won't have the issues that a 10.5:1 N42 would have. Good luck! Interested to see how you go, the 05L seems a good starting point for a nice head to me.
  5. I'd say just one cut each through an inlet and exhaust port will give you a good idea of how much material can be removed. If you are going 10/10ths then you could do the lot, but you'd probably be better investing in a good sonic thickness tester in that case. Any chance you could put some photos up? Have a few 05L heads myself here.
  6. 1 fast Z, have you ever seen a S7 Tool steel camshaft core break due to being too brittle? I've ground and supplied camshafts out of through hardened tool steel with no issues and in fact you will find many top tier motorsport engines that tool steel cams is common. This stuff is so tough I have never seen it crack from use. It is extremely tough, shock resistant and holds its hardness up to 500C. You can also run a decent bit more cam lobe surface stress on tool steel over a carburizing steel. Hell I've seen tool steel cams out of pushrod v8's that have taken hits from a thrown rod without major damage and are still useable.
  7. I believe it is overlap in advertised degrees, and I agree it is a vague metric!
  8. I live in Australasia and am in the industry. It is definitely not a large generalisation. There is a huge difference between tweaking, stretching and chopping cam profiles (how they have been played with by cam grinders for years) and an engineered mathematically defined valve lift curve that is then worked back through the valvetrain geometry to produce the cam profile. What cam are you running out of interest? I prefer to educate and discuss these things. Its hard being in an industry where your customer thinks they know what they are talking about because of internet jargon. The amount of times I have to tell someone that a larger lifter does no good unless the cam profile is optimised for it is amazing - all because internet said 'larger lifter gives higher ramp rate!"
  9. Furnace brazing can be applied with a paste, shim, round wire for fillets and as inline6 mentions uses capillary action to flow. You could have the brazing shim all cut to perfect size and held in place then should be fairly easy to find someone with a vacuum furnace to do the job for you - doesn't need to be a proper furnace brazing outfit, they are normally set up for continuous parts run. Hell you could even do it by hand with a gas torch and the block on the BBQ if you are keen.
  10. Could be worthwhile talking to Darton or LA Sleeves. I think it could be worthwhile to develop a system, as Z prices increase and people are more happy to drop more money on high end builds.
  11. No need to be a jackass Tony. I merely disagreed with you and stated my opinions and tried to help the OP. The fact that you use 'ramp rate' tells me you are in over your head. Are you familiar with valve lift LVAJ diagrams and different ramp designs? And the specifics of the L valvetrain in regards to its limitations on the different curves? The only time I would limit lift off a flow bench test is if the port got very unstable and turbulent. This is a much better indication of how the port will handle high lifts. I know what you are saying - added lift has diminishing returns - and this is true. But not at 12mm based of flow bench flat-line. That comes around 14-15mm with these motors. Like I said, at ~12mm lift the valve curtain area is still the choke on a 44mm valve. Thanks. Starting a cam company from scratch (including building and designing the CNC cam grinder) is not an easy task, one that I am still working on. I doubt it is ever going to be very profitable, I just want to offer modern CNC ground cams for old motors. Profile design has come a long way in the last 10-15 years and most cam companies are too busy spitting out LS cams to warrant development on older more unique stuff. Robbie
  12. Nope, you've missed the boat. Stopping the valve lift where the flow flat lines is a common misconception of performance engine design and is a good way to get beaten at the track (or on the street)! Adding valve time-area for a given duration is always a good thing. These ports don't go that turbulent at high lifts. .480/12mm" lift is NOT a lot for these motors. On a stock L28 valve size, 12mm lift is still choked by curtain area. Lift it past this and you start to get some diffused flow into the chamber and get some added pressure recovery. Personally I don't run anything under .550" on a street motor and my competition profiles all start at .590". Practical implications - More power, less of a drop after peak torque, a bit more thought involved with valvetrain setup, need decent valvesprings. Lift doesn't hugely impact on valve-to-piston issues on overrev - as long as the valvespring is correctly chosen for the cam. That has more to do with timing, closing the exhaust late (lots of lift at tdc) with not enough valve to piston clearance (So big duration with lots of overlap)
  13. I'm curious to understand how you are planning to sleeve these? If you want a 89mm bore you would need to bore out to ~95mm and braze in a 3mm wall thickness iron sleeve?
  14. Maximum valve lift has very little to do with piston to valve clearance issues. Duration and lobe separation is what you need to look out for. By the time the valve is anywhere near max lift the piston is way down the bore. Long duration with lots of overlap means opening the valves when the piston is near TDC and this is when you need to flycut the pistons for valve reliefs. So, moving from that, your question is really open ended. .600" ish seems to be about where most of the L cams offered around seem to max out. Past this you are looking into custom territory where you are going to be paying for one off parts. In saying that, .700" is possible. For a 'normal' performance L build, around .550" is where I would be aiming.
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