In conjunction with a thread I started on the next step in my “modding” where I was talking about going with a modified head, https://www.motoringalliance.com/threads/next-step-in-my-modding.30837/page-2#post-408719 In this thread I would go more into the general details of the head and the main components involved; the ports, the valves, and the cam shaft, First, an engine brings air in and pushes it out, it’s a pump. The more air that can be processed the more power being generated. There are two types of engines, aspirated – bringing air in by the shear suction created by the rotating pistons and the exhaust pressure, and forced induction – supercharger/turbocharged where the suction created by the pistons/exhaust is supplemented by a pump pushing/pressurizing the air. The air that the engine processes is brought into and exhausted via openings on the front and back of the engine. These openings are called “ports.” The larger the ports, the more processed. The size and shape of the port along with the smoothness or the port walls all affect airflow. In some instances, having a change in the shape of the port can impact air flow. These shape changes can either decrease or increase the velocity that the air can travel through the port. The finish of the port wall, roughness, also impacts velocity. The intake manifold bolts to the engine allowing a pathway from the air filter into the engine. The exhaust manifold or header is also bolted to the engine and allows the exhaust gases to pass through the catalytic converter and then out the mufflers. If the engine head ports are enlarged than the ports on the intake and exhaust manifolds should match for the best performance. Thumper Performance, Way Motors and Sneed4Speed sell ported intake manifolds. Local area machine shops also may be able to perform the porting. We move to the next step of the air process, the valves. Intake valves are normally larger than exhaust valves that you can see in the picture below. A valve is a doorway into the combustion chamber and the valve spring is what keeps that door closed. A valve has two parts, the stem and the head. The diameter of the stem and angle that the bottom of the head is shaped impacts the amount of air that can pass through the “door.” A lighter valve can have a smaller spring. These weight decreases means the engine requires less force to operate and results in a faster revving motor A valve can be made lighter by shortening the stem length and also by drilling out the center. Valve weight can also be affected by the metal alloy used. The alloy being used also affects the ability of the valve to handle the heat generated by the engine combustion cycle. Some valves are coated and some are drilled and filled with a different material all in an attempt to address either intake or exhaust impacts. Below are two informative articles on valves. http://www.enginebuildermag.com/2006/12/performance-valves/ http://www.sbintl.com/tech_library/articles/understanding_valve_design_and_alloys.pdf The final piece of this process is the camshaft. The Gen1 MINI has one camshaft while the Gen2 and 3 cars have dual camshaft engines. A camshaft is a long hardened steel bar that is machined to produce a particular shape. The camshaft is attached via a chain to the crank pulley that rotates the cam shaft, forcing it to open and close the valves that are held shut by the valve spring. As the crankshaft rotates the camshaft is turned by the drive chain. The lobes on the cam make contact with the rocker arm (some may call this the lifter) that pushes down on the valve stem thereby opening the valve allowing air either in or out of the cylinder. Most camshafts upon purchase have a “Cam Card” or spec sheet. This card should provide; 1.) Lift - The amount in inches/mm that that cam lobe will push down on the valve stem. 2.) Lobe Separation and Overlap –To function properly the intake and exhaust valves are open at the same time for a very short duration of time. Low-end Torque will be increased by a larger (more degrees) lobe separation. A narrow/smaller lobe separation will decrease low end torque but provide more top end horsepower. This will have a more rough idle. 3.) Center Line – These values expressed in degrees are used in calculating the Lobe Separation. 4.) Duration and Cam Degre eing/Timing– These values are also expressed in degrees. This measurement is based on crankshaft location, not camshaft rotation. This correlates to when the valve opens in relationship to the position of the piston. I have included two informative videos for you. The second video utilizes the push-rod engine but the discussion can be easily applied toward our overhead camshaft engines. I have a RMW Dominator Cam, it came with no Cam Card. From information on the RMW Site it appears to have 250 deg duration and .400 lift. What it does not provide is what the duration reference point is that would be designated by @xxxxxx inches/mm. It also does not provide the Lobe Separation or Overlap.
Just an FYI - Jan and many other vendors that make custom parts do not provide Cam Cards with the custom cams because anyone could copy and duplicate the product they put so much R&D into.
By getting a Cam Card a person can either check that the cam received is the cam purchased or can take the cam to a shop that can do the verification. There is no rocket science in figuring the information out. I am thinking that Jan has Newman make his cams and you can see various info on the Newman site. I also think that Newman may be selling direct in the US now. http://www.newman-cams.com/wp-content/uploads/2017/12/newman-cams_bmw-mini.pdf?fbclid=IwAR1A5_ymxpKC-b7RRJyKnLbKFO5YswZx4qMnrE407MeQk5S4KwGdAADKMmg
And remember that if you put in a different cam be sure to verify whether the lobes hit the spark plug tube. I have seen tubes with hole worn into them by the lobes rubbing.
Also to maximize any cam or custom head the block / motor pistons need to be sealed. The biggest problem on any factory car is blow-by. A very good leakdown test should be run on higher mileage motors first before updating the head as most of our cars including mine could benefit from new / upgraded piston rings. http://015ef8d.netsolhost.com/TechPage.aspx#trGaplessPistRings
I agree about the cam card but most people have no idea what the info on the card even means. I think you are right about Newman available is the US now, but I do not think they can sell the RMW spec cams just the standard Newman cams they have available.
My motor is putting out 268 270 ish HP on the Helix “Heartbreaker” Mustang dyno and my Tq is 200 as off right before the Dragon. The Helix dyno has the heartbreaker name because everyone shows up saying my car should make 250-300 hp according to their butt dyno. The heartbreak comes when the car gets strapped down and the real numbers are determined. Also Mustang Dynos are a lot harder to fake real results on unlike a dyno-jets. Let’s leave it at that as I do t want to start a “which dyno is better thread” . My motor has just about 104,000 miles but I beat on it and also baby it with maintenance and frequent oil changes with Motul or Amsoil every 3000 miles. As you know I run 100% VP M-1 Meth all the time and I am tuneed for it, so while I am making great power the oil needs to be changed more often because with <with the oil get dirty faster and breaks down quicker. I think my next motor mod may be pistons, rods and top seal gap-less rings to seal and eliminate blow-by which robs our cars of power and TQ. Then again if my leak down test is still good I may just add a TVS-900 and get away from the less efficient heat pomp M45 SC.
It’s funny that you bring that up. The running joke about some manufacturers Cams is make sure you “Ding theTubes” so the cam will fit. Hahahahaha
Whaaaaat ? I would have called JAN and sent the CAM back. That should not happen ever with any cam. I had the RMW street cam for years and it fit fine. Then because I wanted more power I upgraded lots of stuff again and skipped the dominator and move up to the Grand AM Cam and it fit fine without any issues.
For Gen1 folks, here is a little more information on head ports. According to Jan at RMW, when he flow tested the Gen1 Stock S head he found 106 CFM. On the JCW that has larger exhaust ports than the S but the same size valves he found 126 CFM. When he flow tested his BVV head that has enlarged ports and larger valves he found 180 CFM. Thumper Performance provided me some pictures that reflect the ports in relationship to the exhaust gasket. You can see the differences. Stock Head JCW Head Ported Head
Is it just me or does something look strange about the ported head. The bolt holes do not line up and the ports themselves are uneven. Is it just the picture. I have never seen a head and gasket in person though so that is why I'm asking.
Since this is an educational thread on heads, I'm still wondering if an (imaginary) RMW CNC'd head with stock valves would be better for lower end torque than a finished RMW head with big valves. Is valve size and port shape/size somewhat independent of each other? Curious as I only have an auto now and can't take full advantage of larger valves at high RPM's. What made me wonder was an incomplete big valve Cosworth head with CNC'd ports, but stock valves that was recently for sale, and looking into the possibility of ordering a custom head from Jan with the CNC port work alone (at full price in case anyone thinks it's only a cost cutting issue).
That’s the Thumper magic! The first two are with the OEM gasket, the ported head has an aftermarket gasket. You cannot make a good comparison. He also ports by hand, so you get unevenness and no two are the same.
When I started down this road the first person I reached out to was Jan at RMW as I was looking for something a little different than his BVH but he never got back to me. When I heard nothing from Jan, I then reached out to Thumper Heads with my questions. Mike got back to me the same day. On the head and torque, I am thinking this has to do with "timing" of the cam that the guy in the second video gets into a little bit. When the valve opens relative to the piston rotation impacts torque.
Yes, chances are that no two Thumper heads will be the same. In competition this would result in more testing being required to find optimum settings. For the wanna-be "Bandit'," this means you have more money in your pocket to do something else with. On the ported head picture, the shadows within the bolt holes indicate that the camera aperture is above and to the left of the port centerline.