Phred

As I said in the post above, CWC ( at least mine) has lugs. They are a bit more sharp, or square than the "Japan" cores. Phred

Tony, I have six L6 cams. One of them is a CWC, and it has lugs too. All the others are Nissan "Japan" cams, and all but one have lugs. I do have one "Japan" cam without lugs, its internally oiled from an unknown engine. Phred

Crank bolt is 16mm x 1.5 pitch Phred

I have worked for three nationally recognized racing engine shops. At shop #1 we built Trans-Am (and many other series) Chev engines. We had a specially built torque plate that allowed both boring, and honing through the same plate. The final results of this method was simply quicker than boring without a torque plate, then honing with a plate. This is because you could bore closer to your final size, and therefore have less material to hone to final size. There is always a minimum amount that needs to be honed, as the boring process (even with a finishing tool bit and a .003 finish cut) microscopicly tears the metal. Honing to a selected finish depends on the rings to be used, and the material being honed. After torquing on the plate of a small block chev,the surface of the bore will be displaced from the previous "round" bore, in an area next to the bolt (or stud). This displacement, is a small area about the size of a nickel, about an inch below the deck. This happens to be right where the rings are at their most important point, attempting to seal all the compression just before and during ignition. If a torque plate is not used, upon compression, a very small amount of compressed mixture will sneak by the five "windows" around the top of the cyl. With plate honing, the bore is true whith no windows to leak compression. Similarly, the main bolts/studs are also torqued before honing as they also distort the bottom of the cyl's., But this distorsion has more to do with lower bore integrity. During this time I used the same process to build all sizes of Datsun L engines with sucess. Although these blocks were not as adversly affected because the head bolt holes are further from the bore, and distorted the cylinders less. The 2nd and 3rd engine shops I worked at, were involved with professional formula car engines. These were Cosworth, Lotus, English Ford, and Toyota as used in Formula Atlantic. These shops, in addition to torque plates, used hot water pumped through the blocks. The hot water has as big an effect as the plate, as the entire block will distort as heat expansion and distorsion varies depending on the thickness of the cyl wall. It is also much more precise in setting the clearance between piston and cyl. Now, weather you want to avail yourself of these extream methods is up to you and your needs, and wallet. But, there is no dought these methods are measurable, and do increase the power potential of the engines discussed here. The increases were repeatable, and noteable on a first person basis, as I did the machine work, assembly, and at times the dyno work. Phred

This is not a cam card as normally supplied by cam grinders. Cam Analyzer is computer program, used with a fixture that rotates a cam in a jig on a bench. Electronic sensors send the rotational, lobe, and lift info to the program which converts the info to data and lobe profile charts. All this info is of little use to an end user, but is very usefull to an engine builder who can use the data to compare cam profiles from one grind to another. The program allows onscreen overlays to quickly visualize and compare grinds, and make a decision as to which profile to use for a given engine. The chart you attached also has all the info that is normally supplied with a std. cam card. If you want to compare this cam to others, the specs you want to pick out of all this mess is: Lobe centerline Lobe lift or valve lift Duration See the cam timing sticky on how to degree your cam, and it will make more sense. FWIW This is just general info supplied by someone who has used this type of equipment.

It won't happen again. This is excactly why I rarely post here. People who know nothing, know everything. Phred

Info from someone who used to port, and flow heads; I don't have an answer as to who can do this, but... The general idea in porting a head is to decease obstuctions to flow. Porting, is understood by most as increasing the cross sectional area, and volume of the port. In a race engine this is good, in a street car, not so good, and can be detrimental to performance in certain situations. Port velocity is very important to engine function, be it a race, or street engine. When port volume/size is increased, velocity is decreased. In a race car this desired, as the engine can then pump more air, and all that is needed is more rpm to get the velocity back. In a street car, the increased rpm needed to feel the difference in flow and performance, becomes detrimental to good low rpm/street performance. So, for a street engine the idea is not to increase port size, but rather to smooth casting imperfection, and to reconture the area around the valve guide and the area leading up to the valve seat. The seat then needs to have very accurate muliple angle's, which match the valve. There are also modifications which can be made to the valve that will help flow, without increasing port size. The extra cost to verify flow improvements on a flow bench, for a street engine, is not a reasonable or justifiable use of your money. Inreased engine performance comes from a lot of other things, which when done, will then be awakend by increased air flow. For a street car, porting a head, is a classic case of the cart before the horse. Phred

First, ZZZeee shot peening is very rarely used on piston domes as it can be very aggresive and damage softer alloy's if not done very carfully. The strength of a piston dome comes from it's design and alloy. The only reason to blast piston domes is to clean during a rebuild, or prepare for a coating, or to blend the surface after reconturing, or diegrinding the dome after machining valve reliefs, or machining to lower dome volume. Many pistons as recieved from the manufacture, have sharp edges on the domes or valve notches. So it is not uncommon to take a brand new piston and deburr and blend the sharp edges away. Sharp edges on a piston dome can cause distubances in the mixture flow, and also cause hot spots which may lead to preingnition or detonation. After this work, the domes may be glass beaded to blend, and remove the surface scratches. Media blasting is the generic term for all the different substances that are used for surface modification/preparations. There are many different grades of glass and shot, garnet, plastic pellets, walnut shells, and the least known, soda. Soda is a wonderful basting media. The only downside to it, is it requires a special basting delivery system, which can be very expensive. The one I use at work cost well over $12K. It is a constant loss design, which carrys away the dirt and crud with the soda. The soda crystals explode on contact, and are sucked away as dust or fine powder. The most important feature of soda blasting is that it is biodegradable. You don't have to worry about getting all the soda out of the water or oil jackets. You just flood the part with water, and the soda is disolved. Presto, a perfectly clean part! Soda leaves a slightly duller, smoother finish than glass, as it does not change the surface texture or machine marks. A bright, freshly machined piece of aluminum will be turned a dull silver however. Which means soda can be used on the entire piston if desired, as it will not damage ring lands or pin bores. Different parts of the engine require different blasting media. Some parts require shot, some glass, and if you have it, soda. They all serve a different purpose, and you just need to know the limitations of each, and the desired results for a givin part. Phred

jt1 is correct, all you others, relax. Glass beading is commonly used in all race engine shops for domes, combustion chambers, and just about every other area. I have been doing this for over thirty years on every type of racing engine from Cosworth formula engines to Trans-Am, to Turbo'd big blocks. The only concern is complete cleaning after the process. A few glass beads in the wrong area can severely damage an engine. Glass beads come in various sizes for different applications, just like steel shot used in shot peening. And to a small degree, glass will have a similar impact on the metalurgy of the surface being impacted. I wrote the following paper which describes shotpeening, and how glassbeeding can enhance the shotpeening effect. Phred The principal function of peening is to increase the fatigue life of cyclically stressed parts. Small steel balls (shot) hammer the part, coompacting the surface, which relieves both surface, and subsurface, granular stresses. This process builds a tough outer layer which is very resistant to fatigue cracking. This protective skin actually strengthens the part. The useful life of a properly peened part is usually twice to five times that of an untreated part. Shot peening is of most benefit on con rods and crankshafts. It can also be applied to almost any part subject to fatigue cracking. The following preparation is necessary befor a part is peened. 1. The part should be Magnaflux or Zyglo inspected 2. All sharp corners, nicks, machining flash, and similar stress risers should be removed. A polished surface is not required. 3. Precision finished surfaces, such as pin bores, or journals, require masking prior to peening. Intensity is the critical component in successful shot peening. High intensity peening will distort a thin section part. Peening intensity must be high enough to produce an effective skin, but not so great as to damage or distort the part. Controlling intensity in the peening process is accomplished by using shot of different density and diameter. It is also controlled by the distance from the gun nozzle, angle, air pressure, and exposure time. The intensitiy used for different parts also varies with the type of metal being peened. The ideal intensity for a specific part is determined by knowledge of metalergy, experimentation, and experience. Double Shot Peening Most parts benefit from "Double Shot Peening". Wherein the part is first peened using larger shot and high intensity. Then peened a second time using smaller shot (usually fresh glass beads) and lower intensity. This produces a much improved surface appearance and considerably improves the fatigue life over single shot peening. Double shot peening is a patented process, (U.S. Pat. No. 3, 073,022) issued to General Motors. The rights of which are not being enforced. It is mentioned only to underline the value of the process. The patent papers cover seven pages and include fatigue life charts showing life cycle comparisons between unpeened, single peened, and double peened parts. They leave no dought in the readers mind as to the advantages of double shot peening.

How to modify your Nissan & Datsun by Frank Honsowetz. ISBN 1-55561-237-7 Phred

Sometimes it doesn't take too much grinding. Phred

Woldson, FWIW. I have been building engines much longer than Paul (BRAAP), and I have never had issues with any advice he has given. Phred

Cam cards give an engine builder a good idea how a cam might perform, but don't draw any hard conclusions by them. There are a lot of other engine component factors that can upset the apple cart. Generally, a "bigger" cam will produce more power higher in the rpm band, with a corresponding loss in the lower rpm range. Having said this, any cam can be made to change it's characteristics by changing the cam timing. Example: a stock L24 cam in an SCCA ITS car set at 1.375 degrees retarded will make power all the way up to 6500rpm. But it doesn't do very well under 3000rpm. Take the same cam and advance it a few degrees, and it will now respond well at lower rpm levels through the mid range. But, the engine will probably fall flat from 6000 and up. I have degreed and dynoed till I was blue in the face, and after all these years I have a good idea what to expect, but I won't throw a cam under the bus just because of what the cam card says. It's very hard for a home builder to pick the perfect cam for his engine. Just remember how important cam timing is, and how it can change an engines attitude. Oh, and to make this thread relevant, use a good break=in oil additive when you first fire it up. Phred

Whats wrong with these people. Why they can't have a standard height for checking cams? FWIW 25.4 is the constant for converting mm to in. and vise-versa. Either multiply or divide. My choice would be the "bigger" cam. The advertised duration is not that much more. If it were me, I would install the cam 2 degrees advanced for street use. This will help pick up the bottom end performance a bit, and help offset the slight loss you'll get by going to a bigger cam. My 2 cents. Also, the springs at 180 open will be good for a street racer. Phred