Before you get to involved in the cylinder head, here is a complete setup for the engine to properly degree any L series cam. When you need to know exactly where your cam timing is, you will need this setup. There are a number of units out on the market. I recommend utilizing a part that is adjustable like this part. The cam will make or break any engine build, in fact it is possible to have the ideal cam installed, but if the cam timing is incorrect you could easliy kill your engine performance.
The top cam gear is an HKS part I bought a number of years ago. At the time the only other option was the multiple hole sprocket MSA and NISMO offered. I did not care for the method of making adjustments to the cam timing. I found this part at a later date, and in my opinion this is a much better part then the HKS part. The first Tomei sprocket I bought cost me $145.00 shipped from Japan to my door. I rescently bought a second sprocket for a new project and the price went to 170.00 if I bought two parts plus the shipping. The cost of these parts are getting quite expensive, but to do the cam timing correctly a necessity. When installing a aftermarket cam for a race engine, it makes no sence to just install the cam and hope for the best. The manufacturer sent a cam card along with the cam for proper timing of the cam, to disregard setting the timing is just a waste of your time. Without properly timing the cam, you will get a number of results like a short power peek, peek power dropping off early, and low power/ or changed designed power band of the cam just to name a few. Note that the Tomei part does have the laser degree setting on the part. The HKS unit does not, and that makes a quick adjustment almost impossible on the fly.

Chain Tensioner/Assembly

The second part of the chain assembly is the chain adjuster. This part is less critical then the sprocket adjuster. However, to get the smoothest running engine upgrading the chain tensioner will help not only that area, but will also serve to aid the builder with a cylinder head that has been machined, whereby by the machining changed the distance center to center of the cam and crankshaft. This tensioner also makes the standard hydrolic tensioner from Nissan obsolete. The one thing this tensioner also does is to keep the chain tension consistant, thereby stabilizing can timing on accelleration, and decelleration of the engine. This helps to maximize overall performance of the engine under any operating condition. This part is not readily available, but with a little leg work you can get the part.

Utilizing a setup is the very best for chain tensioning and cam timing, and overall performance of the engine. The thing that is most important is to produce the correct variables and reduce the undesirable, uncontrolable, variables that hinder the best possible performace of your engine.
The cost of the tensioner has gone up dramatically from the first time I bought the part, thank you mr president, and the state of CA. You don't realize just how much the cost of a product has increased due to the dollar value in the market, and all that stimulus dollars being printed that devalues the US dollar, but that is a different discussion. The first time I bought the part it was $450.00 USD and I thought that was expensive. I just bought another part and now the part cost me $680.00 USD. This is going to get to the point that Canadian money will be worth something in the US.

Rocker Arms

Here pictured are three rocker arms from various engines. They do look new, as they have been reworked by Delta Camshaft. The cost of the rocker arms have gone up significantly since I bought my first set at MSA for about $190.00 a set now they are more expensive, and I was surprised to see shops selling them for about $40.00 USD per rocker in some cases. I also looked at the Kameari light weight rockers and got a quote of $837.00 with tax ans shipping. Now I am a guy that likes to get the best part for the engine, but this is a little out there even for me. Maybe if I had gobs of cash to spend, but realistically, I have been able to learn that the stock Nissan Rockers are good to 10,000 RPM's or so.

NOT ALL NISSAN ROCKERS ARE CREATED EQUIL!

Take a close look at the rockers pictures here. Do you see anything that may be different? Ok it is the way the tappet end of the rocker was ground. Note that the tappet on the right looks to be ground with the mating surfact of the rocker to the lash pad off center of the rocker "rail" to the right. The center rocker tappet looks to be off center to the "rail" of the rocker to the left of center. The rocker on the left although a little harder to see looks to have the tappet on center of the "rail" of the rocker. Note: When I speak of the "rail" of the rocker is center of the pivot point, and oil hole down the top of the rocker on center to the tappet part of the rocker. I have taken the time to verify the tappet offset grinding, and have found rockers ground as much as .035 off center. The tappet can not be ground to center after it has already been ground by Nissan. The width of the tappet is designed to work with the lash pad to position the rocker and keep it from laterial left to right movement as the rocker moves. The last things to address, is the rocker weight, and the surface finish of the rocker. Balancing your rocker/valve train assembly is a lengthy process, and requires a good scale. The idea being make every rocker/valve spring assembly the same weight. This will lead to longer life of the cam and rockers, not to mention the valve and valve guide. Probably more work then most want to do, but beneficial none the less. The surface finish of the rocker can be smoothed to ensure the rocker will not find that one casting line, capitolize on that line and break along that casting line. So a smooth finish is always desirable for a high rpm engine. Loosing a rocker at high rpm's sucks, literally, so keep that in mind also.
On a side note, the beehive spring was designed to keep the compression of the spring uniform on compression and release of the spring. I was looking into installing the beehive springs, and Ferra sells springs for imports, but I could not find an import spring that had enough spring presure on the seat or compressed. Also, I could not find a spring that would not compress to .580" without binding the spring. On the American engine side, I could not find a spring that I could work with in regard to the installed spring heigth. So until technology, once again, catches up to what I want, I will have to go with the race standard Isky 7005 spring.

Camshaft

I don't know about you, but what this off center grinding has done is to first off place the cam to rocker surface area rub pattern off center to the cam lobe. Note the wear pattern of the camshaft in this picture.

The lobe to the left looks pretty good for center to wear pattern. The lobe to the right looks like the rocker was not center of the lobe, and it was not.
I don't know about you but this is not ideal for a high rpm race engine. The other thing to be noted is that the tappet that is off center will also have a tendancy to side load the cam lobe, but more importantly, side load the valve as the rocker pushes the valve to open the valve.
Nissan did not do a good job of engineering this part of the engine. However, seeing that the engine was designed for 150 Hp and a top rpm of 6500-7000 with a lift of .420" (at the valve) or so, maybe more or maybe a little less it really was not an issue with the type valve guides that were used, and the spring presure as well.
The race engine on the other hand is all together a different animal. My cam has a lift (at the valve) of .580". The Isky 7005 valve spring with a 125-130 psi seat pressure and about 260 psi of spring pressure makes this little offset problematic. The valve guides will wear fast, and I am quite sure that if a video was taken of the spring in operation, slowed down to see the compression of the spring and uncompressed spring would reveal the spring not compressing in a linear strait compression, but rather the coils of the spring as it is compressed moving left and right as the spring is compressed. That will create unstability of the valve opening and closing, that will lead to a loss of horse power as well.
I have always had my cam, a stock NISSAN cam, ground to my specifications. There are a number of grinders out there Schnider, Delta, Isky, (old racer Brown ) I don't really care where the cam is being ground so much, but are very concerned about the cam stick itself. Nissan did the best hardening process for the cam, (cold chilled) heat treating to make the lobes hard and wear well. The cams from some grinders are cams that were made after Nissan did their cams, and they were heat treated incorrectly, and that lead to excessive lobe wear. I wont mention who does what, but it sufices to say, have the stock Nissan cam reground and you will not have any problems.

Cylinder Head

And here, the meat and potatoes of the entire engine. The cylinder head is one of the most important parts that the high performance builders can concern themselves with, aside from the cam. With a good cylinder head on the engine, much loss or low power output of the L series engine can be overcome with the use of a good turbo, tuned intake system and adequate exhaust system. Keep in mind the tuning of the various components will yield specific results at specific rpm ranges. Design specifications are decided first for a spicific application, and the engine built accordingly to meet those requirements.
The cylinder head in a nut shell must flow, and also flow well enough to optimize engine efficiency in the normally asperated aplication. As stated earlier, a good turbo can overcome a wide range of inefficiencies in the engine design, but the builder should ALWAYS build for the best efficiency of the engine utilizing the normally asperated operation of the engine. Once the build is correct, it then is a matter of tweaking the engine to a specific application. A turbo application will require different components and specifications then a super charged engine will require.
Above is a picture of two cylinder heads, one being an N42 small combustion chamber, and the other the P90 combustion chamber. The N42 head is sold out of Japan, the other was reworked by Power By Gerolomy (B.C. Gerolomy) Note the similarities of the two heads, but the P90 head having a larger combustion chamber will have a lower static compression ratio then the N42 head.

Porting and polishing the L series head is a good idea to maximize performance. Regardless of the application, performance or stock, if you are going to tear the engine down, I would highly recommend some work on the ports. Keep in mind that these improvements will only serve to produce a better running engine that will produce more power over a wider range of rpm's, the higher rpm ranges being one of the significant improvements.
The top ports were again completed by a builder out of Japan. The lower ports were completed by Gerolomy for my cylinder head. Looking at the two heads, one realizes the quality of work completed to both heads. I guess the old addage of right is right and wrong is wrong. I can see that these heads were done correctly.
My cylinder head flowed 161 CFM on the exhaust port, running a 1.450 Ferra stainless steel valve, and 213 on the intake valve with a 1.730"/44mm (or stock valve diameter) on the intake. Both valves were tested @ 25 inches of water on the flow bench. I also utilized the ISKY 7005 valve springs, ISKY retainers and locks. The valve guide seals are Viton for longer life. The flow numbers could have been improved by shortening the valve guides, and to go really radical a smaller valve stem. I wanted this head to run a good long time, so I kept the stock guide length and stock stem diameters. Again, the design for a full race head will be differnt than a cylinder head that will be run significantly longer on a street car.

Here are the few pictures I took of the cylinder head before I installed it on the engine. Nathan did a very nice job on the head. I was very pleased to see the precession and conformity of the port work completed. This head flows very well. You will notice the welding completed on the surface of the head. I thought the head looked good when I pulled it of the engine from the junk yard, but apparently there was some damage from the water run in the engine from the previous owner. Water is a killer for aluminum heads folks. Myself I dont run water in my engine, and although I have argued the point with a number of people, I run strait antifreeze for this very reason.

bottom end assembly

The bottom end of my engine is built like a tank! I wanted to make sure I was not going to throw a rod so I went almost all out on it. The rods are Crower parts. I called Brian Crower and ordered them direct from him. The rods are 5.350" long center to center. I also had them setup as free floating wrist pins. The wrist pins are a premium part and I had them made with a 22mm diameter, 1mm bigger then stock for more strength. The rod bolts are also Crower. According the Brian, that are stronger then ARP parts. The rod bolts are very important you will want to use the best parts you can get in this respect. The bolts need to be strong enough to stop the piston @ top dead center. All of the stress of the bolts are introduced at this time, so if you have a weak set of bolts you will end up stretching them, and it only takes a few thousands of stretch and your engine is done very quickly. Note also that I have main studs installed for the main journal caps. The studs are ARP, a much better part then a stock bolt, and for what $100.00 and some change worth every penny.

The crankshaft is the famious LD28 crank. I wanted the longer stroke to get some additional torque from the engine. Ideally I was looking into a SCAT crank, but I could not get them to do a oneoff crank for me. To bad, that would have been a nice addition to the build. The LD crank will have to do for this exercise LOL.

I have recently taken an engine apart and was surprised to find what I never thought I would see two times in my life. Take a look at the main bearing and note the wear in the center of the bearing. When I looked at that wear pattern, and noted it was similar on all of the main bearings and all of the rod bearings, I knew what was done to make the bearings wear the way they did, other then unclean assembly procedures. When I was still in high school, I started building a ford 302 engine. I wanted to get as much power as I could, so I bought a few books on the matter, and I got a few older books from my dad and read them. One thing that was mentioned was the bearing oiling. The one hot rod book described a modified journal oiling hole and how that would help oil the journals. So I took to the oiling holes with a jewelers file to get more oiling area for the bearings. Here is a few pictures of basically what I did and what happened to the bearings because of my "performance" modification. I did not do this modification on this crankshaft, but somebody did, and the results were the same as what I got. Note the oil hole on the crankshaft, they seem to have an elongated chamfer of the hole. That modification was not made at Nissan I can assure you. The additional chamfer has made the scratches on the bearing. Giving the builder the benefit of my doubts, lets just say this was completed to the carnk and then micro polished to make sure there were no burrs left after the procedure. The elongated oil hold has to much surface area with a very narrow width. The hole now became somewhat of a scraper on the bearing. The crank is now junk and the bearings are now junk. Word to the wise, Nissan did a very good job of chamfering the oil hole, and the only time I have heard of an engine throwing a rod is under dry oil conditions like in hard turning on a track, right Tony? LEAVE THE OILING HOLES ALONE!

Here is a picture of the top of the block. Note that you see head studs installed. The head studs are ARP parts. Again this is a very prudent part to use for high boost applications. You want to keep the cylinder head on the block and DONT want it lifting under boost because of bolt stretch. The studs will keep this under control. Believe it or not a stud will clamp much better then a bolt will. VERY VERY important to keep the head tight. When I torm my engine down from the first build, I noted that it appearde to have had a leak between cylinder 3 and 4. I inspected the gasket, and it would also appear I had a defective 1.0mm steel gasket, as I could not determine the head was lose on the block. I really wonder how much power that cost me????? A steel head gasket is manditory or oringing the block for longevity. I have heard of people running a felpro or stock gasket for high boost, they in fact dont last to long, but if that is your only choice, then go with the FelPro gasket as it is a better gesign then the stock Nissan gasket.

The pistons were made by JE pistons her locally in Huntington Beach CA. This piston is the high silicone content forged piston. I wanted to keep the tolerances tight for the piston to bore clearances so this was my choice. I have run this part in two engines. Looking at how they have been setup in my engine and the previus engine. I recommend to clearance the piston to .003 I have always clearanced them to .0025, that appears to be a little to tight, if the engine ever gets to hot, you will have some problems with piston expansion and damage the bore and piston. NOTE from the block picture the bore of my engine, see the scrape on the cylinder walls, that folks is from excessive piston expansion when I got the engine very hot driving home from my parents house up north of me. I could see the engine oil temp and water temp was excessive, but when you are out in the middle of the desert what do you do? Shut the engine down?? I was afraid to do that, so I opted to keep an eye on the temps and they did stabilize. I checked the bores with a gauge, and the worst spot in the bore was .0005, I dont get any blowby or leak down, but I sure wish I would have set the clearances to .003 and avoided this situation in the first place. To correct this problem the bores would need to be opened up .0005 more and since the rings were seated, a new set of rings installed. Live and learn folks, like my Aunt always said, if one cant listen, then one can feel. NOTE the width of the wear, all the cylinders look the same, that indicates a very close tolerance of the hone done on the cylinders. Dave Robello instaled the pistons, bored and honed the block. VERY nice hone work, very close tolerance, maybe that is why he does so many engines.

Damper bolts

Here from left to right:

The oil flinger, LOSE IT! That part is useless in the engine; the part is designed in "theory" to keep the oil in the engine thrown back at the timing chain. There is ample oiling of the timing chain without this part. However, what this part will do for you is to aid in the loosening of the crankshaft damper. Think of it as putting a flat washer in-between two mating surfaces that require torque to hold the parts in place. What this part does is to compress slightly and provides a way for the inertia of the damper to create a stress area that will grind itself open. The part will end up in the bottom of your oil pan in flakes. If your damper does come lose, the part will disintegrate and end up making its way through your oiling system, no Fram filter will keep the particulates from reaching your bearings, and all of the places you REALLY don't want them to go.

Second to left:

This is the stock crank bolt and washer utilized in all of the Nissan L series engines. I have taken pictures of the washer and you will notice that the washer is not flat on the crankshaft/damper mating surface. This picture is difficult to see the bend in the washer. When the Nissan FSM indicates a specific torque setting for the bolt, I recommend that you DONT exceed this torque specification, or you will end up bending the washer. What you will do in effect is to clamp the washer and torque it to the end of the crankshaft snout. The damper, which is the primary issue for the bolt and washer in the first place, will have little or no torque applied to the damper. You will end up destroying the crankshaft keyway, the damper and the woodruff key. Then the bolt will loosen up and you will lose your damper if not caught in the early stages.

Third from the left:

This is the NISMO Euro damper bolt and washer kit. This bolt and washer will cost you 40.00 dollars. The bolt and washer will work for the standard damper, however, you will need to check the clearance of the step locator to ensure it doesn't again torque the washer and not apply that torque to the damper mating surface. The bolt will thread approximately 5-6 threads into the crankshaft. The part will torque to specifications, but you will run the risk of pulling the threads if you torque the bolt to tight. I would not recommend anything over 130 foot pounds, which is over the stock maximum torque specifications, especially if you have to install and remove the damper a number of times.

Right side:

Here is the setup I have developed. This utilizes a Nissan bolt PART# 12309-29500 bolt. You can see it is long enough to thread into the crankshaft a more then an ample amount. In fact, the bolt is to long, the bolt will need to be machined and shortened by about .250" when utilized with the Volvo washer. The bolt should be lengthened to screw into the crankshaft approximately the width of the bolt minumium or 125% times the width of the bolt, or 16mm plus 4mm. This setup will enable you to torque the bolt and washer to 150psi. I will say this: Make SURE the bolt doesn't bottom out in the threads of the crank. If it does, you are NOT going to like the results, and if you dont end up stripping the threads in the crank, get yourself a 16mm X 1.25 pitch tap to dress up the threads. I wonder how I know this??? never mind.
The washer is a Volvo B230 damper bolt, part# 1336822 off of a 1989 740 Volvo. I have looked at a number of different volvo cars, and as long as you stay with the B200/B230 four cylinder engines, you will have the same part. You will need to machine the O.D of the washer to 1,730" and that will do just fine for all Nissan l series engines. This setup is the ideal configuration for ANY L engine configuration, yes EVEN the stroker that everyone thinks for some reason has more problems holding this part to the crank. Really there is NO difference between any of the engines in this respect, but it sounds good to guys that don't understand cintrifugal force, and rotating mass.
I recommend using "RED" lock tight on this part as it will aid in lube to the threads when torquing the bolt and secure the threads when it dries.

Flywheel Bolts

Here is a comparison of the stock Nissan bolt to an ARP bolt. Looking at the two parts, one can easily see the advantages of the Nissan part over the ARP part. The Nissan bolt has a flare-mating surface that promotes a self-locking characteristic. The flare-mating surface also has a significant holding surface as compared to the ARP part. I have torqued the Nissan art to 160 foot-pounds with no ill effects. Nissan L series engines NOT having a counter balanced crankshaft have a tendency to vibrate the flywheel bolt lose, as you can imagine, this would have disastrous effects on the engine and tranny. What do you think Norm? I will say one thing, having a flywheel come lose, and clutch assembly, at best will damage the tranny, at worst the flywheel will saw through the body of the car and who knows where else. Don Garlets lost part of his foot because of a flywheel coming lose. I myself don�t want to experience that. The ARP part has little for a mounting and securing base to the part. This bolt may be used on a steel flywheel, but an aluminum part will not work to well. Because of the mating surface area, the ARP part will have a tendency to gall or tear the flywheel mating surface, or worse the bolt. Keep in mind, ARP has no specifications that I know of for application other then stock, so if you use these parts on your Nissan and they create a failure, consider yourself out of luck. You will get NOWHERE with ARP because it is not the recommended, or listed use of the bolt in the first place. Just keep that in mind guys.

Here is a side profile of the stock nissan bolts. You can see there are some differences in the bolts. The center bolt has been modified on the head of the bolt. Some people have had, myself included, had problems with the bolt hitting the clutch disc hub assembley, specifically in the spring area. The fix for this problem is to machine off the step on the top of the bolt. You can see the actual bolt head has a lip that really does nothing for the bolt and really doesn't do anything to aid in torqueing the bolt down as it is rounded.

Here is the top view of the stock and machined part. You can see just enough of the top was machined to just kiss the lettering of the bolt, but not really cut into the bolt head to make it any weaker at all. Note the bolt on the left, you can see one of the two hash marks in the lip,they are a little hard to see, I could not get a really good angle on the hash marks, courtesy of CenterForce PLUG and PRAY clutch assemblies built and sold to the public at large LOL.
This was my FIRST experience with the CenterForce product, and I was not to impressed. I sent the clutch and whole assembly, flywheel, bolt and all, back to CenterForce for them to, GET THIS, "evaluate". When I talked to them on the phone about the problem, they, LIKE MSD DID, tried to come up with an explination that indicated my setup or flywheel was at fault. NO GO GUYS! So I got to pay for the shipping out there to their facility, so that they could make the approperate changes to their equipment, ALL at my cost! I thought that was a bunch of shit to be honest. (Disclaimer: This is my webpage and I will talk the way I want to!) So when I got the assembly back, and they were so nice to pick up the shipping this time, I already had my flywheel bolts modified. Lets just say I WAS NOT IMPRESSED with their customer service, and in the end their product all together. That piece of shit died on the dyno @ 380 foot pounds of torque, so much for the 90% holding force OVER the stock clutch, YEA RIGHT, they, LIKE MSD, are done! Market their crap on a pretext, and when you need it to do what they claim, it falls right on it's ass. Pisses me off, another tranny pull that time just to junk their CRAP. So if any of you CenterForce guys read this,,,, TOUGH SHIT, and again I refer you to my disclaimer!
NOTE:
You should use RED lock tight when torquing the blot. The lock tight will act as a lube to the threads, and when it dries, will hold the bolt in place so that it will not loosen itself while running the engine at high rpm levels. Also ensure there is NO oil, dirt, old lock tight, or any foreign substance, fod, debris, of any kind on the bolt, crankshaft end, or the flywheel when you assemble the parts.

The engine

Timing Sprocket/Assembly