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Datsun 2000 Cam Info÷

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Keep in mind these profile numbers are just for comparing the cams to each other; every manufacturer and cam grinder uses different points in the cycle to take the measurements and they can be listed at almost whatever they want them to be with the same cam. Some of this is advertising nonsense; so when looking at cams for any car; make sure you are comparing apples to apples. Even Nissan's published specs are sometimes all over the place. I would think Nissan would be consistent in their methods and in the cam design but I've seen multiple specs; especially for the "C" cam. I think everyone of the old "Comp" catalogs were different!

Historically cam specs were advertising figures; like horsepower that was based on the THEORETICAL amount generated by the explosion in say 8 cylinders and didn't include drag from main bearings etc!; or having to move the crankshaft mass around and around. Engine HP/Torque means nothing unless it is measured with a chassis dynamometer with a street exhaust and street air cleaner system in place.

Such is the situation with cam measurements. I can look at you (but not with a straight face) and tell you a standard "SU" grind has 330 degrees of duration. It would be "true"; but at what point in the cycle is this measurement being taken?

Then my advertising copy would continue; BUT GO WITH THE SOLEX CAM it has 360 degrees! Again; at what point? And is that exhaust, intake, both. The figures use in the 50s and 60s were the GROSSEST of numbers.

Some of the more thoughtful cam grinders and engine builders use a figure "at .050 lift" to measure duration; which is what we are doing; and we have used a cam profiler machine to show this on the "stock" cams for comparison. Definitely not as flashy a number bu t more accurate; since adding on the clearance ramp on to duration is usually thought of as a joke to engine builders anyway...

Same with valve lift. Stated figures are THEORETICAL lift; or GROSS lift; or WHITE CLOUDS on BLUE SKY lift. They do not account for valve lash; they attempt to account for a rocker arm ratio which may or not be in play with any particular rocker arm at any given time in the cycle or with any given valve/lashpad/head.

Better in comparing camshafts is using LOBE LIFT (CAM LIFT); that is what the lobe rise is over the base circle (what is there if all the lobes were removed).

So with the above discussion on bogus specs in place; we have:

There were two cams in the production cars the "SU" or "A" cam (256 duration .44 lift); and the "Solex" or "B" cam (280 duration .46 lift). The names indicate the type of carburetor the two cams went with. You can use the Solex cam on the SU cars; it moves the power band a bit uphill and increases it a bit; with only a small loss at the lower rpms. Using the SU cam with the Solex carbs; you get the worst of both worlds. No bottom end and no top end.

Datsun Competition (Nissan Motorsports) also sold a third flavor; the "Solex II" cam also called the "C" (296 duration .48 lift). The letter designations come from the marking on the end of the camshaft. You have to use a small mirror to see it with the cam mounted on the cylinder head as it is right up against the cowl/firewall of the car.

Without throwing the cam in a cam profiler you can't tell exactly WHAT you have but there are some hints. The above mentioned "A", "B","C" can help but only shows what the cam STARTED OUT AS. If the base circle (diameter of the cam 90 degrees from the lobe) is still about normal (1.305 give or take a hair) you can check the overhall height. Stock SU cam will read 1.620-1.625; stock "B" Solex will read 1.636-1.640 at least that is what we are reading after checking a large number of them; even new ones.

Printed Nissan specs say the lobe lift is .315 SU and .327 SOLEX which are WRONG; checking numerous cams proves this. A production change? No, because the equally old drawing of the OEM camshaft shows .328" SU and .340" SOLEX which would make the measurements 1.628 SU and 1.640 Solex for IDing unmarked cams; adding the assumed base circle of 1.300; or 1.633 and 1.645 with a 1.305 base circle. The lower figures may be an attempt at figuring in the loss due to the lash settings; but it still isn't correct; but the wide range we have seen "stock" SU and SOLEX cams read makes anything a guess. When we have these recut we have the cam grinder follow the original pattern that was cut into the cam. This reduces changes that could occur to base circles or having to actually weld a lobe to cut it as if the original specs were cut in stone and followed accurately to begin with. Again; these figures are just for comparing cam profiiles. Seeing how these cams vary; you can have two "identical" cams that have varying duration measured at .050" and then at a higher or lower measuring spot the cam that was "lower" shows higher; as if the shapes of the lobes vary as well.

As mentioned earlier even on new cams the base circle varies; why I don't know; but a took a batch of new Nissan cams for a date with a cam profiiling machine and got some interesting results! The 1.305 figure seems about the a third of the cams. I think it is all production variances. And the lobe lift I think varies as those figures .328/.340 may not include any polishing necessary or maybe changes due to hardening??? Or just machine tolerances. Nissan's pubs show 33mm as the diameter (1.300). The 1.305 I think is just how the machinery and cutting procedures sometimes have worked out. I've also seen a USED cam at 1.310! (Remember; lobe lift times rocker arm ratio; typically about 1.4; gives the lift at the valve; well the "gross" lift anyway; which is "supposed" to be .44" on the SU and ".46" on the Solex cams.

And keep in mind it is about impossible to accurately measure cams with a micrometer; I think max lift isn't at TDC on the lobe! A cam profiler is the best way or setting up a dial indicator and an old school V-block jib. Engine builders would most likely measure the activity at the end of the rocker arm or at the valve head. Those talented fellows make me wish I'd paid more attention when I was gifted with being able to work or learn under some of them. In My Next Life, FOR SURE.


We have no idea what kind of stress a used or reground cam has been under previously. Camshafts do not crack from old age; they crack from being run in a head with misaligned towers or a warped head where the top was not restored for proper cam operation (i.e. being able to spin the cam with two fingers when it is torqued down, oiled, WITHOUT rockers.


The only way around this is to buy a new cam; including having a new SOLEX cam cut into a SU profile; or make sure your head is completely correct and take the gamble. It isn't a common thing; it isn't like people are coming to us everyday for camshafts for this reason.

These are just used cams we have not taken to the cam grinder. We do not though sell used cams that have chips out of them or other lobe damage or bearing journal damage visible to a non-cam machinist; other than small scratches that many times can be polished out. Technically speaking you should always use a used cam with its previously run rockers; in the exact positions they were in; but it is rarely possible unless we have recently pulled the head apart ourselves and saved it specifically for that purpose.

Changing the cam means changing rockers if you want it to live; as does proper break in and lube during break-in. There is little point to using a reground cam (or new cam) with old rockers. They all "look smooth" but they will imprint themselves on a new or reground cam immediately.

If you are looking for a Solex cam; reground Solex cams where the original was also the Solex grind are best; but more expensive as the Solex cam itself has always been more expensive. The base circle is always less disturbed the closer the regind profile is to the original. This can of course be dealt with (read on) and doesn't much matter if you're looking for the Solex grind for less $$.

In addition to our own contracted work; we have many cams that came from all over the country. All we can do with those is spec them out so everyone can see what's what. Every cam grinder is different in how they go about their business.

Changes to the relationship between your cam and valves; known as "CAM GEOMETRY" can occur when using a reground cam; although with a careful cam grinder and staying close to the original grind this isn't usually a problem. (like these stock grinds) Many other problem areas (your head may already have these) can cause far worse changes. Link following for more info: CAM GEOMETRY LINK

Having a cam live also depends your rockers; if they have run with another cam they can increase wear in certain spots; if they are the old style 1-piece rockers those can trash a cam as well. Look at them form the side; does the area (wear pad) that contacts the cam look like it has been welded on to the "arm" part of the rocker arm. IT SHOULD. Nissan changed these in mid-69 at engine U20-11849.

Running with improper strength springs will also trash a cam. Unless you are absolutely sure your springs are Nissan springs or built for this engine by intelligent sources; ask your shop to check springs at full lift; so you don't have a case of the springs "stacking" i.e. the springs can't stand that much compression and one coil is hitting the next. Instantaneous cam failure is the result. At full lift there should still be .060 or more clearance between the coils. And although the rated pressure of a spring can be correct; it is usually only correct for a stated design; i.e. valve lift. When forced to go farther; even though it may allow it and not "coil stack" the pressure may increase dramatically. Fantastic valve lifts sound impressive but stay away from this unless you have a head shop in your back pocket that is on top of all of this and has the knowledge and availability to select alternate springs if necessary. In combination with custom springs; the valve stem locks (collets) can be altered as well to raise the height up and to allow for higher lifts (somewhere around .5". I think the Bob Sharp manual recommends collets made by Allied #117.

I've never been a fan of any "wild" grinds for these engines as SO MANY of them are running around with the heads milled (so the valves are closer to the piston) but more importantly and more to the result of valve-to-piston conflicts; the valve timing is off. Shimming the upper tensioner may make you feel good about chain rattle but it does nothing to correct valve timing problems from a loose chain or milled head. Most shops will say .100" clearance is necessary between the piston top and valve. Some shops say .125" on the exhaust valves. In some cases to make everything live together the pistons will have to be flycut for clearance if you can't/won't fix the underlying problem. Again; a good head shop can be your savior.

Before starting an engine that has sat or is having a cam change; remove the distributor and the oil pump/distributor drive gear and spin the pump with a long screwdriver between your palms or use a reversible drill running counter clockwise until oil is pumped through the system. Take note that the oil is able to come out of ALL the cam lobes. When the little oil pump driveshaft is removed take note (or a picture!) of it before removal. The slot in it is not in the center; so note how that looks and keep in mind that to get it out you have to twist it and it will spiral out. The picture in the factory shop book wasn't taken if I remember right at top dead center of #1 piston so it is useless. You have to kind of make your own "repair file" as you go along with these cars... And don't forget the break-in procedures your cam provider has given you.

One of the oil pressure loss factors we tripped over decades ago was when we encountered a car with no plugs in the end of the camshaft. After the oil passage way is drilled in a cam, crankshaft, many other items; they plug the end so the oil just doesn't exit out; losing whatever precious pressure there was. Nissan used to provide the plugs WITH the cam but not IN the cam. Many of these did not get installed. So always check yours. We of course check them here but it is always a good thing to check. Using a tiny screwdriver or long nail; you shouldn't be able to push it in farther than the center of the end journal. We have those listed on the 2000 CYLINDER HEAD "SMALL PARTS" page in the NEW PARTS sections of the website; as well as the plugs for the head if you are missing one and a bunch of other tiny parts that can go bouncing off your workbench...


The "SU" cam will be stamped with an "A", the "Solex" cam will be stamped with a "B".

NOTE: If you have broken a cam, it is typically due to the towers being out of alignment; the camshaft is not usually at fault. This could be caused by past head warpage not being repaired properly; or from removing the towers and slapping them back on. Things are not always as easy as they would appear!

Rockers should be changed when cam is changed.

Cam should be checked for binding in towers (misaligned towers, warped head). With rockers out, chain off, journals oiled, caps tightened, shaft should spin with finger and thumb. This ability to turn freely should not change when head is torqued down. If you are ordering a camshaft because your old one broke in the middle, it wasn't because the cam was "bad" and it isn't the end of your trail. It broke because it has been run in a head that has been bending it back and forth every time it rotates. Your head needs work, or a new cam will also break. Camshafts carry no warranty whatsoever against breaking as they don't break on their own. Check it out with your machinist or head specialist.

Ensure that both ends of camshaft have plugs installed, but not installed so deep that end journals' oilways are blocked. To check with cam in car, use long hairpin or nail, you shouldn't be able to shove something farther inward than the center of the outermost bearing journals.

You can check oil flow by removing rockers, distributor and distributor drive shaft. Insert long screwdriver in oil pump slot and spin screwdriver counterclockwise with palms of hands. You should be able to pump oil out all 8 cam oil holes. (a reversible drill makes it a bit easier to spin oil pump) No oil should come out either end of camshaft. This should be done before your new cam and rockers see life; just before engine is started.

Appropriate cam lube should be applied and break-in procedures followed. There is so much disagreement (or at least "alternate opinions") do some research; talk to engine builders that do a lot of overhead cam engines. There is a ton of stuff on the internet but what is the current "truth"? I don't know... Make sure you look for overhead cam info has break-in procedures for an internal flat tappet cams like the 1600 are completely different.



Core charges are a charge added to the parts cost which is refundable when we receive your old part within 30 days. This is most commonly seen on rebuilt starters and alternators, but can apply to any part new, used or rebuilt. A core charge if applicable will be listed below the part's price.

If your rebuildable old part is sent in with the order, there is no core charge. Core charges are refundable if we receive an assembled, complete and rebuildable part back within 30 days of the date we shipped the replacement part to you.

0-30 days the core has it's *full value if it meets the other requirements outlined below.

30-60 days the core has 50% of its value if it meets the other requirements outlined below.

60-90 days the core has 25% of its value if it meets the other requirements outlined below.

* If originally paid for with a charge card; "full" value means 96.5% of amount paid; since that is all we receive from your credit card.

At ninety days from the ship date of your order the item has no core value. If you want the item returned you can send a check for the original shipping amount and we can return it.

Cores have to be returned to us prepaid. They don't have to be clean but they can't be dripping oil or antifreeze either.

A copy of the invoice needs to be included with the shipment.

Refunds will be in the same manner as you paid us; so we will need the credit card information again less the 3 digit security code.

The invoice number or core slip number (if we provided) must be in plain view on the outside of the box; otherwise it will sit outside in the will call box until you know what freezes over or until you contact us wondering about it.

Cores have to be in rebuildable condition. (Our determination) Please inquire if you are unsure whether your old part is acceptable as a core.

Yes we didn't used to have this policy but after finally realizing that we were kind of being used as a dumping ground and let our core pile shrink we have added these restrictions. Either that or no more rebuilt parts in the future.

Following are some examples of non returnable cores. This is not intended to be a complete list of parts or parts conditions that can affect value of core.

Basically anything other than normal wear.

Camshafts with keyways damaged, some non-original cam grind profiles, stripped threads, broken gear teeth, spun journals. There is a $21 charge for each excessively damaged lobe. U20 cams with any base circle smaller than 1.280" are ineligible as a core except cams with at least one base circle 1.260-1.279 eligible for half credit. An "SU" U20 cam ("A") is not an acceptable core for a "Solex" cam ("B").

Cam Followers (2000 Rocker Arms) that are the old 1 piece type are not an acceptable core (look at the pad from the side and you can see if it is two pieces; rockers that have been repaired before are not acceptable as cores.



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