Help Identify 2 L engine camshafts

[kgrantkey]

One came from anL20B the other came from an L18 aquired when I bought a 620 truck as junk to salvage. I've discussed the salvaged truck before.....bought it for the hood and was told the engine was bad, Decided to pull it and found it to be a newly rebuilt L18 bored with new pistons and other new parts but whoever put it together let the timming chain tensioner push out of its bore sometime during installation.

 

I think they are both L20b camshafts. I;ve included a couple of pictures of each cam labled A abd B,

 

They both have the square pegs in the center which I believe I read indicates an L20B cam.  I'm no good with micrometers so I'm asking for a qualifird opinion with the partial photos attached.

 

Those three pictures are of cam A

 

 

 

 

The last three are of cam B.

 

 

Did I get too close?  They both have markings on them, thats why I got so close up.  One cam is still in its tower bolted to the head. The other is on the workbench with the cam towers just attached around the cam so they don;t get mixed up.

 

By the way the cam on the head has each cam tower stamped 1 thru 4. Looks factory stamped but who knows.

[datzenmike]

U20 is for L20B. Seen that on the cranks too. Possibly it's been reground but can't tell much by looking.

[banzai510(hainz)]

the CWC is a aftermarket casting(cam). Look in back of the cam for a number or manufacture.

 

My Schneider has a CWC marking on it.

 

get a mic and measure it then rotate it 90degs and subtract the number

 

 

hopefully you put the same rocker arm back in the same spot!!!!!!!!!!!!!!!!!!

[kgrantkey]

Thanks for the response.  Its almost too cold in the shop to mess with the engine but I may get the mics out and see if I;m still inept with them. My stepdad used them many years ago. I've had them for over ten years now without ever having any luck with them. The calipers he left me have been more easy to use but not accurate enough for some things .

 

 

hopefully you put the same rocker arm back in the same spot

That would be a no on the two cams in question. I cant even find all the rocker arms for both cam-head combinations. I did keep the cam towers identified and could always go back to the original head, a w58 that is complete with the 3rd cam still attached. I;m gonna use this U67 head even if I regrett it. I just put 4 heli coils in it and played around with the grinder polisher for too long to put it back in the corner for 5 more years. 

[datsunaholic]

U20 isn't always L20B cams.  My mom's '73 came stock, factory with a U20 cam in its L16, and I've had U20 cams in most L18s I've seen (with one older A87 casting I think).  U20 is just the casting number for the cam blank (there were several) but the actual grind on the cam differed based on what they were going to.  Some of the earlier casting cams don't have the wrench block in the middle, which simply indicated an earlier cam blank.  The grind is what's important, not the casting number.  The CWC cam is, as stated above, an aftermarket cam.  Could be a mild performance or RV grind, or could be a factory-spec grind with a new blank.  If non-stock, there would usually be numbers, or something, stamped on the back of the cam.

 

 Most U20 cams I've seen have a letter stamped on the very back of the cam:

 

 

 

That was on a professionally overhauled engine (hence the paint marks and the tower shims), but I've seen letters (A, B, C) stamped on most factory cams.  On L20Bs, the B has been the most common I've seen.

[kgrantkey]

 

Thanks Datsonaholic. 

 

The CWC cam is, as stated above, an aftermarket cam.  Could be a mild performance or RV grind, or could be a factory-spec grind with a new blank.  If non-stock, there would usually be numbers, or something, stamped on the back of the cam.

 Most U20 cams I've seen have a letter stamped on the very back of the cam:

That was on a professionally overhauled engine (hence the paint marks and the tower shims), but I've seen letters (A, B, C) stamped on most factory cams.  On L20Bs, the B has been the most common I've seen.

 

 

 

 

The cam Ive got attached to the U67  came from the junkyard  620 I bought for the hood.  I really wish I had kept that entire head and cam attached, but I took their word it was junked due to a bad motor. It only became obvious the motor had just been rebuilt after pulling it apart. Everything in it looked brand new including the cam tensioner that was in the oil pan. I just had the pistons from it pressed onto my L20b's rods by the shop that bored it to use the pistons that came out of it. It's easy to tell the cam had no wear on it and the roker arms didn't look like they had any wear either. I can say for sure the lift on the exhaust lobe isn't as tall as the L20b cam. If I had to guess I'd say it's reground for a stock l18. That;s what the motor turned out to be.  I probably will go with my old cam but when I took it out I discovered the dowl pin hole had btoken worse than I remember kast time I had it out!

 

Call this cam C I guess but It has less obvious wear than the other L20B cam that is in the 1st post.

 

 

I have still been running this cam. In the past I'd use a screw or something to help align the sprocket before I tighten her up.  I never had it cause trouble but it's an area of concern. It used to just be a hole.

[ggzilla]

U20 is the Applied Model Code for 1972 Datsun 610 (the 610 began manufacturing in Japan in 1972). Applied Model Code is not a unique ID mark - in this exsmple the same U20 casting was later used on different engines and with different machining.