L20b u67 head

[banzai510(hainz)]

replacing the tensioner and slack side guide is most lkely need of replacement than the chain.

[8m0untainman8]

Aye, its on the second mark, and the notch on the sprocket is just to the left of the notch on the cam, it was timed based on what the chiltons manual said. I believe that indicates slack if i remember correctly, but it doesnt seem too bad, unless my truck could be a whole hell of a lot better than i know. Haha

Chiltons manual was saying something about how the third mark isnt really applicable to the trucks. It didn't say why, it just said the third mark was used in cars, or on larger l series motors i believe. I might have my facts twisted as i was reading all over the manual.

[8m0untainman8]

Not digging into it again right now, it doesnt leak,

One thing i did notice though, with a 180º thermostat my truck runs the temp gauge at about 3/4 up the gauge. there was a little coolant inder the truck when i parked, but all fluids are clean now. It looked like it came out of overflow

[wayno]

I heard #3 was for Z cars.

[datzenmike]

The L20B all came from the factory on the second hole so you are good and have one more hole still.

 

 

Install a coolant recovery rad cap from a '79 and run that hose into a container half full and you won't have those wet  spots nor will you need to top up the rad every 3 weeks.

 

Anywhere in the 'run range' is ok. I like about 1/2 but now have electric fans that come on about 3/4.  If you think you are running slightly warm check that you..

 

 

Have a fan shroud

That the clutch fan is firm to turn by hand and not able to spin freely

The rad is not obstructed by dirt and bugs

The lower rad hose is not soft and collapsing from pump suction when revved up

That the heater hoses are joined to by-pass the core.

The fan belt is in good shape and properly tensioned.

The rad support does not allow air to penetrate around the rad through any gaps

[Stoffregen Motorsports]

All this discussion about which cam gear dowel pin hole to use is making one huge assumption, that the original cam gear is being used. Some aftermarket L series timing sets come with gears that look suspiciously like Z series cam gears, which had different cam timing settings. L6 engines had different cam timing settings as well. And then you have to keep in mind that these old engines have more than likely been apart at some point in their life, parts swapped over from other engines, or built from a pile of spare parts.

 

What I'm saying is that the only way to really know what your cam timing is set at is to check it with a dial indicator.

 

Chain stretch is not something I worry too much about. Datsun timing chains are tough as nails.

[datzenmike]

The L and Z series cam sprockets look suspiciously the same because they are the same.

 

L16/18 L20B, L24, L26, L28, L24E, 280zx, 810 and Maxima, Z20/22/24 all use the same sprocket. Even the LD28 Maxima diesel use the same sprocket.

[distributorguy]

Its true.  Look at aftermarket offerings and they all share the same part numbers, which is good.  It allows us 4 cylinder guys to get performance goodies like the Z guys use.  The only problem I found was that the adjustable (8 hole) cam sprocket didn't have a single usable setting that worked in my race motor.  I had to go nearly to the far end of adjustment on an adjustable cam sprocket, but again - it was designed for the 6 cylinder motors, so I'm grateful they are shared parts.  

[Stoffregen Motorsports]

Unless all the OEM offerings had the same part number, I can't agree that they were all the same. Often times I would be shooting for a cam timing number that I couldn't achieve with one cam sprocket. I'd then go through the others until I could get the right cam timing.

 

So in practice, they are not all the same.

[distributorguy]

No, I can verify that parts which SHOULD be the same are not.  That bit of wisdom goes from cam sprockets to brake drums.  Not all parts are created equal, but the cam sprockets are Supposed to be the same across the board.  

[datzenmike]

I checked. Same Nissan part number.

[Stoffregen Motorsports]

Obviously variances during machining.

 

But that's not my ultimate point. Cam timing should really be checked.

[distributorguy]

Degree wheels are one of the most important engine building tools!!!  Agreed.  Checking to see if a notch lines up in a hole is silly.  They're all untrustworthy reference points - especially on a motor you know has been apart prior to your service.  I have 4 different cam pulleys in a bin here that are all supposed to be the same part number...???