Crank Pulley for A/C

[Datfish]

I want to add a/c to my L16...I have a bracket on my block with an idler that was apparently for the York style compressor I assume, but I need to know what I can use to drive my eventual compressor from the crank.

My L16 single groove pulley has a crack anyway in the snout where seal rides..from a PO letting the timing chain go until a piece of guide broke off and fell to the bottom of the cover, causing a bit of a bind I assume. I replaced the timing set with OE but since I'm rebuilding engine and hoping for a/c...here I am. Need a new solution going forward.

I see Sanden clones with vbelt options and York-to-Sanden conversion brackets..so I can adapt a vbelt/early style pulley I hope?

I guess my question is which 2-groove crank pulleys have the same ID as a 73 L16? L20 will work? L28?

I searched...some

[Draker]

Yes, they will fit. Not sure about L28, but probably.

[Seeker > 620 KC]

The 78-79 620 pickups with Nissan factory AC had a balancer pulley with an additional bolt on 3rf pulley. That way it had its own drive belt.

But it also had to use a specific 8 blade clutch fan (5"+ bolt patter) similar to a 720 fan, but it had to be offset further toward the radiator to avoid hitting the crank drive pulley.

 

It's late but I'll get you a pic tomorrow. If the timing indicator and crank pulley marks match maybe that would work if you could find an AC truck.

[Seeker > 620 KC]

There is a guy coming to the ER swap meet that cut down the orig 620 cast iron York comp bracket, then adapted a modern rotary compressor to it. He only had a bolt or two holding the compressor on, but with the roatary compressor there is far less vibration on the mount vs the York compressor. Tried to get pics last time but didn't turn out very good. will try again next Sunday.

[Datfish]

Oooh...forgot about the timing marks...hmmm

I want air, damnit.

[yenpit]

The timing cover SEAL is the same for all of the L-series L16 L18 L20B L24 L26 L28 including the ZX, so the OD of the pulley/dampners are the same. Sounds like seeker>620kc already knows that the "depth" of the various pulley combinations is critical in relation to clearance for the fan blade, makes sense!  We are in the middle of a 240Z resto, customer wants to retain the AC, so we have compared a number of crank pulleys.........the Z however, uses a crankshaft dampner pulley, 2pc with vulcanized rubber in between, to externally counterweight the much longer 6cyl crank........the 4cyl's had a much simpler stamped steel crank pulley.  I bet you can use a 2 row 4cyl crank pulley, 2nd row was originally for the emission air pump OR the dealer installed AC.  I have a couple of 2 row 4cyl pulleys available in my stash, so let me know if you need one.....we can do some measurements, timing marks etc.  Does the AC belt idler unbolt from a bracket......does that bolt come out......can you space the idler in or out to match the crank pulley??

 

TJ 

[Seeker > 620 KC]

http://static.carpartsmanual.com/datsun/pickup-1972-1979/large/620-091C-01.jpg

 

The 620 AC idler pulley was the most stupid design idea Nissan ever had. The base was a steel plate bracket that bolted to the front of the head and took the place of the timing chain inspection cover. Then the belt tension adjuster pulley bolted to an adjustment slot. Ii don't recall if aligned with the third groove on the crank pulley or the second one, and the smog pump used the third. It's too late and I'm already crashing, sorry.

 

You might want to research the AC diagrams for the L20b motors for the 510, 200sx or other models for a simpler idler/adjustment pulley.

 

I'm a later KC truck guy. From the link above it looks like the earlier 620 models used the single groove crank pulley, with the bolt on pulley. It doesn't show the belt set up in this diagram.

[yenpit]

Woah, have never seen that style of AC idler on an L-series!!  I bet you could use 510 or Z-car parts, but would involve some engineering ingenuity on your part.  I have misc pieces, but I do not have ALL of the 510 parts, same for the 6cyl.  One thing I did check recently was the bolt pattern for the big York compressor bracket L20B 4cyl vs L28 6cyl.  The bolt pattern was the same, BUT the location of that 4-bolt pattern was different between the two......both drivers side front of block, but not same exact location!  That means that if you bolted an L28 bracket on a 4cyl or vice versa, you WOULD have to re-engineer whatever idler pulley & bracket you have.  NOT impossible by any means, just very likely NOT a bolt up easy peasy job!

 

TJ

[yenpit]

Just looked at that link picture.........was the AC compressor up high on the passenger side of the 620?  Some (if not all) of the dealer installed AC kits on the 240Z had the compressor up there too, but not an ideal location!  We are installing a late model Sanden on a 240Z resto, BUT we are using the later 280Z compressor bracket that locates it down low drivers side of block.  If you look at your block (any L-series 4cyl or 6cyl), you should see a distinct 4-bolt pattern. 

 

I am happy to take pics, but I simply don't like hosting & posting pics here on Ratsun..........too much of a pain dealing with any of the hosting sites!  PM me an email or text #, more than happy to send!

 

TJ

[Seeker > 620 KC]

Yes. The vibration monster York compressor didn't mount high on the pass side. The mech fuel pump had to be removed, and install an electric one back at the tank.

 

Then that hideous cast iron mount bracket had bolts of all dia, with an attachment point down low on the block, another by the head, another bolting to the idler bracket, utilized one of the timing chain inspection cover bolts...absolutely ugly, stupid, and heavy. I haven't weighed my bracket, but I'd guess 20-30 lbs,

 

If you have an early model 620 and aren't required to have a smog pump like Datfish it is much easier to mount a compressor down low on the driver side. Nissan made a bracket for the 720 on that side. Not sure how the belts line up. A guy in Riverside found an aftermarket AC Sanden bracket and was able to adapt it for a new small rotary compressor. He didn't even use an idler pulley, as the compressor swung out to tighten the belt. He had to buy a really short belt as he only had about 3/8" before it would hit either the steering box or frame, can't remember which.

 

If Datfish comes to Eagle Rock swap meet this Sunday in Eagle Rock and look me up, I can show you a couple 620's with working AC and introduce you to the owners to see what they sourced to make it happen and how the ran the belts. One of em is a chop-top done in the 80's. Pics are difficult as it is a tight fit under the hood. Bring a bright flash light. PM me your ph number and We can meet up and look em over.

[Seeker > 620 KC]

Also, be sure your cooling system is really strong before you add AC. AC on a 4 cyl can quickly kill a tired motor with a 35 year old head gasket!

 

Be sure Rad is clean and pressure tested, no leaks. Orig Nissan AC used an 8 blade (not stock 7 blade) clutch fan with a larger dia water pump shaft, and a fan shroud. Be sure your thermostat is working well, all cooling hose rubber is good. Rebuild your heater control valve to ensure the AC isn't fighting a stuck on heater. Check your freeze plugs are not on the verge of rusting thru. I was able to remove all mine with engine block still in truck and install new affordable brass ones from Rock Auto. Only have the one behind the exhaust left to go. Drove it in once, but gave that one extra whack with a hammer and a 36 inch 3/8 drive extension and it went in too far. Had to pull it out, and I distorted it. Try try again.

[Seeker > 620 KC]

Correction: York compressor DID mount high on Pass side of L20B