Sons first car. 521

[TJ H]

Only Nissan I’ve owed is a R33 GTR while stationed in Japan. Son was getting close to 16 and I asked him what he wanted. His response was an old school mini truck. Found the 521 on Craigslist while camping in Okinawa and contacted the seller. Worked out a deal and picked it up when we moved to California in July 2018. Freshly back from deployment and stroking on this thing to have it ready by his birthday. Just saying hi as a new member. 

 

1971 521, L20b, 5sp, Weber 32/36 on and offenhauser intake, custom Schneider cam, disc brakes, 2.25 stainless exhaust with a flow master, nardi wheel we picked up in Japan. Had to buy a parts truck to get a decent hood, door and tailgate. 

[datzenmike]

521 owners will be clamoring for pictures. Better get some up quick. Welcome to Ratsun.

[thisismatt]

521 owner here.  Pics?

[mrbigtanker]

I want them now.

[TJ H]

I tried to ad them initially but would only allow from an existing or URL. What’s the process? Photobucket?

[datzenmike]

11 minutes ago, TJ H said:

 Photobucket?

 

God no, anything but PB.

[TJ H]

I read the sticky. Imagine that. 

 

[mrbigtanker]

All right. Chevy people also love it. How much for the 58 Apache.

[datzenmike]

Ray, was there a 283 in the Apache? First engine I ever worked on was a 283 although I was more eager that capable and was cleaning parts for my neighbor who was rebuilding his. This was in the almost mid '60s and it was definitely NOT new. I seem to remember it having small wrap around side/rear windows. I think single headlamps.... it was over 50 years ago.

[TJ H]

1 hour ago, mrbigtanker said:

All right. Chevy people also love it. How much for the 58 Apache.

 

Not for sale. 

[TJ H]

Mine is an LS but most came with straight sixes. 

[banzai510(hainz)]

 

Motor looks nice

I would assume you put the head on TDC before putting on block so a piston don’t hit when you in stall chain or turn crank and hit a valve .

maybe yo have no pistons in there now 

Edited September 22, 2019 by banzai510(hainz)

[TJ H]

24 minutes ago, banzai510(hainz) said:

 

Motor looks nice

I would assume you put the head on TDC before putting on block so a piston don’t hit when you in stall chain or turn crank and hit a valve .

maybe yo have no pistons in there now 

Hopefully. In the picture of my son torquing the con rods there was not a head installed. I have built lots of engines but this was the first L series. Long block was assembled and came in the bed of the truck. We opened it up to mic it out to verify everything and replaced the rod bolts with some ARP ones. It’s a z20 block with a U-60 L20b crank and a U67 head that has had some work done to it. The pistons are dished so clearance shouldn’t have been an issue, they were planning on doing a turbo. Low compression but he’s 16... The confusing Datsun timing marks with the 1, 2 or 3 and the shiny links took a couple tries. 

[BrothersGarage]

11 hours ago, TJ H said:

I tried to ad them initially but would only allow from an existing or URL. What’s the process? Photobucket?

 

edit your images and then visit imgur.com 

drag and drop your images into the browser and imgur will start uploading them

right click on the images and select 'copy image url / copy image location' 

you can then come back to ratsun and paste the image in by right clicking the image into the comment window or going ctrl+v and pasting in the url and ratsun will see the image

then we will quit bitching about pictures

Edited September 23, 2019 by BrothersGarage

[datzenmike]

L and Z series engines are interference engines so if valves are mistakenly at full lift or the chain breaks while running, pistons will hit at TDC.  

[TJ H]

8 minutes ago, datzenmike said:

L and Z series engines are interference engines so if valves are mistakenly at full lift or the chain breaks while running, pistons will hit at TDC.  

Good to know. It I thought there was a chance I would tear the motor back apart. I always assume it’s an interference engine although I am surprised these are due to their age. 

[G-Duax]

So keep a fresh timing chain in it, $20 every 10-20 years isn't too much to ask....

Besides, if a timing chain breaks, it will bunch up in the bottom the front cover, and destroy a whole lot more than a few valves anyway.

[TJ H]

So for shits and gigs I did a compression test. With all the responses about TDC and interference I started to second guess myself even though I have played this game before. All cylinders were even which I would expect on a new motor. Cylinder pressure was way lower then I am used to, I expected low compression with dished positions, I approximated 8.5:1. All cylinders pegged at 120psi. I’m more used to 150-210psi. What does a healthy stock L20b usually bring in?

[datzenmike]

I would guess over 150  for a stock cam properly timed.

 

Set accurately to TDC in a clockwise direction. If you overshoot the mark back up 1/4 turn and do over as many times as needed to get it perfect. This will assure all the chain slack is on the slack side and the cam timed to the crank, Take valve cover off and look at the back of the cam sprocket. There should be a V or U notch with a small horizontal mark on the cam thrust plate...

 

You should see this...

 

 

The V should be below or just slightly to the right of the line for proper cam timing. Ignore the number 1 in the picture. This is an L16/18. L20Bs are usually on number 2, but the position of the V groove to the line above it governs.

 

If the cam is off a tooth retarded this will allow the compression to escape from a late closing intake valve.

[TJ H]

We are definitely on #2 and bright links were on the mark. It is not a timing issue, it is a low comp piston issue. Like I said earlier the PO was planning on a turbo. I thought it would be fine for a first car but now I’m thinking it will be a dog. 

[TJ H]

5 hours ago, datzenmike said:

There's a reason a low compression engine is more efficient on boost but all the rest of the time (99.99993%)  it's a low compression dog. 

 

How was the low compression done? Maybe it can be undone. 

Dished pistons... it will be a dog. It’s got a decent cam at least and a five speed. An old Offy intake and a Weber. Having a one piece drive shaft made for it. Hopefully it isn’t horrible. Still waiting for the guy with the finned exhaust manifold to hit me back so I can start his exhaust system. The point of the truck was to get my son into the garage and spend time with him. 

[datzenmike]

On 9/22/2019 at 1:00 AM, TJ H said:

1971 521, L20b, 5sp, Weber 32/36 on and offenhauser intake, custom Schneider cam

 

On 9/22/2019 at 3:00 PM, TJ H said:

 It’s a z20 block with a U-60 L20b crank and a U67 head that has had some work done to it. The pistons are dished so clearance shouldn’t have been an issue, they were planning on doing a turbo. 

 

U60 crank were used in L20B or Z20, U67 heads were L20B. What pistons??? Do you have a picture of them?

[TJ H]

I don’t have a picture but I thought it was that same as these. 

 

https://postimg.cc/HcNm9rrL

[datzenmike]

Look like standard L20B pistons to me. Compression will be about 8.4 with those unless the head was milled down, then could be higher.

 

 

Cam doesn't look like an L20B cam but it does look re-ground. First lobe looks chewed up a bit but could be grease on it.

 

Was this engine just rebuilt?

[TJ H]

3 hours ago, datzenmike said:

Look like standard L20B pistons to me. Compression will be about 8.4 with those unless the head was milled down, then could be higher.

 

 

Cam doesn't look like an L20B cam but it does look re-ground. First lobe looks chewed up a bit but could be grease on it.

 

Was this engine just rebuilt?

Yes, just rebuilt. It does have cam tower shims. The cam is a reground 1.6 cam that  Schneider did for me. Is that my issue? Should I be position 1 for the cam sprocket? I was anticipating about 8.5:1. I had the cam reground before I knew about the different positions and assumed they used the same cams.