L20b Cody's Goon

[Patcon]

Gonna start this thread for Cody's motor build. We have 2 - L20b blocks. They were missing the timing covers. The one we started with was the better looking of the two. The second one looks like it has sat outside for a while. The crank snout on the worse one is really rusted.

So I bought the 6" inch "long" rods from Nissan. I spoke to Dave Rebello about a year ago and he recommended I get the Z20 rods. I've had these for about a year. Evidently these can be hard to get in reasonably closely weighted sets. 152.45mm rods

So the plan for right now is to build the long block and move the current head and head studs over to it. The current L16 head has been freshly redone.

Then when Cody has saved up some money we will select a head to send to Dave and have him work it, the cam and all the valve train up. Then swap it on....

We have 5-6 heads to choose from. I will need help from Dave to pick the right direction

This is the block we're working with

2 cylinders are ugly! And 2 look pretty good. This was why we could rotate the engine. Even with a BFH.

 

These corroded bores shouldn't be an issue because we're punching to 89mm. This block and crank measures to be uncut and untutrned

 

Here are the rods and pistons. None of these will be reused

Here is the crank. Complete with @Captain Obvious s specially fabricated turning tool

 

[Patcon]

When we talked to Dave last night we came up with a loose plan. We are gonna build a 2150cc motor. He didn't see a reason to try to go to the 2360cc motor.

So we will use the Z20 rods and some KA24DE pistons cut down.

Rebello will supply the pistons but I may need him to help with the machine work too.

I want to be able to run AC so that means a double row main pulley.

Dave said the 240z water pump will fit in the L20 timing cover. I will verify that this weekend. We will have to adjust the alternator to line up but it evidently doesn't take a lot to accomplish.

He also recommended running a lighter flywheel. He use to get the 12#ers from Nissan I believe. I found one at one of the vendors that is a 12# Z flywheel (Zcardepot). I believe it will fit but will verify this weekend.

We are looking to make 185-200 Hp in the finished motor. We will run the SU's we currently have to start with. Might switch to an EFI system at some point.

 

Edited December 19, 2020 by Patcon

[Patcon]

We did verify that 240z water pump fits the L20b timing cover. The flywheel also fits.

Is there any reason we cant use a 240z flywheel and clutch set up?

[EuroDat]

The engine looks like its been out in the elements for some time.

The clutch should not be an issue because you are running the 240Z flywheel and a 280ZX transmission.

Is this the motor I sent yhe intake for? If you plan to go efi, that is.

Look like a fun build.

[zKars]

Flywheel is fine. A 225 mm clutch penalty is extra weight over the 200mm version.

Water pump fits front cover fine, BUT the pulley groove position is not the same as the L20 pulley. You can use a Z pulley if you also use a Z damper to get the grove in the same plane. Then you have to play with the alternator pulley position as well.

[Patcon]

8 hours ago, EuroDat said:

The engine looks like its been out in the elements for some time.

The clutch should not be an issue because you are running the 240Z flywheel and a 280ZX transmission.

Is this the motor I sent yhe intake for? If you plan to go efi, that is.

Look like a fun build.

Yes, I had considered using that EFI when we ditch the carbs. Provided it will flow enough air. I might have it extruded honed.

What motor was it off of again?

8 hours ago, zKars said:

Flywheel is fine. A 225 mm clutch penalty is extra weight over the 200mm version.

Water pump fits front cover fine, BUT the pulley groove position is not the same as the L20 pulley. You can use a Z pulley if you also use a Z damper to get the grove in the same plane. Then you have to play with the alternator pulley position as well.

Good point on the heavier clutch but we'll be making more power so a larger surface area seems to make sense. I plan on using a lighter flywheel so the net weight should be better. I will run a two row main pulley so we can run AC in the car. We have a factory AC setup when we get to it. Dave put us onto all of this when I told him I wanted to run AC. He mentioned we would have to move the alternator to make it all line up.

[EuroDat]

5 hours ago, Patcon said:

Yes, I had considered using that EFI when we ditch the carbs. Provided it will flow enough air. I might have it extruded honed.

What motor was it off of again?

It came off a Datsun Silvia s110 (180SX) 1981 with the L18E engine. It may be on the smallist side.

[Patcon]

I think I finally have pistons settled and on order so hopefully those don't take too long. We had to select the final head we'll use and I had to CC the combustion chambers to know what cut to make on the pistons

[Patcon]

So I took the block and rotating assembly to a local machine shop about the end of August. He finished it right before Christmas. I picked it up a week ago.

Stock bore and stroke is 85mm x 86mm. We punched it out to 89mm. I sourced the pistons from Dave Rebello

I believe they're KA's turned down

They sonic checked the block after boring. I was told the minimum would be 0.0100". We are well within that.

All line bored and balanced

Everything has a witness mark so we can reassemble the way it was balanced

Crank was turned 0.010 & 0.010

es w

The challenge now is getting bearings. I have the rod bearings now but am having trouble getting the main bearings. I made another order the other day because the first order got delayed. Many places were saying end of April for bearings!!

Evidently freeze plugs are hard to get too. That is why one of them is steel and not brass.

Any recommendations on engine paint? Not super obsessive about true Datsun blue but would like it to be close.

 

[siteunseen]

That black looks awful good!

I wound up using Pontiac blue on my 240z's block. A lighter color than Datsun Spirit but closer to the OEM spray i found on my car's motor mounts and oversprayed oil pan. There were other places i can't recall right now? 

 

[siteunseen]

Oh yeah, the PCV pipe out of the block.

[SteveJ]

I believe Les Cannaday used to sell engine paint. I'm not sure if he still does.

[SteveJ]

And Mike McGinnis has it: http://www.zzxdatsun.com/catRequests.php

[mailnome]

I sprayed Chrysler Corp Blue engine enamel on a couple of pieces. I’ve read that it’s supposed to be close but I’m not sure.

To me it doesn’t look like it has enough green in it, but if you google the color some do look greener.




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[dutchzcarguy]

Nice block, only the freeze plug just on the right of the oilfilter is a bit outside it's hole.. normally they are just in the hole with the edge of the lid IN the hole.. On a L24-28 they have a edge were the lid sort of clicks in..?  I always use a bit of sealer. (don't know these brass ones i use steel ones with a sort of 85 degrees edge. they catch the edge in the holes..  if you know what the ... i mean haha)

[Patcon]

So I have a question. I have heard that the rod bearings can lack sufficient oil because one main bearing feeds two rod bearings. There was a hack I came across to rebore the galley feeding the main larger. They suggested 1/4" but it looks pretty close to that. Thoughts??

[Namerow]

Considering only the math, increasing the oil passage diameter from 0.239" to 0.250" would increase the cross-section by just under 10%.  I suppose that's worthwhile, but only a Datsun engine expert would know.  It would seem to be a lot of expense for a street-use-only engine.  Have you checked Tom H's book, 'How to Modify your Nissan & Datsun OHC Engine'?

[Patcon]

I have the book but have not checked it. I probably should.

I thought I would call Rebello too for his thought, since I need a recommendation on a head gasket too. I'm not sure the standard L20b gasket has a big enough fire ring to cover our punched out cylinders

[Patcon]

So spoke to Rebello

We need to use the head gasket from  a Z24. It will need some modification to provide all the water access ports.

On another point, should we Glyptol or not? Is it worth it on a motor that is not an all out effort?

[grannyknot]

20 hours ago, Patcon said:

 

On another point, should we Glyptol or not? Is it worth it on a motor that is not an all out effort?

Other than on a race engine it's probably just a feel good thing but nothing wrong with that. That is what these cars are all about.

[Patcon]

So i went to my local paint shop and had some single stage made up to match an alternator bracket that still had some factory blue on it. Cody got the block all taped up last weekend but ti was too cold. S o I sprayed it this weekend.

It's much darker than it looks in the sunlight. Much more like the paint in the can looks. He is planning on working on the rotating assembly next weekend

[dutchzcarguy]

Just on the right, that spot with some sun on it tells me you just hit the jackpot i think.. thats the tippical blue NISSAN engine color! 

[Patcon]

So let’s see about a little update:

Cody and I started working on his motor maybe a week ago or so

We had to decide if we were going to drill the mains out or just slot the block side of the main cap and add a feed hole in the bearing. I looked in Honsowetz’s book and he recommends opening those feed galleys up to 5/16 or 0.313”. Which if I calculated it right is a 62% increase. So Cody and I discussed it and felt more comfortable with drilling the mains. Partly because we’re not making a lot of grit in the engine block.

 

We started by getting the end plugs out of the main galleys. That way we could properly clean and wash the block later. They were stouter then I expected…

 

A little homemade puller big enough for the plug to pass through it

We didn’t want to drill the supply mains and realize we couldn't get the main galley open to clean it out.

Then we worked on tapping the ends of the main galley for brass plugs

We may have to make these deeper but I didn’t want to make them too large since the 3/8 NPT tap is tapered.

On to drilling…

So this is really sketchy because the metal drills pretty easily but only the very edges of the bit are cutting. We used 3 different sized bits to work up to 5/16”. They didn’t need to be special because you’re not drilling overly deep. We were concerned we might break a bit but with a little cutting oil it went pretty good.

 

We were going to clean the block up and get ready for setting the rotating assembly but I can’t find the main bearings I bought! I went by the machine shop last Tuesday and he didn’t have them. Even though I’m pretty sure I took them, but I can’t be sure I didn’t pick them up. The problem is, right now they seem to be unavailable everywhere. Neither Clevite or King. I found some vintage TRW’s on ebay I have coming my way and I have an order in for some Kings from another place. Hopefully one of them will get here soon. Cody would like to have a running car by Zcon. He will have to hustle! It’s doable but he will have to focus to get it done.

 

[Patcon]

So I received the vintage TRW bearings yesterday. We may end up using these. We'll see

 

[Patcon]

So we had to rework the end of the oil galleys. The holes we had drilled and tapped weren't big enough for a 3/8 plug. So I found a 9/16 bit; it called for 27/64 and we drilled them again and tapped them. You have to drill them and tap them pretty deep so the plug will go in flush. You can see one of the feed holes in the threading. the plug doesn't actually go in that far. We measured for clearance.