L16 to L20b parts compatible?

[sondat]

Looking at the pictures of the 2 heads you posted datzenmike I see curved openings just above the combustion chambers. I don't see them on the 210 I posted?

[wayno]

I did measure the intake ports at 30.24mm. That being 5mm smaller than the open chambered head the seller had which I assumed was for the L20B block.

 

That is nothing special, that is stock for any 210 head I have ever had.

[datzenmike]

Looking at the pictures of the 2 heads you posted datzenmike I see curved openings just above the combustion chambers. I don't see them on the 210 I posted?

 

I don't think those were specifically L heads, just open and closed examples.

 

 

 

30.24mm is 1.19". In comparison my L20B U67 head intake ports are 1.365"

A 219 intake port is 1.5" and highly sought out for use on L20Bs.

L20B heads can be ported out to 1.5" but are not closed chamber.

 

L20B and L18 engines use 'letter heads"... A87, U67, W58

L16 uses a 'number head' .... 210 or 219 (used on L18s also in Japan)

[Crashtd420]

What are the chances that 210 head has been milled.. can you verify thickness?.. I think it should be around 4.250. I've read that some of the 210 heads had a semi open chamber designed... I looked at my old head and it looks like you could mill it down about .200 and end up with a small closed chamber.

You can see the peanut outline , and the location of the spark plug seems a little odd....

[datzenmike]

TIG weld it level and then mill it. Shaving 0.2" will add too much chain slack and jack the compression way too high. This is too much for too little. Weld up a U67 head and mill it. Larger ports and valves.

[Stoffregen Motorsports]

You can modify the chain guides for better geometry and more adjustment, and you can add cam tower shims, but not .200" worth. And then the deck of the head would be sooooo thin. And then those small valves...

 

Not worth it.

[Crashtd420]

Ya I guess .200 is alot....

[sondat]

Looking for help on connecting rod bolt size. Assembling the L20 and using Tom Monroe’s “how to rebuild your Datsun OHC engine as our main instructional go to. Tom mentions 8mm or 9 mm connecting rod bolts with torque specs of 20-24 and 33-40 respectively. Our bolts are reduced in diameter half way down. My question is how do we know wether they are 8 or 9 mm bolts? The thicker end closer to the bolt head measures 9.1mm and the narrowest end near the threads are 8.35mm.

[Crashtd420]

My guess is 8mm...

You want to measure the outside diameter of the thread....

[G-Duax]

No..

Threads always measure slightly less than the nominal size.

If they measure 9.1mm where they press into the rod, they are 9mm rod bolts, providing you are using an accurate measuring device.

[Crashtd420]

Do they define the connecting rod bolt by the larger diameter or by the thread diameter..?

 

This is a factory rod bolt...

 

Sondat stated the thicker diameter measures 9.1 near the head and 8.35 near the threads... wouldn't that make the threads 8mm?

[Stoffregen Motorsports]

L20B's used the larger bolts. Most of the L motors did in fact use the larger bolts. The smaller bolts were mostly used in L16's and some early L24's.

[G-Duax]

No 8mm thread will ever measure more than 8mm.

My L16 ARP rod bolts (8mm) measure 7.84mm on the threads.

Their body measures right at 8.1mm.

 

This is measured with a Mitutoyo digital caliper.

[Crashtd420]

No 8mm thread will ever measure more than 8mm.

My L16 ARP rod bolts (8mm) measure 7.84mm on the threads.

Their body measures right at 8.1mm.

 

This is measured with a Mitutoyo digital caliper.

I agree with what your saying... but he never measured the actual threads.... the 8.35 he said was the middle of the bolt near the threads..

[sondat]

I am measuring with Mitutoyo digital calipers as well. Sounds to me by all your feedback that they are 9mm bolts. The measurement at the threads is 8.9mm. I would like to add to the original question of this thread on the compatibility of bolts and components from a L16 to assemble a L20b. My son and I purchased the block, head, Pistons, rods, crank, cam, intakes, carb, oil/water pumps, dizzy, timing chain cover and a bucket of who knows what. This all came disassembled with head rebuilt. We are only at the beginning stages of the build but thought we could post our findings as we go in case someone else ends up working with the same scenario as us. We had the head checked over at local machine shop, all good there. Bored block 20 over, had block decked and crank turned 10 under. We just sent cam to Shadbolt Cams in Vancouver for a M445 grind. So far the lack of the metal shield that goes over the PCV screen in the block was an issue. The l16 shield is 3/4 “ shorter just like the block itself. We extended it the 3/4” with a piece of 18 gauge and a mig welder, ( just when we thought our metal repair on the truck was done) lol. Will post any other differences/ hurdles. Thanks all for help on rod bolt size.

[Crashtd420]

I am measuring with Mitutoyo digital calipers as well. Sounds to me by all your feedback that they are 9mm bolts. The measurement at the threads is 8.9mm.

Well that's a bit different from your earlier statement about the bolt. atleast now you know what it is .

[sondat]

I am undecided on replacing the rocker arms. The only new ones available that I have found are ITM brand. The old ones aren’t very worn but everything else on the head is rebuilt and new including a re grind on the cam. Shadbolt in Vancouver did a M445 grind with new lash caps. Our rebuild resource says if cam is changed then you must go with new rockers. Also have a clutch question. Would I purchase a clutch assembly for any L20b vehicle? The tranny we have is a dog leg which I don’t know what it’s out of.

[datzenmike]

I think if the old rockers are not grooved they will be fine.
 
But you can polish the rockers smooth so they can break in with the new cam surface. Get a sheet of glass that will fit your sink and some 500? 800? anyone? grit wet sandpaper. Stroke the old rockers over the wet sandpaper to polish them.
 
The clutch and pressure plate you want depends on what flywheel you have or want to get. Measure across the clutch friction surface diameter. It will be 200mm or 225mm or could even be 240mm. Car L20Bs came with 200mm flywheels, trucks were 225mm. By flywheel size, I mean the bolt pattern for the pressure plate and the friction plate diameter.
 
This is an L16 (5 bolt) measuring 200mm. 


L series doglegs (there were also A series) came on all standard transmission '77-'79 S10. (first generation 200sx) They were also an option on  '78-'81 A10 (HL510s) 

[sondat]

Just measured the flywheel friction surface which is 9” so I gues the closest conversion would be the 225mm (9”=228.6mm). Looking at rockauto I could get clutch kit for 1976 model620 and should be good. Thanks for the help mike. On those rocker arms, I did read an earlier post of yours on the fine grit sandpaper. A couple of the rockers do have a real slight divit in the pad maybe I’ll try the ITM’s.

[Crashtd420]

The rockers arm still available through nissan.... I bought a full set for my head when I had the cam reground....

[Crashtd420]

[datzenmike]

Definitely replace if there is visible divot!

 

This wear could be from running what passes for oil today. Since the L20B was made oil formulas have changed drastically. No engine is made today without a roller rocker style cam. Slowly makers have been reducing the level of ZDDP (an anti scuff additive) because, not needed on roller cams and it fouls the new catalytic converters and ends up in the environment. Our engines require this ZDDP in the proper levels. Oil makers claim the original levels were too high in the first place and lowering them won't cause any problems on older 'flat tappet' engines. I advise you to look up this controversy and decide for yourself what the risk is. I don't believe the maker's claims and won't be risking my Datsun's engine on this stuff.

 

What I do is run 15w40 Shell Rotella T4 although Chevron Delo 400 is as good. Another option is oils sold as 'racing oil'. Any Chevy guy who races older Camaros will know what you mean. Rotella T4 is a 'light' diesel oil that retains the same ZDDP levels as the old gas engine oils. I noticed that you can also get it in 10W30 but haven't bothered with it. The 15w40 works for me up here at 50 degrees latitude winters and I drive mainly in the summer anyway. 

[sondat]

Great oil info Mike. I will phone local Nissan dealer today with the rocker part number, thank you Crashtd420. Noticed the quantity on the box is 5. Odd number if full set required.

[Crashtd420]

Great oil info Mike. I will phone local Nissan dealer today with the rocker part number, thank you Crashtd420. Noticed the quantity on the box is 5. Odd number if full set required.

Ya Just a box. Not sure why... just ask for 8... you don't have to pay for 10 like other items....

[sondat]

Ordered new rockers from Nissan. Pre paid for 2 boxes of 5, but when they arrived the quantity of 2 units was only 2 rocker arms. (1 part box). The price Canadien was $64.93 per box so total paid was $129.86. Nissan parts looked into it with Nissan Canada and they are saying that 1 rocker arm is $64.93 even though when I ordered he stated I was receiving 2 boxes (10 pieces). Curious what your cost was Crashtd420.