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Giljr2

L18 block questions

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I just bought a 1975 Datsun 620 and it has an L18 and it has a stamp that is

L18 490560 w

And next to the driver side motor mount it says

M2

The head is a w53 which I’ve read is desirable

And it has a cam that has a stamp on the end 272 and u20

Please help me I want to know what I have

In this isn’t from this truck and I am wanting to find out what I actually have

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Only the '74 620 truck, the '74 710 and the 73 610 got the L18.

 

I think the M2 is a much later casting. This is likely an import engine. Take a look at the block vent. It's under the intake on the side of the block. It's a metal pipe with a rubber hose going to the PCV valve on the intake near the carb base. L16/18 came straight out from the side. Later made import L18s and all L20Bs exit vertically.

 

The other thing is the W53 head. It's a domestic Japanese head used for L16/18s with fuel injection. The tops of the intake ports will have notches for the fuel injection nozzles. This would have come with the L18 block.

 

Here's a conventional L16/18...

 

wEYnx4M.jpg

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You'll need to open a (free) photo hosting site account such as imgur, although there are many others as good, but NOT Photobucket. Up load your pictures there and copy the image location, come here to Ratsun and click the green rectangle with the green border around it just below the smiley face above your post. Follow the directions and paste it there and there you are.

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https://imgur.com/4H5Cu6z
https://imgur.com/5zMv7gD
https://imgur.com/A3D4Wwh
https://imgur.com/AGBUksK
https://imgur.com/lCoEQUj
https://imgur.com/MoSKMYd
https://imgur.com/I9g7E5h
https://imgur.com/9mPvLoN
https://imgur.com/kRPStwA
https://imgur.com/CytV0hi

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I just bought a 1975 Datsun 620 and it has an L18 and it has a stamp that is

L18 490560 w

And next to the driver side motor mount it says

M2

The head is a w53 which I’ve read is desirable

And it has a cam that has a stamp on the end 272 and u20

Please help me I want to know what I have

In this isn’t from this truck and I am wanting to find out what I actually have

Looks like you got lucky... the w53 is a nice head... i have one on my l16..

the 272 is probably a cam grind spec...

In The pic you posted it looks like some upgraded parts on the valves....

Probably has upgraded valve springs too if I had to guess....

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Looks like you got lucky... the w53 is a nice head... i have one on my l16..

the 272 is probably a cam grind spec...

In The pic you posted it looks like some upgraded parts on the valves....

Probably has upgraded valve springs too if I had to guess....

 awesome i was hoping for some goodknews but iv been wanting to know more about this engine but can't find any info on it:(

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Only the '74 620 truck, the '74 710 and the 73 610 got the L18.

 

I think the M2 is a much later casting. This is likely an import engine. Take a look at the block vent. It's under the intake on the side of the block. It's a metal pipe with a rubber hose going to the PCV valve on the intake near the carb base. L16/18 came straight out from the side. Later made import L18s and all L20Bs exit vertically.

 

The other thing is the W53 head. It's a domestic Japanese head used for L16/18s with fuel injection. The tops of the intake ports will have notches for the fuel injection nozzles. This would have come with the L18 block.

 

Here's a conventional L16/18...

 

wEYnx4M.jpg

 my block doesn't look like that it has a removable tube that is vertical 

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Looks like a W53 head to me, it has them weird runners in #1 and #2 intake ports.

It also looks like the intake/exhaust face was machined, I have never had to do that to any head I have ever owned, I wonder why it was machined?

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Looks like a W53 head to me, it has them weird runners in #1 and #2 intake ports.

It also looks like the intake/exhaust face was machined, I have never had to do that to any head I have ever owned, I wonder why it was machined?

yeah idk what that is in #1 #2 intake ports and I'm not sure honestly but if you can look at the pictures iv uploaded and tell me what you may know about them i would gladly appreciate it! 

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my block doesn't look like that it has a removable tube that is vertical

Probably looks more like this...

My L16 with a w53 ...

 

20160628_164212.jpg

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Probably looks more like this...

My L16 with a w53 ...

 

20160628_164212.jpg

yes it looks VERY SIMILAR! But Mines anL18 

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So is the l18 in the vehicle?

Is that head the one from the motor?

The other thing that would be good to know is pistons.... if you have flat tops you have a real nice combo....

So if heads off look at the piston.. or look through spark plug hole...

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yes it looks VERY SIMILAR! But Mines anL18 

As Dmike said, later L18s have the case vent like the L20b, so you appear to have a late L18 block.

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So is the l18 in the vehicle?

Is that head the one from the motor?

The other thing that would be good to know is pistons.... if you have flat tops you have a real nice combo....

So if heads off look at the piston.. or look through spark plug hole...

i took the L18 out and i believe they are flat top pistons out of a L28 280Z so idk really what that means

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As Dmike said, later L18s have the case vent like the L20b, so you appear to have a late L18 block.

is having a late L18 Block a good thing?

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Has this engine ran in your possession?

I have recently put together an engine with flat top pistons and a W53 closed chamber head, it supposedly has a 10.9 compression ratio and has to be set up nearly perfect to run, otherwise it is going to knock badly.

L18 blocks are supposed to be revers, I had an L16 once back in the mid 90s, I will never have any L block smaller than an L20b, but I have never had a running L18 to compare it to a running L20b either.

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Has this engine ran in your possession?

I have recently put together an engine with flat top pistons and a W53 closed chamber head, it supposedly has a 10.9 compression ratio and has to be set up nearly perfect to run, otherwise it is going to knock badly.

L18 blocks are supposed to be revers, I had an L16 once back in the mid 90s, I will never have any L block smaller than an L20b, but I have never had a running L18 to compare it to a running L20b either.

not in my possession but the guy i bought iy has tripped the spark plug and got it help coiled then stripped and he got fed up, but ik the guy so i trust he is telling the truth, he did say it has to run premium fuel and what exactly needs to be set up nearly perfect? and are they suppose to be revers?

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Has this engine ran in your possession?

I have recently put together an engine with flat top pistons and a W53 closed chamber head, it supposedly has a 10.9 compression ratio and has to be set up nearly perfect to run, otherwise it is going to knock badly.

L18 blocks are supposed to be revers, I had an L16 once back in the mid 90s, I will never have any L block smaller than an L20b, but I have never had a running L18 to compare it to a running L20b either.

forgot to mention i believe the head has been deckt, and has spacers for the cam

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not in my possession but the guy i bought iy has tripped the spark plug and got it help coiled then stripped and he got fed up, but ik the guy so i trust he is telling the truth, he did say it has to run premium fuel and what exactly needs to be set up nearly perfect? and are they suppose to be revers?

 

I don't really know myself what perfect is, maybe the guy telling me what I need to do only sees perfectly set up as the only way.

Flat top pistons and closed chamber head appears to be 10.9 to 1 compression ratio, when I told my machinist that number he made a face, that cannot be good as everything he has ever told me was true, he used to do mostly racing engines, and he would squeeze in work for me when he had the time, now he is doing normal machining for the public and when he retires the shop will likely close.

There is another thread on here, here is a link below, look at post 35 specifically, the guy made list in that post that mentioned everything I needed to do, and I basically replied with I didn't understand half of what he wrote, un-shroud the valves, time the cam at 107/108, re-curve the distributor, also lighten the flywheel which I did understand, I also understood some of the other stuff but likely don't really understand the extent of the work needed.

http://community.ratsun.net/topic/72985-z20-build/

The L18 has been said to be a revver, but the fact is unless your on a race track it is not likely that any of us would drive it like that on the road, therefore we would not use its true potential and the only reason to have it is for bragging rights.

I built mine just to see if I could get it to run, I had just about every part needed in my parts bins, I am only out time and a gasket set, plus I intended from the start to use this engine to mock up a frame/chassis for my work truck, I want everything ready so I can just transfer everything without having to modify anything as that part will already be done(motor mounts specifically), I have done this a few times so I know what is going to need to be done.

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Well Wayno yours is a long rod z20 motor ... I know from calculating my cr even small changes to numbers in the equation changed things....

Bigger cylinder and long stroke will all effect that final number...

 

The flat tops just take advange of the quench area the peanut head w53 has..

 

I'm at 10.8 - 1 running 93 it's fine, i found anything 11-1 and under is ok

 

Giljr2 out of all the stuff Wayno mentioned I always believed the distributor is the key to having that setup run good...

 

It would be good to calculate your compression ratio specifically so you know... maybe datzenmike will calculate it for you, but if the head was milled that number will be a little higher...

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I don't see the injector notches. Maybe they were on the earlier heads?

 

Wayno those troughs on the intake ports are common. I have them on my L20B and the have them on the matching intake also.

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M2 is a later block, as others have mentioned. Thicker castings and more reinforcing ribs, different/more accessory mounting holes. Other than that, it's basically identical to the early blocks.

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