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L18 block questions


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#21 Giljr2

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Posted 22 November 2017 - 11:50 PM

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



#22 wayno

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Posted 23 November 2017 - 12:39 AM

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.rat...2985-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.


 

 


#23 Crashtd420

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Posted 23 November 2017 - 04:20 AM

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...

#24 datzenmike

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Posted 23 November 2017 - 06:09 AM

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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#25 Stoffregen Motorsports

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Posted 23 November 2017 - 08:03 AM

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.



#26 wayno

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Posted 23 November 2017 - 10:18 AM



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.

 

Yea, them troughs are weird, I have only seen them on W53 heads in number one and two intake runners and they are notched all the way to the mating surface, but I have not been looking for them either, and the A46 intake manifold I have has the thoughs in number 2 and 3 runners and they end right before the intake mount surface where the intake mounts to the head, very strange.

You can see the troughs in 2 and 3 runners.

 DSCN7435.jpg

You can see how the trough ends before the mating surface on the intake.

DSCN7432.jpg

When the head intake runners are port matched to a dual SU intake manifold them toughs are basically gone, very little is left.

DSCN7437.jpg


 

 


#27 Giljr2

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Posted 29 November 2017 - 09:48 PM

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.rat...2985-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.

Thank you!! i will be doing some reading and i really want to make this engine as best as i can, 



#28 Giljr2

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Posted 29 November 2017 - 09:51 PM

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...

i believe my engine has flat piston out of a 280z? I'm going to take my crate to be looked over to make sure that everything is true, but id like to be able to know how to and which distributor is the way to go?



#29 Giljr2

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Posted 29 November 2017 - 09:53 PM

One big question iv been wondering is wanting to know what the engine i have is out of! does anyone have a good way to be able to help me find out what i actually have and am working with?



#30 banzai510(hainz)

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Posted 30 November 2017 - 06:12 AM

who cares  what its out of. Most likely a 610 if it had a 200mm flywheel

 

hope that stripped spark plug hole dont go bad again.

 

you got a nice head and look like a 272 duration cam.  hope the lash pads are correct for the set up  as it s best guess for the wipe pattern.

 

non turbo 280zx had flattop pistons and the W53 Head is a good match for it(best ported to 1.5 to a 15 incha manifold). to get best power I would run Mikunis sidedrafts.  Persoanlly I would do a L20 and the W53 if giving a chance again but all I had was L16/18 and I really can tell the difference between the 2 when equip with a weber 32/36 downdraft


Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#31 datzenmike

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Posted 30 November 2017 - 06:19 AM

'73 610

'74 710 and 620 truck

 

These are the only years the L18 was used. Could be from any one of them and and an L16 flywheel put on. The 620 L18 came with a one year only 225mm clutch on a 5 bolt crank.


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#32 G-Duax

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Posted 30 November 2017 - 07:43 AM

Or it could have been imported from Japan.

Mike, you have any idea what all cars/trucks it was used in over there?

 

I recently came across an L18 that was rebuilt in Japan, and shipped here by a Japanese company that was doing it on a large scale.



#33 datzenmike

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Posted 30 November 2017 - 07:50 AM

No idea. L18 were used on the Auz 720s? so into the '80s 


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#34 Stoffregen Motorsports

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Posted 30 November 2017 - 08:19 AM

As stated earlier, the M2 blocks were usually Japanese takeout engines. The one's you would buy from Jetco (or whatever their name was) back in the 80's and 90's.

 

If you're looking for originality, then you're out of luck. If you're just interested in the application to make sure you get correct parts, then the info from others is accurate and should be what you need.



#35 banzai510(hainz)

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Posted 30 November 2017 - 08:21 AM

I had one of those Jap rebuilds(gold star I think was the brand). the core plugs rotted from sitting to long. No heater holes in the head also


Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#36 racerx

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Posted 30 November 2017 - 08:43 AM

As stated earlier, the M2 blocks were usually Japanese takeout engines. The one's you would buy from Jetco (or whatever their name was) back in the 80's ...and 90's.

If you're looking for originality, then you're out of luck. If you're just interested in the application to make sure you get correct parts, then the info from others is accurate and should be what you need.

....maybe attarco?

#37 docbainey

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Posted 30 November 2017 - 08:46 AM

Ummm, isn't the oil dip stick, block water drain plug & block serial number location on the wrong side of the block for this to be an 'L' motor? My 73 610 L18 had those items in the same spot as an L16 & L20B. Look at the third picture.



#38 Stoffregen Motorsports

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Posted 30 November 2017 - 09:02 AM

You're right. One other thing I noticed (hadn't looked at the pics in the link until now), the crank isn't fully counter weighted like the early L18 cranks were. The fully counter weighted cranks are obviously a better crank.

 

If the motor's in good shape, use it, but drill a new dipstick hole and plug the old one. If you're planning on any type of exhaust header, you'll have to cut the angled boss off under the two center exhaust ports.



#39 Crashtd420

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Posted 30 November 2017 - 10:45 AM

Can anyone actually post the pic your referring to.... You guys have me curious and I cant view them ...

#40 G-Duax

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Posted 30 November 2017 - 11:17 AM

He gave the link his whole album in post #7.

Just click on it, you will go right to them.

 

But here is said dip-stick, and the other side has the casting, but it's not drilled.

Simple to plug one, and drill the other.

 

Love those aluminum spring retainers on the head.

Had several sets that I sold on eScrew (eBay), then they dried up in Japan, so I ended up without any :)

 

A3D4Wwh.jpg