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Ant-dat

My L20B Build

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Thanks to datzenmike for the advice in PM.

 

Today I started a rebuild of my L20 from my Ausy spec 1978 200B (810) that I'm planning on fitting into my UK spec 1400

 

the start :)

 

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Loading on to engine stand

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about an hour later

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Not actually to bad for a 37 year old engine It's done about 40K miles

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and completely stripped, cleaning in progress

 

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Then I attacked the inside with a Die grinder

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Next i'll need to take it to get the block machined to fit the new over sized pistons

L20B0025.JPG

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I did find a couple nasty big end shell damage, I will need to examine crank and get it reground if required

 

L20B0019.JPG

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looking to build a god street engine with the odd track use.

 

the pistons are (I think L18) 1mm over size so do have a small dish,

I have a adjustable sprocket, new timing gear, shells and mains, high flow oil pump.

the cam

Cam Specs

Cam Specs

 

Profile Actuation Make/Model Ratio

733A radius rocker Datsun L4 In 1.55 Ex 1.55

 

Cam lift Duration Adv Duration Valve Clr Valve Lift Cam Lift TDC Phase

Intake 320 270 220 0.012 0.4836 110

exhaust 320 270 220 0.012 0.4836

 

Timing Adv Timing @ 050

Open Close Open Close

Exhaust 65 25 42 -2

Intake 25 65 2 38

 

50 0

Deg Over-Lap Deg Over-Lap

also have set of twin 40's

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Now the interesting part

I have 3 cylinder heads

A87

w53

U67

 

will take some measurements and hopefully with some help (datzenmike already given me some good tips) the best head can be fitted

Remember in the UK we have 95,97 and 99 ron pump gas :)

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What is the A87?

Closed or open?

Big or small valves?

How big are the intakes?

 

The U67 head would likely work good with L18 pistons, and it already has big valves and intake ports, but I don't know the CR.

 

Unless someone has already put big valves in the W53 head, I likely would not mess with it, and the CR also needs to be addressed.

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A87 head

l20prt02.JPG

 

before you ask yes it's new old stock never fitted, reason I would really like to use this head lol

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A87 head

l20prt02.JPG

 

before you ask yes it's new old stock never fitted, reason I would really like to use this head lol

How big are the intake holes/runners?

You need to have someone chime in here with the CR.

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planning on porting the head

I can measure them

and get some pics of the W53 and U67 heads

 

all exhaust ports are square (ish) lol

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L20B with 86mm L18 pistons and

 

A-87 and W53 closed chamber head................ 10.08

A-87 and U-67 open chamber head.................... 9.44

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planning on porting the head

I can measure them

and get some pics of the W53 and U67 heads

 

all exhaust ports are square (ish) lol

An A87 closed chamber head with big valves and big intake ports is basically a 219 head.

I don't have any issues figuring out if a head has big or small valves when looking at it in person, but when looking at photos, I seem to have an issue, I am starting to wonder if that A87 head has the big valves, that's quite a bit of space between the valves, look how close the valves are on the U67 head, they have big valves.

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All three have the same 42mm intakes but the U67 and W53 have the 35mm exhausts. The A87 might have a 35mm or a smaller 33mm exhaust valves

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I'll get some measurements over next day or so :)

I'll dig out the U67 head too and compare all 3 heads

 

close up of the valves (sorry not the best picture was taken a while ago)

l20prt04.JPG

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Hold camera farther back or select macro if t has it.

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Every W53 head I have ever had, had the small valves and small intake ports with them funny grooves in 2 of the runners, the only one I ever found myself with big valves was an open chamber W53 head, I bought it because I had never heard of one before, there is another guy in the pacific northwest that has a round exhaust port W53 head, I just could not rate paying that much for a head I would never use, so I was happy when someone else bought it.

What kind of gas(octane rating) you have over there, the higher the octane, the higher CR you can have.

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we have 95 , 97 and 99 at the gas pumps.

 

I'll grab the U67 head on way home from work tonight then I can get better pics and measurements of all 3 heads

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WOW, 99 is considered race fuel around here.

You would have to talk to someone that knows what they are talking about when it comes to compression ratios and high octane fuels, when I was a kid I could run 10.5 to 1 CR on the fuel I got, now there is no way.

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No it's Scotland, England is another country :P lol

 

currently about £1.30ish a litre for 95 ron

 

Ok 3 heads (I know this is all over the web :) (exhaust ports measured at widest points)

U67 first (which I think won't be getting used, it's seen better days)

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Valves 42 In 35 EX

ports 35 in

outside ex 37 x 28

middle ex 37 x 34

 

W53

L20B0043.JPG

Valves 42 In 32 EX

ports 36 in (ported)

outside ex 37 x 28

middle ex 37 x 34

 

A87

L20B0044.JPG

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Valves 42 In 32 EX

ports 32 in (ported)

outside ex 37 x 28

middle ex 37 x 34

 

Noticed that one of the rods has a different number cap guess I'm going to have to watch I don't mix them up

 

all mains and big ends or marked STD so if I need a crank regrind then should be an issue :)

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the head in the plastic bag is Fucking nice. the A87  and the next one the W53

 

I would choose these 2

 

I had 2 L16 blocks redone the the main bearing and rod bearing were all stock size all were over to 100K miles on them.

 

If you have friends in Austrialia get ahold of Baz at Datsport and hell send parts(of coarse pay$$$)

 

I get my head gaskets from him. 87mm size

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Thanks at Head

I have dealt with Baz/Tracey before there very help and great people.
I bought a load of parts years ago to rebuild the engine for my 810 but ended up dropping in a VG30E.
Parts I have so far
both guides
chain
adjustable sprocket
oil pump
2 complete gasket sets
mains and bigends bearings
tensioners (ended up with a few :$ )etc
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Cam
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Specs
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When I bought this from Baz I asked for the biggest cam (for street use with odd track day) that would work on OEM lash pads and this is what he sent :)

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let us know if it actully uses the oem lash pads. Baz say they make counter sunk type aftermarket pads that fit in the stock retainers. In USA we only have the flat bottom after market lash pads thus they stick up above the stock retainer alot which might fall out so we ussually need to get begger retainers

 

That look like a USA made cam by the CWC marking on there. My Schneider and Webcamshaft have the same CWC marking on there. I assume its the core manf

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