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My L24 Build


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I thought this build deserves a thread of it's own, as the last 'Engine Build' thread I posted seem so popular.

The whole back story as to how I ended up here is a long one deserving of it's own post, but for now I'll stick to the build dairy of my 'Early Girls' matching numbers L24.

 

Some time in the late part of last century, Harry (the dear PO) had Gordon Dobie rebuild the L24, increasing it's capacity to 2.8 liters by using a L28 crank, rods & pistons.

The E31 head had it's ports cleaned up in the short turns & L28 valves fitted. A mild camshaft was also added.
Along with the 45mm ITB EFi it punched out around 150hp at the tyres on the dyno.

 

This will take some time to progress, as I only started stripping the L24 down this weekend.

I do however hope to have it completed by mid year (famous last words?).

 

Why am I doing this you ask? 

Well some of those horses have escaped over the last couple of years & it had a propensity over overheat if I pushed it hard...

 

The specs will be:

L24 E31 block

Standard P3040 L26/L28 Crankshaft

133mm H-Beam Con-Rods & ARP Bolts

SPS 86.5mm Forged Pistons

ATI Harmonic Balancer
2500lbs 200mm HD Clutch

AZC Alum sump.

 

E31 head - ported by Les Collins

Camshaft - TBA

Triple 44PHH Mikuni-Solex carburetors on a Kameari 'SmallPort' manifold w/ ITG JC100 filter.

SWM 'SmallPort' Extractors (ceramic coated)

3" SS exhaust with FlowMaster mufflers.

Expected power: 280hp & 220ft/lbs torque (approx)

 

Here's the poor old L24 before I started stripping it down:

 

post-100072-0-88114500-1501323611_thumb.jpg

I was concerned about the bore thickness since it had been overbored by 3mm already. Thankfully it was OK:

 

post-100072-0-30682300-1501323590_thumb.jpg

 

Numbers are in thousands of an inch - e.g. '150' is 150thou or 3.81mm

Accepted industry minimum bore wall thickness is 120thou or 3.048mm

 

As a note, when I popped the pistons out, all the top rings were broken - not good, but thankfully no serious bore damage.

However due to bore scuffing & general wear, it'll get bored 0.5mm as suitable cast pistons and/or rings are not available any more.

Also cast pistons won't be happy for long over 250hp / 7000rpm+...

 

Stay tuned for the next update :)

Edited by Léon
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Hi Mate

 

So the secret is out :) Looking forwad to seeing how this all comes together.

I am expecting plenty of debate about the costs - should be fun.

I do however hope to have it completed by mid year (famous last words?).

See you at the Xmas BBQ.

 

Cheers

 

PB

Edited by PB260Z
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Gordon Dobie........now that's a blast from the past.

 

Doubt many around here would be old enough to know who he was!

Wouldn't have thought you would be old enough to remember him too Lurch ^-^

 

He loved building engines with flat top pistons resulting in a healthy compression ratio.

 

Will watch this thread with interest as well.

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Gordon Dobie........now that's a blast from the past.

 

Doubt many around here would be old enough to know who he was!

Wouldn't have thought you would be old enough to remember him too Lurch ^-^

 

He loved building engines with flat top pistons resulting in a healthy compression ratio.

 

Will watch this thread with interest as well.

 

  

Gordon is apart of my Zeds history - I suggest you have a read of my Early Girls build thread / history: http://www.viczcar.com/forum/index.php/topic,7104.0.html

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Hi Lurch

 

With the pricing I assume you will be quoting, full retail off the street walkin prices for both parts and labour (including your own labour) ?

 

Cheers

 

PB

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Hi Lurch

 

With the pricing I assume you will be quoting, full retail off the street walkin prices for both parts and labour (including your own labour) ?

 

Cheers

 

PB

Edited: After consideration, I've decided to keep the costings private.

There are too many variables and in the end, the cost can becomes a negative talking point. 

 

Edited by Lurch ™
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Not a lot of exciting stuff happening, it it IS progressing:

I had to extract a broken bolt from the front of the block - an M6 timing case bolt had sheered off.
Twas a bit tricky to remove!

 

post-100072-0-50805200-1501323881_thumb.jpg

 

After block was totally stripped, I removed the OP relief valve & sleeve, then tapped the hole to 3/8 UNF:

post-100072-0-43821300-1501323907_thumb.jpg

 

As I had an E31 head, it ran the camshaft spraybar.

post-100072-0-11477100-1501323928_thumb.jpg

 

This is not an ideal setup as it can get easily blocked, & it is one of the reasons why Nissan changed to an internally oiled camshaft later in production.

Rather than raid a later model head for it's towers, and as my towers were in good condition I simply welded the oil feed & mounting holes in the 3 towers up with my TIG:

 

post-100072-0-62459400-1501323956_thumb.jpg

 

I also found out recently that new billet camshaft blanks ARE available (although not cheap!), so I've decided to order one of them & have it ground.
This will keep the base circle large and help with rocker wear & geometry.

Lastly, these arrived today:

post-100072-0-70040700-1501323988_thumb.jpg

 

133mm H-beams.
I did a bit of eBay research & found a seller that was selling what 'looked' like MAXSpeed items, but for $100 less.
I took the punt & ordered them: to my delight they were! They also look surprisingly similar to the more expensive Eagle brand items...

Initial inspections reveal them to be quite good quality - Les measured the big ends, found them to be parallel & on bottom tolerance.

I just have to check their weight and the little end sizes with the gudgon pins when the pistons turn up.

 

The E31 head has been checked over by Les, to-whit he pronounced it fit for the scrap bin :(
I objected. Les made a face. Then he conceded that Head Stud Developments could probably salvage it - for a price. 

 

TBC...

Edited by Lurch ™
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Nice work, I suspect most E31s are trash by now. As are so many of the earlier heads. Just another reason it's hard to find an original early car with early parts still on it.

 

I'm guessing it was corrosion on your head also?

 

Is there other mods required to fit an internally oiled camshaft? I seem to recall needing to block off another passage?

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I'm guessing it was corrosion on your head also?

Is there other mods required to fit an internally oiled camshaft? I seem to recall needing to block off another passage?

A small amount of corrosion, but nothing to be concerned about.

The bigger issue is that it's likely become soft... :-\

 

 I'm unaware of blocking off a oil feed passage...?

 

 

Now I'm wondering if my E31 head might be knackered too.

 

Mark, my L24 has had a fairly exciting life. I wouldn't stress about your E31 until it's been checked out ;)

 

Edited by Lurch ™
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133mm H-beams.

I did a bit of eBay research & found a seller that was selling what 'looked' like MAXSpeed items, but for $100 less.

I took the punt & ordered them: to my delight they were! They also look surprisingly similar to the more expensive Eagle brand items...

Initial inspections reveal them to be quite good quality - Les measured the big ends, found them to be parallel & on bottom tolerance.

I just have to check their weight and the little end sizes with the gudgon pins when the pistons turn up.

 

 

 

 

 

I suspect a lot of these eBay "4340 H-Beam rods" come out of the same factory. I bought two sets of 6 generic 130mm rods from the same seller a while back, and made 3 sets of 4 out of them. All 12 weighed within a few tenths of a gram and checked out perfect everywhere else.

 

Looking forward to the rest of your build !

Edited by 1600dave
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