2.6 Astron in an L300 2WD

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gemsince88
Posts: 9
Joined: Sat Dec 03, 2011 3:19 pm
Location: Newcastle

2.6 Astron in an L300 2WD

Post by gemsince88 »

This is my boss’s 1995 L300.
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Its done over 380,000 Kms and the 4G63 is stuffed. I have been thinking of this conversion for a while because ever since he got it it’s been slow. We had a drag race between the empty L300 and his loaded up 1.8 Econovan and the Econovan beat it by miles. It was using a lot of oil and recently the water pump went so it was time to change it. I must admit it kept going all these years even after he set it on fire. :roll:

Last year I did some research and figured out that the 4G63 in the L300 was a narrow block and that I would need 2.6 Sigma Astron auto for the easiest conversion. A few months back I asked a friend of mine if he knew of any and found out about a gold mine of old car parts where there was a GJ 2.6 Sigma. It was an ex demo derby car that was originally a granny car with 110,000 Kms on the clock. When it was derbied it lasted about 3 minutes before it was rolled onto its roof.
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You can't see him but my 13-year-old son is steering it. We fired it up before taking it and there was not one puff of smoke!
We took the whole car and ripped out the motor on the street out the front of my place taking everything that we thought was needed then scrapped the shell.
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As I couldn't find anything on the motor to say it was 2.6l I consulted this forum and found this thread.
http://www.sigma-galant.com/viewtopic.php?f=93&t=1800
According to the numbers it is a 2.6 and from 1987 so I'm thinking the granny had the motor changed and this one has done less than 110,000 Kms. So good score for $200.

The thing about these vans it takes an hour just to pull everything out to get access to the motor.
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A fair bit of room in the engine bay for a van.
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Note how much space is in front of and above the motor. This is what led to think the 2.6 would fit.
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Motor is out!
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The two motors side by side. Note the bell-housing bolthole just above the starter boltholes. They are in different spots but the L300 gearbox has holes in both positions.
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Pulled the torque converter and flex plate off the Astron. 6 bolt crank, as you would expect.
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Pulled the clutch off the old motor and saw this then said shit numerous times.
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Now I knew about the 7 bolt cranks but I was hoping it would be the same as the Astron. My X-Ray vision wasn't working so I didn't know until I got this far. Went to a couple of wreckers with the clutch and flex plate with the hope of finding something. The first place didn't have anything but said I would need a flywheel off a 2l Sigma or early L300. The second place first said "Nah we don't do L300's anymore. We won’t have anything unless it’s a Lancer". Then some old bloke came out, had a look then disappeared up the back. He came back with this.
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It’s from a 1.6l L300.

Cleaned up the flywheel and bolted it all together. It still has the factory machining marks in it.
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Now for some strange reason I thought I would need a Magna sump but it doesn't look like you do. Went back to where we got the sigma and found this.
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It is/was a TR Magna.

We needed to get to the sump. So when you are in the bush!
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Some people told me it couldn’t' be done because it wouldn't fit. Then they said you would have to move the radiator or put electric fans on the front and I said "So!" I measured the 2.6 Astron and it looks like the radiator will have to move forward a minimum of 30mm but 40mm to be comfortable. But from the pics you see there is plenty of room. You save a few mm by using the Sigma fan. It doesn't sit as far from the motor as the original.

Next thing is to work out and swap over certain things on the motor and check the engine mount spacing.
One thing I noticed is that the gearbox is tiny. Oh well if he blows it up we'll just have to put something bigger in!
Last edited by gemsince88 on Sun Dec 11, 2011 7:56 pm, edited 2 times in total.
A112H
Posts: 7681
Joined: Tue Mar 24, 2009 5:01 am

Re: 2.6 Astron in an L300 2WD

Post by A112H »

Great write up, can't wait to see it finished, should go really well when finished.
On a side note, back in the day I used the top hat of a van carbie, same as the one on yours, and used it on my Scorpion as a cold air intake, lol. Just fitted a pod filter on the end of it :)
gemsince88
Posts: 9
Joined: Sat Dec 03, 2011 3:19 pm
Location: Newcastle

Re: 2.6 Astron in an L300 2WD

Post by gemsince88 »

Thanks Jason.
Good idea with the cold air intake!

Checked the engine mount spacings because I saw this.
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The L300 bracket has the mount sit closer to the block. As it turns out the Sigma brackets are fine. Might be handy to drop the motor down a bit for some reason. The bracket on the other side is completely different to the 4G63 bracket.
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Note how short the dipstick is and bear in mind the drivers seat will be over this part of the motor.

Went to bolt up the L300 mounts to the engine and had a small interference problem. Solved it with a grinder.
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I wanted to use the temp sensor out of the old engine as the electrical characteristics may be different in the Sigma and the connector was different. To be on the safe side I bought a adaptor.
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I fitted the L300 alternator to the Sigma position and made up a bracket with the intention of using the AC compressor bracket above it with the L300 compressor. This will be moved later as there is a problem with it there.
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Next modified the air intake and test fitted.
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It was then I thought I wont be able to get the dipstick when the seats are in so started to look at how to fit the dipstick off the old engine and saw this.
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Drilled the broken stud out and fitted a slightly longer one from Kawasaki 1100 head that I had. Pulled the short dipstick out and put in the longer one. Used the kick down cable bracket from the other side to bridge the gap and secure the tube to the replaced exhaust stud.
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Still thinking I could use the AC compressor bracket I wanted to fit the L300 compressor but the thermal vacuum switch was in the way. So I fitted a brass elbow.
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So after a fair bit of wiggling, jiggling and swearing we got the engine in bolted to the gearbox and mounts.
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I went to fit the compressor and found that it hit on the suspension torsion bar and the chassis rail. Now if we didn't want to have AC then this would have been the end of it but my boss loves his AC so we had to figure it out.
My friend had a TR Magna demo derby car in his back yard so we grabbed the compressor and bracket off that. Fitted it up to the motor and found the pulleys didn't line up. We then tried to make a bracket to suit the L300 compressor that bolts to the Magna bracket but that ended up the same as the first set-up hitting the chassis rail. So having to use the Magna compressor we went to see my friend at Freeze Equip (automotive AC specialists) to ask if there was another pulley we could use. There isn't!
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The difference was a whole pulley width so we grabbed a spare pulley and cut the centre out with the lathe.
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Welded it onto the compressor.
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The Magna compressor is a Denso and has different fittings to the L300 Sanden unit but Freeze Equip can make up hoses to suit no problem. Bolted the compressor to the engine and simply spaced the idler pulley out to suit.

Now that the compressor is mounted where it is there is no room for the alternator. This means it has to go on the other side and a bracket had to be made. That’s all right as this is where it was on the 4G63 and now I don't have to extend the alternator wiring. :D
Made up a bracket for the alternator using some 5mm flat bar and a welder that bolts to the threaded holes at the front of the block and timing case. Fitted the alternator and found another small problem. The belt comes really close to the bottom radiator hose on the water pump. Too close! Made up a back idler pulley from more flat bar, part of the AC idler from the old engine and an EA Falcon idler pulley.
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Still have to figure out the bracket to tension the fan belt and then the radiator mounts. :think:
A112H
Posts: 7681
Joined: Tue Mar 24, 2009 5:01 am

Re: 2.6 Astron in an L300 2WD

Post by A112H »

So not really a slip it in and fire it up change over then lol.
Glad to see you have some great ideas, skills, tools and mates on hand. This is turning into a very good thread and I am sure it will encourage others to do the same.
Nice one :thumpsup:
gemsince88
Posts: 9
Joined: Sat Dec 03, 2011 3:19 pm
Location: Newcastle

Re: 2.6 Astron in an L300 2WD

Post by gemsince88 »

On the home stretch now!

I shortened the 4G63 alternator bracket and attached it to the bracket I made for the idler pulley.
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Ended up cutting the end down a bit to clear the radiator hose better.

I went to pick up some Gemini guards from my panel beater of 20 years and mentioned what I was doing with the L300 and the radiator mounts. While I was there he made this up for me.
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It’s a piece of 1.2mm steel bent up to 40mm with 10mm sides.

Cut it down to 400mm long and drilled 2 20mm holes the same as the cross member.
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With the piece in position the holes have to be 35mm forward of the originals.

Welded the new bracket in on top of the cross member. Don't take notice of my crap welds. :$
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Made a new top bracket.
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This tilts the radiator forward as far as it can go. You need every mm!

Cut about 100mm off the bottom hose so it fits better.
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Installed the radiator, shroud and fan. The top of the shroud is missing from the fire. Used a Sigma top radiator hose.
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See how close the bottom tank is to the steering rack.
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Also the fan blades are about 10mm from the bottom tank and about 15mm from the AC idler pulley. Its really tight but it works!

Modified the original brackets for the AC condenser to sit 35mm forward. The bolts just clear the steering rack too.
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Finished doing all the usual motor change stuff like the plumbing and electrical connections. Fitted the L300 starter motor as the Sigma one doesn't have threaded holes because it had bolts that screw into the bell housing. The Sigma starter also is so long it requires removal of the engine mount to fit it.
Still have to connect the exhaust.
Filled with oil and coolant.
Kicked it in the guts.
The L300 starter I think struggles a little but after the fuel hit the carburettor it fired up. There are no obvious leaks and the belts on the front run true but there is a problem. The automatic choke worked properly but I noticed a few hiccups and when the choke came off it had trouble idling. It sounds like a vacuum leak or a blocked idle jet. I'll have to check all the vacuum lines as I pretty much guessed where they went. Then I'll check what’s going on with the carb. I'll do it tomorrow so not to piss the neighbours off as It was getting late and I had it running straight off the manifold.
gemsince88
Posts: 9
Joined: Sat Dec 03, 2011 3:19 pm
Location: Newcastle

Re: 2.6 Astron in an L300 2WD

Post by gemsince88 »

It's finished!

I found a vacuum line diagram and checked everything. Swapped a few things around and blocked some off. Then discovered oil was pissing out of the bottom the fuel pump and so replaced it. Checked and adjusted the ignition timing.
Next I started on the carburettor. I put the carb off the old motor on to see what would happen and it idled really well so I knew the idle problems were coming from the carb. Couldn't leave the 2l carb on as it's not jetted right and would probably burn valves out from a lean mixture. Pulled the 2.6 carb to pieces as far as I dare and cleaned as much of the crud out as I could.
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Bolted it back on the motor and it still wouldn't idle. There is some sort of bypass valve at the bottom of the picture that was the main problem. Swapped it with the one from the other carb and things improved. Still occasionally wouldn't idle so put a bottle of carb cleaner in the tank.

Made up an engine pipe from the manifold to the cat.
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Spent a whole day at Freeze Equip getting the AC running. A lot of the original pipes and joints were seized and some broke when pulled apart but got there eventually.
These are the new connections on the compressor.
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You need the Magna pipe connections on the compressor, as they are unique to that compressor.

Put the seats and cargo barrier back in.

Final touch.
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All done and running.
http://www.youtube.com/watch?v=5SVIuh1Kyss&context

To conclude!
It drives a lot better and has a lot more torque which is what the boss needs with the 600 odd Kgs in the back.
If you don't have or want AC then this would have been a relatively simple conversion. You would just have to modify the air intake, exhaust, extend the alternator wiring, leave the radiator where it is then put an electric fan on the front and your done.
Half the time taken with this one was trying to make the AC work and getting it to run properly.

Worth the effort in the long run!
A112H
Posts: 7681
Joined: Tue Mar 24, 2009 5:01 am

Re: 2.6 Astron in an L300 2WD

Post by A112H »

Congratulations, looks like a job well done and a brilliant write up. Perfect smooth idle in the vid.
:thumpsup: for the finishing touch, lol
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ddt
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Location: Perth

Re: 2.6 Astron in an L300 2WD

Post by ddt »

Top job :thumpsup:
Very thorough and well documented write-up.

Have you driven a 2.6L astron before? -just wondering to what extent the smaller 1.6L flywheel affects driveability?
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'Member's Rides' Link for LIL RED WGN: http://www.sigma-galant.com/viewtopic.php?f=46&t=4742
A112H
Posts: 7681
Joined: Tue Mar 24, 2009 5:01 am

Re: 2.6 Astron in an L300 2WD

Post by A112H »

ddt, Mine is a 1987 Magna block and it uses a 1.6 fly and clutch. I haven't driven it for real as yet but it certainly revs nice and smoothly and is very 'sharp' to the throttle.
gemsince88
Posts: 9
Joined: Sat Dec 03, 2011 3:19 pm
Location: Newcastle

Re: 2.6 Astron in an L300 2WD

Post by gemsince88 »

I can't say that have driven a 2.6 before but I know what the 2l was like and this set-up seems to have a better throttle response while still being smooth. So I would agree completely with what Jason said.
When I said to my boss what flywheel I was using he just smiled. He used to get the flywheels lightened on his Holdens to help with the throttle response so even though he drives like an old fart he really is a rev head.
2Lgalant
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Re: 2.6 Astron in an L300 2WD

Post by 2Lgalant »

Very helpful thread I recently got a express van and want to do the 2.6 conversion only thing is does it need an engineers cert as they never came out with the 2.6s did they ? Any know
gemsince88
Posts: 9
Joined: Sat Dec 03, 2011 3:19 pm
Location: Newcastle

Re: 2.6 Astron in an L300 2WD

Post by gemsince88 »

If it’s the same model as ours then you probably wont need an engineers certificate. The RTA says you are allowed up to 15% increase on the largest capacity motor available from factory for your model without the need for a certificate. AFAIK this model came out with 2.5 diesel and later models with the same body had the 2.4 petrol, so in theory you could go to 2.8l. Even though it’s a different fuel they do count the diesel as the largest motor.

It probably depends on the inspector and how far you are willing to argue the point. I haven't even attempted to have ours inspected yet as my boss doesn't give a shit as long as it goes.
2Lgalant
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Re: 2.6 Astron in an L300 2WD

Post by 2Lgalant »

Ok awesome all I need is the manual conversion as its auto then I'm away im not worried bout a/c so be easy to change over will be sick making a shagin wagon out of her ha ha ;)
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