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LJ70 2.4 LT-2 ,any ideas to get more power out of it without destroying the engine?

Boboc.theo

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Oct 2, 2023
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romania
So,I think my 2.4 engine is a little too weak for the weight of the car and im looking into modifying,please just mods for the engine,I dont want any swapping done on it hence its a historical vehicle in my country and I dont pay taxes for it,but I cant seem to bare the lack of power in the forest,thanks:)
 
So,I think my 2.4 engine is a little too weak for the weight of the car and im looking into modifying,please just mods for the engine,I dont want any swapping done on it hence its a historical vehicle in my country and I dont pay taxes for it,but I cant seem to bare the lack of power in the forest,thanks:)
I have a 92’, not as nice as yours but i am working on it. My thoughts on the power was installing an inter cooler. Cools the air before it comes into the turbo. I myself have not tried this, I am still working on getting this road worthy but this will be next step. good luck
 
The weak part on these engines has always been the flawed design of the cylinder head, which sooner or later cracks, even with proper/regular maintenance on the cooling system.
I would be wary of trying any tweaks to get more power, but extra cooling as above can't do any harm.
Check out your egr/throttle body/inlet manifold, mine was choked with black, tarry sh*t
Incidentally, I never found my 78 with same engine underpowered, even towing or loaded with tools, it just needed considerate driving for the occasion, they are not built for out and out power.
The 3.0 kz engine seemed to be a popular choice for replacement, but I understand why you don't want to go there.
 
The weak part on these engines has always been the flawed design of the cylinder head, which sooner or later cracks, even with proper/regular maintenance on the cooling system.
I would be wary of trying any tweaks to get more power, but extra cooling as above can't do any harm.
Check out your egr/throttle body/inlet manifold, mine was choked with black, tarry sh*t
Incidentally, I never found my 78 with same engine underpowered, even towing or loaded with tools, it just needed considerate driving for the occasion, they are not built for out and out power.
The 3.0 kz engine seemed to be a popular choice for replacement, but I understand why you don't want to go there.
Is there a intercooler brand i should be looking at?
 
Not that I know of. There is not much room anywhere, and it would have to be front mounted IIRC.

Ben on here now in Oz, I think fitted a diesel Vauxhall Frontera one to his, between rad and front grill at the top, and adapted hoses to suit, and it was skinny enough not to block too much of rad.
He is a legend has a massive blog on here of mainly 70 series stuff when he was living in uk, and after, a lot on his 1st cruiser named LJ, if you do a search, you should find it, but it is many, many posts long, and some years ago.
 
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Hi there! Installing an intercooler is definitely the way to go to get more power reliably, but you need to make sure your cooling system is up for it. Also, ideally you'd have the latest design of cylinder head or one from a 3L, since the early ones are prone to cracking and adding more power certainly won't help.

On my LJ79 (factory n/a 3L engine) I put a water-to-air intercooler. Plumbing the system is a little more complicated but allows for shorter piping aiding spool-up, and better slow speed performance when offroading. Also easier to route water piping to the front and adding a secondary radiator.

IMG_20231007_174446.jpg
 
Interesting, so are you saying that 3L head will fit the 2L block?

Nice set up, my brake booster is on the left… i am going to have to figure out how to make it fit. Tomorrow the original head off the LJ73 is going to the machine shop to be cleaned and refitted, exited to see this running.

Thanks for the info,

s
 
Next is tires, i am looking for what i have heard to be called pizza cutters. looking for a bone stock look or maybe kinda mil spec.

s
 
Yes 3L head will fit on a 2L-T.

"Pizza cutters" refers to tall and skinny tires, like 33x10.5R15.
 
Wha, nice. Ok very good. Very exited.

Yes, on the pizza cutters, I just recently learned of this term and i did not know if this was universal slang.

On the subject of tires, do you think its better to get larger wheels , for example 17” to reduce the weight of the 33” tires? I feel like the 15” wheel with 33” tires is a lot of tire weight to move. I am never going to go on extreme off road climb boulders and such. I did find a tire comparison chart on line, it’s fascinating.

I will start researching the 3L head soon.
 
As I understand it, a 3.0 head is not a direct swap, it's a 2.8 from another vehicle in the earlier Toyota range, like hens teeth.
This came from a discussion on here back in the mists of time.
Look for threads in 70 series by Roger Fairclough, a very knowledgeable guy, we no longer see.
I can't remember all the details, as it was a while ago, so I replaced a standard better engineered head from Roughtrax.
I hope you don't get any nasty suprises when your head goes in the machine shop, although any/most cracks if there, can easily be seen by yourself. Fingers crossed !
 
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Wha, nice. Ok very good. Very exited.

Yes, on the pizza cutters, I just recently learned of this term and i did not know if this was universal slang.

On the subject of tires, do you think its better to get larger wheels , for example 17” to reduce the weight of the 33” tires? I feel like the 15” wheel with 33” tires is a lot of tire weight to move. I am never going to go on extreme off road climb boulders and such. I did find a tire comparison chart on line, it’s fascinating.

I will start researching the 3L head soon.

You could, will definitely weigh less and always beneficial to have less unsprung weight, especially if you're not planning on doing any heavy offroading.
 
Love it, I am going to research, all this info is so helpful and I do appreciate it.
I realize in the US, the 70 is scarce and the resources are too. Diesel is not common either and on top of that the (VW) TDI scandal has made it even more unpopular. I took me a year to find a mechanic in NY and he is from the Dominican Republic. Most of the diesel mechanics here are familiar with the TDI or a Cummings. I was on the fence and ready to give up til recently. Ok, I am off to the machine shop.

Thanks all.

s
 
As I understand it, a 3.0 head is not a direct swap, it's a 2.8 from another vehicle in the earlier Toyota range, like hens teeth.
This came from a discussion on here back in the mists of time.
Look for threads in 70 series by Roger Fairclough, a very knowledgeable guy, we no longer see.
I can't remember all the details, as it was a while ago, so I replaced a standard better engineered head from Roughtrax.
I hope you don't get any nasty suprises when your head goes in the machine shop, although any/most cracks if there, can easily be seen by yourself. Fingers crossed !

By 3L I meant engine code, not 3.0ltr (1KZ)

2L, 3L and 5L engines all have interchangeable heads.
 
I am hoping for the best here and if this head is done then its on to the next path of least resistance to get this J70 on the road.

Thanks for the well wishes though.

s
 
Well, bad news for the J70 project, the head is a paper weight. Guys at the machine shop confirmed the classic disfunction of said 2LT, its cracked.

Roughtrax or maybe OEM head from a different year, or even a motor swap (diesel only) I am going to check this next but if anyone has a suggestion, a direction i could take, i am all ears.
 
Part list for the cylinder head job from another forum….

11101-54121
Head Sub-Assy, Cylinder

[04.1990 - 06.1992] 2LTE…LJ7#
04112-54103

Gasket Kit, Engine Valve Grind
[08.1991 - 05.1993] 2LTE..LJ7#
11115-54084-FO

Gasket, Cylinder Head
[04.1992 - 05.1993] 2LTE.LJ7# MARK F

Order 14 of these:
90910-02080

Bolt(For Cylinder Head Set)
[04.1990 - 05.1993] 2LTE…LJ7# NO. 1

Order 4 of these:
90910-02081

Bolt(For Cylinder Head Set)
[04.1990 - 05.1993] 2LTE..LJ7# NO. 2

11802-54021
Bearing Set, Camshaft


CAMSHAFT
[04.1990 - 05.1993] 2LTE. LJ7# ST D

Their consensus is to get the OEM japan parts, according to post, parts have been improved.
 
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