Essential Prado LJ78 upgrades/mods... (1 Viewer)

[Zalinko]

There is a rising number of us who are driving RHD Prado/LJ78's and many of the threads on this forum are very useful.
I would like to have those of us/you who have discovered necessary/essential upgrades/mods to your Prado's (early 90's, 2L-TE) to post them so we can all befefit from each others' experiences.
Perhaps the other/already posted threads could be added here so as to create one thread where we can learn together?
Thanks in advance for you wisdom and insights!

-Paul

 

[light_duty]

So far the only upgrade I've made is to change out the cylinder head (almost done!) Wayne's done more than anyone I know in terms of modding his LJ78 - I think he's put a snorkel on there, and was going to try to lift it, as I recall.

This link shows what's possible with these rigs, though...http://www.baby-troupe.i8.com/4wd-Monthly-Article-Issue-70/4WDM-ISSUE-70-Article.htm

 

[Zalinko]

Indeed, Baby Troupe is looking good!

I guess I'm more stressing the "essential" part than I am the "mod" part. Because we know that the heads/cooling system are weak points, what are the essential upgrades a person needs to consider before thinking about what size of tire they can fit on a stock LJ78.

Is there an order? For example: If the head ISN'T cracked: 1. synthetics 2. Pyro 3. exhaust, etc...
If the head IS cracked: ...???

More practical than hardcore.

Perhaps the answer is "If you're going to purchase a Prado with the 2L-TE engine then also purchase a new improved head." Everything after this is up to you as far as mods go.

Maybe I'm beating a dead horse here?

Thanks,

-Paul

 

[crushers]

Paul,
i recieved your email.
the tail light issue, get a set of 42 series tail lights and cut them into the chrome bumper. or drive it till you do get pulled over and worry about it then.
side reflectors are easy, go to the local CT and by stick ons and you are good.
the front signals are not DOT either.
as for upgrades, i just finished my first "fixed fan" test drive and i can say the fixed fan eliminated all the concerns of over heating on hills or under power so that would be one of the first to address.
also run high boost levels and that drops the EGTS as well as larger exhaust and surprisingly a snorkel does too.

any further questions ask away.

cheers

 

[PacToy]

Paul,

I have been driving my 92 LJ78 for four years now. I bought it from an export auction in Yamaguchi. I put it on a boat down to Okinawa where I installed a 4.5" lift and put 33" mud tires on it. Remember this is Okinawa where it is hot and humid most of the year. What did I do for essential mods?

I did nothing to the engine at all. I did nothing for the tranny either.

I just drive the Prado within the limitations of the 2L-TE. I never push it hard and never run the RPMs past 3K. Keep it in the powerband. I do my regular maintenance. My 2L-TE has 212,000 kilometers on the clock, the head has never been off and it still runs like a champ.

Now if I was in Canada and wanted to know where to start to make a just bought LJ78 run for ever, what would I do?

If the head is not already cracked:

1) Change the t-belt
2) New water pump
3) New thermostat
4) Fresh fluids
5) Stay off the throttle. The EFI pushes the RPMs way too high for that application.

On this board there my friend who has username: BJ44. He is probably the best Toyota mechanic on island. During the summer months I watch him change about 3-5 2L-TE heads a month. He points out every time where he is replacing a cracked head that the engine was abused. Either they ran them hard (high RPMs) or never did any kind of maintenance.

The 2L-TE is a good engine if you drive it within it's limitations. By no means a powerhouse but a good fuel efficient engine.

I would guess that the cracked heads showing up in Canada is from a lack of maintenance from the PO here in Japan.

Regards,

Randy

 

[2rivers]

Well said Randy and Wayne.

It is easy to flog the 2l-te like you said with a heavy right foot.

Can we agree that the EGR is a suspected contributor of high intake temps/head problems? Can you ask BJ44 what he thinks of the EGR Randy? To block off or not too block off - mind you in Japan you might not have that option with the authorities...



Johnny

 

[2rivers]

ANother thing I guess that would be an essential mod is to fit some bigger meats on the truck to:

a) assist 4 wheeling
b) lower revs on highway cruising
c) get rid of the dinky stock tires most come with!

I still have to cough up for some, but very soon, I will buy some 33" or equivalent in metric..

Johnny

 

[light_duty]

There are great ideas here. A pyro is a great tool. With these little engines, it's a little difficult to tell when you're pushing your engine too hard. A pyro will let you know when you need to back off the throttle.

However, I think a mechanical water temp gauge might be even more critical for this engine. I was running the stock gauge and an aftermarket gauge, and the difference in needle response was pretty amazing. The mech gauge would be spiking all over the place (we're talking 40-50 degree swings in temp) while the stock gauge hardly moved at all. I've heard many complaints about this on aussie Surf forums - your stock gauge doesn't let you know you're overheating until it's too late.

I've heard that the folks at Allhead blame 2L-Tx head cracking on poor impeller design on the stock water pump. They say it causes cavitation, which in turn causes steam to form in the head, which in turn causes thermal shock and head cracks (steam can't carry heat away, so some parts get super hot while others don't). Allhead has designed a different impeller that they claim reduces the problem. I'm not totally sold on this idea - I just put a new Toyota pump in my truck.

Also, make sure you're running Toyota Red coolant - another Allhead recommendation.

Wayne has shown that a large-bore exhaust will reduce EGTs as well.

I think I'm also going to bolt my clutch fan up solid.

Cheers and good luck with your truck! Post some pics!

Robin

 

[crushers]

Robin,
the kit is the same as the one for the 1HZ but you have to drill the holes in the fan a tad bigger...
works like a charm.
Warning:
i am not sure which either the new mud tires or the fan makes the bugger LOUD at 140k/h...

 

[BJ-44]

I don't think the water pump or the EGR are stand alone factors in the head cracking. The heads are a bit weak from the get go, but like Randy stated it usually is acombination of things due to lack of maintenance. It is usually poor cooling system maintenance that kills the 2L's that I see ie. thermostat stuck, clogged radiator, and Okinawan favorite straight water in the rad. etc. The water pump looks like a good factory design compared with others but like with any factory part usually there is room for improvement. Allhead sells new heads and an upgraded waterpump naturally they will tell you you need it to make a sale. I'm sure it is better than stock. The EGR valve if it is working properly with actually reduce Combustion temperatures which reduces NoX gases. With the EGR blocked off or plugged off (because of inspections) which is what I have done before definitely improves performance. Also the engines will rev to 5,000 rpms which is a too high of an rpm for a diesel. The engines don't really make much power past 3,500rpms, so don't overrev it and keep it properly maintained and it will live a happy life.

Shane

 

[crushers]

Also the engines will rev to 5,000 rpms which is a too high of an rpm for a diesel. The engines don't really make much power past 3,500rpms, so don't overrev it and keep it properly maintained and it will live a happy life.
Shane

Shane,
thanks for the info.
question, i am wondering how the rpm afects the head issue. i have yet to see the bottom end of a 2LT go and i know that for every 1000 rpm you double the load on the bottom end. although i do not recomend 5000 rpm i am questioning how this relates to the head cracking/over heating issue...
cheers

 

[BJ-44]

Excessive rpms can lead to excessive heat. The bottom ends are pretty much bullet proof.

 

[PacToy]

Thanks for chiming in, Shane.

Guys I can honestly tell you that Shane knows his business when it comes to 2L-TEs. Please ask him every thing you want to know about a 2L and he will tell you first hand knowledge and experiance what to look out for and what not to do with a 2L-XX.

Wayne, Shane will make you look arrogant with the patter of a few keys and his EXPERIENCE. Please stop being the typical Wayne-o on this forum, shut up and listen for once. Shane is a honest guy with more experience than any other member on this forum for the engine in question.

Heck, Wanye-o we like you. I mean everytime we have some crazy misfortune wheeling our LandCruisers we laugh and ask " What would Wayne do?". Your our hero! (Kinda Sorta)

 

[crushers]

Wayne, Shane will make you look arrogant with the patter of a few keys and his EXPERIENCE. Please stop being the typical Wayne-o on this forum, shut up and listen for once.

ouch.
8^(

curious, what is the average speed limit in Japan? the reason i ask is i am assuming that the speed limits here are higher thus the engines are driven harder. could this be the case?

 

[PacToy]

ouch.
8^(

curious, what is the average speed limit in Japan? the reason i ask is i am assuming that the speed limits here are higher thus the engines are driven harder. could this be the case?

I totally agree with you on this. Yes, absolutely.

The average speed here on Okinawa is 80 KPH on the highway. Most Okinawans will not even do that speed on the highway. Mainland Japan you run 120KPH or get out of the way. No need for massive power here on Okinawa.

I do believe that if you run a 2L-TE over 3000 RPM for any length of time you will eventually kill it. No questions asked, it will happen. So don't do it.

Yes, North American highway speeds will kill a 2L-TE. Keep it within it's powerband and be happy no matter how slow you are going compared to traffic.

Heck, Wayne , you can laugh as they pull over for gas while you still have half a tank.

Truth is most of the poeple that have had busted heads on Okinawa trashed their engines on the highway. Go figure!

Shane can speak better than me on this.

 

[2rivers]

OK. So all the more reason to get some bigger tires to reduce revs? Or is that working the motor more and stressing the motor? thought I had it all figured out .damn.

Question: Has anyone who has done the head swap/upgrade noticed the difference in the groove depth between the valves? I noticed the newer head had less deep of an indent (hope that makes sense) therefore, more meat between the valves (where they usually crack). Is there any other differences between the castings? pre and post 93?

Was there ever any kind of Toyota service/warranty bulletin in Japan addressing this problem? Surely they have sold 100's of not 1000's of heads because of this.

JOhnny

 

[PacToy]

Johnny,

Bigger tires will not hurt a thing on your LJ78. You have stock 4.88 ring & pinions as it sits. Perfect ring ratio to put on a set of 33s and keep the RPMs down.

Disadvantage of bigger tires will be long accending grades. You will loose momentum for sure. Just hit the little ETC (watever it is) button and there you go. Don't let the tranny down kick if at all possible.

I have had 33" muddies on my LJ78 for almost 4 years now. No problems and I drive the LJ78 everywhere.

 

[2rivers]

Thanks for that tid bit Randy, did you ever run 33" without your lift - I think you gots 4" lift right? If so, ever any problems with rubbing?

thanks agin,
Johnny

 

[PacToy]

I got the lift used from the 70 series Owners Club via a friend. My friend bought it and his wife said no way so I got the lift kit for cost. So I never planned on having a lift or bigger tires but I got a deal so I had to lift it and put bigger tires on.

The lift is a 4.5" Zeal blue coil w/ RS 9000 shocks. Took me and a friend all of 2 hours on install the lift.

One friend put a 2" coil lift on his 1990 LJ78 and ran 33"s.

No I never ran my 33"s without a lift. The one friend who had the 2" lift and 33"s had a rough ride and a little tire rub. He bought a el' cheapo lift kit from somewhere.

 

[crushers]

i have been running the 235/85/16 since i brought the first LJ71 in and no problems with stock suspension, no rub off road, no substantial power loss but then i also am running more than factory boost.

one thing i did notice is when climbing the long hills the pyro would climb steadily but when i shifted from OD to 3rd the pyro actually dropped (i have witnessed this on many different turbo'd cruisers) but the water temp does rise hence my test of the fixed fan alterantive...

just my personal observations...
cheers