HJ61 cruiser owners, fuel economy and tires sizes....

Submitted: Monday, Mar 15, 2004 at 07:34
ThreadID: 11250 Views:14430 Replies:3 FollowUps:0
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I recently bought my first diesel, a 1988 HJ61 "deluxe" which I believe is the automatic version of the Sahara. I purchased it from my ex wife's brother, (I knew I married her for some reason) who regularly changed the oil for the two years he owned it, but that about it. I only paid $8,500 for the car, and yes it does need some work. However it has numerous accessories fitted including ARB bullbar, IPF spot lights, Kaymar swing away rear wheel carrier, cruise control, and more, plus the factory luxuries drink cooler/ice maker, dual aircon, etc. etc.

It has the 12-HT engine which compared to my old 82 2F petrol troopy, is a dream on fuel, not to mention the vastly improved ride and lack of noise. (I drove the troopy from Cairns to Adelaide and back, twice, once via Melbourne, is there an award for that??)

I don't mind the auto, but unfortunately the lock up on the torque converter is shot, and when it changes into O/D it shudders, and also on acceleration in O/D. So, out with the auto and in with a 5 speed, which I have lying around in the shed. (I am a cruiser hoarder, I still have my 82 troopy, plus a 77 FJ55 with 302 Cleveland and 5 speed Trans that I have been restoring for 6 years now....)

So after all that waffle, I was wondering if there are any other 12HT owners out there who can give me some advice on the following:

1. A good diesel mechanic/tuner in the Cairns area.

2. What sort of fuel economy are they getting? (auto and manual)

3. Any tips on what modifications work, and what to look out for with 12-HT engines. (mine has a 3” mandrel bent exhaust fitted, I was wondering if this would improve or impeded performance)

A work colleague has an identical cruiser to mine with the exception that his is manual, and he gets around 26mpg around town. I get around 22. I do recall a post on this site a last year about someone getting 40mpg out of a 2H diesel 60 series cruiser, which caused a few sparks to fly. One thing I was amazed at is that no raised the issue of tire size and speedo correction. I had 31 x 10.5 x 15" wheels on my troopy, and my speedo was reading a higher speed that I was actually doing, when meant that fuel economy would have been incorrectly good. (well, not good but better on a 2F!!)

So I measured the diameter of my tyres, and found that a 31" tyre is in fact only around 29" in diameter. I fitted new wheels and tyres, 265 x 75 x 16” which did not improve the fuel economy on paper, but made a huge difference in engine noise/rpm when driving the vehicle in top gear. (only a 4 speed transmission, no over drive).

So, does Toyota have two gears for the speedometer drive? or, do they calibrate the speedo to the tires fitted at the factory? My HJ61 has the original tyre fitment sticker in place inside the driver’s door, and shows both 10R x 15” and 7.5 16” were factory options.

Thanks in advance for you views,


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Reply By: Member - Des Lexik(SA) - Monday, Mar 15, 2004 at 12:17

Monday, Mar 15, 2004 at 12:17
G'day Fly, I don't have the old girl anymore but I found the speed indicated on the speedo was about 5% higher than actual speed which was OK as I never got a speeding ticket either. The K's shown as distance travelled was also higher too but so what! I would get similar economy as you are getting maybe a little less.
The motor should last you 5-600000k's before any signs of trouble.
The 61series are a great truck (Stir intended)
AnswerID: 50377

Reply By: mijochka - Monday, Mar 15, 2004 at 12:45

Monday, Mar 15, 2004 at 12:45
I have a '89 HJ61 manual factory turbo which I bought 6 months ago along with a 24' Quest caravan of similar vintage. Both are in superb condition and were purchased from a retired couple who had maintained the equipment meticulously and were forced by ill health to sell. He's a retired truckie (as am I) and has remained my mentor in all matters relating to the vehicles. I think if he thought I was being unkind to his pride and joy he would come and repossess them. The Cruiser has 250,000 ks up and is basically stock except for a 3' exhaust,snorkel,turbo timer, extra leaf in the rear springs, vaccuum over hydraulic van brakes and a hayman reece hitch.The previous owner advises me that the 3' exhaust made a perceptible improvement to the performance and fuel economy.
I get about 12l per 100k (23.5 mpg) around town and 17l per 100k (17 mpg) towing the van. This was on a Brisbane-Tamworth return trip which is very hilly terrain. Still quite acceptable as the whole thing goes close to 6 tonne. Going to Townsville at Easter and would hope to do a little better.
We're not really hard core 4wdrivers, but I did a course with Duncans, found it very informative and found that the old cruiser was at least the equal of some much later and more expensive jiggers present on the day.
Haven't done an unladen highway trip so don't know about that.
Tyres are new 31x10.5 R15. Haven't had a speedo check done, but when travelling in convoy with our other vehicle with known speedo error, it seemed about right.
AnswerID: 50383

Reply By: Member - Chris O (VIC) - Monday, Mar 15, 2004 at 18:59

Monday, Mar 15, 2004 at 18:59
G'day Fly,

I have a 1986 manual Sahara HJ61 with the 12 HT engine.
I use it to tow a 15ft Trakmaster caravan.
I get 12lt / 100 k without the van on the back & 14lt / 100k whilst towing.
Mine has done around 215,000 km

Hope this helps
AnswerID: 50423

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