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12HT 60 Series vs 1HDT 80 Series

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12HT 60 Series vs 1HDT 80 Series

Hi guys,

I currently have a 89 series cruiser with the legendary 12HT motor with approx 310,000 k's on the clock with all the lift, tyres exhaust etc. Its pretty clean with no rust and paintwork as new, but im currently weighing up whether I should get an 80 series or not. Is the 80 series much more powerful and can handle aircon on while going up hills with 33's etc?

Also when I turn the aircon on in my 60, it is not idling up like it should. Apparently they have an idle up mechanism but mine is obviously not working... Any help with fixing this would be appreciated.

Josh

Unread postby jpyle553 » June 29th, 2011, 8:58 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

jpyle553 wrote: handle aircon on while going up hills with 33's etc?




Christ yeah, factory td has gobs of go even with 35 and fully loaded up winding mountian hills, i have never ever run out of puff, ever. Thats without playing with fuel or temps, throw a 3" zaust on and they go very very well and if you tune them a bit, go like stink.

Unread postby MJ80 » June 29th, 2011, 9:08 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

Well im running 32s on my 60 and going up toowoomba range she will heat up a bit and gets a biy sluggish...

Unread postby jpyle553 » June 30th, 2011, 1:02 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

12HT is a powerful engine, no question on that. 1HDT is more than you expected. Try it and you'll learn to lover it.

Unread postby wongtsenhin » June 30th, 2011, 3:04 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

Well im trying to get my 12HT running right, as I am sure it is possibly running a bit more sluggish that what it is supposed to. I heard they should take 33's no worries, but when I put 32's I noticed a loss of power straight away.

Unread postby jpyle553 » June 30th, 2011, 9:16 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

Hi Jpyle553,

I had a HJ61 with the 12ht with 550000klm on it & 33's a few year ago & it was the most impressive turbo diesel engine i have driven in 4wd's,
no doubt the 80 series is more comfortable & has more power & torque but that is technology for you, the 12ht is more basic & still performs very well IMO when running correctly, I can't say I had to turn the air con off to climb hills though, i towed a VS statesman on a car trailer from the south side of brisbane to the north & was amazed at the pull the old girl had in her. I have an 80 series now but only 1HZ & the ride comfort is much better than the 60, however the later model is more expensive to maintain & service. ie valve adjust, timing belts, injection pumps etc. In the end it will be your personal preference as both trucks have pros & cons.

If I remember correctly the idle up mechanism is vaccum operated, you may need to check all the small hoses around the pump as well as the fast idle solenoid I think it is on the driver side inner guard (will also have small vacuum hoses to it).

Hope this helps

Unread postby KCHZ80 » July 1st, 2011, 8:51 am


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Re: 12HT 60 Series vs 1HDT 80 Series

If your only issue is power, th rest of the car sounds great, it is relatively easy to get about 90kw at the wheels from a 12ht, which is more than the new v8 turbo deisels

Unread postby hulsty » July 1st, 2011, 12:53 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

jpyle553,

OK back to basics.
Change the oil and filter, change and bleed the fuel filter, change the air filter.
Check and adjust the valve clearances, pump timing.
Have the injectors serviced.
A compression and cylinder leak down test would also be a good idea
You have a few good diesel places in Toowoomba, time for a visit.

Over heating;
make sure there is no bugs/mud clogging the radiator or aircon condesor
Check the viscous coupling on the fan is operating correctly, if in doubt change it.
Change the Thermostat.
Change the coolant for the Toyota red coolant and distilled water.
Change the radiator hoses.
Flush the crap out of your heater core while you're at it.
Is your water pump weeping?

Another thing to get checked is whether the radiator has a partial internal blockage.
Toyota did their sums pretty well on cooling capacity on the cruisers, they gave you exactly what you need, and not a lot of extra capacity. It doesn't take much to overwhelm the cooling system if you have fuelling issues, are running hard and have age related deterioration in the cooling system.

Cheers

Unread postby dhc4ever » July 2nd, 2011, 9:02 am


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Re: 12HT 60 Series vs 1HDT 80 Series

hulsty wrote:If your only issue is power, th rest of the car sounds great, it is relatively easy to get about 90kw at the wheels from a 12ht, which is more than the new v8 turbo deisels


ehh, the new v8 single turbo diesel is putting out 151kw at the engine, i doubt it'd be less then 90kw at the wheels...

Unread postby maddog_75 » July 2nd, 2011, 8:20 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

climbing the toowoomba range, she would do it in 4th pretty much full throttle and it would start to heat up. Its got plenty of zip down low, but up high its a different story.

If the injectors were stuffed, wouldn't she throw out alot of smoke? It currently just blows normal amount of smoke.
And as for checking the valve clearances and timing, I don't know how to do that, but maybe theres a place in toowoomba or ipswich??

Unread postby jpyle553 » July 3rd, 2011, 9:26 am


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Re: 12HT 60 Series vs 1HDT 80 Series

Hi jyple553,

There is a funny thing about mechanical type injectors, in that they will actually increase performance the older they get due to nozzle erosion (ie the holes in the tip get bigger & allow more fuel into the combustion chamber so they will blow a little more smoke but will also give you more power) there have been many case where new injectors are fitted & instant low power complaints arise. When you say low power up high what rev range are you talking about? The 12Ht will develop its maximum torque at around 2000rpm & maximum HP at 3500rpm so any higher revs than that & you will not feel any more acceleration, but you will use more fuel. If you are not towing try shifting gears just before 4000rpm & see how it feels you may be surprised.

Ditto with dhc4ever about the cooling system checks. Any half decent mechanic in Toowoomba should be able to adjust the valve clearances & check injection timing on a 12HT.

Hope this helps

Unread postby KCHZ80 » July 3rd, 2011, 9:51 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

I wish I never sold my old girl. I could come up the the toowoomba range in 5th gear with 33's and back to 4th with 35's on. Tony at Mtq in toowoomba use to look after the old girl keeping her in tune and making sure the egt did not get to out of hand. In the end I had 95kw at the rear wheels with the 35's on. The only time she got hot was coming up the range towing another 60 on a trailer but that's because of wrong gear selection and ended up having to use 3 gear in low range to help ease the strain on everything. Long live the 60 and live longer the indestructible 12ht. Pitty they are getting harder and harder to get hold of, they are an orsome engine.

Unread postby good old 60 » July 5th, 2011, 10:54 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

My 12HT has only done 175k so still very young. I have 33s and can pull up Willunga Hill (for those in Adelaide) with a horse float with and two thoroughbreds in 4th gear nearly all the way to the top. It does sort of die in the arse over 2K RPM but has mountains of torque.

Get an intercooler, they rock

Unread postby Toy12HT » July 14th, 2011, 10:28 pm


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Re: 12HT 60 Series vs 1HDT 80 Series

maddog_75 wrote:
hulsty wrote:If your only issue is power, th rest of the car sounds great, it is relatively easy to get about 90kw at the wheels from a 12ht, which is more than the new v8 turbo deisels


ehh, the new v8 single turbo diesel is putting out 151kw at the engine, i doubt it'd be less then 90kw at the wheels...


Why is this hard to believe a td42t stock will struggle to get 65rwkw

Unread postby dann » September 1st, 2011, 10:44 pm



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