2.8 to 3.8 conversion. What is the downside?

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Corindi
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2.8 to 3.8 conversion. What is the downside?

Unread post by Corindi » September 27th, 2007, 11:31 pm

My two boys and myself all have 2.8 hiluxes - 90 model with 250,000Km, 92 with 440,00Km and a 97TD with 120,000Km.

The 90 blows engine seals. In the past 12 months it has blown the rear main twice and the front main once and now they are both leaking again.

The 92 was fully rebuilt 40,000 ago. It is very slow, pours out black smoke sending everything on the trailer black and it averages 14 litres every hundred without a load. After the rebuild it was not performing so the injector pump was sent in and the quote to repair/rebuild it came in at $2000.

The 97 was taken off the road last week because of too much crank case pressure. It was stripped down and found to have 3 cracked pistons, broken oil rings and a sloppy turbo.

The boy with the 90 has bought the motor off the boy with the 97 and is rebuilding it. I estimate it will set him back about $6000 as he is sending the turbo away to be rebuilt and the injector pump to be bench tested, replacing the valves grinding the head replacing the injectors .......... and the list goes on.

The boy with the 97 is converting it to a 3.8 commodore engine. The conversion kit was $2,200 and he picked up a donor car for $800.

I asked a few people what was the downside and couldn't get a decent answer.....Is there one, other than 1 metre deep creek crossings? Keep in mind that the 2.8's alternator is located under the engine while the 3.8's is on top and two of us have blown alternators from mud and water.

I have clocked up probably 500,000 on 3.8's over the past 10 years and have never had a mechanical failure other than a tesioner pulley. I have only ever heard of one blowing up and this was due to lack of services.

The negatives

Can't go through 1m deep water.
May use more fuel

The possitives

More power
Replacement motor is $500 not $5000
More reliable
Services every 10,000 not 5,000
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spanna chucka
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Unread post by spanna chucka » September 27th, 2007, 11:42 pm

I had a chev V6 in my old 82 lux it had a 350 holley on it and used about 20 liters per 100km's, but it was running 33" tires.
Heaps of grunt cool exhaust note just realy thirsty albeit mine was a carby fed chev not an injected buick based V6
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Corindi
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Unread post by Corindi » September 28th, 2007, 12:04 am

It will be running 35's, I think this will be a good thing though because it will lower the revs closer to what the 3.8 was designed for. ie. 2000 RPM in top gear at 100Km/h.
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boof
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Unread post by boof » September 28th, 2007, 6:51 am

Biggest downside is they are thirsty and although it will be more powerful than the 2.8 they are low on power and are gutless at low revs. IMO there are so many better options in the Toyota 6 cylinder range.
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babylux
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Unread post by babylux » September 28th, 2007, 7:50 am

The 3.8 has good low down torque thats why the used it in the scat
ln106 hilux- Lockers, Little tyres on road big ones off road..... just look at it yourself here's my shed[url]http://www.4wdmonthly.com.au/shed/index.php?id=430&im=1[/url]

duza
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Unread post by duza » September 28th, 2007, 8:32 am

If you are running 35s, the standard diff ratio will not work. Yes, the Commy was designed to rev low and when you get it up to speed on the freeway it will be great. However, getting it there will be the problem. I have 4.875:1 (standard) diffs in my Navara with only 31 inch tyres and accceleration is OK I suppose, but fuel consumption is 22lt/100ks. When I first did the conversion, I put in Pathy diffs which are from memory 4.5ish and the acceleration was crap. I think the whole problem is that the Commodore is lighter and more aerodynamic than a 4by and the lack of low down torque on takeoff just does not suit final drive ratios similar to the original setup in the Holden. My son had one in an old 4runner which had 4.88 diffs and 31 inch tyres. When he drove it to Perth, he commented how poor the fuel consumption was and how high it revved at highway speed, so you see the trade off between revs, acceleration and fuel consumption. Maybe you can find a happy balance, but it can get expensive when you play around with diff ratios. I still have the Pathfinder diffs at home which no-one seems to want. $800 wasted.

Having bagged the V6 for years now, I must admit it has been reliable. As for water crossings, the alternator is not the problem. The power packs are at the front of the motor high up, but unfortunately directly above the serpentine belt. so as soon as you go thru water higher than a couple of feet, the belt sprays the modules and no more go. However this is quite common for a lot of motors. The starter motor is very low too, so when you do get stuck, it will be full of water, so you'll have to wait for a while before you can crank it over again.
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4runner8
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Unread post by 4runner8 » September 28th, 2007, 1:16 pm

the v6's are a good, strong motor. yes thirsty, yes less powerful than "some of the toyota V6 alternatives but ring around for parts prices and availability, you could build a complete commy 6 for the price of half of the bolt on's on the toyota.

lack low down torque? ha, flog the crap out of what your replacing it with! as for the coil packs they can easily be remounted on to the guard as long as you have a good earth.

credit to those who replied who have actually had one, so many usually reply to these v6 conversion questions that haven't and give false information
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Getting a lil bit excited
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boof
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Unread post by boof » September 28th, 2007, 1:39 pm

4runner8 wrote:the v6's are a good, strong motor. yes thirsty, yes less powerful than "some of the toyota V6 alternatives but ring around for parts prices and availability, you could build a complete commy 6 for the price of half of the bolt on's on the toyota.

lack low down torque? ha, flog the crap out of what your replacing it with! as for the coil packs they can easily be remounted on to the guard as long as you have a good earth.

credit to those who replied who have actually had one, so many usually reply to these v6 conversion questions that haven't and give false information


Having daily driven a commo ute for several months imo they suck in a commodore, they lack torque so severly even an empty trailer saw it dropping two gears to get up a hill at highway speed. Marginally better on fuel than my Hilux sitting in the air running 35s with a V8. I was going to put one in my Hilux until I did some research for every 3 people I spoke too who had done 1 was happy. As for costs yes they are cheap but so are the other alternatives. Like anything if you know where to look parts are cheap, and generally when you purchase something you get to know the places.:thumb:

Thats my opinion and as I said before they will be an improvemnet power wise to a 2.8 diesel although its hardly a fair comparison :D
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Corindi
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Unread post by Corindi » September 28th, 2007, 1:40 pm

Although there are alternative motors we couldn't find one that could be replaced for $500. Yes, he intends to flog the absolute ...out of it and keep a spare donk on standbye just incase he manages to blow it up. Do they have rev limiters? Thanks for all the excellent and usefull info guys, you are a credit to the forum. Cheers, Dave
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Corindi
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Unread post by Corindi » September 28th, 2007, 1:44 pm

I know what you mean about 2nd gear up hills. I recently dragged a 2 ton caravan beind my VT up mount victoria. Although it was in second most of the time at 5500 rpm, it held the speed limit and passed many other cars not towing.
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4runner4
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Unread post by 4runner4 » September 28th, 2007, 1:53 pm

i put one in my 84 4runner mate it is wicked it runs a chiped computer to just have a look at the comp 4x4 seen. if they were that crap they wouldnt run them in comps my 2cents ps i was pritty happy with the fuel better than the old carby engines any way

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Unread post by 4runner4 » September 28th, 2007, 1:55 pm

and yeah i found a rev limiert when i was getting out of a bog

spanna chucka
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Unread post by spanna chucka » September 29th, 2007, 2:33 am

I have owned 3 commodores, my first was a series 1 VR executive, it had good power thanks to usual headers, 2.5" exhaust, air filter cam and chip about 185 rwhp on a 20 degree day, it felt more powerful up high in the rev range and got about 420km out of a tank from memory it was 62L.
second commodore was a VX S Pac supercharged V6 (L67) it was wicked in low down torque but suffered up top, I fitted a 10 psi pulley, 1.9:1 high ratio roller rockers headers 3" exhaust air filter and had it dyno tuned wow what a difference it made went from 177rwhp to 240rwhp and had heaps of grunt down low and was still just as economical as the VR!
The 3rd commodore I owned was a VZ SV6 190kw alloy tech piece of crud slower than the VR and didn't make any torque till after 4000rpm

always thought the L67 supercharged V6 engine would be a perfect 4wd motor because of it's low down grunt seriously I had an lsd and from idle it would light both 245 wide tires up at anything over 1/3 throtte input leaving traffic lights
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Stupa
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Unread post by Stupa » September 29th, 2007, 6:13 pm

depending on which 3.8 your using, come racing to strocker kits for about 2.5k. the ecotecs get up to around 200kw, really make it fly

boof
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Unread post by boof » September 29th, 2007, 6:20 pm

Stupa wrote:depending on which 3.8 your using, come racing to strocker kits for about 2.5k. the ecotecs get up to around 200kw, really make it fly

Why pay 2.5k to get 200kw when a standard 1uz for the same money as the ecotec is putting that out standard???

Spend 2.5k on the 1uz and watch your drivetrain destroy itself everytime you get into it :D
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