What are some of the disadvantages of doing a 6G75 conversion?

For example, insurance premiums will go up, or maybe getting insurance will be difficult.

Does it affect cruise control function?
Does fuel consumption go up, and does the fuel consumption figure display become inaccurate??
How will it affect resale value of the vehicle?

Anything else that it might have a negative impact on?

I'm not going to condone anything illegal/non-disclosure to your insurance company but to the average eye you'd be pretty bloody hard pressed to see that a 6G75 wasn't the standard motor.

As with any modifications, you're not going to get any money back on it.

I asked AAMI about putting a 6G75 in my Magna and the lady said it wouldn't effect my premium as they didn't have anything to change for it on their end. Lowered suspension increased my premium, and she said aftermarket extractors would also increase it.

What are some of the disadvantages of doing a 6G75 conversion?

Errmm, cost? Unless your car's current engine is flogged beyond resurrection, looking to source/install/sell off a used 3.5L engine takes some effort. Only you can decide if the extra Kw & torque from the extra 300 cc is worth it.

As for resale, you may have difficulty finding a buyer who is willing to take on a non standard elderly Magna.

After a 6G75 conversion you are pretty well committed to keep the car for the next 20 years just to recoup your investment, surely? Makes resale irrelevant really. lol

The downside for me, was that I had leftover engine and gearbox.

The 6G75 and 5 speed auto conversion to my Xi was done for financial reasons, by the time I spent significant $ on the 200,000klm service (valve stem seals, timing belt, plugs, leads, etc etc) the 6G75 made sence for the outlay.

It reinvigorated the car. I then sold it pretty much that week so the investement was recovered also.

Would I do it again? Every time.

If you have a base model magna, no. A comfy verada specced to suit, sure. A comfy street weapon.

The 6G75 and 5 speed auto conversion to my Xi was done for financial reasons, b

Was it the 5sp auto from the 380? What revs does it do at 100km/h?

Mike, I am in a similar situation where I am approaching 200K and the service will be over $1K, as well as leaking valve stem seals.

In the grand scheme of things, the additional $1,200 or so for a 6G75 seems worth it, but the fact that the car may not sell when the time comes is a concern.


No one made mention of whether the cruise control and the fuel consumption meter work accurately with the 6G75 motor?

Mike, I am in a similar situation where I am approaching 200K and the service will be over $1K, as well as leaking valve stem seals.

In the grand scheme of things, the additional $1,200 or so for a 6G75 seems worth it, but the fact that the car may not sell when the time comes is a concern.


No one made mention of whether the cruise control and the fuel consumption meter work accurately with the 6G75 motor?

Cruise works fine, Fuel consumption was fine, no change, the enjectors carry over from the previous engine as does the loom, ECU and almost all anciliary components.

So since the trip computer reads number 2 injector, and the ECU (ralliart ECU in my case) was better with the 3.8, I saw zero need to worry about it.

Cruise control works off a vacuum pump on the throttle body. It uses speed sensor to determine the speed and maintain it. It is independant of the engine power, with respect to speed. The more power the engine has, the quicker the cruise gets to speed.

In fact because of the torquier engine, and the gearbox change, my cruise control wouldnt change the box down as often etc etc.

TCL was the same. Zero change.

Mike

Was it the 5sp auto from the 380? What revs does it do at 100km/h?

The 5 speed that went into the Xi I had, was from a VRX magna. It was rebuilt, and it was given fresh fluid and a flush after 500 klms of use with the new engine.

It did 2100 revs at 100kph.

Roughly the same as the old box, maybe slightly more due to the 4 speeds different final drive ratio.

How will it affect resale value of the vehicle?



...but the fact that the car may not sell when the time comes is a concern.


You're not Frankenstein-ing a SLR5000 or a GT-HO. Whether you keep it matching numbers or not is neither going to turn its resale value to dust, nor will the conversion grant you any significant long-term boons
It is what it is. Come resale time, those who don't know about the conversion won't care, those who do will probably not try to screw you over as much when it comes to haggling as they'll appreciate the work thats been undertaken, to a point.

As with any modification, do it for yourself. If we were all to undertake mods only if it provided any potential future financial benefit come resale time, no-one would modify their cars.
Rarely does work carried out turn into a significant bargaining chip for the seller to the point where they at least break even, unless you're selling within the enthusiast community - and even then its rare.

The 5 speed that went into the Xi I had, was from a VRX magna. It was rebuilt, and it was given fresh fluid and a flush after 500 klms of use with the new engine.

It did 2100 revs at 100kph.

Roughly the same as the old box, maybe slightly more due to the 4 speeds different final drive ratio.
So you had 2,100RPM with the 6G75? I get just under 2,000RPM with my 6G74 (4 speed), is yours rather high or is mine rather low? I suppose Veradas would be a bit higher than Magnas due to the extra weight?

So you had 2,100RPM with the 6G75? I get just under 2,000RPM with my 6G74 (4 speed), is yours rather high or is mine rather low? I suppose Veradas would be a bit higher than Magnas due to the extra weight?

As I said, the 5 speed has a different fina dive ratio. Which accounts for the extra revs.

As I said, the 5 speed has a different fina dive ratio. Which accounts for the extra revs.

I thought the 5sp Magna autos reved a lot higher than 4sp autos, as in closer to 3000rpm. When you rebuilt your 5sp did you put in a higher ratio final drive?

Also with the trip meter fuel readout, if you reset it with a full tank, how closely do the litres total and fuel pump readout match when refilling?

5sp Manual revs higher, the 5sp auto revs a lot lower

If you are doing mods such as a bigger motor who gives a heck about a few extra $$ in fuel, you either want to save on fuel and get a 1.3l Kia or you want to mod your car and know it may use more, can not have both

In terms of fuel consumption, since my manual conversion mines actually using less than what it was when it was the 3.5 5 speed auto. I'm into the low 12's which I've never been less than 13.
Other than that as everyone has already stated, you do mods for yourself. Resale value and all that shouldn't factor into what you do to your car.

No one has actually mentioned this, but if youre doing the conversion because your 3.5 needs a 1k service, arent you silly to not do the same service to your 3.8 before fitting it? Surely you would do the timing belt and other bits and pieces before fitting it?

Might just be me, but sure fitting a 180k 3.8 isnt that much more expensive than the service, but arent you only post poning that initial cost? Just my input anyway

No one has actually mentioned this, but if youre doing the conversion because your 3.5 needs a 1k service, arent you silly to not do the same service to your 3.8 before fitting it? Surely you would do the timing belt and other bits and pieces before fitting it?

Might just be me, but sure fitting a 180k 3.8 isnt that much more expensive than the service, but arent you only post poning that initial cost? Just my input anyway
I think that's kind of a given, as Mal (and maybe Tony) does the timing belt etc. before he sells them. End of the day you gotta get that major service, might as well get a 6G75 for an extra 1-1.5k

Yes the timing belt is done before fitting, which then essentially postpones the $1K service for another 100,000km. I would also wait for a low mileage 6G75 so that things like water pump, tensioner etc won't be changed (part of the $1K service).

When i did a 6G74 conversion and manual, vic roads couldn't find the numbers on the engine so I had to tell them and they just believed what I said and what was on the receipt from Mal. You get more power and torque plus a new motor (as long as it hasn't been thrashed)

I thought the 5sp Magna autos reved a lot higher than 4sp autos, as in closer to 3000rpm. When you rebuilt your 5sp did you put in a higher ratio final drive?

Also with the trip meter fuel readout, if you reset it with a full tank, how closely do the litres total and fuel pump readout match when refilling?

Nope only about 100-200rpm higher. No I did not rebuild the box. I wouldn't change the internals in any event.

With the trip computer readout, it was spot on. the injectors were carry over equipment from the 3.5. So it would read and operate the same. The ECU controls the injectors and seems there was zero issues. Still have zero issues.

The engine used less fuel on average, as the extra gear was placed between 1st and second on the 4 speed. So it isnt holding high revs taking off from lights all the time waiting to change. This means it gets up to speed quicker, smoother and in the town, uses less fuel than a dim witted 4 speed especially one with a low capacity ECU (TJ onwards have double the memory in the computer and some significant fine tuning regarding torque converter lockup points etc). The highway revs mean the thing is insignificant.

The 3.5 was great on fuel in any case, but to give you an example, I have at home now a Polo GTI which averages 7L per 100 klms from a 1.4 twin charge engine, and the A8 which averages 10.5L from a 4.2V8. The Xi after the conversion used the same 12L it always had. That is from a simple tech car with heavy kerb weight.

At the end of the day, the power was worth the extra 1 tank a year conversion.

Mike

In terms of fuel consumption, since my manual conversion mines actually using less than what it was when it was the 3.5 5 speed auto. I'm into the low 12's which I've never been less than 13.
Other than that as everyone has already stated, you do mods for yourself. Resale value and all that shouldn't factor into what you do to your car.
Sorry if im going off topic but im getting average 12.6, and at best 12.1 when im being very very good 3.5 5spd auto :) AWD

Has anyone found any disadvantages from the 6G75? Cause from what I can hear it's all positive apart from splashing some cash, which in my opinion is well worth it.. And just for the record my fuel consumption has reduced by around .5lt/100kms since upgrading to a 6G75, so I'm getting as low as 6.5lts/100kms on the highway

Has anyone found any disadvantages from the 6G75? Cause from what I can hear it's all positive apart from splashing some cash, which in my opinion is well worth it.. And just for the record my fuel consumption has reduced by around .5lt/100kms since upgrading to a 6G75, so I'm getting as low as 6.5lts/100kms on the highway

Same with my old 3.8l avg around 0.5 overall. That's a fairly big difference

Has anyone found any disadvantages from the 6G75?
It costs money.

To be honest and blunt (not like me to be so) this is one of the most useless threads made on AMC in a long while

Really, disadvantage of using a motor which is much newer than you have, once some bolt on changes are made it bolts straight in, am yet to hear of any road authority who have an issue and Shannons at very least will insure.

If you are a dick and drive like one you can lose your licence in a car with a 3.0 or a 3.8 so there is no difference there. If your car is not up to having a 3.8 installed the chances are it should not be on the road anyway

To be honest and blunt (not like me to be so)...

I see what you did there...

Useless is subjective and relative.
Before making a decision to pour a few thousand dollars into something I find it very reasonable to research advantages as well as disadvantages which may not be clear. For example whether the cruise control will still function properly, or if the fuel consumption meter will still be accurate, will there be constant error codes, or any other issues that someone who is not the most knowledgeable person in regards to cars would overlook or simply not consider.

Since I was the one who asked, I can assure you this information is anything but useless to me, even though it might be to most AMC members. In fact if cruise control would stop functioning (as per my original query) it would be a huge negative point to a 6G75 conversion for me personally.

Either which way, I could never categorically say that doing research beforehand is "useless".

Cruise control works as it should

I'm not sure if it's just me, but my fuel used is off using a KH dash cluster by about 3 litres at the end of a tank, however I chose "3.5" as my engine, maybe I was meant to choose "3.0" as that is what mine was originally. Mal might know better on that one. Could be an issue for you though.

As far as disadvantages, I can't think of any really, loving the 6g75 in my wagon, you just have to drive it to know it.

Might be a dumb question, but if I got pacemaker extractors for a TJ, would I be able to use them with a 6G75?

You can but pacemakers are rubbish and more often than not end up cracking. Design is also quite average

I encountered no problems with the conversion which I did threw Mits-Fix. On the contrary the car was lighter & more powerful but also smoother & quieter. I liked the noise it made too - deep & high tech warble.

Jaimsey was yours auto or manual?

Manual