Outer Limits 4x4 Board

Has this been done?

How far can it be taken, how much (approximately) and is it worth it?

I have previously asked whether there is enough metal in the block to bore out to use the tb45 pistons but noone could tell me at the time.

You'll also soon be suggested to use a tb45 head as the ports are larger but then you need the exhaust to suit (question your extractor supplier whether they are actually bigger) and you will need the inlet manifold and if not allready injected convert to injection.

would it not be easier to buy a TB45?

Yeah, I know. It was just a brain fart kind of query really.

BUT, TB42's are ultra cheap and widely considered the strongest of all TB's, including TB48E.

I've been quoted $2200 for a TB45E, 2nd hand with all electronics required for a conversion into a GQ. I assume a TB48E would be at least double that.

I've seen TB42's for giveaway to $750, which leaves a bit for machining and parts. If someone had the info (how much to stroke crank, rods to use, pistons to use etc, how far it can be bored/sleeved, head work to lower compression because of increase swept volume) you'd end up with a rebuilt, big cube motor for a reasonable cost.

You'd make it pretty stock, just to take advantage of the extra cubes and associated torque.

I have a vague memory (at the time I had a TD42 so didn't take any notice) of one that had been stroked to 5 litres.

Does anyone know the bore and stroke of the TB48E compared with TB42?


Dave Mc

bigbluemav wrote:Yeah, I know. It was just a brain fart kind of query really.

BUT, TB42's are ultra cheap and widely considered the strongest of all TB's, including TB48E.

I've been quoted $2200 for a TB45E, 2nd hand with all electronics required for a conversion into a GQ. I assume a TB48E would be at least double that.

I've seen TB42's for giveaway to $750, which leaves a bit for machining and parts. If someone had the info (how much to stroke crank, rods to use, pistons to use etc, how far it can be bored/sleeved, head work to lower compression because of increase swept volume) you'd end up with a rebuilt, big cube motor for a reasonable cost.

You'd make it pretty stock, just to take advantage of the extra cubes and associated torque.

I have a vague memory (at the time I had a TD42 so didn't take any notice) of one that had been stroked to 5 litres.

Does anyone know the bore and stroke of the TB48E compared with TB42?


Dave Mc

TB42 - 96 x 96
TB48 - 99.5 x 102

mickyd555 wrote:

bigbluemav wrote:Yeah, I know. It was just a brain fart kind of query really.

BUT, TB42's are ultra cheap and widely considered the strongest of all TB's, including TB48E.

I've been quoted $2200 for a TB45E, 2nd hand with all electronics required for a conversion into a GQ. I assume a TB48E would be at least double that.

I've seen TB42's for giveaway to $750, which leaves a bit for machining and parts. If someone had the info (how much to stroke crank, rods to use, pistons to use etc, how far it can be bored/sleeved, head work to lower compression because of increase swept volume) you'd end up with a rebuilt, big cube motor for a reasonable cost.

You'd make it pretty stock, just to take advantage of the extra cubes and associated torque.

I have a vague memory (at the time I had a TD42 so didn't take any notice) of one that had been stroked to 5 litres.

Does anyone know the bore and stroke of the TB48E compared with TB42?


Dave Mc

TB42 - 96 x 96
TB48 - 99.5 x 102

Ta Mick

WHo would have thought a TB42 was a square bore x stroke. The numbers seems SO small when you look at them!!

How much extra bore for a 5.0? Would a TB48E crank fit, or best to just stroke the original?

Ta for the info!!

There is a gq patrol here in Broken Hill and the TB42 has been stroked to 4.9L by regrinding the original crank etc. Not sure on the other specs,but it does seem to go well. Raced in the 08 Aus Safari. Its white and has PWR plastered down the side of it. There is a quick video of it in the 07 or 08 condo 750 on you tube.

bigbluemav wrote:

mickyd555 wrote:

bigbluemav wrote:Yeah, I know. It was just a brain fart kind of query really.

BUT, TB42's are ultra cheap and widely considered the strongest of all TB's, including TB48E.

I've been quoted $2200 for a TB45E, 2nd hand with all electronics required for a conversion into a GQ. I assume a TB48E would be at least double that.

I've seen TB42's for giveaway to $750, which leaves a bit for machining and parts. If someone had the info (how much to stroke crank, rods to use, pistons to use etc, how far it can be bored/sleeved, head work to lower compression because of increase swept volume) you'd end up with a rebuilt, big cube motor for a reasonable cost.

You'd make it pretty stock, just to take advantage of the extra cubes and associated torque.

I have a vague memory (at the time I had a TD42 so didn't take any notice) of one that had been stroked to 5 litres.

Does anyone know the bore and stroke of the TB48E compared with TB42?


Dave Mc

TB42 - 96 x 96
TB48 - 99.5 x 102

Ta Mick

WHo would have thought a TB42 was a square bore x stroke. The numbers seems SO small when you look at them!!

How much extra bore for a 5.0? Would a TB48E crank fit, or best to just stroke the original?

Ta for the info!!

same bore and stroke as the TD42

Speak to Sandy at AUS4WD, he has done a lot of homework on this.

gouldy wrote:There is a gq patrol here in Broken Hill and the TB42 has been stroked to 4.9L by regrinding the original crank etc. Not sure on the other specs,but it does seem to go well. Raced in the 08 Aus Safari. Its white and has PWR plastered down the side of it. There is a quick video of it in the 07 or 08 condo 750 on you tube.

I just like the idea of it!

Engine swaps ed up hideously priced ($10k +) and the TB42/TD42 are just such a STRONG family of motors and are big and simple. A straight big bore, long stroke 6 just appeals to me. Lots of low down torque for towing and offroad, low speed stuff and still simple, strong internals.

Doesn't need to rev to 7000rpm, just low down power and torque.

Hmmmmm..................

Ta for the help everyone!!

TB42: bore 96mm, stroke 96mm
TB45: bore 99.5mm, stroke 96mm
TB48: bore 99.5mm, stroke 102mm

I'm guessing that TB42 and TB45 use the same crank? Could I use a TB48 crank in a TB42? Would it be a straight swap? Is the block on all three engines essentially the same? Can you put a TB48 head on a TB42? What parts are interchangable?

LOCKEE wrote:Speak to Sandy at AUS4WD, he has done a lot of homework on this.

Hi Lockee

Do you have a web contact for Sandy?

bigbluemav wrote:

LOCKEE wrote:Speak to Sandy at AUS4WD, he has done a lot of homework on this.

Hi Lockee

Do you have a web contact for Sandy?

Best to call him 0414 288 399

create wrote:TB42: bore 96mm, stroke 96mm
TB45: bore 99.5mm, stroke 96mm
TB48: bore 99.5mm, stroke 102mm

I'm guessing that TB42 and TB45 use the same crank? Could I use a TB48 crank in a TB42? Would it be a straight swap? Is the block on all three engines essentially the same? Can you put a TB48 head on a TB42? What parts are interchangable?

96 X 102 would give a capacity of 4.431L

brad-chevlux wrote:

create wrote:TB42: bore 96mm, stroke 96mm
TB45: bore 99.5mm, stroke 96mm
TB48: bore 99.5mm, stroke 102mm

I'm guessing that TB42 and TB45 use the same crank? Could I use a TB48 crank in a TB42? Would it be a straight swap? Is the block on all three engines essentially the same? Can you put a TB48 head on a TB42? What parts are interchangable?

96 X 102 would give a capacity of 4.431L

If the TB family have the same block, there would be enough space to have 100mm bores. Could a TB42 block just have bigger liners put in? How much would this cost approx?

tb48 completely different configuration motor. ohc vs ohv...
As stated previously what you need to find out is whether you have enough material avail to run last oversize tb45 pistons in your tb42.
Apparantly the tb42 rods are stronger than tb45 but never seen this proven.

just turbo it. will be the cheapest way for decent horsepower

Brett S wrote:tb48 completely different configuration motor. ohc vs ohv...
As stated previously what you need to find out is whether you have enough material avail to run last oversize tb45 pistons in your tb42.
Apparantly the tb42 rods are stronger than tb45 but never seen this proven.

its true don't even have to measure you can see it by eye, 4.5 tend to bend with 15psi or less...4.8 went back to good gear...and its true money wasted turbo even at low boost on stock motor cost less and will make much more power.

NutterGQ wrote:

Brett S wrote:tb48 completely different configuration motor. ohc vs ohv...
As stated previously what you need to find out is whether you have enough material avail to run last oversize tb45 pistons in your tb42.
Apparantly the tb42 rods are stronger than tb45 but never seen this proven.

its true don't even have to measure you can see it by eye, 4.5 tend to bend with 15psi or less...4.8 went back to good gear...and its true money wasted turbo even at low boost on stock motor cost less and will make much more power.

To evolve the thread, not knowing much about turbo petrols, what would be good setup to get MAXIMUM low range power/torque?