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I bought a blown complete TB45 engine on Ebay. I stripped the head off and had it rebuilt for gas with hardened seats, new valves and guides. I also had it machined down to its limit. I now have a compression ratio of about 11:1.
Over the last week i have installed it into my GQ. I have retained a TB42 block and bolted on the TB45 head and inlet manifold.
I still have a couple of teething issues to sort out but it seems well worth the effort.
Inlet manifold was port matched. The engine shop did a little bit of a internal cleanup but did not flow bench it. I was still driving the car while building the engine, so exhaust is not port matched. I am also using an XF throttle body which I had port matched and internals polished.
I had the cam re-ground to suit LPG. It has quite a lumpy idle.
I have only spent about $1800 on this build and that includes a TB42 and a TB45 engine. I still have the original TB42 engine that came out of the GQ also it had done 417,000km.
The bottom end I have only put new rings and had the block decked. I would like to build up the TB45 block when funds allow (read "minister of finance approval") and swap over.
I would have done a camshaft, we have played a bit with them, with that higher compression a camshaft with extra lift and duration would be a treat. I'd suggest you might need to run a piggyback ecu to get the most from it, you may not hear audible pinging but there is a likelyhood the factory timing is too high at higher rpm due to the compression.
I have a 4.2 carbi petrol/gas and when i got the guys from PGS 4wd put the new head on they also put in a camshaft and OMG what a difference in power!!! highly recommend it!
steveoo wrote:I have a 4.2 carbi petrol/gas and when i got the guys from PGS 4wd put the new head on they also put in a camshaft and OMG what a difference in power!!! highly recommend it!
do u know what cam shaft your using as i too am going to do this and how much more power off the bottom do u get? i cant justify puttin a v8 in a truck built to go slow !
4 in king springs, pro comp long travels, gu diffs, 4.6s ,front lokka,35" mtzs, custom made everything ,custom dual cab and a growing list of spare parts
PGS 4WD wrote:I would have done a camshaft, we have played a bit with them, with that higher compression a camshaft with extra lift and duration would be a treat. I'd suggest you might need to run a piggyback ecu to get the most from it, you may not hear audible pinging but there is a likelyhood the factory timing is too high at higher rpm due to the compression.
Joel
Joel,
I'm not runing an ECU at all. As its straight gas I have no need for one. The mechanical rev limiter was cutting in at 3800revs. I removed the springs and shorting from the back of the rotor button. I have only been game to rev it to 5000rpm so far. I will let the motor settle in first and then give it some stick.
PGS 4WD wrote:I would have done a camshaft, we have played a bit with them, with that higher compression a camshaft with extra lift and duration would be a treat. I'd suggest you might need to run a piggyback ecu to get the most from it, you may not hear audible pinging but there is a likelyhood the factory timing is too high at higher rpm due to the compression.
Joel
Joel,
I'm not runing an ECU at all. As its straight gas I have no need for one. The mechanical rev limiter was cutting in at 3800revs. I removed the springs and shorting from the back of the rotor button. I have only been game to rev it to 5000rpm so far. I will let the motor settle in first and then give it some stick.
Over the past couple of months I have had the TB45 bottom end rebuilt. I had the bores honed, new rings, decked and weight balanced. I couldnt afford to get the engine rotational balanced so just got all the components weight matched.
I pulled out the old motor and stuck the complete TB45 engine in. I used a TB42 distributor which I changed the cog and cut the spiggot off. I also used my TB42 camshaft which is a reground LPG cam.
The motor goes a whole heap better than a TB42. It runs much smoother too.
I still have a couple of things to sort out but its all but done. A conversion that is worth every cent! I'll post some pictures tomorrow.