Build Lexus LX450 Cummins 6bt/NV4500 swap

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I don't remember if you put in 3k or 4k springs in the pump, but I wouldn't be sweating the lack of power above 2500rpm. Remember, the big Brothers to these engInes are usually governed around 2000rpm. These aren't gassers that make their power high up in the rpms. I still haven't put the 4k springs in my truck, haven't really felt the need. Never got my tach hooked up, so dont know wherr im @ rpm wise, but with 3.55 gears and 265 tires it pulls hard to 100mph and had more to give. Wasn't running out of steam. Your results make me jealous and antsy to get started on mine
 
nuncaperdido said:
I don't remember if you put in 3k or 4k springs in the pump, but I wouldn't be sweating the lack of power above 2500rpm. Remember, the big Brothers to these engInes are usually governed around 2000rpm. These aren't gassers that make their power high up in the rpms. I still haven't put the 4k springs in my truck, haven't really felt the need. Never got my tach hooked up, so dont know wherr im @ rpm wise, but with 3.55 gears and 265 tires it pulls hard to 100mph and had more to give. Wasn't running out of steam. Your results make me jealous and antsy to get started on mine
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I have the 4k gsk kit in it. I think it's a combination of stock fueling and timing at 12.5deg. It's honestly plenty of power for this truck. I just know how much more it can do with a few turns and tweaks lol. Resisting the urge till at least the fall to start tuning it.It really does not need it though.

I love the reactions I get from people thinking one thing then looking at the truck and you get that blank "wtf" look on there face. It's defiantly getting a lot of attention, even had a Jeep owner give me a thumb's up the other day drivin....... I used hand sanatiser after ;P
 
Resist the urge to advance the timing and throw more fuel at it, unless you have that thing loaded down and pulling a trailer there isn't a good reason to do it!
 
So a fun post trip update for everyone. Did a quick post trip inspection and found 4 vertical clean stripe's on the passenger side of the block. I'm running water in the cooling system at the moment and as it leaked out of the headgasket it cleaned 4 beautiful vertical striped on the block........
 
You're kidding! I can't believe the run you've had with this
 
WTF? Boil out? Were you running water only for a reason?
 
Yes I appear to have the worst luck bar none. I'm actually so numb to this all now I just don't really care anymore.


Water is not boiling out, I just noticed the overflow bottle a bit lower after every drive. The water is leaking out under the pressure of the cooling system 15ish psi. The engine temp has never gotten over 173f and that was for a very short time up a mountain pass. It cruises along at 165 to 169f under regular conditions.

It does not appear to be a compression issue where compression is getting into cooling jacket like the Isuzu. I'm not forcing water out the overflow at all unlike the Isuzu.
It's just seems to weaping from the pressure the cooling system runs at under normal condition's.

Maybe a re torque will fix it maybe not. I don't even know what to do if it does not.
 
in a old diesel power mag vol 7 no8 they do a head gasket on a cummins, the way the artice reads it does happen .praphaps sitting with out water did not help cheers bob
 
My buddies 4bt just has been leaking out the side of the block for 2 years and got bad enough now that he is machinin the head and new gausket. Guy he is working with says it's more common than most people realize. Typically front right side near Thermastate all.external not many over heating issues.

Good to hear it's running well. But that sucks
 
Yeah it's not super uncommon.

It is uncommon after a new headgasket, studs and head machining though.

I don't belive having water in the cooling system was at fault. I did have some antifreeze in it just a low percentage. It was only in there for 3 weeks I was running it with plans to do a full flush this weekend. Still plan too.
 
Scanned thru the thread and didn't see it mentioned, did you have the block decked or just have the head done?
 
warezdog said:
Scanned thru the thread and didn't see it mentioned, did you have the block decked or just have the head done?
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Just the head, I did not have the bottom end stripped down. Looks like I'll probably be going down that nightmare of a path now.
 
GD Noob I feel for you.

Is there any possibility that since you're running such a strong water mix that the EGT's are just boiling a small amount of water and pushing steam thru the HG?

I know your temps seem fine but they're not measured where the hottest water would be passing thru. I say you mix 50/50 and see what happens before you go tearing it down it could be just steam weeping thru because it doesn't have anywhere to go.
 
warezdog said:
GD Noob I feel for you.

Is there any possibility that since you're running such a strong water mix that the EGT's are just boiling a small amount of water and pushing steam thru the HG?

I know your temps seem fine but they're not measured where the hottest water would be passing thru. I say you mix 50/50 and see what happens before you go tearing it down it could be just steam weeping thru because it doesn't have anywhere to go.
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It's a possibility, hottest egt has been 980f for only a few seconds. This engine is not being pushed one bit, it should have no issues holding 2x the boost and 300f hotter EGT and 9 deg more timing.

I have very little intrested in tearing this thing down, to the point I would likley not and just sell the truck.
 
Oh ya I forgot about the motor work you did. That is what my f buddy is planning just head studs and oem gausket. That is pretty s***ty
 
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