Builds Isuzu 4BD1T Lexus LX450 (Land Cruiser) Build (1 Viewer)

[ForealBoreal]

sounds like your overfueling.
800-1000f at cruising is high constantly.
sucks about the turbo.

 

[Wheelingnoob]

Timing too far advanced?

I don't know? Are my symptoms indicative of that? I though retarded timing lead to heat and high EGT's.


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[Wheelingnoob]

sounds like your overfueling.
800-1000f at cruising is high constantly.
sucks about the turbo.

Yeah it does but this turbo was mapped out by others to be able to use all this pump could deliver. Im way far from that right now at something like 90cc/1000 out of 180cc/1000 deliverable.

Yeah with everything going on right now I have had my eye on temp gauge more than the EGT's but every time I have been on the hwy and looked its been in the 750+f area at 2-5 psi.

I do not know maybe Im just avoiding the inevitable head pull.


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[Dougal]

I don't know? Are my symptoms indicative of that? I though retarded timing lead to heat and high EGT's.


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I've run the usable range of timing adjustment on my 4BD1T. Just because I could.

Over advanced is loud (diesel clatter) and boost is slow to build. It dropped enough boost that one hill put me down a gear.
Over retarded is quiet and smooth with boost building faster but engine response softer. Cold starts are harder and fuel economy not as good.

I haven't checked with spill timing how many degrees BTDC I'm at, but it's back to the factory marks.

You are not overfuelling. Such a thing at cruise is not possible. Only under-boosting is possible.

 

[Camotubebender]

M

 

[fabmec]

Low injector pop pressure = more advanced, high pop pressure = retarded. Not huge numbers either unless pressure is way off. Check if the advance unit is working with a diesel timing light. Can't really see how timing will make it hot in such a short distance with virtually no load.

Bummer about the compression leak through the gasket. I've never had much success with spray on type sealants on head gaskets binned them 20 years ago 4 out of 5 requiring head removal. Head & block max 2 thou distortion anywhere, sleeves 2 to 3 thou above deck. head has got to have a good finish to seal gasket @ the fire ring. I just use a machined alloy block wrapped in wet & dry with WD spray, but a good flat oilstone as Dougal suggested would work also.

What size exhaust housing have you got on your turbo? it should be a 6cm as you know, but there is a 7cm and I think even a 9 or 12cm in that same style that could cause lower boost & higher temps.

I still reckon you have a circulation problem and the plumbing on the water filter could cause problems especially if the hot water/steam from turbo is dumping there too . When it's hot is the bottom of the radiator the same temp as the top? When you slow down does it cool down quickly to normal temp or hang up? Could it be air flow stalling through the radiator at speeds over 80 k?

Did you end up trying it with no thermostat? maybe check air temp between radiator & fan clutch while driving by fixing a probe there connected to gauge inside, air temp will probably be 180 to 200 before being fully on.

 

[Dougal]

Air intake restriction could cause low boost and high EGT also.

 

[Wheelingnoob]

Ok so more data today. I installed a low pressure gauge on the cooling system and plumbed it into the truck. I wanted try and pin point if its the HD/head. If I have boost/combustion gasses getting into the cooling system then the pressure should be at the rad cap pop pressure of .9bar (13psi) all the time.

I started driving around locally got it up to temp and started testing off the hwy to get a base line. Normal driving I have 2-6psi in the system. It does not matter if I am boosting 18psi or none the pressure holds steady. If I turn on the heater in the cab fan on full it actually will drop to 1-2psi.

I then sent for my normal circuit down the hwy. this time before the needle even stated moving on the temp gauge the pressure hit 13psi and bounced there for 2 min then the temp started its creep up on the gauge. I stopped at a parts store and got a inferred temp gun. And started checking thing in the driveway. Everything seemed ok, i could not get it hot enough to crack to thermostat. 175f i the thermostat housing. So I started my loop there is one large hill before the hwy that is my mid point that I decided would be my point to check before I hot the hwy.

I got there cooling pressure was 5-6psi. And temp gauge had not move off middle yet. So I hopped out to find the top tank of the rad at 220f the bottom outlet to the engine at 218f and everything else at 230+ the head its self was actually showing 256f. WTF!!!

Do I actually have an air flow problem? Obviously the coolant is circulation the system was totally heat soaked. The fan was free spinning with no air movement.

I have put two large screws through the old Isuzu clutch and am going to swap it on and gingerly try it now. I cringe at the thought of how hot this thing was getting when the temp gauge was almost I the red!!

Remember this last test the stock gauge had not move yet and it was at 220f on the rad.








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[Wheelingnoob]

Sorry did not try with no t stat singe there is a hot water since pope it blocks off when hot.

This turbine is a 6cm.

Air filter is clean, 3" pipe feeding it. If its got a restriction some where all be dammed since I built it all to be as free flowing as possible.


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[Dougal]

Ok so more data today. I installed a low pressure gauge on the cooling system and plumbed it into the truck. I wanted try and pin point if its the HD/head. If I have boost/combustion gasses getting into the cooling system then the pressure should be at the rad cap pop pressure of .9bar (13psi) all the time.

I started driving around locally got it up to temp and started testing off the hwy to get a base line. Normal driving I have 2-6psi in the system. It does not matter if I am boosting 18psi or none the pressure holds steady. If I turn on the heater in the cab fan on full it actually will drop to 1-2psi.

I then sent for my normal circuit down the hwy. this time before the needle even stated moving on the temp gauge the pressure hit 13psi and bounced there for 2 min then the temp started its creep up on the gauge. I stopped at a parts store and got a inferred temp gun. And started checking thing in the driveway. Everything seemed ok, i could not get it hot enough to crack to thermostat. 175f i the thermostat housing. So I started my loop there is one large hill before the hwy that is my mid point that I decided would be my point to check before I hot the hwy.

I got there cooling pressure was 5-6psi. And temp gauge had not move off middle yet. So I hopped out to find the top tank of the rad at 220f the bottom outlet to the engine at 218f and everything else at 230+ the head its self was actually showing 256f. WTF!!!

Do I actually have an air flow problem? Obviously the coolant is circulation the system was totally heat soaked. The fan was free spinning with no air movement.

I have put two large screws through the old Isuzu clutch and am going to swap it on and gingerly try it now. I cringe at the thought of how hot this thing was getting when the temp gauge was almost I the red!!

Remember this last test the stock gauge had not move yet and it was at 220f on the rad.

Is your cabin heater full-flow or does it close off the water when not needed?
How is the condition of the water pump?
Did you get air and coolant venting out the cap on that test run? Easy way to confirm a temp of around 218F is to spit on it and see what sizzles.

The head on the exhaust side will be hotter. Don't sweat about that too much. You definitely have a problem with your radiator not shedding heat. See how the locked up fan hub goes. You have a shroud around it right?

 

[Fromage]

My thoughts:

It's not a fan issue. I have essentially the same setup with a different engine. I have never run a shroud and it has never gotten hot, not even pulling heavy loads and running flat out for 15 minutes with the turbo glowing hot. I actually ran without a fan for months and never noticed that it wasn't there until I had to tow something in summer weather.

I also don't think it's a head gasket issue either. The surfaces looked great in your pics, and everything was done right.

My sneaking suspicion is that the majority of your coolant flow is being diverted through your coolant filter and your turbo plumbing. looking at the way they are set up, they are essentially bypassing your rad entirely. I can't tell from the pics, but it might also be causing your T stat to never open up by bypassing it. Coolant will flow through the easiest path, and with two 5/8 hoses, you could be blowing a lot of volume through there. Pinch those lines off and take it for a spin. That's my hunch.

 

[Dougal]

My thoughts:

It's not a fan issue. I have essentially the same setup with a different engine. I have never run a shroud and it has never gotten hot, not even pulling heavy loads and running flat out for 15 minutes with the turbo glowing hot. I actually ran without a fan for months and never noticed that it wasn't there until I had to tow something in summer weather.

I also don't think it's a head gasket issue either. The surfaces looked great in your pics, and everything was done right.

My sneaking suspicion is that the majority of your coolant flow is being diverted through your coolant filter and your turbo plumbing. looking at the way they are set up, they are essentially bypassing your rad entirely. I can't tell from the pics, but it might also be causing your T stat to never open up by bypassing it. Coolant will flow through the easiest path, and with two 5/8 hoses, you could be blowing a lot of volume through there. Pinch those lines off and take it for a spin. That's my hunch.

A hot radiator outlet tank is a fan issue.

Once you've got the radiator pulling heat out and the outlet tank cool, you know the fan is good. But there are other issues here too. I agree on losing the turbo water plumbing.

 

[fabmec]

If you are relying on the Toyota dash temp gauge they are dampened from the factory, usually the gauge will get to half way at about 180 to 190 f and move off that spot at around 235 to 240 f . Toyota did this decades ago to stop customer complaints of engine running too hot. I know you can remove the dash gauge and modify it by changing a couple of resistors, it will then give you a more accurate indication. I think there was write up on how to do it on one of the other forums just google landcruiser temp guage mod. It has caught a lot of people out.

If the head was that hot and the top of the radiator cooler there is probably not a lot of coolant flow to the radiator and too much recirculating. That thermostat has to be 3/4 open to shut the main bypass hose with the little valve on the bottom as well. Sometimes the lower t/stat housing will be badly corroded in this area.

Sounds like you do not have compression leak into the coolant by what your test drive with pressure gauge showed.

That radiator is definitely doing nothing. With no fan at all the tanks will be the same with no airflow, should have at least 70 f difference with fan pulling air. Have a look at the radiator inlet and outlet pipes as well like I mentioned in my first post. they have caused similar but not as severe fan clutch problems. Try your locked fan keep the revs under 2800.

Air stall happens at speed when air pressure in front of your diff behind the radiator is greater than air pressure in front of radiator (spotlights,winchbar etc have low pressure behind them) it is usually worse with lift. There is usually a panel under the radiator to block the high pressure air, bit like an air dam.

 

[Wheelingnoob]

Ok so the locked fan worked. Drove up the test hill and down the hwy stopping to test it every exit. It did not get over 185f the whole time. I ran it up hill up to 140kms/hr and the temp gauge did not move. Tested top tank of rad (hot side) at 185f and the bottom was 170f (cold side). Hottest part of the engine was head below the thermostat housing at 192f. That part had been 250f on the last test.

I have had my coolant filter and block heater blocked off with vice grips for the past couple days. So they are out of the equation as far as causes. The turbo is not blocked off but I will do it.

I agree and I was not expecting to have overheat issues. Everyone else seems to talk about how they never get hot.

The head surface was good before it went back on and after today's testing I have too agree I do not think this is a HG issue. If it was the cooling system pressure would always be forcing the rad cap open bubbling overflowing the rad overflow. Its only done that once when the rad had air in it still.

I think the reason I did not have issues on my first hwy drive was because I did not have the bumper, winch and lights on so it was forcing enough air through to keep it cool. Once I put the bumper that combined with the large trans coolers, condenser intercooler and finally rad was enough to cause the heat issues.

I still want to try and get it behaving like everyones else's though. I would prefer to no have my fan locked on all the time. Maybe Ill try blocking the turbo cooling lines, the turbo was cooled factory I just moved the lines.







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[wrongway around]

i still think this is a two issue problem, you got the fan spring but flow restriction or could be bypass . forgot you had the fancy coolant filter and bypass . can your pump do this all . i know you cant with a low pressure system . might have to get a g impeller for the water pump. some people dont always offer the problems theyve had in their swaps either too right. i guess this due to the fact that when they try and sell there build later they referr to their build thread. i wouldnt think that the water running through the turbo would be a main issue. i consider this a clasic band aid fix. i would want as much cooling for the turbo as possible if your actually going to be useing it.

 

[Dougal]

i wouldnt think that the water running through the turbo would be a main issue. i consider this a clasic band aid fix. i would want as much cooling for the turbo as possible if your actually going to be useing it.

Turbos do not need to be cooled in use. In fact they are more efficient the hotter the turbine side runs. The water lines are only for hot shut-down protection and Jeremy doesn't strike me as the type to shut down a red hot turbo.

I do not water cool my 4BD1T turbo and I've never had a problem from that.

 

[Wheelingnoob]

Fabmec,

Thanks for the ideas and suggestions. You are correct the temp gauge is dampened. I plan to do the mod as soon as I remove the cluster for a few other mods.

The lower panel is not on yet, I will put it on today. My truck has a 4" lift.

When i took the mesh filter out of the upper rad hose I forgot to check the orientation of the opening, i did have fairly even heat distribution across the rad though.

All my add on coolant lines are blocked except the turbo, I plan to do that today. I do not have the rear heater connected, I live in Canada so it rarely gets cold enough to need it.

I have not finished the fan shroud yet but i know of a few others that have never had them (Formage, Lostih ect) and have not had any issues at all even in 100f heat.

Ill plug off the turbo lines today and install the lower defector. Not sure if ill get a fair comparison now that the locked clutch is on it.


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[Wheelingnoob]

Not sure what my heater is when I turn it on the heater, the valve opens sending hot water through the heater. When its closed there is no movement of water on the circuit.


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[wrongway around]

dougal thanks i didnt know that the water was not for cooling. i thought that not haveing water cooling was just a design cost saveing . I feel alittle better hearing this because ive seen my turbo glowing more than i like to see it ,and frankly try not to abuse it to that point anymore. So sounds like a turbo would actually benifit with no water for efficiency, barring you shut down properly.

 

[Dougal]

I have not finished the fan shroud yet but i know of a few others that have never had them (Formage, Lostih ect) and have not had any issues at all even in 100f heat

That's your problem.

It would have been much clearer to know that earlier. There is no way I'd ever run without a shroud.
Without a shroud there is no way for the fan to pull air through the radiator. Fans work by creating a pressure difference and it is that pressure difference that moves the air.
With a shroud the pressure difference is across the whole radiator and you get air-flow across the whole radiator. Without a fan shroud your fan is only creating a draught behind the fan and circulating air around the engine compartment.

It is only vehicle movement that can push air through the radiator and given a panel underneath was missing, that wasn't working properly either.

Ill plug off the turbo lines today and install the lower defector. Not sure if ill get a fair comparison now that the locked clutch is on it.

You'll have to disconnect it and leave one cap open. Just blanking it off with water inside will cause it to boil and build pressure until something gives.

But given the above, I'd forget everything else and finish that shroud.