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bobpr

astra, The only other area to check unfortunately is the oil pump where the relief valve is located. Has No3 main bearing spun? of all the engines that I have seen No3&4 journals are the ones that have been damaged. It is not only 4HE1 tc engines that damage these journals all 4H engines damage these journals especially if the oil is not kept in good condition.
 

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Discussion Starter · #22 ·
bobpr: Thanks for your response. I have a new oil filter ordered. It is shorter than my current one and cross references to the one that Isuzu is now specifying. I assume that my bearings are fine as I get no strange noises when I run the engine. I don't believe anyone has mucked with the oil filter adapter so I expect that the original O rings are still there.

I assume that the new filter is a single "full flow" filter and all the oil that passes through it goes to the main oil galley rather than bypassing some of the oil through the secondary filter directly back to the oil pan?

Those going to the new style filter solve the bearing problem permanently?

Should I consider dropping the pan to check the bearings?
 

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bobpr

astra, I am of the understanding that the oil flow was significantly impaired with the dual filter, hence the reason Isuzu have gone to the full flow only. Even the 6HK engines have gone to the full flow, and by the way ,the long filter fitted to the 6HK engine will screw onto your housing provided you have the room it is twice as long in length. In these modern engines the flow of oil is more critical than pressure, provided the flow is maintained the oil additives will do their job.If you drop the pan you will not see much as the lower case doesn't let you.
 

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Discussion Starter · #24 ·
astra, I am of the understanding that the oil flow was significantly impaired with the dual filter, hence the reason Isuzu have gone to the full flow only. Even the 6HK engines have gone to the full flow, and by the way ,the long filter fitted to the 6HK engine will screw onto your housing provided you have the room it is twice as long in length. In these modern engines the flow of oil is more critical than pressure, provided the flow is maintained the oil additives will do their job..
Thanks for the info. I'll check into the larger 6HK1 filter.

I
f you drop the pan you will not see much as the lower case doesn't let you.
I forgot about the ladder bottom end construction.:D
 

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pressure releaf valve 4H isuzu engines

astr did you ever get to the bottom of the high oil pressure in your 4HE1?Check the valve that is located in the front of the engine and is behind a nut just above the timing marks. This valve can stick if any debris becomes lodged in the slide

Bob
 

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Discussion Starter · #26 ·
astr did you ever get to the bottom of the high oil pressure in your 4HE1?Check the valve that is located in the front of the engine and is behind a nut just above the timing marks. This valve can stick if any debris becomes lodged in the slide

Bob
Thanks for the tip. I will check it out when I get home.

What I have been doing is letting it warm up for quite a while and then the oil pressure seems to come down into a reasonable range.
 

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power steer pump

astr,As you are using a 4HE1 engine I thought you might like to know that if you could get your hands on the dual pump which is used in the 8 ton NQR isuzu's then you can have hydraulics for any application you like.


Bob
 

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Discussion Starter · #28 ·
astr,As you are using a 4HE1 engine I thought you might like to know that if you could get your hands on the dual pump which is used in the 8 ton NQR isuzu's then you can have hydraulics for any application you like.


Bob
Is this the power steering pump /brake assist pump that replaces the standard power steering pump? I never thought of doing that. Sounds like a great idea. I was originally planning on using the pto on the automatic transmission to drive a hydraulic pump but the pto is so big it may not fit in the FJ62 Land Cruiser without major body mods.
 

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power steering hydro pump

Yes that's the one it has a flow of 8 lrpm and max pressure of 1700 psi which should be enough to operate your small hydraulics.
 

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Discussion Starter · #30 ·
astr did you ever get to the bottom of the high oil pressure in your 4HE1?Check the valve that is located in the front of the engine and is behind a nut just above the timing marks. This valve can stick if any debris becomes lodged in the slide

Bob
Bob,

This is what I found in the FSM. Is this valve in the front or the rear of the engine? I assumed it was in the rear and would require pulling the whole gear train and housing to access. Or are there two bypass valves - one in front and one in rear of the engine?
 

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Andy

I think the drawing is not quite correct there is a ball check valve in the oil pump that is driven off that gear shown in your drawing. The pressure valve is at the other end of the engine in the front cover.To get to it undo the nut that is about an inch or so above the timing marks on the cover. There is another by-pass valve in the filter housing it to is a slide type there is a nut on top of the filter housing and the valve is behind it.

I am at present working on a 4HF1 and you wouldn't believe how much damage this guy has done 4 out of the 5 main bearings have spun which has been caused by him not changing the oil more regularily.Especially as the engine has done 600k and he does constant stop start deliveries and idleing to keep the air con going.Although I have the oversize bearings to repair the tunnels I think that this one has gone that bit too far. The centre main has actually split in half and and a slug of metal was jamed in the oil hole.I'll photo it and post them.
Bob
 

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Discussion Starter · #32 ·
Andy

I think the drawing is not quite correct there is a ball check valve in the oil pump that is driven off that gear shown in your drawing. The pressure valve is at the other end of the engine in the front cover.To get to it undo the nut that is about an inch or so above the timing marks on the cover. There is another by-pass valve in the filter housing it to is a slide type there is a nut on top of the filter housing and the valve is behind it.

I am at present working on a 4HF1 and you wouldn't believe how much damage this guy has done 4 out of the 5 main bearings have spun which has been caused by him not changing the oil more regularily.Especially as the engine has done 600k and he does constant stop start deliveries and idleing to keep the air con going.Although I have the oversize bearings to repair the tunnels I think that this one has gone that bit too far. The centre main has actually split in half and and a slug of metal was jamed in the oil hole.I'll photo it and post them.
Bob
Bob,

I finally got a chance to get some time in on my engine. I see the big hex nut just above the timing marks. I'll open it up and check out the valve. I did pull the valve cover to adjust the valves which were all right to spec. The whole top end was unbelievable clean - not a spec of sludge, no sign of varnish. I've never seen such a clean engine but then I'm new to diesels. All the cam surfaces looked perfect. I did recieve the new oil filter but have not yet installed it. Probably the best thing to do is one thing at a time then check the oil pressure. Hopefully, this approach will solve the hight oil pressure and identify the cause.

Thanks aagin for your input.
 

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damaged main bearing

These are the photos I've taken ofthe failure and the valve I mentioned. The valve in the filter is only on the early engines.

Bob
 

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Discussion Starter · #34 · (Edited)
These are the photos I've taken ofthe failure and the valve I mentioned. The valve in the filter is only on the early engines.

Bob
That looks like an expensive repair!

I pulled the valve out that you have in your photo. It moves freely and it starts opening around 30 psi. I've also changed the oil filter and am still experiencing pressures of 80 psi when cold and idling. This is down from the 100+ psi when cold but also our weather has warmed up from 30* F to 60*. Once the engine has warmed up to operating temp, the idle pressure drops to 35 psi. If I rev the engine, the pressure will top out at around 110 psi, hot or cold.

The oiling diagram in the FSM shows a total of five valves in the oiling system:

#1 is a relief valve at the oil pump that will dump oil pressure in excess of 114 psi back to the oil pan.

#2 is a bypass valve to the full flow oil filter. If the full flow oil filter gets plugged to the point that there is a pressure differential in excess of 14 psi across the filter, this valve will open to allow oil to bypass the filter.

#3 is a bypass valve for the oil cooler. If a pressure differential in excess of 28 psi exists across the oil cooler (as a result of blockage or thick oil when cold) this valve allow oil to bypass the cooler.

#4 is a check valve which will open when the oil pressure in the main galley exceeds 28 psi. When this valve opens, oil is directed to the oiling jets that direct oil at the bottom of the pistons.

#5 is a relief valve that dumps oil pressure from the main galley to the oil pan when the pressure exceeds 64 psi.

I can guess the purpose of each valve. Unfortunately, the FSM doesn't identify the location of each valve. Even though I pulled the valve from the front of the engine, I can only guess that it is #3 or #4, based upon its opening pressure.

Bob - am I interpreting the functions of the valves correcttly? Where is each valve specifically located? My guess is that valve #5 is stuck shut and is the one responsible for my problem as it should limit oil pressure in the main galley to around 64 psi. If the diagram is correct, I'm reading oil pressure in the main galley as I've connected my gauge to the same location as the oil pressure switch.
 

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The valves that you are looking at are the right ones. I have just overhauled a 4HF1 and the readings that you are getting are the same as what I'm getting and this engine is totally clean. My pressures are 70 psi at high idle and 110 at 2500rpm with the engine just warm. Even though the readings are high I'm not concerned at this point. However when the truck returns after 1000k's or so I'll recheck it.

The No 5 valve is the one at the front of the engine No4 valve is the 4 piston coolers and No 3. is normally the thermal by pass, in the late engines and is located on the left side of the engine behind the front cover.This is not responsible for the main gallery pressure.

The No 2 valve is located on top of the oil filter.

No 5 valve is the one that you have checked and allows oil to dump to the sump via a passage beside it between the front cover and the block it's the one for the oil pressure control.

I have just spoken to my engine supplier and he has informed me that these pressures are the same on all the engines that he has tested. So it appears that there is not a problem.
Regards

Bob

Just for reference I have been informed that if you can get you hands on any of the 4BG1 or 4JJ1 engines used in the excavators of Komatsu, Sumitomo, Hitachi and other Japannese excavators of this size the engines are bullet proof and can be adapted to truck use very easily.The 4BG1 is 4.5 ltr and the 4JJ1 is 3.3 and both engines develop there highest torque at 1600rpm. Not bad !

Bob
 

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Discussion Starter · #37 ·
The valves that you are looking at are the right ones. I have just overhauled a 4HF1 and the readings that you are getting are the same as what I'm getting and this engine is totally clean. My pressures are 70 psi at high idle and 110 at 2500rpm with the engine just warm. Even though the readings are high I'm not concerned at this point. However when the truck returns after 1000k's or so I'll recheck it.

The No 5 valve is the one at the front of the engine No4 valve is the 4 piston coolers and No 3. is normally the thermal by pass, in the late engines and is located on the left side of the engine behind the front cover.This is not responsible for the main gallery pressure.

The No 2 valve is located on top of the oil filter.

No 5 valve is the one that you have checked and allows oil to dump to the sump via a passage beside it between the front cover and the block it's the one for the oil pressure control.

I have just spoken to my engine supplier and he has informed me that these pressures are the same on all the engines that he has tested. So it appears that there is not a problem.
Regards

Bob

Just for reference I have been informed that if you can get you hands on any of the 4BG1 or 4JJ1 engines used in the excavators of Komatsu, Sumitomo, Hitachi and other Japannese excavators of this size the engines are bullet proof and can be adapted to truck use very easily.The 4BG1 is 4.5 ltr and the 4JJ1 is 3.3 and both engines develop there highest torque at 1600rpm. Not bad !

Bob
Bob,

Thanks for the response. I'm very pleased to know that I don't have a problem. bouncebouncebounce Now I can get back to my original project of building a hybrid transmission from the combination of the Isuzu AW450 and the Land Cruiser A440F.

The only "4H" series motors that I have seen in the US are the 4HE1TC's and the newer 4HK1TC's. In Costa Rica, I've also seen a 4HF1 installed in a truck. They appear to all be laid out the same. Is it reasonable to assume that the transmission end have the same bolt patterns and that transmissions would be interchangeable?
 

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hi Andy

The transmissions are the same bolt up pattern 4HE1,4HE1 along with 4HK1 are all the same bolt pattern but the bellhousings of the 4HE1/K1 are a taller housing because of the longer stroke to the 4HF1/G1.

Bob
 

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To access the relief valve means pulling the transmission, flywheel, and some of the timing gears. The timing gear train is on the back of the 4HE1, between the engine block and the flywheel rather than the front of the engine like in a 4BD1/2. :( I was hoping to avoid the task! Kinda wished that I had run some sea foam through the system before changing the oil and filter.

I haven't cut the oil filter open yet. I just got back my "filter cutter opener" tool from a friend that borrowed it a month ago, I'll do it tomorrow.

I'm beginning to think that the truck's prior life as a Chem Lawn truck may be partially responsible for some of the anomalies: the truck had less than 90,000 miles yet an hour meter that I found under the dash showed close to 9000 hours. That would indicate an average speed of 10 mph - a little slow. The truck had a pto on the transmission and I'm beginning to think that the standard mode of operation was to drive a few miles to a customer and then run the truck for an extended period at idle, using the pto to drive the pumps to apply the lawn chemicals. This might also explain the great compression of 500# on each cylinder, higher than usual. This high compression reading may be from the carbon buildup in the cylinders from hours of idling. Excessive idling might also have contributed to sludge build up which could be responsible for the stuck oil relief valve.

Maybe the next step is to pull the valve cover and get a peek inside.
Hi, i need some help. We have a newly rebuilt cummins 4bt motor, ran good for about 20min then a oil leak started at the back of the fly wheel at a 17.5mm plug, oil started to pour out more...by startup the oil presure was right at 80psi(never went down), rev it up the presure maxed out. We used 10w30 brake-in oil to start.....after looking at it more we changed the plug out and used schelec sealer aswell same problem....oil pouring out that plug, changed oil filter and the problem is still there.can someone please help me with some advice?
 
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