Cylinder compression loss after timing chain replacement (1 Viewer)

[nashqadri]

With 279,000 miles on my 1997 80 series I recently bought, I had no assurance if the timing chain was going to last. Since the plan is to use the rig for off Roading and camping, felt like I should get it done regardless. It wasn’t straight forward. Turns out that the head and the upper oil pan must be removed to remove the timing chain cover. I hired a Mobile Mechanic to do the job for $60 an hour while I ordered parts. It took long to get the parts delivered somewhat due to my own mistakes. For two weeks the cylinder head and the block were sitting. At times not covered from dust and debris.



After a thorough cleaning of the block and head, timing chain kit is installed with a new head gasket, and on my instructions without touching any of the valves or anything in the head or the block. The mechanic then disappeared due to health issues. I had another mobile mechanic come in and check the timing chain install. He confirmed that marks of the camshaft and the crankshaft wheel are perfectly aligned. Then he checked the compression on all cylinders. That’s where it’s all messed up. cylinder #2 is down to 50. All other cylinders are about 30 down. When I bought the rig all 6 cylinders were at +/- 180.



Wondering what should be my next step to investigate where the compression loss is coming from? Please share your opinion.

 

[Fj80oregon]

How are you Checking compression? Has this engine been run after all the work.

 

[Mark W]

,

 

[Mark W]

With 279,000 miles on my 1997 80 series I recently bought, I had no assurance if the timing chain was going to last. Since the plan is to use the rig for off Roading and camping, felt like I should get it done regardless. It wasn’t straight forward. Turns out that the head and the upper oil pan must be removed to remove the timing chain cover. I hired a Mobile Mechanic to do the job for $60 an hour while I ordered parts. It took long to get the parts delivered somewhat due to my own mistakes. For two weeks the cylinder head and the block were sitting. At times not covered from dust and debris.



After a thorough cleaning of the block and head, timing chain kit is installed with a new head gasket, and on my instructions without touching any of the valves or anything in the head or the block. The mechanic then disappeared due to health issues. I had another mobile mechanic come in and check the timing chain install. He confirmed that marks of the camshaft and the crankshaft wheel are perfectly aligned. Then he checked the compression on all cylinders. That’s where it’s all messed up. cylinder #2 is down to 50. All other cylinders are about 30 down. When I bought the rig all 6 cylinders were at +/- 180.



Wondering what should be my next step to investigate where the compression loss is coming from? Please share your opinion.

Easy to say this after the fact. But this is not a job that you should farm out to a $60 an hour general experience wrencher who comes to your house to fix the rig in the driveway or your home garage.
But you're beyond that now. Do you have the knowledge and experience to fix this yourself? As in, could you have done the job in the first place? If not, then I would recommend finding a qualified mechanic to work on your Land Cruiser (specifically qualified to work on a land Cruiser... ANYONE qualified to be doing this job for hire would have known before picking up the first wrench that the head and oil pan had to come off to do it right) and get it to him.

Did your guy even have an FSM? (you can download a pdf of the manual right here on Mud)

Anyway, If you can in fact handle it, then...

From what you are describing I would put money on the cam(s) and crank not being timed properly. Even if the second general mobile mechanic signed off on it.

I will have to glance at the rig I am tearing down this evening to be sure (I've never made this mistake or tried to do it just to see), but IIRC it is is possible to install the timing gear onto the intake cam incorrectly thereby throwing the cam timing off significantly, even if the timing marks on the gear look to be correct.

It is absolutely possible to install the exhaust cam incorrectly, throwing all the exhaust valves out of time.

Look at this first. Definitely where to start.

Mark...

 

[nashqadri]

How are you Checking compression? Has this engine been run after all the work.

Checking the compression using a compression tester that gets screwed onto the spark plug hole, one at a time and crank up.

 

[nashqadri]

Easy to say this after the fact. But this is not a job that you should farm out to a $60 an hour general experience wrencher who comes to your house to fix the rig in the driveway or your home garage.
But you're beyond that now. Do you have the knowledge and experience to fix this yourself? As in, could you have done the job in the first place? If not, then I would recommend finding a qualified mechanic to work on your Land Cruiser (specifically qualified to work on a land Cruiser... ANYONE qualified to be doing this job for hire would have known before picking up the first wrench that the head and oil pan had to come off to do it right) and get it to him.

Did your guy even have an FSM? (you can download a pdf of the manual right here on Mud)

Anyway, If you can in fact handle it, then...

From what you are describing I would put money on the cam(s) and crank not being timed properly. Even if the second general mobile mechanic signed off on it.

I will have to glance at the rig I am tearing down this evening to be sure (I've never made this mistake or tried to do it just to see), but IIRC it is is possible to install the timing gear onto the intake cam incorrectly thereby throwing the cam timing off significantly, even if the timing marks on the gear look to be correct.

It is absolutely possible to install the exhaust cam incorrectly, throwing all the exhaust valves out of time.

Look at this first. Definitely where to start.

Mark...

I do acknowledge that even if the timing marks are aligned, the timing can still be off if the camshafts are not installed correctly. To double check…the new mechanic rotated the crank two times and the timing marks are falling in place in perfect alignment. Based on what I read online, this method provides an assurance that timing is correct. Or am I wrong?

 

[nashqadri]

I do acknowledge that even if the timing marks are aligned, the timing can still be off if the camshafts are not installed correctly. To double check…the new mechanic rotated the crank two times and the timing marks are falling in place in perfect alignment. Based on what I read online, this method provides an assurance that timing is correct. Or am I wrong?

The new mechanic is much more professional than the old one. He brought in a laptop and he has a whole stack of manuals on it. I personally looked at the manual on his laptop and it belong to this rig so I have a decent level of confidence he knows what he’s doing, I am not a wrench myself. I just like to know the details.

 

[Mark W]

I do acknowledge that even if the timing marks are aligned, the timing can still be off if the camshafts are not installed correctly. To double check…the new mechanic rotated the crank two times and the timing marks are falling in place in perfect alignment. Based on what I read online, this method provides an assurance that timing is correct. Or am I wrong?

Well, let's just say, "not correct:".

If the exhaust camshaft is installed incorrectly, looking at the timing mark on the chain/gear tells you nothing. And spinning the engine will not change anything. *IF*, as I mentioned might be possible (I have not taken a look yet to refresh my memory if it is possible)... if it is possible to put the timing gear on the intake cam incorrectly, then again spinning the engine over is not gonna change anything.

You will need to carefully look at the timing marks on the cams themselves to verify that the exhaust cam is timed properly with the intake. Unless someone else chimes in first, I'll post here about the possibility of the timing gear itself being installed wrong later this evening/late tonight. This error will throw both intake and exhaust cam out of time with the crank.

Mark...

 

[nashqadri]

Well, let's just say, "not correct:".

If the exhaust camshaft is installed incorrectly, looking at the timing mark on the chain/gear tells you nothing. And spinning the engine will not change anything. *IF*, as I mentioned might be possible (I have not taken a look yet to refresh my memory if it is possible)... if it is possible to put the timing gear on the intake cam incorrectly, then again spinning the engine over is not gonna change anything.

You will need to carefully look at the timing marks on the cams themselves to verify that the exhaust cam is timed properly with the intake. Unless someone else chimes in first, I'll post here about the possibility of the timing gear itself being installed wrong later this evening/late tonight. This error will throw both intake and exhaust cam out of time with the crank.

Mark W, looks like i may have found the culprit. Can you tell what this is ? Found it in the tool box in the garage.

 

[nashqadri]

Cold compression test results

1. Cylinder 1 : 160
2. Cylinder 2: 60
3. Cylinder 3: 130
4. Cylinder 4: 115
5. Cylinder 5 :150
6. Cylinder 6: 135

 

[manofthewoods]

With 279,000 miles on my 1997 80 series I recently bought, I had no assurance if the timing chain was going to last. Since the plan is to use the rig for off Roading and camping, felt like I should get it done regardless. It wasn’t straight forward. Turns out that the head and the upper oil pan must be removed to remove the timing chain cover. I hired a Mobile Mechanic to do the job for $60 an hour while I ordered parts. It took long to get the parts delivered somewhat due to my own mistakes. For two weeks the cylinder head and the block were sitting. At times not covered from dust and debris.



After a thorough cleaning of the block and head, timing chain kit is installed with a new head gasket, and on my instructions without touching any of the valves or anything in the head or the block. The mechanic then disappeared due to health issues. I had another mobile mechanic come in and check the timing chain install. He confirmed that marks of the camshaft and the crankshaft wheel are perfectly aligned. Then he checked the compression on all cylinders. That’s where it’s all messed up. cylinder #2 is down to 50. All other cylinders are about 30 down. When I bought the rig all 6 cylinders were at +/- 180.



Wondering what should be my next step to investigate where the compression loss is coming from? Please share your opinion.

I hope you get everything straighted out.
Some good advice already given.
That said, the timing chain and sprockets live an easy life riding in a bath of oil. I replaced mine while doing a complete rebuild, only because it doesn't add much to the cost. 372k miles and they looked great. To be fair, the plastic guides had seen better days.
Fingers crossed fer 'ya

 

[TheBussman]

how long have you let it run? carbon and dirt may be preventing the valves from closing? have you had a leak down test preformed on cyl 2? Whats the vacuum gauge look like?

 

[ppc]

The 1FZ-FE overhead cam engine is very much different than your normal overhead that most mechanics deal with. The cam timing setup is not difficult when following the factory service manual but there are some shuttle things that can easily missed. A lot threads over the years over the years with posts like yours.

I'd say there is a 100% chance that is your problem.

For you and others with MUD OCD, in the 21 years I've been a member of this forum there has ben 2 or 3 instances of timing chain failures. The chain tensioner is easily replaced in a few minutes time and the plastic chain guides get brittle and may need replacement but that is usually done just during a head gasket job. It's not something that will lead to a catastrophic failure leaving you stranded. There are many other things more important to address like the entire cooling system.

Bottom line you didn't need to replace the chain. It's bad to have the mindset of fixing everything until it breaks.

 

[Malleus]

@nashqadri
If you really "want to know", download the service manual (it's in the Resources section) and read the couple of pages in the engine section on the cam timing procedure. The file is a pdf and is searchable using the CTRL+F function and typing the words you're searching for. For example, you can go to the page you want by typing the full page number in the search bar (caps are ignored).

The timing chain replacement installation procedure, for your truck in your year model service manual, is on pages EM-12 through EM-22.
The cam installation procedure, for your truck in your year model service manual, is on pages EM-23 through EM-63.

You particularly want to pay attention to the camshaft procedures, removal, step 32 (page EM-31) through step 37 (page EM-35) (this is what should have been done, but that's water under the bridge) and installation, step 3 (page EM-54) through step 8b (page EM-56).

NOTE: here's what your mechanic DIDN'T DO when he "checked" the installation of the timing china on the timing gear:

There is no way he verified the lower end chain installation, because the cover was on. Unfortunately, this has to be pretty much done again in order to ensure it's correct. The REMOVAL steps have to be performed until you can see the crankshaft gear and then you have to complete the installation process from there.

I would not assume the crankshaft gear was installed correctly, just to save the work of removing the pan.

Since the head was removed, which isn't a step in the timing chain removal, it's very possible the cams are not installed properly too.

You do not have to remove the head to fix this problem, but you may well have to remove the cams. This is entirely doable by a novice with a general set of tools, and a torque wrench, which you can "rent" for free at an auto parts store, if you read and follow the directions in the service manual.

You will get varying opinions on whether the gaskets you will have to remove are usable or not. IMHO, they are not, simply becasue I wouldn't want to spend the time and effort replacing them again if I was wrong.

If you want to try to fix this yourself, you'll get any help you need, free for the asking, from this forum.

If you're not going to do it yourself, you have to find someone who understands this engine to do the job for you. The procedures for working on this engine, especially the head, are unlike anything a general mechanic is likely to have seen and they won't read the instructions because they think already know what they need to know.

 

[Mark W]

NOTE: here's what your mechanic DIDN'T DO when he "checked" the installation of the timing china on the timing gear:
View attachment 3759006
There is no way he verified the lower end chain installation, because the cover was on. Unfortunately, this has to be pretty much done again in order to ensure it's correct. The REMOVAL steps have to be performed until you can see the crankshaft gear and then you have to complete the installation process from there.

The above is all correct. But... in the real world, unless you almost try, it is hard to disturb the chain on the crank sprocket.

And, just so long as the crank is at TDC,... well the crank gear has to be as well so all you really need to worry about is correct alignment/position of the cam gear.

Of course since the whole point was timing chain replacement, hopefully the original wrencher did it buy the book. The second guy... I am gonna disagree that he needed to tear things down to verify if he knew what he was doing. I most certainly would not need to.

Head removal IS a step in timing chain replacement . I believe that if you only look at the timing chain removal section in the manual, it does not mention it. It is assumed that it has already been pulled. Notice the diagrams show it off. In the installation section it refers to reinstalling the head. Installing the timing cover with the head in place is a surefire way to damage the head gasket... I doubt that this could be avoided. It will result in major oil leak.

Mark...

 

[Mark W]

Cold compression test results

1. Cylinder 1 : 160
2. Cylinder 2: 60
3. Cylinder 3: 130
4. Cylinder 4: 115
5. Cylinder 5 :150
6. Cylinder 6: 135

I was under the impression that all of your compression was down in the range that #2 is. If cam (gear) timing is the issue, I would generally expect a more uniform drop. Out of sync exhaust cam would be more likely to cause inconsistent drop.

Mark...

 

[Mark W]

Mark W, looks like i may have found the culprit. Can you tell what this is ? Found it in the tool box in the garage.

View attachment 3758845

View attachment 3758846

It looks like a driveshaft Ujoint cap sans needle bearings. But the retaining clip slot looks too big. pretty sure that is not your problem.

Mark...

 

[Mark W]

Okay, I had a chance to take that glance I mentioned.

IF someone does not know what they are doing... if they are not paying attention. If they are making uninformed guesses. If they are overconfident and do not stop and examine what they are doing... if they just have a bad day and a (significant) oops moment maybe...

The cam gear *can* be installed in such a way as to throw the cam timing off by a LOT. And the timing gear mark will be lined up properly. But the cam will not be lined up with the gear correctly. Even someone who knew what they were doing could miss this if they were not second guessing everything the first mechanic might have done AND were familiar with this engine.

You are still at the same place. You need to verify that the gear has been installed on the intake cam correctly and you will also want to ensure that the exhaust cam is timed to the intake cam correctly.

BTW, I am assuming that the rig will not start/run? Your compression numbers by themselves do not say that it will not. But I have never seen a 1FZfe that has jumped time or been cam timed wrong that will.

Again, While I am pretty confident this is your problem, I can not see, touch, hear, smell or taste your rig via the internet. This is just a my best first guess based on what can never be complete information.

Mark...

 

[Malleus]

The above is all correct. But... in the real world, unless you almost try, it is hard to disturb the chain on the crank sprocket.

And, just so long as the crank is at TDC,... well the crank gear has to be as well so all you really need to worry about is correct alignment/position of the cam gear.

Of course since the whole point was timing chain replacement, hopefully the original wrencher did it buy the book. The second guy... I am gonna disagree that he needed to tear things down to verify if he knew what he was doing. I most certainly would not need to.

Head removal IS a step in timing chain replacement . I believe that if you only look at the timing chain removal section in the manual, it does not mention it. It is assumed that it has already been pulled. Notice the diagrams show it off. In the installation section it refers to reinstalling the head. Installing the timing cover with the head in place is a surefire way to damage the head gasket... I doubt that this could be avoided. It will result in major oil leak.

Mark...

Yes, but is this real world, the doofus he had doing the work removed the parts, so there's no way to ensure they were put back together properly.

Replacing the chain only requires removing the camshafts. That does not require removing the head. If I'm missing something, I be very interested to know what it is.

 

[Mark W]

Yes, but is this real world, the doofus he had doing the work removed the parts, so there's no way to ensure they were put back together properly.

No argument there. We can assume that something has to have been put together wrong.

Mark...