Misfire on Cylinder 8 and Oil in Intake Pipe -Investigation and Engine Swap (1 Viewer)

[awesomeissquid]

Here is the full set of images I got of the valves in cylinder #8. I don't necessarily see anything obvious, but I am not sure I would know what to look for besides a chunk missing or a crack.

Images from original engine with assumed blown piston in cylinder #8.

I might give the leak down test another try this weekend. I want to run it while trying to turn the crank the 720 degrees to confirm I didn't miss something, like hitting TDC correctly.

 

[abuck99]

Looks like something was banging around in there from the marks on the head

 

[awesomeissquid]

Looks like something was banging around in there from the marks on the head

Oh yea! That was those pieces of threads I pulled out of the engine. Picture of them in post 22. From the POs records I think they were in there for over 3 years making a mess of everything.

 

[2001LC]

3 years! OMG, and it last this long.

 

[awesomeissquid]

3 years and nearly 40k miles. Shows how resilient these engines are even with some serious abuse.

 

[awesomeissquid]

Got away from the day job for a bit to do some more work. In case anyone is curious the RH PCV connection on the valve cover was changed between 2000 and 2003. Makes sense since they also have the grommet vs screw in PCV on the LH side.

In addition I got both exhaust manifolds off with little fuss. The LH side was missing a nut in one spot and had a newer looking one in another, so I am thinking someone might have been in here before. I didn't find any obvious cracks in either. Planning to clean them a bit and use some strong lights to see if I can find anything. Really don't want to install these with the engine and then find out later that it is cracked.

Next I was looking closely at the coolant connections to see what I need to replace and what can be cleaned up. I did not find any pitting on the connections, but I did find some other interesting bits. On the two radiator hose connections there is some discoloration showing where the clamp was. On the T-stat housing I see some pink crusty bits and on the bypass pipe I found some white sand like material. At the rear of the engine there was just some white line at the top of the two connections behind the ridge.

I am thinking in all cases the coolant may have been getting paste the initial ridge, but the clamps stopped it from going any further. Currently thinking I can just clean and reuse them, unless someone wants to talk me into spending more money.

 

[2001LC]

Only concern is pipe pressed into "water bypass joint rear". If that's been washed and those are stains. You may have a leak at point pipe pressed in bypass. Before washing you should have seen, dry and or wet coolant there and below. But non above on hose or coming down along side of pipe.

 

[awesomeissquid]

Hmm, have not washed anything yet. The rear hoses were cut when they pulled the engine and based on the coolant I drained from the block I believe it was all still full when it was removed. Given that was about 3 months before I bought the engine, I am thinking this was wet coolant that ran down the pipe during the removal and dried as we see it in the pictures. I will pull the bypass and give it a light rinse to see if the staining is more permanent or superficial.

 

[awesomeissquid]

Alright, time for an update. I finally got around to removing more components and scoping the new engine more in-depth to see what I am working with better.

Before starting anything I spent some time blowing everything off with compressed air. The engine was already pretty clean with just some minor leaves and dust covering it. For the disassembly, I pulled the fuel rails and injectors and sent those to Fuel Injector Specialists in CO per the recommendation of a few here so they can be cleaned and tested. Trying to give the rebuilt engine the best chance it can. I included the 8 injectors off the bad engine so they can be used as spares should any from the new engine turn out to be no bueno. No pictures of this unfortunately since there was more fuel leakage then I was prepared for...oops, but I will post the info/pictures I get back from FIS.

Next up was pulling the intake manifold, various coolant connections/bypasses, and the starter. This all was so much easier with the engine out of the truck. All the various gaskets looked good with no signs of corrosion found on any of the bypass hose connections.

Even after all the time I spent blowing out the engine I was really surprised by how much sand and debris stayed in the valley.

 

[awesomeissquid]

Part 2 of the update with the results of the new engine scoping. Pinging @JunkCrzr89 and @OwnerCS.

To start, a view of the Toyota ignition coils and half the spark plugs I pulled out. Cylinder 1 in the bottom right, cylinder 8 in the top left. Note that cylinder 3 was pretty burnt. When I bought the engine all the plugs were loose, so not sure if that was how the engine came in or if the yard pulled the plugs to look in each cylinder and didn't tighten them all the way. I didn't ask, but I have a suspicion they were not touched and all were just loose.

I have compiled each of the cylinders into a group of shots for ease of viewing. As observed when I purchased the engine, each cylinder has some carbon build up on piston heads and valves. Cylinder wall cross hatching appears to be in good shape. There is some discoloration on each piston head which I originally assumed was some minor surface rust, but now wonder if it might be a clue about something else. You will also notice that each cylinder has some valves that appear to be wet. I think this might be some oil leakage past the valve seals since the engine has sat for 4 months. Cylinder 8 does appear to have a significant amount of oil coating the cylinder wall. From my investigation, I believe this is coming from above. Its a little hard to see in the images, but it looks to be coming from one of the valves. I assume this one has a failed valve seal. Currently planning to replace all valve seals and debating about pulling the heads.

Images of replacement engine cylinders.

Cylinder 1

Cylinder 2

Cylinder 3

Cylinder 4

Cylinder 5

Cylinder 6

Cylinder 7

Cylinder 8

 

[OwnerCS]

Does cylinder 8 look better in the 2nd picture?

Here is the full set of images I got of the valves in cylinder #8. I don't necessarily see anything obvious, but I am not sure I would know what to look for besides a chunk missing or a crack.

View attachment 2936228

View attachment 2936229

View attachment 2936230

View attachment 2936231

View attachment 2936232

View attachment 2936233

View attachment 2936234

View attachment 2936235

I might give the leak down test another try this weekend. I want to run it while trying to turn the crank the 720 degrees to confirm I didn't miss something, like hitting TDC correctly.

Cylinder 8
View attachment 2949421

 

[awesomeissquid]

Does cylinder 8 look better in the 2nd picture?

The difference you are seeing was because of the angle of the camera and how the light was reflecting. Here are the remaining shots at slightly different angles all taken at the same time. I don't recall seeing anything there in my pre-purchase scope views, but I did not record as detailed of shots at that time so I can't say definitively.

Images of replacement engine cylinder #8

 

[awesomeissquid]

Does cylinder 8 look better in the 2nd picture?

Just realized what you were referencing. The first set of images in post #41 is from the original engine with the assumed blown piston head in cylinder #8. The second set of images in post #50 is the used replacement engine that was bought. Ill add some better labels so its clearer

 

[awesomeissquid]

Redid the leak down testing on the replacement engine today. Not great results, but it gives me an idea of what I am working with.

As you can see, not great. Prior to testing, I observed a lot of gunk on the intake and exhaust valves. During the testing, the leakage past the valves was very obvious since I could see valve seats (and some bubbling occurring) and could feel the air pressure. I will probably get a lot of hate for this, but I am thinking of tearing it down some more and seeing if it is fixable before going with the nuclear option and telling the junkyard the engine is bad and I need a new one.

So the heads are coming off, maybe tomorrow? Current thinking of the following plan of attack to determine how to proceed. My first thought is that the valves have debris on them and that is preventing them from seating properly. To test this theory I will disassemble the heads, clean everything up, check the valve seats per the FSM, and then reassemble (temporarily reusing the original head gasket, or maybe picking up a cheap replacement set) so I can rerun the leak down test to see if it is any better. Depending on how the valve seats look or how the second leak down test comes back, the next attempt would be to try lapping the valves to see if I can restore the seals.

Assuming those two methods dont work, I would have two final options. Option 1, bring the heads to a machine shop to get a valve job done, or Option 2, swap the heads from the current engine over to the replacement and pray those are better. Option 1 obviously is putting a lot of faith in the shop but has the potential to work well. Before deciding on a place to bring these I would like to do a good amount of research. Option 2 really just seems like a hail mary, but maybe it would work fine.

 

[ClassyJalopy]

Redid the leak down testing on the replacement engine today. Not great results, but it gives me an idea of what I am working with.

View attachment 2951025

As you can see, not great. Prior to testing, I observed a lot of gunk on the intake and exhaust valves. During the testing, the leakage past the valves was very obvious since I could see valve seats (and some bubbling occurring) and could feel the air pressure. I will probably get a lot of hate for this, but I am thinking of tearing it down some more and seeing if it is fixable before going with the nuclear option and telling the junkyard the engine is bad and I need a new one.

So the heads are coming off, maybe tomorrow? Current thinking of the following plan of attack to determine how to proceed. My first thought is that the valves have debris on them and that is preventing them from seating properly. To test this theory I will disassemble the heads, clean everything up, check the valve seats per the FSM, and then reassemble (temporarily reusing the original head gasket, or maybe picking up a cheap replacement set) so I can rerun the leak down test to see if it is any better. Depending on how the valve seats look or how the second leak down test comes back, the next attempt would be to try lapping the valves to see if I can restore the seals.

Assuming those two methods dont work, I would have two final options. Option 1, bring the heads to a machine shop to get a valve job done, or Option 2, swap the heads from the current engine over to the replacement and pray those are better. Option 1 obviously is putting a lot of faith in the shop but has the potential to work well. Before deciding on a place to bring these I would like to do a good amount of research. Option 2 really just seems like a hail mary, but maybe it would work fine.

I'd send it back without spending my time or money on it. Plenty of other fish in the sea - get another engine.

 

[2001LC]

Cold test aren't the best, but comparison useful as you know.

I'd try cleaning and retest.

If fails again, and if no cash refund offered (exchange only). Consider rebuilding heads (both). Perhaps, they'd give a partial refund or credit, if you rebuild!

One issue that happens when rebuilding just one head. Compression can end up higher in a bank. Yield rough idle, but Not a big deal!

 

[abuck99]

Interested to know what your compression test methodolgy was while the motor was on the stand or strapped to the crate: did you hook up a battery and spin the engine over? Comp test calls for 250 rpm-so if turning by hand you're not likely to get an accurate reading right?

Curious too what valve clearances were?

 

[awesomeissquid]

Compression test was attempted on the replacement engine by hand but I could not get an accurate read. Decided to buy the engine after the original scope results looked decent by my inexperienced eye. Once home I did the leak down test. The compression test I posted about earlier was done on the original engine still installed in the truck using the starter.

 

[2001LC]

Interested to know what your compression test methodolgy was while the motor was on the stand or strapped to the crate: did you hook up a battery and spin the engine over? Comp test calls for 250 rpm-so if turning by hand you're not likely to get an accurate reading right?

Curious too what valve clearances were?

Valve clearance? Good question. Someone had their coffee today

 

[awesomeissquid]

Alight you guys are getting a live update as I pull apart the replacement engine to check the valve clearances. Pulling the valve covers and they look decent. There is a weird mark on the driver side intake cam between cylinder 3 and 5.