Rebuilt 3B Advice after 2K Miles (lots of Blow by)

[82BJ40]

I measured the cylinder linear using a micrometer and a telescoping gauge.

The linear at the bottom is pretty much in spec. The bottom measurements seems to be bellow any wear from the rings. The top being a but over spec. The middle is bad with number 1 and 2 being really bad. Number one had the destroyed piston. There wasn't a noticeable difference between axial and thrust inner diameter.

Is there a possibility that the pistons wearied the middle of the liner do to some other problem?

I don't know much about machining cylinders but it seem hard to visualize how a machine shop could machine the center different then the top and bottom. Maybe I just didn't measure very well. I will drop off the block to a different machine shop next week
Thanks

 

[82BJ40]

I took the engine in to the machine shop and they confirmed that everywhere the rings came in contact with the cylinder was worn out of spec and the very bottom was within spec. Similar number as listed above.

When they inspected the pistons it turns out the ring were in the wrong position. The top ring was installed in the middle and the middle ring was in the top position. They think this was likely why there was a lots of blow by from the very beginning.

One possible chain of events could be the pistons were not properly lubricated due to the incorrect position of the rings. This caused accelerated wear and lots of blow by. When the wear got so excessive on the number one piston it started slapping the linear and eventual broke, which great accelerated the wear on that cylinder.

It is a tough thing to verify if you have the machine shop put the rings on the piston and install them in the cylinder.

 

[FJBen]

I took the engine in to the machine shop and they confirmed that everywhere the rings came in contact with the cylinder was worn out of spec and the very bottom was within spec. Similar number as listed above.

When they inspected the pistons it turns out the ring were in the wrong position. The top ring was installed in the middle and the middle ring was in the top position. They think this was likely why there was a lots of blow by from the very beginning.

One possible chain of events could be the pistons were not properly lubricated due to the incorrect position of the rings. This caused accelerated wear and lots of blow by. When the wear got so excessive on the number one piston it started slapping the linear and eventual broke, which great accelerated the wear on that cylinder.

It is a tough thing to verify if you have the machine shop put the rings on the piston and install them in the cylinder.

Yikes. Is this the same machine shop that did the initial work?

So shoddy machine shop work.

The goodish news to this is that you should be able to put new sleeves in, new pistons and probably bearings in and rebuild. The shop should 100% make this right and do a full rebuild. If it were me, I would have them verify stuff/important steps or document it along the way when they rebuild it.

 

[lacalvette]

"When they inspected the pistons it turns out the ring were in the wrong position. The top ring was installed in the middle and the middle ring was in the top position. They think this was likely why there was a lots of blow by from the very beginning."

Just a word of caution with this machine shop: Depend on which piston they used, but the ones I have here: Engine Australia and 82/83/86 toyota ( ART ) I can't mix piston's rings.
The first "T" and second "2T" are different enough that you can't even install the first backward.
On the picture, two different toyota piston, old (pre-85) ? have two row for liners lub, 1986 have only one but half in the groove/ half outside.
second picture are the two fire / compression ring from Toyota, you can see that the first have an angle. Have TPR #35909 & #35855 and they are pretty similar except the small inside cut?

Not 100% sure but since the piston pin are quite tight in the piston ( see press-fit ), I tend to believe that liners lub. don't come from there but mostly from the oil jet which also cool the piston itself.
I just remove piston's pin from an 1982 3B unknown km and from a 86 with 380k km and the pin were completely toasted on the 82 with a lot of play and the pin from the 86 were worn too but not too bad. Not a lot of lub there for sure...

Edit: Just had a look at the connecting rod and realized that there is a small hole on the top of it connected with the central groove of the connecting rod bushing. So there is lub there for the liners. try to see if the hole in the bushing align with the con rod hole on the top.

I would check oil jet for position, oil passage free and also the oil jet check valve.

Better to have a look at the parts you receive in the rebuild kit, mine had the wrong cam shaft bearing ( been a real night mare) and wrong Con rod bearing.
Cheer!

 

[lacalvette]

Semi-finish liners should be cast iron since they need to be bored and honed.

https://www.engineaustralia.com.au/wp-content/uploads/2018/04/SB023.pdf

the TPR rings that I got seem to be chrome. hard to find the exact spec. But these semi-finish liners should work with chrome plated rings and shouldn't wear fast with good lub.
Can't use finish chrome liners with chrome plated ring.

 

[roscoFJ73]

The whole "breaking in" thing is b.s. A properly built engine doesn't need to be broken in. Definitely looks like some shoddy work there.

Considering Toyota use a special oil for new engines which is changed a the first oil change, there is obviously something going on. I would agree that a properly built engine requires less running in. The microscopic "rough" edges need to rubbed off. I remember the heat coming off my rebuilt engines for the first few hundred klms tells me there is lot of friction happening.

 

[82BJ40]

I got two different rebuild kits in this week one of the kits was from the same company as last time and the second was from a different company.

It was interesting that the one of the kits had finished linear, that were right at Toyota factor bore ID of 4.0158 and the other was unfinished with an ID bore of 4.0080".

The pistons were very similar, with the same hole patterns. One set was 20grams lighter than the other. I would assume they used different die cast mold to produce the pistons. They don't have the upper steel groove like the pistons I pulled from the motor and the box had the "Do not use pistons with a turbo warning"

I can't tell if the liners are chrome steel or cast iron, they appear to be the same material. and the rings appear to be chrome steel.

the rings were in individual bags for the top, Second and Oil. It should be easy to not mix them up.

Is there recommendations on using a specific oil for the initial run in? I did a bit of searching and didn't find any specific Toyota oil and it looks like engines these days don't use a different oil. I figured just a conventional 15-40 diesel oil and change it after a couple 100miles to flush out all the assembly oil and any debris that might be in the engine from the rebuild.

 

[82BJ40]

I was able to get the engine all put back together and start the break-in process. I have about 20 miles since the rebuild. I did put a new turbo on; once you have a "turbo'ed" 3b there is no going back.

I measured the blow by at idle and it is 1.5CFM. Varying the rpms I can get 2.0 CFM reading. If I Punch it, it maxes out at 4.0cfm for a moment and then drops right back down 0.0CFM (probably a slight vacuum) then back to 1.5CFM.

This is about 3 times less then before the rebuild and is likely what a good rebuild should be. Visually the Crankcase vent gas is clear and free of excessive oil.

I am feeling good about the starting point for the rebuild. I will monitor oil usage and put some miles on it.

Thanks for all the help
Dan

Video of Blow-by Test
Google Photos - https://photos.google.com/share/AF1QipPfnsqzRd1plCgBu8pIaxcXqA3WhDqe-r99DtYyrr_0l40UdXkagZt_ilI6aeVDJw/photo/AF1QipOGcpeHlAbyzsgsjtklSB_39cy3AMH1DDCpKpt7?key=TGhvNGpMSklNZDJKdWc5TkZYVkRUOXdCNzA1SWtn