Toyota 3B Engine failure and knocking noise (2 Viewers)

[OGBeno]

Thanks for posting your results. So it looks like cylinders 1 and 2 are firing but 3 and 4 may not be. But cylinder 3 is clearly still getting fuel. Was there fuel at cylinder 4? I assume your 3B is from Canada and has an in-line pump - I have no experience with these, but in general it's very rare for injection pumps to be problematic. Although I have my doubts that two adjacent injectors suddenly went bad, it's easy to take them out and get them checked.

I have no experience of turbocharged 3Bs and am more familiar with the later non-Landcruiser B engines, so I defer to those who have more direct knowledge - perhaps broken crankshafts are some peculiarity of turbocharged 3Bs. But when Toyota turned the 3B into the turbocharged 13B-T, they reinforced the pistons, con-rods and cylinder heads (by way of being direct injection, they never turbocharged an indirect injection B engine like the 3B). The one thing they left alone was the cranshaft (late 1984 and on 3Bs and 13B-Ts have the same crankshaft). So it would seem surprising if 3Bs had a weakness for breaking cranks when turbocharged. However, empirical evidence may contradict this. There was one. let's say 'famous' turbo 3B rebuild on this site which appeared to be very well executed but was underlain by some very questionable post-mortem and engine building practices. That ended, if I remember correctly, in a broken crankshaft, and that may be fresh in people's minds.

Pulling the sump pan off is not a fun job with the engine in place, and it will really only tell you if the crank has snapped or if there is a smashed piston. Taking the cylinder head off is a more conventional alternative. It's a bit more work but will show you the valvetrain, pistons and, by turning the engine over with a bar or tapping the piston crowns with a hammer hamdle, whether all the pistons are connected to the crank. It's your choice though.

EO

Are you talking about me?

 

[duncanrm]

Although I have my doubts that two adjacent injectors suddenly went bad, it's easy to take them out and get them checked.

I agree.. its more likely that the headgasket has failed between 3 and 4.

 

[FJBen]

Are you talking about me?

You’re famous!

 

[Eurasiaoverland]

The weakness when 3Bs are turbocharged is due to the fact it’s an IDI engine, higher compression, upped fuel, possibly advanced timing. Greater peak pressures and higher forces on everything.

Sure, but looking at Toyota's own engine development, the crank would not appear to be the weak link.

Also, I wonder if peak pressures in a turbo 3B would be higher - it's still using a lower pressure IDI pump and a pre-combustion chamber. The DI engine has significantly higher injection pressure and combustion right on the piston crown which I imagine gives more momentary ignition and a higher peak pressure; hence the higher torque in a 13B compared to a 3B. I gues it depends on the fuelling of the 3B pump though.

Are you talking about me?

Hmm, the name does ring a bell... but can't be sure.

I agree.. its more likely that the headgasket has failed between 3 and 4.

I think these old 3Bs run graphite head gaskets so definitely possible.

For the OP, a slow and cautious approach would be to get the injectors serviced and compression test the engine. Removing the sump pan will tell you if the engine is a write off without spending any money. Pulling off the cylinder head will likey tell you the whole story but will leave you needing to partially rebuild the engine - which would be frustrating if it's just a stuck injector. But I think it will be more than that...

 

[bj70bc]

oil pan is easy on the 3b, and you can use fipg so you dont have to order anything else
but yes, upon further diagnosis it would seem to be injection related.
If you still have an original head gasket it will be shortly behind this in the failure department with a turbo.
Yes.... if you take the head off there will be other things you will be forced to do $$

 

[bumi1048]

Thanks for posting your results. So it looks like cylinders 1 and 2 are firing but 3 and 4 may not be. But cylinder 3 is clearly still getting fuel. Was there fuel at cylinder 4? I assume your 3B is from Canada and has an in-line pump - I have no experience with these, but in general it's very rare for injection pumps to be problematic. Although I have my doubts that two adjacent injectors suddenly went bad, it's easy to take them out and get them checked.

I have no experience of turbocharged 3Bs and am more familiar with the later non-Landcruiser B engines, so I defer to those who have more direct knowledge - perhaps broken crankshafts are some peculiarity of turbocharged 3Bs. But when Toyota turned the 3B into the turbocharged 13B-T, they reinforced the pistons, con-rods and cylinder heads (by way of being direct injection, they never turbocharged an indirect injection B engine like the 3B). The one thing they left alone was the cranshaft (late 1984 and on 3Bs and 13B-Ts have the same crankshaft). So it would seem surprising if 3Bs had a weakness for breaking cranks when turbocharged. However, empirical evidence may contradict this. There was one. let's say 'famous' turbo 3B rebuild on this site which appeared to be very well executed but was underlain by some very questionable post-mortem and engine building practices. That ended, if I remember correctly, in a broken crankshaft, and that may be fresh in people's minds.

Pulling the sump pan off is not a fun job with the engine in place, and it will really only tell you if the crank has snapped or if there is a smashed piston. Taking the cylinder head off is a more conventional alternative. It's a bit more work but will show you the valvetrain, pistons and, by turning the engine over with a bar or tapping the piston crowns with a hammer hamdle, whether all the pistons are connected to the crank. It's your choice though.

EO

Thanks EO and to everybody else who gave their 2 cents.

I have pulled the injectors in question and plan to take them to a shop. If that comes up with nothing, then I plan to take the truck to someone who knows a thing or two and work on it with them to check out the internals. Either way this has been very helpful, and I appreciate all the advice I recieved. If the thread is not long dead by the time I firgure it all out, I may provide an update.

Bumi