Number on crankshaft big end caps

[Rupunzell]

Block bores, pistons and rings are specifically fitted as a system. If any item is mixed up or tolerances go beyond what was designed in, there will be problem from moderate to serious engine failure. Not so easy to measure bore diameter as it requires precision measuring tools with skills and knowledge to use them properly. Pistons might not be round at room temperature as they expand to fit the cylinder bore. Common method to check piston to bore clearance is by feeler gauge, but this is not always accurate.

Piston rings wear into the bore they live in. If they are removed then installed into another bore, they will be mis-matched causing poor sealing and they ring to cylinder sealing are not going to be happy anymore or will they become happy again.

Once an engine is taken apart, the property way to make it good again involves new parts and machine work. Taking an engine apart, then simply re-assembling it is a really bad idea that often has bad results.

As for the spare engine, to make it good means all the usual checking, measuring, replacement of questionable-worn parts and GOOD speciality machine work. There is no escape from this if good results are expected.

Would it be a good idea for the lesser experienced, lesser skilled, lesser provisioned to take apart two philippe patek watches, mix-match their parts and expect them to work properly again?


Bernice

These letters? CCBB. I am sure I installed them in the same order as they came out, but not if from the same block. As explained earlier I switched blocks halfway and might have just switched installed pistons to the other block. If the pistons in the spare block don’t match the block then I have a problem and a possible solution.

 

[Dr.Jeff]

No new pistons

Sorry, guess I was thinking of something I read elsewhere.

 

[Mxgrds]

Measurement of pistons
Spare block letters CCCC
1 80,45 mm
2. 80,45 mm
3. 80,45 mm
4. 80,45 mm

Not measured with a high precision tool, but pretty good tool.
It looks I didn’t switch pistons between blocks. Because the other block is BBCC. I tried to measure the cylinder bore but that was not possible. (80,45 on the top ring also for what its worth).
Putting the pistons in in the wrong order? The C pistons are now in the B cylinders?
It is not the starter motor because I switched that already in the beginning when I thought that was causing the problem. But without results. I released the tension of the alternator belt and waterpump and also from the distribution belt to exclude as much as rotating elements. When warm there was still this friction. Only the clutch is now still on the engines rotation.

 

[Rupunzell]

What was used to measure the pistons, at what location of the piston and measuring tool orientation to the diameter of the piston?
Do not believe these measurements as pistons are never going to be this round and consistent.

To resolve 0.01mm, requires a high quality digital or similar large body mechanical micrometer and temperature will absolutely affect the measurement. Here are some example measurement tools. The external micrometer is a Mitutoyo digital, these will measure down to 0.01mm with almost acceptable accuracy and repeatability. Anything less than a three legged intrimik like a Mitutoyo Holtest digital or Etalon intrimik can not achieve reasonable accuracy to 0.01mm. 0.01mm = 0.00039"

If the pistons measure 80_ish mm, this implies a 1200cc Lampredi SOHC engine from an early Fiat 128 as the
1200cc Lampredi SOHC was never originally installed in the exxe. Standard bore diameter and matching pistons would be
about 86mm. Pistons will be smaller than the bore diameter by some number metric.

What is really going on here?

Bernice

Measurement of pistons
Spare block letters CCCC
1 80,45 mm
2. 80,45 mm
3. 80,45 mm
4. 80,45 mm

Not measured with a high precision tool, but pretty good tool.
It looks I didn’t switch pistons between blocks. Because the other block is BBCC. I tried to measure the cylinder bore but that was not possible. (80,45 on the top ring also for what its worth).

 

[gene cooley]

What was used to measure the pistons, at what location of the piston and measuring tool orientation to the diameter of the piston?
Do not believe these measurements as pistons are never going to be this round and consistent.

To resolve 0.01mm, requires a high quality digital or similar large body mechanical micrometer and temperature will absolutely affect the measurement. Here are some example measurement tools. The external micrometer is a Mitutoyo digital, these will measure down to 0.01mm with almost acceptable accuracy and repeatability. Anything less than a three legged intrimik like a Mitutoyo Holtest digital or Etalon intrimik can not achieve reasonable accuracy to 0.01mm. 0.01mm = 0.00039"
View attachment 38982

If the pistons measure 80_ish mm, this implies a 1200cc Lampredi SOHC engine from an early Fiat 128 as the
1200cc Lampredi SOHC was never originally installed in the exxe. Standard bore diameter and matching pistons would be
about 86mm. Pistons will be smaller than the bore diameter by some number metric.

What is really going on here?

Bernice

Uno 1.3 turbo engine.

 

[Rupunzell]

In Europe.. yes. Uno Turbo block is made different than the non-turbo blocks. The bore diameter was reduced to gain coolant circulation around the entire cylinder as needed for a turbo engine. Non turbo Lampredi SOHC blocks have Siamesed cylinders to increase strength and rigidity of the cylinders.

There are other turbo specific features in the Uno turbo block.
These Uno turbo blocks are not common in the US of A as turbo Uno was not officially imported.


Bernice

Uno 1.3 turbo engine.

 

[Mxgrds]

These piston rings.

 

[Dr.Jeff]

Aux shaft issue? Cam issue?
I have a head that was purchased from another member as "great condition". Turns out it was so badly warped the cam box actually warped to the point of the cam not turning smoothly. It was as you describe; easy, difficult, easy, difficult, as it turned.

I still think the engine should come back out and torn down to inspect everything.

 

[Mxgrds]

Aux shaft issue? Cam issue?
I have a head that was purchased from another member as "great condition". Turns out it was so badly warped the cam box actually warped to the point of the cam not turning smoothly. It was as you describe; easy, difficult, easy, difficult, as it turned.

I still think the engine should come back out and torn down to inspect everything.

Cam turns smoothly. Don’t forget, when cold everything turns smooth and the engine starts excellent. It is after warming up the engine the problem starts. The only thing I need to check is the order of the end caps. And check the clutch. If nothing found, the engine goes out.

 

[Mxgrds]

Checked. All in the right order. Also the pistons. 2 end caps were turned 180 degree. Corrected. Will try to make some photo’s of the cylinder with an endoscope.

 

[Mxgrds]

The letters on the crankshaft, what do they mean?

 

[Mxgrds]

Camshaft binding? Coil binding? Retainer to seal bind? I have installed a sportscamshaft with higher lobes. If that gets hot, it might bind the camshaft. Thought I checked that already.