Technical 126 Engine Overheating issue.

[Kalimir]

I Recently purchased a 1980 Fiat 126, the body is in great shape and it was said that the engine had been renovated in 2023 with part of it being piston rings that was changed, but it overheats.

The thermostat is brand new and works, it opens fully up when it gets hot.
We thought at first since it was missing rubber gaskets around the ignition it was that, but it wasnt.
Now here comes the question that i need an answer to.
When driving 80-90 KMH it works for 10-14 km's but then it becomes extremely hot and starts making a ticking noise when pressing down on the throttle as well as losing power. The previous owner made a system (im not a mechanic so please bare with me) to release crank pressure into a bottle instead of directly to the filter. (Pictured) But in the journey today about 20km og highway at 80-90 kmh this bottle got filled almost all the way up with oil guessing around 700ml. How can it be this happens? i have heard elsewhere that it could be the result of Pistons and Cylinders being worn out.

We have checked if there are any blockages not letting air come in aswell as cleaned the breather pipes and such.
We have also checked the ignition timing and that is fine.
If it matters, its gotten Electronic fuel pump and Electronic ignition.

Hopefully you guys have some ideas, or we just have to bite the sour apple and rebuild the engine to find the issue.

 

[bugsymike]

I Recently purchased a 1980 Fiat 126, the body is in great shape and it was said that the engine had been renovated in 2023 with part of it being piston rings that was changed, but it overheats.

The thermostat is brand new and works, it opens fully up when it gets hot.
We thought at first since it was missing rubber gaskets around the ignition it was that, but it wasnt.
Now here comes the question that i need an answer to.
When driving 80-90 KMH it works for 10-14 km's but then it becomes extremely hot and starts making a ticking noise when pressing down on the throttle as well as losing power. The previous owner made a system (im not a mechanic so please bare with me) to release crank pressure into a bottle instead of directly to the filter. (Pictured) But in the journey today about 20km og highway at 80-90 kmh this bottle got filled almost all the way up with oil guessing around 700ml. How can it be this happens? i have heard elsewhere that it could be the result of Pistons and Cylinders being worn out.

We have checked if there are any blockages not letting air come in aswell as cleaned the breather pipes and such.
We have also checked the ignition timing and that is fine.
If it matters, its gotten Electronic fuel pump and Electronic ignition.

Hopefully you guys have some ideas, or we just have to bite the sour apple and rebuild the engine to find the issue.

Obviously more tests would need to be made , but possibly two problems, the over heating being one, but if it is blowing oil into a catch bottle would indicate piston/cylinder bore wear "blow by" or a poor seal.
It is also possible the engine could be trying to seize causing overheating due to work on the pistons/ rings.
When I replace rings only on an engine I would lightly hone the bores, clean the pistons and ring grooves, then first check all the correct size piston rings when inserted in to the cylinder bore had the correct ring gap,if the gap is too small when engine gets hot the ring gap closes and engine would try to seize. So if pistons and bores in fair condition I would fit the rings making sure they move freely in the grooves, then position them so the ring gaps are equally spaced (not all in line) next well oil and using a ring compressor carefully install pistons in cylinders and continue assembly, at every stage I would turn the engine by hand to ensure no tight spots.
When engine gets hot and makes noises, with it switched off try safely to turn engine by hand and feel if it moves as normal or is tight.
Another thing is, if badly fitted rings can be installed broken causing scoring of the cylinder bores and resulting in damage and partial seizure.

 

[Kalimir]

Obviously more tests would need to be made , but possibly two problems, the over heating being one, but if it is blowing oil into a catch bottle would indicate piston/cylinder bore wear "blow by" or a poor seal.
It is also possible the engine could be trying to seize causing overheating due to work on the pistons/ rings.
When I replace rings only on an engine I would lightly hone the bores, clean the pistons and ring grooves, then first check all the correct size piston rings when inserted in to the cylinder bore had the correct ring gap,if the gap is too small when engine gets hot the ring gap closes and engine would try to seize. So if pistons and bores in fair condition I would fit the rings making sure they move freely in the grooves, then position them so the ring gaps are equally spaced (not all in line) next well oil and using a ring compressor carefully install pistons in cylinders and continue assembly, at every stage I would turn the engine by hand to ensure no tight spots.
When engine gets hot and makes noises, with it switched off try safely to turn engine by hand and feel if it moves as normal or is tight.
Another thing is, if badly fitted rings can be installed broken causing scoring of the cylinder bores and resulting in damage and partial seizure.

We have been through every test that we can think of, i have decided to order a kit of pistons and cylinders and my friend who has built the engine for his own one, will build it for me. Hopefully it should fix all the issues.

 

[Kalimir]

Obviously more tests would need to be made , but possibly two problems, the over heating being one, but if it is blowing oil into a catch bottle would indicate piston/cylinder bore wear "blow by" or a poor seal.
It is also possible the engine could be trying to seize causing overheating due to work on the pistons/ rings.
When I replace rings only on an engine I would lightly hone the bores, clean the pistons and ring grooves, then first check all the correct size piston rings when inserted in to the cylinder bore had the correct ring gap,if the gap is too small when engine gets hot the ring gap closes and engine would try to seize. So if pistons and bores in fair condition I would fit the rings making sure they move freely in the grooves, then position them so the ring gaps are equally spaced (not all in line) next well oil and using a ring compressor carefully install pistons in cylinders and continue assembly, at every stage I would turn the engine by hand to ensure no tight spots.
When engine gets hot and makes noises, with it switched off try safely to turn engine by hand and feel if it moves as normal or is tight.
Another thing is, if badly fitted rings can be installed broken causing scoring of the cylinder bores and resulting in damage and partial seizure.

Hey, just an update if you find that interesting. After getting the parts we finally took apart the engine today. You were 100% correct. Attatched are pictures of the pistons. They were in insanely bad shape with grooves in them when moving your nails over them. no picture of the cylinder but there were deep vertical lines in them. There were also other things not in great shape but thankfully we have 2 donor engines and it will be finished tomorrow and be put back in the car. So basiclly thanks for your advice it helped me decide on what to do next.

 

[bugsymike]

Hey, just an update if you find that interesting. After getting the parts we finally took apart the engine today. You were 100% correct. Attatched are pictures of the pistons. They were in insanely bad shape with grooves in them when moving your nails over them. no picture of the cylinder but there were deep vertical lines in them. There were also other things not in great shape but thankfully we have 2 donor engines and it will be finished tomorrow and be put back in the car. So basiclly thanks for your advice it helped me decide on what to do next.

Ha ha. No one like a wise ass eh! That's what 55 years in the motor trade does.
Seriously glad you are able to get to the bottom of it, that's the main thing.
No redress through the previous owner who said engine was "renovated in 2023"?

 

[Kalimir]

Ha ha. No one like a wise ass eh! That's what 55 years in the motor trade does.
Seriously glad you are able to get to the bottom of it, that's the main thing.
No redress through the previous owner who said engine was "renovated in 2023"?

I talked to the previous owner about this, he said he didnt think they looked bad when he ''renovated'' it but who knows, we ended up making a deal where he has paid for all the parts needed to fix it so i am happy about that.

 

[bugsymike]

I talked to the previous owner about this, he said he didnt think they looked bad when he ''renovated'' it but who knows, we ended up making a deal where he has paid for all the parts needed to fix it so i am happy about that.

At least you will have the satisfaction of knowing you have rebuilt if properly.

 

[Kalimir]

At least you will have the satisfaction of knowing you have rebuilt if properly.

Yeah, we choose to think positivly about it knowing that its now 100% good. The body is also in very good shape

The red one is mine, the blue one is my buddys.

 

[bugsymike]

Yeah, we choose to think positivly about it knowing that its now 100% good. The body is also in very good shape

The red one is mine, the blue one is my buddys.

Looking good