Technical How to remove pistons in 899cc, and other overhaul stuff.

[Fiuders]

Hey,
In the 899cc engine apparently the piston rods wont fit thru the cylinder bore. They neither come out from the down side, as there are the bearing block castings.
How is one supposed to get them out really?

Should try and get the piston pin out while the piston is still in the block?
There is hardly space to do that.

 

[Fiuders]

Here is a photo of the "situation"

 

[Fiuders]

And as the topic says "other overhaul stuff" im kinda in between to change or not to change the bearings on the crankshaft and piston rods. The engine has done only about 80 000km.
How do they look to you? Kinda would want to change everything as there is a good chance now, but all the costs will add up. Not that im doing this to save money in the first place tho, but you know the struggle.

 

[Fiuders]

Was fiddling with this more now. Its unbeliveable. There seems to be no way to get the piston out. It's like the cylinder pipes would have been installed on with the pistons all ready inside them or something. Could it be?

 

[portland_bill]

I have looked in the Haynes manuals for classic Panda and Cinquecento, which both use that engine. In both cases, the piston is removed out of the top of the bore, with the rod attached. This is normal with most engines, as removal downwards is very rare.

The rod should therefore fit through the bore, although may be very close in size, so avoid scratching the bore with the rod edges.

I no longer have my CD manual of the Seicento, but you can download it here: https://www.fiatforum.com/downloads.php?do=download&downloadid=328

Download all files to a single directory.
Use Winrar or similar to extract the .rar files to create an ISO disc image.
Write that image to a CD, which should then run and give you the factory manual.

 

[Prawny12009]

The block in your picture looks to be machined for piston clearance "under" the bearing shell.

If you remove the shell the piston should clear.

 

[dante giacosa]

*major* work!!!

 

[Ralf S.]

The connecting rods usually have narrow enough shoulders to fit through the bore (push the rod from below, until the piston emerges from the top of the block).

They tend to be designed that way, so you can remove the piston and rod together without having to remove the crank, if you just have a piston/ring problem and not also a crank problem.


But your first picture seems to show the con-rod (?) shoulders are way bigger than the bore. Is that correct? I can't tell from the picture quite what's happening (a side view would be clearer).

If the con-rod shoulder is too big to fit into/pass through the bore, then it *must* be removed from below (i.e. you would need to remove the crankshaft first, as you have done). What's stopping you pulling the piston out from below? You should be able to pull it straight out. Have you removed the spark plug (the valves will be closed, so you may be pulling against a vacuum).

Failing that, you might be able to push the piston out of the bore from below, enough to remove the gudgeon pin and circlip from the piston, while it or the con-rod is still in the bore.. but that would be what I would do if I wanted to change the piston or rings wthout removing the crankshaft. (since it will be a fiddly Mo-Fo of a bitch-fight to refit the new gudgeon pin and circlip with the piston/con-rod half in and half out of the bore).

When they build engines at the factory, they don't do fiddly Mo-Fo bitch-fights.. they must stick the piston and con-rod in as an assembly, so it *must* fit from one way or another. Probably from below.


The bearing shells look "okay" if the one on the right is the worst one. The left one looks splendid. You can just about change the shells later without removing the crank (sump and oil pickup would have to come off) so if they're €60 each or something, run the old ones a bit longer unless the engine makes a knock. If they're €20 for a whole set, I'd fit new ones now. The right hand shell does show some wear (a lot of revs and/or not the best oil to blame).


Ralf S.

 

[Fiuders]

Hey, thanks for all the suggestions. I think ill try to post some kind of a crappy unedited video of how everything is there to clarify the position more throughly.
Btw, the engine is in pieces, attached to an engine stand. Would anyone want photos of certain details im happy to provide.

 

[Fiuders]

Too tired to work on the engine today. I anyway went to take a measurement on a cylinder bore, and the diameter seems to be about 57.8. I was thinking should be 65mm. What the heck is this engine

 

[Fiuders]

Here are some markings from the engine if they tell something for anyone.

 

[David C]

That 1170A1.046 engine type is correct for the 899 Cinq engine.

and yes it should be 65mm bore.
and 67.7mm stroke.

Could you take some pics of the top on the block showing the cylinders & pistons?

 

[Ralf S.]

The piston you have your hand on above (no.1 or no.4) looks like it would come out if there wasn't the shell casting on the right. But that piece looks like it's just floating there (i.e now that you have removed the studs/bolts and the crank, there's nothing to stop it coming out).

Is it a separate piece that can be detached? It seems to have a line of sealant.

Don't bash it too hard, in case it's part of the engine block (I can't see the piece as a separate component in ePer).

Meanwhile, what's preventing the other pistons coming out...? No2 and No3 won't have any castings next to them, to stop the pistons coming out.


And measure the bore again. 65mm bore gives you a nice 899cc .. whereas 57.8mm comes out at 710cc, if the stroke is the same.

Can the engine ever have been sleeved down? Is there some engine size/formula that makes the car cheaper to insure/for young drivers etc. in Finland? Or some 700cc race formula? The shells are quite worn for a road engine...

Meanwhile, there is no 4-cylinder "700cc" standard Fiat engine. The twin cylinder 700cc engine out of the 126 and Polish market Cinq's wouldn't have a 57.8mm bore... and your engine comes up as a standard 899cc on ePer.


Ralf S.

 

[Fiuders]

Hey,
im absolutely sure there are no shells that could come out from under the bearings to give clearance. Will post better pictures in the evening, also from on top of the engine with a measuring device in the photo.

The engine is not originally from Finland, but from germany. Sei was never really imported to Finland i think.

As for why the cylinders are smaller, i have no idea. Is it even possible to put together an engine by pushing in sleeves, which allready have pistons inside them? That is the only way i see that this thing could had been put together. Was thinking the sleeves should be machined after inserting, maybe someone with more knowledge can tell more.


Neither i have been able to find anything from the internet about an engine like this.

The idea that this could had been some kind of a race engine seems wild but possible i guess.

At least the head has not seen any kind of racing modifications as far as i can tell, but who knows .

 

[Fiuders]

Hey, here are some more pictures.

The cylinder sure looks like it has an extra pipe inside it. But why on earth would somebody go smaller??

Head gasket shows nicely the difference in size. The cylinder hole in the headgasket is about 66mm.

Anyone wanna swap cylinder blocks with pistons? im offering something very special here

 

[Fiuders]

Anyone know what these pistons are? No markings other than on the top.

 

[David C]

That is very odd.

What car did it come out of?

 

[Prawny12009]

Tbh it looks like that block has been sleeved down. But even the 126 bis/ cinq twin has an 80mm bore, 126p is 73.5.

Are there any vintage, capacity limited race series in Germany that would require reducing bore size?

I see with the shell removed the is no cut out or Cresent for the piston to clear which only leaves one option.

Rotate the piston 90° and push the wrist pin out then remove the piston from the top

 

[rallycinq]

The standard 899 is a sleeved down 903 block, but its about 1mm sleeve, nothing as big as that.

D

 

[Ralf S.]

That is one freaking strange Mo-Fo...

The engine type number stamped on the block means your engine started life as a 899cc motore.

The bore is 57.8 now so it has clearly been sleeved down (you can see a thick liner). It would be interesting to know what the "bore" would be if you measured the liner as well. The standard 899cc bore was 65mm.. and when I measured your bore on my screen and multiplied that measurement to be 58mm.. then my measurement of your bore plus your liner with the same muliplier comes out at 66mm (+/- for some distortion...) so it looks like your new liner was just squeezed into your old liner - although the old liner may have been machined out a bit first.

At the moment your motor (if the stroke is standard) is 710cc.

It's nothing to do with the 126 650cc or Polish 704cc Cinquecento engine, since that was a twin cylinder engine and they had a bore of ~73-80mm. The pistons would be huge compared to yours.


Taking a step back.. why are you fixing it? If you want to use it in your car, then the questions to answer are;

1) Do you want a 710cc or an 899cc engine, bearing in mind that the 710 is not standard

2) If you want to continue, what will you do if find other issues or problems (like where can you find some new piston rings for these "unknown" pistons)?

If it was me, I'd send that engine back to the seller, or if it's not viable, keep it as a hobby but try to find another engine that is still standard and 899cc for your car. There must be plenty still around in breakers yards, for not much money.


** Meanwhile, what's stopping you from pulling the pistons out (with the con-rod attached) from the bottom of the block. If you press down on the piston crowns (especially 2 and 3, which are in the middle of the block) why don't they come out of the bottom?

If you can get the pistons out, you'll have a chance to save the block - i.e. knock out those liners and fit standard ones, so you can make the beast an 899 again... although the parts might cost more than a whole second-hand engine.



Ralf S.