Cylinder hone after 10k km 2

[Deividas]

Hello,

Half year in weekends I was rebuilding my old Alfa Romeo engine. Cylinders were re-bored and honed, new larger pistons with new rings installed, main and conrod bearings replaced, new valves, valve guides, valve stem seals installed, all other seals and gaskets replaced. And, as it was my first engine rebuild, in break in period I used 5w40 synthetic oil, and as I found out later, it was not good idea. Oil was changed after 1000 km to same 5w40. Right after rebuild, engine was using oil, I thought maybe it's due to break in period, but now, after few thousands km, engine still consumes a large amount of oil, about 1,5 - 2 litres for 1k km.
I can't understand where is the problem and I planning to try disassemble engine again after winter, when it gets warmer outside. I think, that there can be issues with oil rings, and my question is, do I need to get cylinders honed again, if I will replace piston rings? I know, that it's recomended to hone cylinders when changing rings, but if cylinders were honed few thousands km ago?

 

[Deividas]

Tmoose - it's 2000 Alfa 156. When I was rebuilding engine, I sent cylinder head to machine shop to resurface it and they also changed exhaust valve guides and exhaust valves, they removed old valve stem seals, so now I don't know if they were out of place or not. I used non OEM valve seals, because they cost about 10x more than aftermarket brands, and as I saw in catalog, all brands have same dimensions

 

[SwinnyGG]

Same dimensions != same performance

 

[Tmoose]

I could not find any Alfa 156 valve stem seals on line that were not pictured with metal shells or other features on the OD to enhance the grip of the seal on the guide.

Do your seals lack that kind of feature?

https://alfa-restoration.co.uk/shop...0/60513469-AG-A33-etc-valve-stem-seal-(1).jpg

https://www.kmotorshop.com/document/shop/701.289/tn_600_701-289B.jpg

https://www.ebay.com/itm/263719475450

https://www.bestpartstore.co.uk/engine/valve-stem-oil-seals/alfa-romeo/156/156-932

 

[Deividas]

Tmoose - sorry, I misunderstood you. These seals in your link are same as mine

 

[3DDave]

Reading the posts, including ones from the OP on the Alfa owner's site, it appears possible the valve guides that were installed do not match the OEM guides. The engine seems to be a niche engine; there were multiple mentions that many of them did not have seals on the exhaust guides and many did not have any guide seals at all.

Since the engine shop tossed the original parts it's not possible to know if the replacements were a match for them. It's possible it's now a frankenmotor.

 

[Deividas]

3DDave - yes, machine shop replaced exhaust valve guides and exhaust valves, but intake valve guide seals also popped off, and as far as I know, intake valve guides are still original

 

[TugboatEng]

There is a type of seal often called an umbrella seal. These ride up and down with the valve stem and don't attach to the guide.