Volvo 850 engine rebuild and exhaust recommendations

[Bigsi15]

After some honing the problem areas can be seen, im hoping this small area wont be enough to affect the engine too much. the machine shop seem to think it will run ok but ideally needs a bore and larger pistons (£600+ at least) so thats a no go for me. engine was always just a 'project' and i never wanted to race it just a bit more welly when needed so i think i may just see how she goes. figure an engine that clean on an auto box shouldnt have been ragged too hard so if people can get half decent tunes on cars with 160k+ miles they cant be too much better inside. shame though as would have liked a fresh engine

[oblark]

I got a 109K mile block that was also a auto and it just as worn, a born will wear regardless of what type of gearbox is connected to the engine, it's how often the engine was serviced.

[Bigsi15]

Oblark what did you do with yours? Seems a low mileage to be wearing to the point of nearly needing reboring

[oblark]

Oblark what did you do with yours? Seems a low mileage to be wearing to the point of nearly needing reboring

I scrapped it

[Bigsi15]

Balls

[Dangerous Dave]

Balls

Indeed

Not sure what advice to give I'm afraid, I don't know whether shelling out for new main bearings is worth it....

[Bigsi15]

No indeed... Guess until it's built and compression is tested I'm not going to know. Kinda hoping it isn't going to be complete crap! If it is then will have to put the other one back in and start saving I guess!

[Bigsi15]

I think the Haynes manual suggest 4/1000ths is about the acceptable wear limit so at least 4 cylinders are about that just the one which is below that. We will see... Thanks guys

[Bigsi15]

Ok new thought. How would fitting a larger letter piston work? Figure as its only really 1 cylinder that's really worn could I pop an e piston in say rather than the d I have already?

Thanks!

[oblark]

Another option you could consider is to bore it out from 81mm to 83mm making it a 2.4

If you down the the road of boring it out to 2.4 you WILL need a custom map.

[Bigsi15]

Oblark that sounds tempting however I think sourcing pistons and the cost may not be cheap either

[oblark]

I have a set of 83mm secondhand pistons tucked away in the garage.

I'm off on holiday tonight for a fortnight so if your interested I'll have a look for them when i get back

[Bigsi15]

Ah yes I would be interested thank you. Can you pm me a price and details? Thanks buddy

[Bigsi15]

Are the 83mm bores the same as the r series cars? In which case can you run 139mm rods with those Pistons in my block or do you need te longer ones? Cheers!

[Orca2]

I would deffo bite the bullet and rebore that Si, you are too far in to build back up knowing the bores are a bit suspect, if you factor in the time and hassle of stripping it back to where you are now it makes sense to deal with it now rather than have to return to it, its pretty demoralising too when you build them back up and they arent quite what you had hoped ,
I did it years ago with a Metro turbo, and never again.

[Bigsi15]

Yeah it's a difficult decision hopefully if oblark or someone has some larger Pistons at a reasonable cost then I will do it. I just can't justify 600+ pounds for newargwr Pistons and rebore sadly. Thanks for your advice though dude

[Orca2]

Good luck with it mate, hopefully someone will have what you need,

[oblark]

The pistons I have are only for the 139mm rods.

You have PM

[Bigsi15]

Thanks for that buddy