Volvo 740 'K' block piston rings

SLT16

Hi all,

FCP and IPD don't seem to sell piston rings to fit my 1987 740. I am doing an engine rebuild at the moment, and the engine is a K block turbo.

If someone can suggest an Australian supplier and/or part number that i need for the piston ring set, that'd be great.

Philia_Bear

Email ipd and or fcp

Both can source them but frequently don't list them

Major Ledfoot

For B230 turbo pistons -

275372-1 = std

275373-9 = 1st os

275374-7 = 2nd os

Backordered at FCP

Not listed at CVI or VP Autoparts

In stock at gcp.se = 350 SEK + shipping

In stock at volvopartswebstore.com = $37.08 USD + shipping

volvodriverman

https://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=402789628701&category=33623&pm=1&ds=0&t=1624328157967&cspheader=1

I'm fairly sure rings are the same between et & ft they just had different piston dish.

Be worth a little research as these are in oz.

buddyglitch

I used these to rebuild my 1994 B230FB no worries. In stock in Melbourne.

As far as I know the ring landings are spaced differently between the NA and Turbo pistons, however the rings themselves are the same spec.

https://www.precisionintl.com/part/v/volvo-940-945-2-3-turbo-1990-1994-petrol-wagon/c/100000-standard/107000-rotating-assembly-components/107105-piston-rings-chrome/b/mahle/volvo-940-2-3-turbo-b-230-ft/037%252042%2520N0.html

Major Ledfoot

As far as I know the ring landings are spaced differently between the NA and Turbo pistons, however the rings themselves are the same spec.

Nope. According to the book, NA and +t rings are different part numbers.

That link above goes to B23 pistons.

B230 pistons are below.

For completeness -

K blocks (63mm mains with centre thrust) were fitted from 1988-90.

Roinik

It's probably got something to do with the extra heat and the extra expansion of the turbo rings.

SLT16

I've got the letter 'K' clearly stamped in my block but I've got a date stamp of August 1987 on it. How come?

Major Ledfoot

SLT16
I've got the letter 'K' clearly stamped in my block but I've got a date stamp of August 1987 on it. How come?

Year model 1988 began manufacture after the Swedish Summer Holidays, in July / August 1987.

Typically, Volvo 'year models' begin manufacture up to 6 months earlier than the new calendar year. So YM1975 was made from August 1974 to June 1975, etc.

SLT16
But either way, would I be correct in the assumption that the correct part number for a turbo b230 piston ring standard size set is 275372-1?

Absolutely correct.

While you're in there, since it's an early K-block engine, it may be worth checking to see if you have 9mm or 13mm conrods.

SLT16

But either way, would I be correct in the assumption that the correct part number for a turbo b230 piston ring standard size set is 275372-1?

buddyglitch

Oh yeah don’t listen to me!! they are the same width from memory but the end gaps might be larger for the turbo variant. I looked back at my invoice, these are the ones I bought. Also in stock:

https://www.precisionintl.com/part/c/200000-performance/b/hastings-piston-ring/2C4477.html

Major Ledfoot

That link shows the same ring set for both NA and turbo, and the book says they're different part numbers. Which suggests there's something different about them - maybe material, maybe heat treatment, etc.

Nothing personal, just going by the numbers in the book.

The Hastings catalog shows two types of ring for B230 engines, one being a cast iron ring, the other being a chrome ring.

https://www.hastingspistonrings.com/wp-content/uploads/2020/07/2019-hastings-emea-catalog.pdf

Seems to me like the chrome type would be better in a +t application, as heat and pressure are more extreme.

Roinik

This explains it nicely.

https://youtu.be/hJBlMMES77I

Vee_Que

Rings are not different material for a turbo or na, they will be different ring gap. They all have the same outside dimensions I've found.

SLT16

Hey guys,

Thanks a lot for your help.

On a completely different note, where can i order the sodium filled turbo exhaust valves? IPD and FCP only have the naturally aspirated valves for sale listed. I've heard of some people running stainless valves from an NA motor in a turbo. Is this a good idea or is there anywhere i can source the turbo valves?

Vee_Que

SLT16
Hey guys,
Thanks a lot for your help.
On a completely different note, where can i order the sodium filled turbo exhaust valves? IPD and FCP only have the naturally aspirated valves for sale listed. I've heard of some people running stainless valves from an NA motor in a turbo. Is this a good idea or is there anywhere i can source the turbo valves?

You can buy stainless valves from a few Swedish supplier's. For the stock valves, it's only worth it if you're staying original and the original ones are deemed throwaway by your machine shop. If you plan to make more than stock power and using a non standard ecu, the na valves re cut do a good job.

Alternatively you can also buy larger valves and get the seats cut from the Swedish sites as well as a guy on turbo bricks.com, there is usually a group buy advertised for them.

VolvoHordz

Normal non sodium filled valves will work just fine. Plenty of people running redblocks that way over the long tern without issue.

Stainless will cost more but you can run slightly larger valves which will in theory improve flow and hence performance