B5254S head into B5234T block

xb corp · Post by **xb corp** » 26 Sep 2010, 20:51

To all who may have answers..
I have a ported NA head for B5254S (96' 850 2.5 NA) with all valve seals replaced and valve grinded, polished and weighed.
i was thinking of putting it into my 2.3T5 block, together with its intake manifold and TB.
Will it work?

Compression for NA engine B5254S is 10.5:1, while turbo B5234T is 8.5:1.
Fuel is RON97.

Please comment. Thanks

xb corp · Post by **xb corp** » 27 Sep 2010, 02:20

Lee....Lee...where are you? shed me some light please.

Post by **precopster** » 27 Sep 2010, 07:47

Sounds like an interesting swap. If combustion chamber shape is the same, deck height is the same and valve size is the same don't see why not. Something tells me that Volvo may have done more than just strengthen the block and change piston compression to achieve the power of the R series. But then again if basic flow is good perhaps that's why these motors have one of the highest specific power outputs (107 hp/litre) on the market at the time.

As soon as I p/u my spare laptop from the MIL's (mother-in law's) i'll look on my copy of Vadis to see if part numbers for heads vary b/w B5254s and B5234s.

Post by **jblackburn** » 27 Sep 2010, 08:11

I know for sure that the head design is a bit different - the 2.3 engines have larger water jackets around the cylinders thus the small change in displacement, but one thing you will want to keep in mind is that the turbo engines have sodium filled valves to help them handle the heat of the higher compression ratios induced by the turbo. Will it fit? I'm not sure, but fitting the NA head without those, you might burn one of the valves much more quickly.

That said, the easiest way to get more compression? More boost!

Post by **Ozark Lee** » 27 Sep 2010, 22:02

Don't try to use a N/A head on a turbo. The head itself is exactly the same but the valves are completely different and it will run great - for a couple of thousand miles - until you burn the exhaust valves.

If you want to replace all of the valves it should work just fine but that is the same price as a rebuilt turbo head and the rebuilt is a lot less brain damage since it should have been decked and ready to go.

My 2c,

...Lee

xb corp · Post by **xb corp** » 27 Sep 2010, 22:09

i have inspected both engine's valves and the dimension are identical. about sodium filled....i dont know, cant see the surface differences..i will transfer all the turbo valves into the NA head just for safety.

the head gasket for both engines are same, i assume the waterjacket should be same too? but i noticed the volume of the combustion chamber are different. see these pictures.
http://www.facebook.com/photo.php?pid=1 ... 0760776001

Lee, anymore precaution? Please comment...if the car dont start, nevermind...just dont want to breakdown at roadside..

Post by **Ozark Lee** » 27 Sep 2010, 22:29

The stock N/A valves are not sodium filled in the standard configuration of the head but the mechanical specs are identical.

Sodium filled valves are very expensive - almost Formula 1 crazy expensive - and without evidence that you actually have the sodium filled valves I would not run them in my turbo.

Your situation may be different but I have nothing in VADIS that says that the Euro spec or Asian spec cars are any different.

...Lee

xb corp · Post by **xb corp** » 27 Sep 2010, 23:07

Lee, you mentioned that "the valves are completely different"...if i transfer all turbo valves from B5234T into NA head B5254S, would be safe to run?

Post by **Ozark Lee** » 28 Sep 2010, 20:13

I think you would be "good to go" but you will need to lap them in with lapping compound and the purple dye to make sure that they seal.

...Lee

xb corp · Post by **xb corp** » 29 Sep 2010, 19:50

thanks Lee. will do it in end Oct due to some financial...

will post some pictures when the project is done...and the dyno result too..