1996 850 Turbo/GLT Newbie attempting head swap!

Broodoobob · Post by **Broodoobob** » 26 Mar 2015, 11:24

Hello friends! I am new here. I hope it is okay if I start asking questions right away

I have found on Craigslist a 1996 Volvo 850 GLT (B5254 engine) that likely has a spun main bearing. I have also found on Craigslist a 1996 Volvo 850 Turbo (B5254T engine) with a warped head. What I would like to know is whether I can take the head from the GLT, put it on the Turbo's engine, and then put the resulting engine back into the GLT. In other words, my question is, is the non-turbo B5254 head compatible with the B5254T block, thus un-turboifying the engine? Also, am I going to run into any problems with sensors not being in the same places or other headaches?

Thanks a bunch!

Broodoobob · Post by **Broodoobob** » 26 Mar 2015, 14:22

I've discovered that the Turbo 850 that I thought was a B5254T is actually a B5234T3, which has a bore of 81mm instead of 83mm. I'm assuming that this means that the head definitely won't be compatible. I would love to know if I'm wrong though! Sorry for the mistaken thread.

Post by **Ozark Lee** » 26 Mar 2015, 15:00

The heads themselves are actually the same but the turbo has different exhaust valves. The turbo exhaust valves are sodium filled while N/A engine has standard steel valves.

You could swap the valves from the turbo to the N/A head but you would, of course, need to lap them in. Re-lapping the valves and replacing the valve stem seals is always a good practice anyway when you have a head off. If you really want to do it right I would replace the guides as well. Run the numbers though and see if it makes sense and include several hundred dollars worth of seals, head bolts, timing belt components, etc.

...Lee

Post by **precopster** » 26 Mar 2015, 20:39

The difference in compression ratio between a B5254T and a B5234T is achieved through a different dish/scalloping in the piston top therefore allowing a lower compression ratio in the high pressure turbo engine. Heads are the same lump of metal excluding the sodium filled valves.

Broodoobob · Post by **Broodoobob** » 27 Mar 2015, 15:49

Thank you so much, that's great info. Seems like it won't be worth the time and money, but it's satisfying to know the details.

Cheers!