Dauntless Swap Out

Thanks all. This 231 had a thick, heavy flywheel already on it. Guess PO had no issue. I just hope the 231 just sits right in and the exhaust lines up with my 225 manifolds and crossover.

 

Jeepster Commando used the 225, t-14, d20 set up.

 

The 1980 buick 231 may be rated as low as 110 HP or up to 125 HP. The dauntless or any odd fire buick 225, is rated at around 160. Just because it bolts in doesn't mean it's a great idea.

 

This is the turbo 231. Isn't it supposed to be 170 hp?

 

So, you're sating you have a complete turbo charged 231. With the turbo installed it creates 170 hp at 4k rpm. Without the turbo, its going to have a lot less power. What I don't understand is if you have a complete turbo 231, why you're asking questions about compatibility with the 225. You're going to need to do a lot of stuff to make all that work.

Honestly, the 225 is rated at 160+/- hp with a 2 barrel carb, normally aspirated. The complexity of a turbocharged 231 to gain a couple HP seems like a lot of work for minimal gain and a HP curve not optimal for off idle HP.

 

Net vs. gross? Can't compare a 1980 HP number to a '60s era spec. They are measured to different scales.

No knowledge of the turbocharged Buicks, but the 231 block is essentially a 225 bored out 50-thou. They didn't literally bore it out. The casting would be changed to make the raw casting bore 50-thou larger with the same wall thickness.

Without the turbo, I expect the 231 will be way down on power. Turbocharged engines typically have lower compression ratios than conventionally aspirated engines. This plus the smog-related modifications to an '80s engine will impact its power quite a lot. And not in a good way.

You could build the 231 block as a more powerful conventionally aspirated replacement for the 225 pretty easily. It would drop right in.

 

My 1984 Buick 231 Turbo V6 SFI is rated at 200HP. Stock 8 : 1 compression. No smog or Catylitic ' Cuz it's in my '75. Completely ECM controlled. Chris is right . It's a different animal. It's a ton of work & $'s to go from NA to a turbo.
It takes alot more than a block to get HP increase. Please try to use the casting #'s to identify Year & Bore :

 

Tim, you seem to be the knowledge well I'm needing. I do currently have a 225 with stock single exhaust. It has a cracked block. I also have the 231 available. It is carbureted. What I really would like to do is just swap blocks, if possible. If needed, I could install the 231. It was in a cj mounted to a T90. It also already has the heavy flywheel. So, can I use the 231 as a short block for my 225?

 

The 231 and 225 use different heads with different coolant passages. The intakes are different too.
Differences Between Dauntless 225 And Buick 231 Odd Fire?
Buick V6 History

 

As Chris points out, you'd keep the 231 heads with the 231 block. Unless I'm mistaken, I don't see how that changes the effort or expense needed to make a usable engine. But you can't just use the 231 as a short block.

You understand that the bore of the 231 is larger than the bore of the 225? Assuming this is a 231 from a rear-wheel drive car, I would use the 231 block to build an engine to use without the turbocharger. This would need different pistons, to provide the higher compression used with conventional aspiration (ie no turbocharger). Hard to say how much would need to be done without knowing the condition of the 231, sp. measuring the bores. Likely you'd need to buy oversized pistons and straighten the cylinder bores. Pistons are your single biggest parts cost in a rebuild, so I'd probably assume that I was going to bore the block and thereby get maximum life from the engine. Buying new pistons for a crooked block seems wasteful. Buying new pistons and straightening the bores is essentially a complete rebuild, but starting with a block that's not cracked.

 

So, would a complete aspirated 231 from a 82 Century that is complete from top to bottom with the thick flywheel and previously installed in a cj5 with a T90 just drop in or are any mods needed such as exhaust?

 

Should be direct replacement.

 

The exhaust manifolds are the same. It's the internals like the water jackets that are different on the heads. and then the .50 overbore. footprint should be the same. If you've got a good 231 & a bad 225, pull that 225 & line up the 231. It should drop right in. The V6's flywheels are balanced internal.
You could check with Novacks about the T-90 & T-14 differences.

 

The T-90 and T-14 have different front patterns. You'd need an adapter that works with the transmission that you have. The bell housing is just a Buick manual transmission bell housing, same for both transmissions - the difference is in the adapter.

 

I'm bolting to my T14, so is all I need is a T14 pilot bushing?

 

Yes use the bell housing from the 225 v6 . Yes get a new pilot bushing for the T14 tranny. The bell housing for the t90 should have a different adaptor on the back . If it is not the one piece aluminum bell housing .first mount the bell housing then rotate around main hole with indicator mounted to fly wheel to check for alignment pilot to bell housing bore.

 

Picture of what you have to work with would definitely help.

 

The chart shows all years of 231, turbo or not, all have the same bore and stroke.

 

Just trying to help, but follow what Chris & Tim said.
Good Luck in your endeavor.

P.S. Have you tried repairing the crack in your 225 ?

 

Not the worlds expert on this, but crack repair is generally reserved for when you can't find a better core. Disassemble, clean (tank or washer), magnaflux - barring other damage, repair. I expect the 225 is not scarce enough to warrant such repairs. Especially with the 231 being such an easy swap.