Turbo vs. Non-Turbo 231

[JasonB]

I was at one of my customers today and they used to do rebuilds for Auto parts stores. Well they are getting out of it and are getting rid of all their stock. It just so happens that they have an 85 231 long block but, its not a turbo motor he said. What is the difference? Im guessing pistons and heads but, I dont know. He only wants 100.00 for it and it comes with all the gaskets. I will probably buy it anyway and sell it if its to different. If all i have to do is change pistons then thats great, I will keep it till mine goes. Thanks in advance for any info.

 

[6pack]

I think the crankshaft is the only different piece....

Correct me someone if I am wrong!

 

[Rob_85Ttype]

Crankshaft and pistons are different. Block, connecting rods and heads are the same for the turbo motors and carbed motors.

 

[Nocooler]

http://www.gnttype.org/general/v6hist.html

HTH

BTW, I run a n/a crank......for now

 

[mygrain]

my cousin has a n/a crank in his 84 gn. at 15psi its holding up fine. the pistons and crank are the only dfferences.

 

[b4black]

Isn't the cam different as well?

I bet there are plenty of Turbo Regals out there with NA motors. You don't always know what the previous owners have done .

I also bet they hold up a lot better than most people would think.

 

[Nocooler]

I assumed cam was a given...my bad. I run 20psi on pump gas with my n/a crank......

 

[COPTZR]

Huh. That's interesting to know. I knew that on the 86/87's the rods are different as well as the usual stuff. I didn't know that the hotair shared rods with the NA engines. I guess you do learn something new everyday.

 

[cool 84]

Even on the 86-87s, the rods are the same as the NA rods. No difference. There might be a difference in the rod bolts used but the rods are the same. The 86-87 blocks are all the same too. Only difference is pistons and crank. The NA crank seems to break around the mid-high 11 sec zone. There is a big difference in strength.

 

[COPTZR]

I'm not so sure your right about the 86/87 rods my friend. I've been told numerous times by many different people that they aren't the same. Even Poston doesn't carry the Turbo rods cause they cost so damn much. They carry the NA rods which according to them and other people I've spoken with(including the folks at GreenFlag Speed Shop where my T-Type's engine is at) tell me taht is why a new set of Turbo rods are over 350 bucks. The NA rods are much cheaper. If they are the same, GM has been scamming a whole lot of people over the years. I'm gonna talk with some engine builders and see what they say about, but the ones I've talked with in the past have all said the same thing. They are different.

 

[Rob_85Ttype]

I agree with Cool, the rods are the same in both motors.

 

[cool 84]

The rods have two dots on the beam and 763 next to the dots. These are used in every 3.8L (and 4.1L, I think) from at least 84-87 including FWD cars. They are everywhere in the junkyards. I believe they were in use before then. There's absolutely no difference in rods between the turbo and non-turbo motors. The only thing I'm not sure about is the type of bolts or studs they came with stock. The only turbo specific parts were the pistons and crank. That sucks someone was telling you different, probably to make some money. I can pick them up at the junkyard for $20 a set. I'm going to put up a post in the tech area just to make sure.