i am considering another avenue for my 350 buick, turbo i was wondering if anyone new if i could use the pistons/rods from a buick 231, i know they have the same bore/stroke but i was wondering if there was any other differances that would not allow them to work also, someone please correct me if i am wrong, but the pistons and rods from a 231 turbo would be forged pieces? thanks guys
The stroke of the 3.8 is different, its 3.4 " I think theres something different about the pistons also, But I dont remember. One of the engines can use the others pistons, but not vise versa, or something like thato No: Somebody on here should know for sure. The rods for the 3.8 are cast like the 350, but there shorter, If I remember, all were of the cap screw design, and the even fire motors had an offset to the rod. Im sure some one on here knows the details better than myself Mark
I see Flatlander Racing has a set of the hypers. (H522p) listed for both the non-turbo 231" and the 350". They both have the same pin height at 1.855", same dish of .135" and same bore, of course. I asked the rep. from Grooms Engines in Nashville, TN that same question. They had a booth at the GS Nats. He said although they physically interchanged, there were some differences and didn't recommend it. Only exception might be, he was talking about the Turbo V6 pistons.o No:
I seem to remember that the 225 V6 pistons have the same bore diameters as the 300, not the 231, which has .050 larger bore. All stock 225, 231, 300 pistons should have the same compression height. If the forged pistons you have are stock comp height and stock bore, you may have a winner. There were two different pistions for the 300, low compression had a large dish for 8.80:1 c/r, the higher comp ones had a very shallow dish for 10.50:1 c/r. All stock GM 225 pistons were the large dish style, for 8.80:1 c/r. Sonic check the block and see if the bore holes are close to center in the water cores, and possibly, if the wall thickness is good, removing .025 from the bore wall would allow the 231 pistons to work.
piston swap I bought a rebuild kit for a 350 to put in my 79 Skylark. The box that the pistons came in stated buick 231/350. I am not happy with these and plan to get a different set .The piston dish measured out at 31cc's. The compression for the 231 was based on the 48cc head, but the 350 has a 58cc head. The piston would fit but the CR would be too low. Now if I was going to turbo it they would be great. The factory turbo pistons are hypereutectic. Hope this helps. Clint
Hmm, I gotta revise my above post. 225/300 had a bore of 3.750, stroke of 3.400 231 had a bore of 3.800, stroke of 3.400 340 had a bore of 3.750, stroke of 3.850 350 has a bore of 3.800, stroke of 3.850 To run the 231 pistons, they'd need to have a compression height change, or much longer rod length would have to be used, or a combo of each.
Actual the compression height between the 231 and the 350 is very close if I remember correctly is is 1.87 v/s 1.88, so you shou,d be able to use 231 pistons in a 350
In addition to the 1.855" pin height, there are also shorter pistons offered (shorter in the bore), with a pin height of only 1.800". Make sure of what you're getting!!:Smarty: Since the stock pistons are already 'deep in the hole', it would be nice if there was a 1.900" pin height available. Would save alot of decking!!
Pin height Can you tell us how to measure pin height? Is it from center of pin to top of piston? This way I could determine exactly what I have. Thanks Clint
You can use the pistons but not the rods. The v-6 rod is a different length and bearing size. The factory turbo v-6 pistons are cast and so are the rods. You will have to calculate the compression with that piston in the 350 , while the v-6 piston was designed around a smaller chamber, you are now installing it into an engine with a longer stroke. We have used 350 pistons in the past to build higher compression v-6 engines. Here's a tip for you guys, if you want a flat top piston for your 350, use a 3.0 Buick v-6 piston. Jim Burek
Re: Pin height That's were you measure from Clint. You can measure from the top of the pin bore to the top of the piston flat - then add HALF the diameter of the pin. That will give you your compression height.:TU:
Re: Re: 231 forged pistons in a 350? Jim - Were they a true flat top or a shallow dish? If a small dish - what cc? Thanks.:bglasses:
Re: Re: Re: 231 forged pistons in a 350? It's a true flat top piston. I t has no valve notches. Jim Burek
I have been asking this question for a long time. Since the 350 pistons are so hard to come by. Jim, you said the 3.0 pistons? Is that correct? Or is it the 198 ci pistons?
Scott, Thanks for the help. The pistons are 1.80 pin height. I went ahead and ordered some different ones. Need to get this engine built.:Brow: Clint
Are you going to be decking the block, to wind up between -.005" and zero? Have you checked the current piston to deck clearance? The pistons with the 1.855" comp. height would be beneficial (unless the block has been excessively milled).
Clint, Is this the twin turbo intercooled nitrous motor? Is it going in the car in your avatar? I thought you had a twin turbo BBB in that thing at the OK Buick shootout a couple of years ago... Jason
interesting I found some interesting info while surfing: http://www.babcox.com/editorial/us/us20114.htm
