Why not grand national internals (stefan?)

[jmorgan]

Since no one answered my question in another post I will ask it here.

Why wont grand national pistons and rods work? The bore is the same so technicly they should fit fine right? I can understand the cranks because theres is 120 deg (i think i read that some where) and ours is a 90 deg engin.


please dont be dumb and write back cause stefan said they didnt work. I wanna know why they wont.

Thanks Jason

[Dominic]

http://www.angelfire.com/my/fastcar/pistonspec.mht

Here is part of your answer.

[jughead]

Let me first say... I had a GN... but anyways...

The stoke is just a little different... The GNs stroke is bigger... even tho its a 3.8L,, but hey, the 305 and 302 are both 5.0 engines.

[jmorgan]

please explain why the piston wont work I understand the rods and crank might not but why not the piston same bore so why cant it?

[Jason]

the piston wont connect to our connecting rods. Youd need COMPLETELY CUSTOM connecting rods and that costs MAJOR diniro. VERY cost prohibitive. you want super strong pistons? get some L67 pistons and rods from the gtp and have em hardened, Because your gonna spends THOUSANDS getting those GN pistons to work.

[12secondv6]

Grand nat, t type, tta etc 3800 series 1
v6 f body 3800 series 2
You are comparing apples to oranges.
Different engines
http://my.stratos.net/~killerklown/Buick/MfgSpec.html
I just clicked google.com and did a search for grand national engine
You can find our specs on this site

[DEE97GTP]

<blockquote>quote:</font><hr>Originally posted by 12secondv6:
Grand nat, t type, tta etc 3800 series 1
v6 f body 3800 series 2
<hr></blockquote>

Actually, since we want to be exactly correct, the GN engine is not a 3800 series 1. ;) The 3800 series I was is the 1995 maybe some '96's and earlier cars like the '94 lesabre I had. It had more in common with the series 2 than the GN engine. That 3800 terminology didn't come about till after the GN had passed.

If you want stong, go with FORGED pistons. I think you can order them from thrasher right now. Those in combination with L67 rods would make a very strong setup.

DEE

[ April 12, 2002: Message edited by: DEE97GTP ]</p>

[12secondv6]

My bad, all I know is they are completely different :D

[mike24]

DEE97GTP what is thrashers web address? How much r they there?

[DEE97GTP]

<blockquote>quote:</font><hr>Originally posted by mike24:
DEE97GTP what is thrashers web address? How much r they there?<hr></blockquote>


http://www.thrasher-ep.com/

They still have their outdated website up. But I have heard through the grapevine that they do have forged pistons available. You will have to contact them though.

Cost, i don't have a clue.

DEE

[Pro Stock John]

Question you need to ask...

1. If the bore size is the same, will they fit? They won't work if the location of the wrist pin is different.

2. Do GN's have the same length connecting rods as a 3.8 Series II? I have no idea. Also need to know the differences in stroke (crankshaft).

I'm sure someone sells a forged piston for the 3.8 motor. I bet the L67 stuff is interchangeable if the cylinder bore is the same.

[strobhen]

L67 internals are interchangeable w/ L36...

Forge everything and that will be plenty strong...

[Shadly]

I read about someone doing this a few years ago. It wasn't solely for the strength of the pistons, it was for the strength of the rings. This WAS a few years ago, so there wasn't a lot of aftermarket stuff available. The guy wanted to boost past 12 psi, but leaked compression after 10 psi with his stock stuff. Really, if you're going to spend that kind of dough, buy a different engine.

[slacker69]

i talked to thrasher about there pistons for the 3.8 I was gonna get 10.1 compression and they wanted like 700+ dollars for it so i think i will keep looking

[Dominic]

Really? Which compression ratios did Thrasher offer for $700? Thats not too bad of a price if theyre REALLY good pistons!