PDA

View Full Version : 2.5 stock forged?



Lee'sdaytona
04-23-2006, 10:23 AM
Did the 2.5 Turbo engines that came in say, an 89/90 caravan have forged pistons/rods/crankshaft?

And, If I were to put turbo II rods and pistons (not the crankshaft) into my 87 TI block what would need to be done? Could I just get away with honing the cylinders, new rings and rod bearings? I Don't want to take the crankshaft out because you have to take the tranny out and I don't want to do that since I don't have an engine hoist.
Thanks for any info
-Lee

89acclaim
04-23-2006, 11:36 AM
Rods are normal forged T2, the pistons and crank is cast like the rest of the 2.5T1s.

Daniel Merrill

Murphy
04-23-2006, 01:24 PM
http://thedodgegarage.com/turbo_shortblock.html
2.5 TI came with forged rods, cast pistons and crank
TII, TIII, T!V came with forged crank
TIII came with forged pistons
2.5 crank + 2.2 pistons wolnt work....the 2.2 pistons are too tall
now the 87 block is probly going to be a weakpoint since they can only handle about 250hp

Lee'sdaytona
04-23-2006, 04:28 PM
ok so your saying that if I had a stock 2.5 turbo it could handle 20 psi of boost with cast pistons/forged rods? Thats what that turbo mini site says anyway...

and if I keep my daytona, 87 TI block, I could put in just TII pistons and rods without having to turn the crank, and I could just hone out the cylinders correct? How much boost would that support?
thanks,
Lee

Murphy
04-23-2006, 04:43 PM
I have made well over 300 hp with cast pistons with boost pressures over 30 psi


and if I keep my daytona, 87 TI block, I could put in just TII pistons and rods without having to turn the crank, and I could just hone out the cylinders correct? How much boost would that support?

correct....you might not even need to hone the cylinders if the crosshatchings are still visable. I think its more of a question of power than boost. I do not know how much boost you will need to push 250hpbut whatever it is i would try to keep it under that

another thought...this is a non CB t2 your swapping from right?

GLHSKEN
04-23-2006, 04:53 PM
http://thedodgegarage.com/turbo_shortblock.html

now the 87 block is probly going to be a weakpoint since they can only handle about 250hp


Hmmm interesting... are you 100 % sure??

Murphy
04-23-2006, 06:31 PM
nope

just goin by the bible

GLHSKEN
04-23-2006, 06:41 PM
LOL... I know... I survived a LONG time above those levels Never did have a block failure (but it IS more likely to happen with the early block).

Lee'sdaytona
04-23-2006, 07:44 PM
another thought...this is a non CB t2 your swapping from right?
Well yeah its not a TII block though. Its a non CB, since it was an 87 TI, I converted just the upper half of the engine to TII last year. I made the mistake of not honing out the cylinders, and I am now dealing with those compression readings (130, 100, 150, 135) I don't know why cyl 3 is so high, but I assume thats the only cyl that sealed up nicely. Of course, my brother did put 87 octane in there by accident and didn't realize it until I drove it and heard detonation at 10psi :( and that was a few months back....
Good to know that I don't have to turn the crank when putting in different rods....
PS: For the new engine rebuilder, how much can an engine hoist and stand be had? I don't know how many times I'll use it after I get out of the TD market....but I guess I could sell it...
thanks,
Lee

butchsuppe
04-24-2006, 02:45 AM
Well yeah its not a TII block though. Its a non CB, since it was an 87 TI, I converted just the upper half of the engine to TII last year. I made the mistake of not honing out the cylinders, and I am now dealing with those compression readings (130, 100, 150, 135) I don't know why cyl 3 is so high, but I assume thats the only cyl that sealed up nicely. Of course, my brother did put 87 octane in there by accident and didn't realize it until I drove it and heard detonation at 10psi :( and that was a few months back....
Good to know that I don't have to turn the crank when putting in different rods....
PS: For the new engine rebuilder, how much can an engine hoist and stand be had? I don't know how many times I'll use it after I get out of the TD market....but I guess I could sell it...
thanks,
Lee
I bought a new eng. hoist from kragen for $172. with tax. built my motor on the kitchen table in my upper apartment, had to buy a dolly to take it downstairs. Where theres a will, theres a way!

The S is Silent
04-24-2006, 09:23 AM
ok so your saying that if I had a stock 2.5 turbo it could handle 20 psi of boost with cast pistons/forged rods? Thats what that turbo mini site says anyway...


With pistons, it isn't about power level at all, or how much boost your run with them...it's about how good you are at tuning. Forged pistons are stronger because they are softer. They have more give to them before they break, so they are more forgiving when you make a tuning mistake. As long as you stay out of detonation, the cast pistons will work just fine, but as you start making more power, the forgiveness starts to get a little bit low. By the time you are making 250 or 300 hp, one hickup and your cast pistons become cast ashtrays.

Lee'sdaytona
04-24-2006, 04:42 PM
With pistons, it isn't about power level at all, or how much boost your run with them...it's about how good you are at tuning. Forged pistons are stronger because they are softer. They have more give to them before they break, so they are more forgiving when you make a tuning mistake. As long as you stay out of detonation, the cast pistons will work just fine, but as you start making more power, the forgiveness starts to get a little bit low. By the time you are making 250 or 300 hp, one hickup and your cast pistons become cast ashtrays.
Yeah....if it weren't for my brother putting 87 in there I'm sure it would be running well now....oh well, maybe I'll just throw a new/good used TI piston back in there....just feel like If I'm tearing down the engine again, I should do it right. Anyone know why there is a big difference such as 130, and 150? thats not normal right? I know 130 is an ok number, but I don't know why all the pistons accept the cracked one is not 150
-Lee