NON-turbo pistons can't take BOOST!

[94Talon2]

My talon has been turbo charged for over a month now. Last week it started smoking blue exhaust. It turns out the drive side piston has a crack in it. All the other pistons rings are pretty much done as well.

My compression was 130psi across the board before we took it apart. One month prior they were all around 180psi. I was only running the minimum boast I could 8-11psi.

So now I'm doing a complete rebuild, 2g pistons, chrome rings, crank bearings, t-belt, water pump, b-shaft elimination. My head is only 5 months old so by Saturday I will have a brand new engine that is capable of making more power.

 

[aliczander]

My talon has been turbo charged for over a month now. Last week it started smoking blue exhaust. It turns out the drive side piston has a crack in it. All the other pistons rings are pretty much done as well.

My compression was 130psi across the board before we took it apart. One month prior they were all around 180psi. I was only running the minimum boast I could 8-11psi.

So now I'm doing a complete rebuild, 2g pistons, chrome rings, crank bearings, t-belt, water pump, b-shaft elimination. My head is only 5 months old so by Saturday I will have a brand new engine that is capable of making more power.

whoo if you where running 11 psi then no wonder your motor blew, max i would dare would be 7 to 8 11 on a stock motor is suiside im surprised it lasted as long as it did :thumbdown

 

[GSGoinFast]

how much can 1g NT internals usually hold?

 

[mavisky]

i usually tell everyone to keep it around 7-8 psi on stock nt internals. after that you're just plain gambling.

 

[LaserDad91]

Is that due to fact the N.A. motor has higher compression?

 

[mavisky]

there are a couple of reasons actually.
1. the higher compression
2. the upper ring lands are located higher on the nt piston than on the turbo piston
3. the ecu doesn't have provisions for a knock sensor and timing retard, so if it starts knocking, there's nothing but your ear and your right foot to help stop it.

 

[94Talon2]

I wanted to change my pistons anyway in order to make big time power. I just didn't plan on doing it so soon. It turns out my crank bearings were about ready to go, so maybe it's good I'm doing the rebuild now.
The only way to run less boost is get a 13g turbo, or do some internal stuff to the 14b wastegate.
Isn't there a guy that claims he is running 16psi on non-turbo pistons?

 

[mavisky]

supergoat was, then he started having problems and was eventually going to sell his car.

 

[pr0]

8 psi max on stock n/t motors. Was this the 420a engine? I don't know what was in the 1st gens...

 

[mavisky]

the 1st gens used a 4g63 with 9:1 compression in some of the nt's the others got a 1.8 liter 94hp monster motor put in them.

 

[aliczander]

i dont know exactly the compression on the 1 gen n/t but i no it was high, my old lady blew hers up before i could really learn to much about it :thumbdown

 

[mavisky]

i dont know exactly the compression on the 1 gen n/t but i no it was high, my old lady blew hers up before i could really learn to much about it :thumbdown

here....

the 1st gens used a 4g63 with 9:1 compression in some of the nt's the others got a 1.8 liter 94hp monster motor put in them.

 

[94Talon2]

Well it turns out my car has crank walk.

 

[hkdl]

Well it turns out my car has crank walk.

err what? The symptoms you described sound absolutly nothing crankwalk, if they did you'd see plenty of people crying "CRANKWALK!" all over the place.

What makes you think CW?

 

[94Talon2]

Your right This has nothing to do with getting new pistons. The crank is loose. There has been a few times where it felt like my flywheel was warped and the car would shake a bit when I got off the clutch. There is definatly play in the crank.
This sucks!

 

[hkdl]

How much play? I do remember there is some acceptable play in the crank, not sure how much though. Its really rare for a 1G to CW

 

[aliczander]

crank walk everybodys got it, and nobody knows what it is

 

[mavisky]

absolutely any piston engine can have crankwalk (crankshaft endplay). all crankshaft boils down to is excessive movement of the crankshaft from side to side. unless your thrust bearing (the one in the middle) has excessive wear on the side portions of it then you're not suffering from crankwalk, but simply worn bearings. thrust bearing failure can be brought on by many different things such as excessive cold engine startup with the clutch depressed, heavy duty pressure plates, low oil pressure, holding the clutch in while waiting on stop lights, and many others.

 

[BacknBlack92ESi]

I ran 10-12lbs daily on my N/T pistons for 4-5 monthes no problem.

 

[94Talon2]

I'll have to check it more closely. I can move the crank quite a bit. I wonder if my crank is gone. I will get it spec-ed out next week, my buddy doing all the work suspects it is.
I wonder if my udp was an attributing factor.
3 years of driving this car with no problems and in this 2month period after the rebuild is done with all the turbo stuff and exhaust I will spend $5000.

 

[tbTalonES94]

You should have just put in new pistons in the first place. You also should have thought about a rebuild before you turboed. But it was fun while it lasted wasnt it This time do it right man and you will be happy. If you put 2g pistons in and some new bearings and stuff think about it. You will practically have a 2g turbo motor without oil squirts and a better flowing intake manifold and head! Boost crazy......well not too crazy but a lot more then those damn N/T pistons can hold. WHen you get your N/T pistons out (if there not too messed up) and if you get 2g pistons just hold them right up next to eachother! Take a look at the middle ring land difference. TINY vs... Massive! Wonder why the pistons dont hold up!! Have fun man and if you need any help or anything just yell my way.

 

[mavisky]

actually the 2g piston install isn't even that good of a deal anymore unless you can get some used ones really cheap. the cost of 2g pistons + machining the rods is higher than simply having a new set of forged pistons in 8.5:1 installed on your 6 bolt nt rods. so long as the rods aren't damaged you can re-use them since they're the exact same as the turbo 6 bolt rods.

 

[GSGoinFast]

You should have just put in new pistons in the first place. You also should have thought about a rebuild before you turboed. But it was fun while it lasted wasnt it This time do it right man and you will be happy. If you put 2g pistons in and some new bearings and stuff think about it. You will practically have a 2g turbo motor without oil squirts and a better flowing intake manifold and head! Boost crazy......well not too crazy but a lot more then those damn N/T pistons can hold. WHen you get your N/T pistons out (if there not too messed up) and if you get 2g pistons just hold them right up next to eachother! Take a look at the middle ring land difference. TINY vs... Massive! Wonder why the pistons dont hold up!! Have fun man and if you need any help or anything just yell my way.

he probably couldnt afford to do both at the same time, and if i had the choice to rebuild or go turbo, id choose turbo too.

 

[mavisky]

i just did a rebuild awhile ago with all new parts for only $500 for new bearings, rings, and a full gasket set.

all he really needs is the front case and oil filter housing gasket, new headgasket, new bearings, and rings. call up napa and get the bearings and rings from clevite and then hit up the mitsu dealer for the few gaskets you need. if you need me to get the part numbers for you let me know.

 

[94Talon2]

My engine is a 7-bolt the 2g pistons fit right in. My engine was in very good condition before i turbod it. The head was brand new and good compression. I knew before hand I would eventually need to do the bottom end I just didn't think it would be so soon. The pistons with chrome rings was $350canadian ($250us).
It turns out my crank is done (too much wear on it) it's too small for the bearings.
I have all the gaskets and bearings I need. My friend doing it has built up a number of dsm's including his own. I would do it myself but I don't have the time, or a place to do it.

thanks for helping out