Depends on the type of alloy you want to use. I don't see a problem with it, just will need time to warm up.

 

Typically yes forged pistons have looser tolerances and so they move more in the cyliders when it's cold. Part of the reason there are not many cars with lots of miles on built motors. I've seen some people on the forums go down to .002 piston to wall clearance with success though so that would probably help. Depends on the alloy though if you can do that. The stock cast pistons don't expand much so they use tighter clearances. I can't remember how much I want to say .001 though.

 

thanx idk really what to use. i am not having any engine problems car runs great no smoke or anything. i was just wondering if i did switch if i would have any problems at all. probably wouldnt happen for a while just didnt know if i would be better off just rebuilding stock motor with stock internals again if the day came to have todo it.

 

Well I don't see many people with high mileage built motors. I personally think it can be done though. I think with the 4032 alloy pistons and .002 p/w clearance it can last. Really difficult to say for sure though. A lot will depend on how it's driven too.

 

You just need to make sure you let the engine warm up to operating temperature.

Lots of people have asked this before, and a lot of guys with built engine's say the same thing. Let it warm up to somewhere in between 60-100% operating temperature so the pistons have the opportunity to warm up and expand to form a proper seal.

 

Alright thanx for all your imput. Just wanted to make sure i wasnt gonna do this and have more of an issue.

 

4032 alloy is what you want, get mahle or st pistons and call it a day. Anything above that is over kill unless you have serious detonation like NOS or high rpm where the piston is going to get beat up a bit. CP and JE are good for the higher tensil strength in that area. :tup:

 

If you have indoor parking, it shouldn't be much of an issue.

 

How bout outdoor parking and only a 3 miles commute. e.g. frequent short trips.

 

On average, (I know there are many variables) how long should a built engine last? I'm running Mahle Hardened Race Pistons, if that helps at all.

 

How long have u had the mahle pistons in for lb126? i take it its running like a champ ... thanx for your help guys..

 

I have low miles, I had just it built two months ago and don't daily drive it. Just was wondering how long I can expect it to last. It is running great though, it's never felt so alive/strong.

 

Unless there is a problem with the build itself, the rest is up to the owner. if you check your oil constantly and keep up on maintenence, then theres no reason why a built motor shouldnt last long....

 

Well some oem engines have forged pistons and the average expectation is at least 100k from them so that's what I would expect assuming the whole build is solid.

 

Now that I have a proper vehicle, yes

I am going to be there friday in order to prep the STi for the TPG subie tuning day on the 12th.

Unfortunately, I am in the interim period of needing a cheap DD, so I am driving my STi in this horrible cold. 34f today. It just seems like a 2 minute warmup and staying below 3k rpm and no boost isnt enough to protect my engine, especially since its got that syrupy 10w40 in it currently.

 

what would be the eefects on days like today and the past couple weeks of it being in the negative degree temps here? even with stock internals the car wont warm up at idle until i move.. how would the forged internals warm up any better if at idle on days like this if that makes siince??

 

Inside a cylinder it gets very hot. Gas combustion when ignited is hot to begin with. Sure it might take the block awhile to heat up but the pitson and cylinder should heat up very fast.

The tempature you're looking at is the block tempature. The car has a threshold which is controlled by the T-stat. The motor will always get hot unless it's so cold that gas freezes.. then you might have a bigger problem. If you're car is not warming up you probably have a bad T-stat, guage.. or something else is wrong.

 

Was reading the 2.5L engine threads of interest and found the Motor Oil lessons by Dr. Haas: very interesting (see also: long) read

http://www.iwsti.com/forums/2-5-lit...ctory-motor/77262-motor-oil-all-chapters-inclusive-hat-tip-ferrarichat-com.html

Its not your tstat, but your oil temperature/thickness on cold days that is most important to target when attempting to reduce wear on super cold days like today.

 

Yeah, oil also plays a pretty big role. Yes it could be a T-stat that could cause it though.

 

nice thanx for the informative info

 

I'm glad someone bumped this, I am wondering about the proper oil weight for a car with forged pistons in the winter, thinking a 5w30 or 0w30. Additionally, I'll be getting dyno-tuned on this oil as well, so adding that into the mix...I need to balance protecting the engine at startup with the lighter weight and protecting it on the dyno with a heavier weight oil.

 

im runing schaffers 9000 5w-30. the oil is great. i have 57k now and i burn about 1qt max every 3000 miles. havent had a problem with my oil i love it. only problem ive had lately is the fuel dampner is making noise when cold. just trying to make a decision before she blows haha but i hope she doesnt...

 

Any UOA on the 9000 oil?

 

Not yet but soon. The guy comes in a couple weeks and ill get one and keep u informed

 

It's winter time again and it's time to re-bump this thread. I religiously let my car warm 80-100% at idle before driving it in the morning and I read on another forum just today that you don't want to do that because it takes too long.

I just ordered an engine block heater and I'll have that sucker on a timer summer and winter for now on to go on 2 hours before I leave for work in the winter and 1 hour in the summer. I want this thing to last at least 100k and as a DD I'm more and more afraid that won't jive.

100k is the magic number, beyond that is gravy. I just worry...

 

I am running cp pistons with about 40k miles on them. I smoke on start up, but when I start driving they seal up. But if I sit in traffic it starts smoking a little bit again. Doesn't smell oily but when I back up and the smoke goes in the light you can see a blueish tint to it. This ONLY happens in the winter for me. I know all is good because oil consumption is normal and compression is good. I have read on here that cp's can smoke on cold start up/winter. Just depends on the clearances.