Forged Internals vs Stock for sub 400hp in a daily

[snm95ls]

The 1.5XTR on a 2.5 spools like an 18G.

 

Every non-caged Subaru I've been in that had over about 450whp felt as sketchy as ****... like 'I was lucky the engine didn't get it's way and tear the car apart' kind of sketchy.

Not just pay for machine work but also 1) give up the very good factory hone on the cylinders in exchange for whatever your shop can pull off (and we know how that can vary), 2) break apart the bottom end for really no good reason.

 

I run mine at 0.08mm PTW clearance. It's not recommended to run them tighter, even though many do get away with it. There are consumers that want the reliability of forgies, or just the bragging rights. They don't want extra noise or oil consumption or anything else and they insist the builder uses a tighter PTW clearance than the piston manufacturer recommends. All is well until the first time they go to the track or even do a longer or harder than usual run up a pass road.

 

This is a very valid point. I know how much effort and money we have to put into consistent cylinder finishes at work (engine manufacturer), thus it further reduces my trust for the average automotive machine shop. I feel that most are well behind the curve when it comes to modern engine cylinder finishing equipment and techniques.

 

This is also why I can't frickin' decide what route I will take when my block finally dies. OEM shortblock with Manley's graded pistons and a set of head studs is really tempting.

 

I do also enjoy building engines when I get the chance also, but I don't have a backup vehicle at the moment, so that will also be a factor if/when it finally lets go.

[boxkita]

This is a very valid point. I know how much effort and money we have to put into consistent cylinder finishes at work (engine manufacturer), thus it further reduces my trust for the average automotive machine shop. I feel that most are well behind the curve when it comes to modern engine cylinder finishing equipment and techniques.

 

This is also why I can't frickin' decide what route I will take when my block finally dies. OEM shortblock with Manley's graded pistons and a set of head studs is really tempting.

 

I do also enjoy building engines when I get the chance also, but I don't have a backup vehicle at the moment, so that will also be a factor if/when it finally lets go.

If engine builder why can't you use the tools at work?

[snm95ls]

If engine builder why can't you use the tools at work?

 

I can't exactly shut down a production line nor will the company allow me to bring my own parts into an FTZ to work on my own stuff. Not to mention because we are a mass production facility, the fixturing is very specific to the engines that we make every day.

 

Besides, we don't have anything that has a 99.5 or 100 mm bore. The hone sizing rings aren't cheap.

 

 

Engine manufacturer != engine builder.

 

If I did have access to equipment at work to use at will, then holy crap balls, I would be there all the time.

 

[xtea]

Well you're screwed at the point. Start saving for your next engine. no plan = rebuild

 

Well the heads are not on yet so I suppose I could have the oem pistons put back in.

 

I dont think its fair to say I dont have a plan. The plan was to have a safe build for the power Im running. With as tight of clearances as I can get on the manleys with a fresh shortblock, offset wristpins reducing piston slap and proper break in am I really "screwed"?

 

The latest best advice has been to trust the builder. Builder thinks I should relax.

[fahr_side]

Let the car warm up properly before moving it, use appropriate oil and change it often. I'm at 40,000km on the Manleys and have only just begun to use enough oil to start to think about maybe installing the AOS I've had laying around for a year. Remember Subaru themselves were installing forged pistons in EJ20K and G motors their whole production runs and in the EJ207 until a few years ago.

 

 

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[Horm2124]

So question to all those with forged internals. How do you know your up to temp before you drive of?

[Tehnation]

..... lol, the thermostat! Ya know that temperature gauge on your instrument cluster!!!

 

So simple but i guess its not so obvious! That's why most if not all cars have temp gauges, now a days everything is gone, oil pressure, battery etc. But temp is always there for any car!

[xtea]

Thats coolant temp, not oil temp. Coolant heats up before the oil does is my understanding.

[Tehnation]

If your not going over 400whp and/or above 6k rpm, no point going forged.... stay oem imo

[Horm2124]

I was wondering because some said 3 min. I timed it it takes way longer then 3 min to get to op-temp on the coolant temp gauge. Edited May 22, 2016 by Horm2124

[Tehnation]

Thats coolant temp, not oil temp. Coolant heats up before the oil does is my understanding.

 

so? Once the gauge is at operating temperature that is all that matters! It takes a good amount of time for your gauge to get to operating temperature! Have u actually sat there and watched the gauge? It takes about 5-15 minutes for a car to get to normal operating temp.

[Horm2124]

From boxkita

 

 

A forged motor warmup means idling in your driveway until the water/oil temp have reached operating temp. As soon as you release the clutch, you're doing damage and risking failure. My engine warm up regardless of lateness was always 3 minutes. On colder days it was 5 minutes.

 

Here it is.

[Tehnation]

however you want to interpret it but the keywords are "operating temperature", once ur engine is at operating temperature, which unless u install an oil temp gauge, is based on your coolant thermostat which is the ONLY thing our cars have to let you know your engine is at operating temp.

 

I'm in north east, and it gets really ******* cold up here, so in deep winter it takes some time to get to "operating temperature"!!

Edited May 22, 2016 by Tehnation

[Tehnation]

I get the feeling you all might not be ready to step of the porch! Its better to stay on the porch with the rest of the puppies!

 

Operating temp is not rocket science!

[Horm2124]

Not exactly true. When you first start the engine the idle rpm is high then starts to settle to normal after a few moments I'm guessing it has to do with the oil and cylinders getting to op-temp. That's just about the time the thermostat opens and the coolant temp gauge starts going up. That's my theory which that's what the thermostat stat does opens when the engine hit op-temp.

 

Unless everything I just learned in my auto class about the cooling system is wrong.

[Tehnation]

There's a temperature gauge on your instrument cluster!! that monitors your coolant temp, that same gauge in ur car is what you use to check your engine operating temp, below the line is below operating temp and above the line is above operating temp. Very simple system!

 

I don't know wtf they are teaching you kids in class... The temperature gauge is used to measure the temperature of the block, hotter coolant means hotter block, colder coolant means colder block. This is shop 101....

[Tehnation]

basically when the needle in your instrument cluster for temperature goes to normal operating temperature mark.... that indicates your car is "warmed up"!!! Very easy system, once again..

[Tehnation]

Not exactly true. When you first start the engine the idle rpm is high then starts to settle to normal after a few moments I'm guessing it has to do with the oil and cylinders getting to op-temp. That's just about the time the thermostat opens and the coolant temp gauge starts going up. That's my theory which that's what the thermostat stat does opens when the engine hit op-temp.

 

Unless everything I just learned in my auto class about the cooling system is wrong.

 

If your guessing and making theories you obviously didn't learn much!

[xtea]

My new shortblock with manley drop ins. I'm hearing a tick from the bay that is probably normal but I because it's got forged pistons I am really paranoid. Here's a video of the sound. Sound normal? Easiest to hear it at :40.

 

https://youtu.be/gs_-glby-W4

[Horm2124]

Ok first of I say it's a theory and a guess because I have no Hands on experience and I don't want to run the risk of misleading some and I want counter Theory's to check my fact.

 

Second what I said about the temp gauge not reading right till the thermostats opens I typed before I checked my facts that's my bad.

 

Third I know how a dam gauge works you don't have to be an ass about it.

 

Finally I asked the question because I'm finding conflicting answers in this thread and others and I want to learn and do what is best for my car in the long run.

[fahr_side]

Lots of later model cars have no gauge, just a low and high coolant temp warning light. 2012 LGT for example. When does the blue light go off? I don't have a clue, it's not in the ECU code.

Boxkita is quite right in that the oil wants to be up to temp before putting much load on the engine. That's the best parameter there is for how much the pistons have expanded to take up the PTW clearance.

I live on a mountain so I tend to just let it warm up enough that the idle drops below 1k0rpm and then basically roll down the hill. Coming home I'll let it idle until the gauge is in the middle but I do not romp on it until several minutes after that.

 

As to the power level for stock pistons...

 

Any amount of knock is going to kill them. Those running on piss gas are lucky to break 300whp safely.

 

Any time spent above 18psi is pushing the stock head bolts. This becomes even more of an issue as the mileage creeps up. How are you going to get to 400whp if you stay at or under 18psi?

 

Most of the expense in swapping to forgies is pulling and splitting the motor, plus all the parts you'd be dumb not to replace while the motor is out. Therefore it's dumb to put stock pistons back in or reuse stock head bolts unless you're 100% sure you're happy at or below about 300whp.

 

In summary, below 300whp you should be fine with the stock SB as long as you're not knocking and don't get greedy with the boost. Above 400whp we can all agree you need the forgies and head studs. Anything between those numbers you are either over-building a little for safety or skimping and hoping for the best.

If you're sure 335.66whp* is the perfect build for you and you'll never get greedy then maybe you are that one special snowflake for whom the 4032 forged piston was developed.

 

* or some other arbitrary number between 300 and 400.

 

 

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[fahr_side]

My new shortblock with manley drop ins. I'm hearing a tick from the bay that is probably normal but I because it's got forged pistons I am really paranoid. Here's a video of the sound. Sound normal? Easiest to hear it at :40.

 

 

Sounds pretty normal. Piston slap is worse with lower ECT, rpm and higher load. Worst will be cold and with loads like the a/c on or the car in D (on autos). As revs come up above 1k0rpm it should go away. If you run the car hard for 10m or so the sound should also go away. You get used to the clip-clop of horseshoes while idling, or turn the radio up to cover it.

 

 

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[Horm2124]

Thank you fahr side that is helpful.

[rebourne]

Lots of later model cars have no gauge, just a low and high coolant temp warning light. 2012 LGT for example. When does the blue light go off? I don't have a clue, it's not in the ECU code.

Boxkita is quite right in that the oil wants to be up to temp before putting much load on the engine. That's the best parameter there is for how much the pistons have expanded to take up the PTW clearance.

I live on a mountain so I tend to just let it warm up enough that the idle drops below 1k0rpm and then basically roll down the hill. Coming home I'll let it idle until the gauge is in the middle but I do not romp on it until several minutes after that.

 

As to the power level for stock pistons...

 

Any amount of knock is going to kill them. Those running on piss gas are lucky to break 300whp safely.

 

Any time spent above 18psi is pushing the stock head bolts. This becomes even more of an issue as the mileage creeps up. How are you going to get to 400whp if you stay at or under 18psi?

 

Most of the expense in swapping to forgies is pulling and splitting the motor, plus all the parts you'd be dumb not to replace while the motor is out. Therefore it's dumb to put stock pistons back in or reuse stock head bolts unless you're 100% sure you're happy at or below about 300whp.

 

In summary, below 300whp you should be fine with the stock SB as long as you're not knocking and don't get greedy with the boost. Above 400whp we can all agree you need the forgies and head studs. Anything between those numbers you are either over-building a little for safety or skimping and hoping for the best.

If you're sure 335.66whp* is the perfect build for you and you'll never get greedy then maybe you are that one special snowflake for whom the 4032 forged piston was developed.

 

* or some other arbitrary number between 300 and 400.

 

 

Sent from a device using some software.

 

Pretty much sums up my reading over the last year... I hit thanks five times, it only showed up once.

[colecotoia11]

IMO, if this is your only car, do a ej257 short block.

 

If you have another car that you enjoy driving as a DD then build this with forged internals.

 

I have another car but chose to go new ej257 because I wanted a fun DD that I could drive for many years.

 

Hey this is a Subaru Legacy not a classic car with RWD that you want to drive and beat on.

 

My wagon is fun to drive, has plenty of power for a DD and is realiable. The car has great power in 2nd and 3rd gears when I want to pass someone on the street.

 

 

i have my 2005 legacy gt base model and it has alot of money into it in parts would they fit on a ej257 longblock?

 

 

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