Building a block since mine went boom

[burks569]

So my RST bit the dust a couple days ago and I'll be building a new short block for it. I'll be using a 257 block thats been bored for 100mm pistons and ready to go, 2009 OEM STi crank, manley h-beam rods, manley 100mm 8.5:1 pistons, ACL standard size race bearings, ARP head studs for the 251 SOHC heads, and OEM gaskets.

Unfortunately since this came as a surprise I can only financially cover things for the short block, so I won't be able to get a new valvetrain til next month and a bigger turbo and such until January.

Anybody have any reason why they think this would be unreliable on my td04 turbo setup? I see no reason for this to go bad unless I push it over 550awhp in the future, I just want to make sure I know exactly what may or may not happen before I do this.

Once everything is done, tuning will be done by TPG tuning near Pittsburgh on a mustang dyno, but of course that will be after my heads are finished, and the aem standalone and proper turbo and injectors are bought. For the short term I'll be using the standard rs-t method with a ss vc2-5 voltage clamp 12:1 vortech rrfpr and the walbro 255 pump running 7psi on the td04 until everything else is bought and in line.

 

[bugeye_fever]

Hi, I currently run a tdo4 (75k mi) on a hybrid setup, ej205 heads on a 257 block w/ forged pistons. Not quite as crazy as yours, but the little turbo is fine on it. I run it at 17psi and have for the last year 10k+ miles. Obviously its not the best turbo for the application, but if your just needing it to run while you break the motor in and save up some money, it'll work fine.

 

[burks569]

Unfortunately I can't run that much boost yet, no "real" tuning and after 10 psi the valves in my sohc heads will start to float. So I'm just gonna keep it tame for a little bit, then in february, BOOM 450whp with a gt3076 and an aem series 2

 

[Bluedemon_II]

Before anything else, why did the first engine go? I see that your tuning strategy is a band aid to run that turbo with the ecu. But what pooped it?

 

[burks569]

PCV valve went bad, engine didn't breathe, blew the dipstick out of the motor and blew a ringland. According to three different subaru mechanics, so I'd say that must be correct.

 

[Bluedemon_II]

Well if the pcv valve goes stuck, crank case pressure will build up and put stress on the rings and that could lead to premature ringland failure on a cast piston. Did the engine loose a lot of oil threw the dipstick? Did you take the heads to be inspected?

 

[burks569]

It lost what seemed like was a lot through the dipstick, but after checking the oil I was only about a quart low, I shut the engine off immediately after it happened so that could be why it didn't lose more. And no, the heads have not been inspected yet, but everything is getting pulled on friday so we'll see then.

 

[burks569]

Everything was assembled over the weekend, had to wait for a few random o rings for the oil pan and water outlet to come in today before I can put everything back together and in the car. Somehow the td04 I had got locked up in the process so I picked up a vf24 for it.

As far as a break in period goes, whats the best mileage amount for that? I'll be driving the car on about 180 miles of interstate on wed and then back again on thurs. Hopefully this wont hurt it, here in WV its a lot of up and down so I should get a relatively decent range of rpm's on the trip. Should I treat it like a new car and not go over 4k?

 

[HolyCrapItsFast]

Everything was assembled over the weekend, had to wait for a few random o rings for the oil pan and water outlet to come in today before I can put everything back together and in the car. Somehow the td04 I had got locked up in the process so I picked up a vf24 for it.

As far as a break in period goes, whats the best mileage amount for that? I'll be driving the car on about 180 miles of interstate on wed and then back again on thurs. Hopefully this wont hurt it, here in WV its a lot of up and down so I should get a relatively decent range of rpm's on the trip. Should I treat it like a new car and not go over 4k?

How many mile are on it now? You should not go over 3000rpm for about the first 100 miles and 3600rpm up to 500 mile. If you have to drive highway miles then please vary your speed and rpm. Try to do allot of engine breaking by decelerating from time to time in gear. You might want to plan your trip to use some back roads during portions of your trip. :tup:

 

[burks569]

The car has 80,xxx on it. The block had around 40k on it I believe but was cleaned and machined beautifully and all other parts were brand new. Thanks for the tip on breaking it in!

 

[Bluedemon_II]

The car has 80,xxx on it. The block had around 40k on it I believe but was cleaned and machined beautifully and all other parts were brand new. Thanks for the tip on breaking it in!

Since you went with 100mm pistons your cylinder sleeves should be fine and the block should be ok. Just fallow the breaking procedure that Holy posted and you will be fine. I would change the oil at the first 100 from dyno oil to synthetic just to be sure.

 

[burks569]

Shes been running the past few days now, god it feels good to get her back on the road. I decided to just go with the 99.5's for now so i just had the block honed instead of bored. i do have a little bit of piston slap going on, but I think it's kinda cool. Some dude asked me yesterday if it was a diesel hahaha

 

[Bluedemon_II]

Shes been running the past few days now, god it feels good to get her back on the road. I decided to just go with the 99.5's for now so i just had the block honed instead of bored. i do have a little bit of piston slap going on, but I think it's kinda cool. Some dude asked me yesterday if it was a diesel hahaha

My friend, piston slap will not be cool when you hit about 25k miles. It will get worse.

 

[burks569]

Well the slap sound is very tame compared to a couple of built blocks I've been around, one of which has 80k on it now. It's really only noticeably audible when the hood is up. I'll be fine with it for now. And if it does get too bad in 25k, oh well I suppose, good excuse for a stroker kit