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[shanerv]

ok so i built my turbo lsvtec year ago. typical low budget rhmt setup
hx40, eagle rods and turbo nippon pistons and nippon rings which look exactly like a stock pr4 piston with a coating on them maybe hyperutectic
car has always run great until recently. car is down on power and mpg has dropped off a couple and started using more then the normal oil from turbo seals that are going bad.
and at the track the other day it really started pushing oil into the catch can. pushed 2 quarts in around 4-5 passes @15-16 psi and smokes really bad at anything over 6-8 psi
did comp test cold
#1-180
#2-180
#3-180
#4-150
added oil to it and it was back up with rest perfectly at 180.

what do you guys think it is rings or ringlands?
other then hard pulls it does not smoke at all.

[crxvtec91]

Do a leak down test.

[turbohf]

its been my experience and opinion that in a setup like this RINGS dont go bad, you broke a piston.

replace piston (visually check the rest), rinse and repeat as necessary. 

[shanerv]

its been my experience and opinion that in a setup like this RINGS dont go bad, you broke a piston.

replace piston (visually check the rest), rinse and repeat as necessary. 

ya I am leaning that way too. was hoping the "turbo" pistons would be a little stronger then the stockers. thing has only been run up to lil over 400 whp. with most of it's life spent at around 300 whp. was my dd for last year.

that being said does anybody have a set of forged pistons for sale 81mm?

Do a leak down test.

why do a leak down test?  if putting oil in cylinders brought up comp we know it's piston/ring related from this.

[shanerv]

So got bored today and decided to do comp test on the motor again this time at temp though.
So test this time reveals all cylinders to be within 5psi of each other.
Added oil to see if it changed anything and only changed by 5 psi on all cylinders.
All are sitting at around  185-190. Ideas thing still has excessive blow by. Just rings? Or do you guys still think cracked ring lands?

[turbohf]

was that the first time at the track? it still pushing oil into the can?

i have seen people that said that they had oil push to the can on hits/dyno but not on the street so much. and it has to do with the design of the can. i had serious issues with a setup that all came back to the can setup and the location of the ports on the motor.


so that one cylinder that was 150 just is magically back to 180 when warm? or just on this test?


pics of catch can setup please.

[shanerv]

no it was second time at track with the car. first time since dyno tune. build has around 7k on it I would guess.

I will get some pics tomorrow. but I can tell you I am running a -10 line from back of block and a half in line from valve cover  to  a non baffled 1 quart can with moroso 1" 1/8 breather filter on top. can pushed oil out of catch can after 2-4 hard pulls say from 40-130 or 2-4 1/4 mile passes. It did push a lil bit of oil on the dyno but only say 1/2 -3/4 quart after 15-20 pulls.

yes the cylinder that was 30 psi lower is exact same psi as other 3 once it is a running temps.

also did a leak down test today and all 4 are nearly pegging gauge at less then 20%@90psi  with engine at full temp.

wtf???

[turbohf]

mine would blow oil out the back of the block in large quantities basically blocking airflow causing shit tons of backpressure causing it to smoke like a train and fill the can at the same time. motor was perfectly fine otherwise.

remember that the back block fitting is also an oil drain back from the head to the oil pan. so if there is any good pressure it will just push that oil right into the house and up to your can. 

[ratcityrex]

Yep, I always try and pull lines off the valve cover. I talked long and hard with spiker about this YEAR'S ago. He said one of the other guys here (think it was drpque <-- spell check that....idk) had a similar problem. He had a line from the back of his block and when he was going down the track oil was sloshing to the back of the block, up the line and overflowing the can. As soon as he blocked that line and ran them from the valve cover he stopped having the problems it sounds like you are experiencing. On the 1 cyl being down when cold, idk about that. But fuck it. Drive it like you stole it, after you fix the oil problem. Just unhook the line from the back of the block, cap it and run another line from the valve cover. Just make sure the valve cover is baffled or your line isn't right in line with a cam lobe. I had a problem with my old ls where the cam was literally slanging oil down the line and filling my can up.

[shanerv]

thanks for feedback guys. I had thought about that before with the oil being pushed up lines under a hard pull.I will try the valve cover vents with some -10 see that happens.

do you think 2 -10 lines would be enough vent for say 500+ whp? last year when I tuned it we were at 420whp on low boost 16 psi ish. this year I want to crank it up to around 20-25 psi with the hx40 see where we get with it.

[ratcityrex]

2, -10 off the valve cover is plenty for most setups. I think that speed factory was running 1, -12 off there 700 hp d16. I ran 2 - 10 off my lsv  with omg sloppy pistons/rings and it made 435hp and didn't bat a eye. Still out getting beat on today, but it was 100% street car.

[shanerv]

well I finally pulled motor down last thursday. comp test said 200 psi but still didn't run like it used to. results were 4 broken ring lands. soooo anybody got some used 81mm forged pistons for sale?  surprisingly car still ran 11.8@125 with engine in this condition. can I am guessing it would have run a high ten second pass had the engine been running like it was last year. pics to follow soon

[turbohf]

throw it back together as is?

[HiProfile]

I'm just curious, what did you set the ring gaps to?

[Tim]

I have a set 16052, throw me an offer

[shanerv]

I'm just curious, what did you set the ring gaps to?

Hard to remember but I think it was .002-.003 larger then factory. Didn't wanna go to lose for dd.

throw it back together as is?

Na got a beater wrx wagon to get me around while I score parts on the cheap

I have a set 16052, throw me an offer

What brand and size