RB27 Tuning Update! Need Help.... Issues stilll...

[Shocker]

Late, and it's annoying, but I don't want to spend to get a smaller turbo. I think full boost is around 5500. The car starts to move right before 4k. I was at the track 2 weeks ago and coming out of corners it's pretty tough. Really gotta get on it early so i have power after the apex. It's making me think about getting a 4.63 final drive.

ehh sounds about like mine, I think I'm closer to 5k full boost when doing a pull, but if i come out of boost from a miss-shift and so forth, and fall down to 5k at VAC... I've gotta wait again...

[Shocker]

Well, got some awesome results from the latest compression test. I let the motor warm up to opperating temp while idling... here is the run down!!!

1 - 132psi2- 132 psi3- 132 psi4- 118 psi5 -118 psi6- 72 psi (ouch)...

So hmm bad of course, lets put a table spoon of oil in each cylinder and try again. (testing to see whats causing the leak)

1- 180psi2-175 psi3- 155 psi4-188 psi5-170 psi6- 157 psi

Yeah my rings are definitely not seating/scuffed/****ed all of the above?

Heres some pics of what I was talking about.

Poping off hose



Mess its making on my hood when it does.



150 mile old Rotella T 15w40 diesel oil

.. nice and black

Plugs burning equally, have a bit of fuel on them from the cold start. (motor leans out to 14.5's once warm at idle) The rest on the threads seems to be nasty oil ****



#6 cylinder spark plug showing no signs of pre-det



Nasty goo on the tops of my pistons I scraped off with a magnet



So yeah, rings are looking like they are at a point of no return since the comp test has gone down since the one ~ 2 weeks ago....

Most likely will be pulling the head this weekend to get a closer inspection..

I'll be calling my builder tomorrow to let him know whats up.

[mott6904]

Damn that sucks. What is your builder going to do about it? Did he give you anykind of turn around time. Looks like you wont be able to enjoy that beast for a little bit

[Shocker]

Damn that sucks. What is your builder going to do about it? Did he give you anykind of turn around time. Looks like you wont be able to enjoy that beast for a little bit

Most likely nothing. Thats why I plan to pull my head myself to get a personal look so I get no BS....

When I called him the first time last week talking to him about my issue, he was almost speechless after I told him I went through his break in procedure and was having these issues.

We will see I guess, yeah it will be a while most likely till she runs again. I've got a nice DD now, so its not so bad.

[Coolwhip]

damn man that stinks.

Yea, get a good eye on everything yourself and see what is happening.

But check out the torque on the headstuds before hand see if they are all still locked down.

But even then I think its time for some

[ItzGenX]

That uneven compression across the board isn't so pretty either. The number 6 seems uber bad. I would have to guess that the rings were installed poorly (all gaps are lined up with each other), but when this is done, usually the compression isn't THAT low. The other thing I can think of is that whoever did the gapping of the rings did so impropperly (too small of a gap and they can bind up when they expand with heat). I knew it was a bit strange for you to be boosting more around 5k. My SR22 becomes an implosion machine at 4800-5k. Your 0.5L and 2 more cylinders should easily spool that turbo. If you are going to tear into it, might as well fix it and bring her back to life yourself. We'll help you in the process . That way, at least you don't have a mystery engine. You'll know if things are done right.

[Shocker]

That uneven compression across the board isn't so pretty either. The number 6 seems uber bad. I would have to guess that the rings were installed poorly (all gaps are lined up with each other), but when this is done, usually the compression isn't THAT low. The other thing I can think of is that whoever did the gapping of the rings did so impropperly (too small of a gap and they can bind up when they expand with heat). I knew it was a bit strange for you to be boosting more around 5k. My SR22 becomes an implosion machine at 4800-5k. Your 0.5L and 2 more cylinders should easily spool that turbo. If you are going to tear into it, might as well fix it and bring her back to life yourself. We'll help you in the process . That way, at least you don't have a mystery engine. You'll know if things are done right.

Thanks for the words. Honestly the boost seemed to be coming on later and later as time passed....

I no longer have a garage, I now have a driveway. I'll have to convince the rents to let me put her together in the single car garage if I decide to go that route. I've got other **** I need to currently pay for so tear down might not happen for a month or so. Hopefully I don't need a rebore, just a hone so I can reuse my pistons.

Care to share anymore info on piston ring/engine assembly I know a bit about it, but should know more of the technical stuff. I'll be sure to read up on it in the mean time.

[rb25drag]

The piston ring gap really isn't rocket science. When you received your pistons it should have came with a paper stating the ring gap, we measured mine with a Mic after installing them on the piston, It just allows a proper seet when the engine warms up and the metal expands. Also just make sure when putting the rings on the piston they are all clocked a different direction or else it can cause failure.

If anyway possible when tearing the motor down check you cylinder bore and make sure he didn't over bore, Also remember if you go to hone the motor if you hone a cylinder too much it can cause over bore, which is possibly what your engine builder has done.

[the converted]

I doubt it was over bored, there probably would have been knocking noises if so. The rings probably just washed out with all the fuel. I've seen it before and you just need a quick hone to break the cylinder glaze and new rings. It sucks but at least there isn't a hole through the side of the block.

As far as AFR goes 14.5 at idle is to rich. Typically I'd tune cars to somewhere in the 15's because it actually burns cooler there.

Running that rich I'd be checking the bearing clearances while I was in there as well.

Also can we get a real close up of the end of the #6 plug looking down at the insulator? I'm curious.

[Darius]

Sorry to hear about all this bad luck. Also sucks that your engine builder is not standing behind what he put together. Hell he didn't even sound like he tried to defend himself.

Rings are simple.

1) Get a set and gap them to the manufacturer's recommendation.

2) Buy a carbide ring grinder (priceless tool to have when doing this because these rings are hard as hell)

3) Place ring down in the bore and push down with some tool to make sure the ring is square to the bore. I used the end of a caliper where the metal rod pokes out.

4) Measure the ring gap with a set of feeler gauges

5) Adjust ring gap more if necessary.

6) Install rings on piston and orient gaps according to manufacturer recommendations when installing them in the bores.

7) Drink a beer.

[Coolwhip]

3) Place ring down in the bore and push down with some tool to make sure the ring is square to the bore. I used the end of a caliper where the metal rod pokes out.

Or the dome of the piston (upside down pushing down on the ring.

Check the roundness of the bore to and see how the walls were in contact. Uneven wear could indicate out of round bore. But from the progression of the loss of compression I don't think thats your problem.

[Shocker]

thanks for the response's guys.

I spoke with my builder a few min ago. Told him whats going on. He said pull it apart and take a look at it. He also said he'd "work" with me on it. I didn't ask for it either he suggested it.

As for the 14.5 idle I was having issues adjusting that, I took one part fuel out up to 16.0's added 1 down to 13.2's... so its what it was.

[gawdzilla]

14.5 idle is fine. you don't want to default to running lean. better a tad rich than lean. 14.5 isnt washing out your bores.

is there any reason you're running such a thick oil? is your oil clearance bigger than stock?

you should try to get the notes from your builder if he has any. when the machine shop did mine i asked for everything back including their measurements. i double checked their measurements on the bare block/crank before assembly. i'm not too familiar with causes of those inconsistencies in your comp test #s, but maybe it is the roundness of your bore. could also be ring gap/alignment

[Shocker]

14.5 idle is fine. you don't want to default to running lean. better a tad rich than lean. 14.5 isnt washing out your bores.

is there any reason you're running such a thick oil? is your oil clearance bigger than stock?

you should try to get the notes from your builder if he has any. when the machine shop did mine i asked for everything back including their measurements. i double checked their measurements on the bare block/crank before assembly. i'm not too familiar with causes of those inconsistencies in your comp test #s, but maybe it is the roundness of your bore. could also be ring gap/alignment

Thats what I thought as well. heh.

Oil is for break in, builder recommends it, my tuner also does, and uses it as run in oil for his motors. I don't think I'll be using it for the next run in..

Oh I will be checking everything. Worst comes to worst, I've got a spare block I could use so I don't need to go to larger pistons just costing myself more $$

[johnzm]

Thats what I thought as well. heh.

Oil is for break in, builder recommends it, my tuner also does, and uses it as run in oil for his motors. I don't think I'll be using it for the next run in..

Oh I will be checking everything. Worst comes to worst, I've got a spare block I could use so I don't need to go to larger pistons just costing myself more $$

take pictures of the piston when it comes out of 6. i think i know what went down. and i dont think the rings had anything to do with it..

[Shocker]

take pictures of the piston when it comes out of 6. i think i know what went down. and i dont think the rings had anything to do with it..

What do you guess then? Melted piston or blown HG? The car still runs/drives fine...

[Coolwhip]

sounds like this RB25 I have here, gonna go look into it when ever I have the chance,

[Shocker]

sounds like this RB25 I have here, gonna go look into it when ever I have the chance,

yeah I might pull the head tonight... no real hurry, but its supposed to rain all weekend.

I'm doubting melted piston, but you never know with me. HA

I'll check the headstuds before I loosen them for removal.

[WhatsADSM]

Yea 14.5 at idle is FINE. That is not causing you to wash the rings. However, yea it looks like the rings are shot. If you are careful you should be able to hone the cylinders and install new rings with the block still in the car. Like mentioned before, although shot rings are bad it could be worse - such as a hole in the block.

As for timing, since it was brought up before. Honestly the "base" timing that is set is nothing more than to ensure that what the ECU thinks is TDC is also what is TRULY TDC (since you are able to rotate the CAS). Nothing more. So it really doesn't matter that the "base timing" is 20* on one motor and 25* on the other, again it is just used to make sure TDC is correct.

Now as for the other comments on timing. Honestly, to each his own, but some of my research seems to show that you really don't want to be pushing the RB in terms of timing. I actually have my timing at ~18 degrees or so at 17psi on pump... And in fact for my daily driving tune I will likely bump the timing down a bit and increase the boost to around 20 on pump (probably 15 or so degrees of timing). But then again I tend not to tune to the limit for engine reliability sake.

*EDIT*Also if you have an EMS I would definately urge you NOT to push your timing far since the aftermarket EMSs SUCK in terms of knock control (stock ECU is leaps and bounds superior in that respect).

[Coolwhip]

( Need an update)

[Shocker]

I cant believe you bumped the stupid thread Ricky. lol

UPDATE IS!

I'm currently having way to much fun with my daily driver.



Stg 4 WRX vf30'ed 16lbs putting down 269awhp and 259awtq, its a ton of fun and I'm auto crossing her this weekend.

I'm basically to lazy/lacking any motivation to wrench on my car. I'm basically taking a break from it for the moment.

Meanwhile I've been spending money/time on partying and women instead of cars. For the moment its been more fun.

I'll get around to doing something to my car before summer is out...

[mott6904]

I'll get around to doing something to my car before summer is out...

....Like selling it to me for 10 dollaz
Modified by mott6904 at 7:11 PM 7/14/2008

[Shocker]

Well Ricky and the rest. I have an actual update now.

Pulled the motor last weekend, took it to my builder and we removed the head together. (so he sees what I see)

We popped out the pistons and what do you know. Pistons were starting to melt, but only on the intake side between the dome and 1st ring. Very weird.. the melting closed down on the ring and squeezed it preventing it from moving, thus leaking out my combustion.

Signs of pre-det? but the spark plugs have no signs of pre-det....

Anyone think my super high EGT's might have done this when my exhaust cam was maxed retarded? I've been thinking about this for a while now and I cant for the life of me get a solid explanation out of it.

[l0nestar]

... and so the saga unfolds.

[Carl H]

this is the exact same way that my rb went when it blew, melted a hole thru the ringlands of the number 5 piston.only think i can think happened is that it was exposed to super high egts and or lean out due to the front facing plenum.I watch the egt gauge religiously when i boost for extended periods of time now, when it hits 875*c i back out.what kind of timing are you running, at 14psi i have about 24* with it dropping to 22* at 22psi, egts were mad high and didnt make as much power with lower timing.

[Shocker]

Here are some pics of the damage this is the #6 cylinder piston and it is the worst. Also a few close ups of 3 spark plugs, as far as I can tell they show no signs of pre-det. Just carbon/oil marks from being rich and well burning oil due to rings.



As you can see in the pic the damage is ONLY on 50% of the piston all on the intake side. The exhaust side of the piston is as smooth as they day I bought them...

Timing was 16 degrees WOT @ 16-17 psi through the 67mm. Super super conservative. A/f's were 11.0's till 7250rpm were I was letting out. I didn't appear to be having EGT issues during this time. It was before when my cam was super retarded w/o me knowing (finally found the issue) and I was missing 50% of my power when my manifold/turbine housing would be glowing as red as a stop sign after a pull or two.

I have no EGT meter and I do think I'll be installing one where my current o2 bung is on my downpipe.

I love burning money.

[Carl H]

egt needs to be next to the head for the best reading.sounds like your timing is too retarded causing massive egt spikes...mani doesnt need to be red to have high egts.

[Shocker]

egt needs to be next to the head for the best reading.sounds like your timing is too retarded causing massive egt spikes...mani doesnt need to be red to have high egts.

So are you agreeing this seems to be an EGT issue not a pre-det issue from lean a/f or to much timing?

[Carl H]

could be a mixture of both.my car had ok 11-12:1 afr and didnt appear to be detonating but i think the timing is what did it in thru egts...also might want to consider the front facing plenum effect.

[Shocker]

could be a mixture of both.my car had ok 11-12:1 afr and didnt appear to be detonating but i think the timing is what did it in thru egts...also might want to consider the front facing plenum effect.

Care to enlighten me a bit on the effect? Causes a lean out?