2nd blown motor--Please help

[robandnoah]

My son and I have done a turbo integra with a b18b1 motor with MS2. I'm great with electronics and engine repair, but new to tuning. We have done a ton of homework and been having a blast with this project. Boost is truly addictive!!

First motor let go under around 12 lbs of boost. All four pistons had cracked ring lands. I had built a ignition table with 38 degrees of total timing and my son thought that was too much. We have a WB O2 and was running around 11:1 or so and we saw no signs of detonation. I figured we just had too much cylinder pressure.

So after rebuild with new pistons, we did new ignition table and pulled around 8-10 degrees of timing. Motor ran great again. We had a 4lb wastegate spring installed during break in. Instead of fiddling with springs we installed boost control solenoid and got that working good. Started in small increments and lots of test pulls and ended up at duty of 55 giving about 12.5 lbs of boost. After we noticed a loss of power we limped home and did a comp test. We got 55,90,145,180
We found a blown head gasket and 3 pistons with cracked ring lands.
We got about 150 miles out of it and were running 91 octane pump gas.

We used Autotune several times and did our best at manual tuning to get where we are.
I was running a datalog when the engine blew this time.

So before we get forged pistons and H-beam rods ordered will you please review my tune and give us some feedback. We're not sure if this is tuning related or we just hit the limit of the engine internals.

Running Tunerstudio 2.6.19 and MS2extra 3.4.1

We never could have gotten this far without you experts on this forum. Thanks

[nathaninwa]

I can't view your msq at he moment, but you were running 38* of timing at 12psi on pump gas? Even pulling 10* on the second time around is still in the all motor territory. Check with some local Honda tuners and ask about timing or hit up the dyno, where timing should be tuned anyways

My 2j which is on the efficiency of your Honda setup runs 20* at 175kpa and thats with race gas starting to get mixed in from staging over fuel systems

[robandnoah]

Here's my timing table. I had about 23-24* of timing under that much boost. That's assuming it blew under full boost

Screenshot 2016-02-28 15.56.27 (Custom).jpg

Here's the pistons

20160228_121147 (Custom).jpg

20160228_120909 (Custom).jpg

[slow_hemi6]

I had a little dohc 1600 integra. Honda build great little,light, high revving N/A engines. Your pistons are just not well designed for a boosted engine. However what did you have the rings gaped to? Turbo needs about an extra .004" gap over N/A. If the rings grab in the bores it's smashed lands.

[robandnoah]

Good point. The first motor had 160,000 miles on it and "might" have been loose enough. Most of the new piston rings were on the loose side of spec. Almost to factory service limit. Probably because the bores have wear. I just mentioned your comment to my son and he told me he had to file fit 2 of the new rings because they were tight. He said he fit them to the loose end of OE spec. All but 1 new ring survived, so we will measure them in the bores to check gap.
Would'nt stuck rings with broken ring lands damage the bores??

I agree with your comment about the stock pistons. When I first saw them I thought the ring pack looked pretty wimpy.

[elturbonitroso]

thats to much timming for 91 octane i run 22 deg on c16 fuel on a b18b motor at 18 psi.

[slow_hemi6]

You would have to inspect the bores. I didn't say the stuck as such, I said they grabbed, as in all they have to do is grab for a fraction of a second, to crack the land. I don't think being on the outside of N/A tolerance is enough gap. It's normal gap + 0.004". This was just the first thing that came up on google but there is plenty out there on ring gap. http://www.aa1car.com/library/ring_end_gap.htm

[robandnoah]

elturbonitroso, I was pulling out .8*/lb of boost. at 18lb boost I would have been running like 20.6* timing. How much timing do you run at 12lb boost?
also do you know what your ring gaps are?

slow_hemi6, Thanks for the info. I'll check gaps tomorrow, but I'm pretty sure there too tight. I should have known better.

[elutionsdesign]

Broken ring lands = wrong ring gap.

[nathaninwa]

There is generic calculators. You just don't add .xxx amount. It's like bore times .00055 or something. My 2j is like .019/.022 and my current LS is at .025/.029. We run larger second gaps to prevent ring flutter

[slow_hemi6]

There is generic calculators. You just don't add .xxx amount. It's like bore times .00055 or something. My 2j is like .019/.022 and my current LS is at .025/.029. We run larger second gaps to prevent ring flutter

So like what is shown in the link I posted, also on most of the piston manufacturers web sites.

[kb1982]

Traditional v8 thinking has always been .006 for every 1 inch of bore size. Increase the second ring size by .005 to help top ring flutter from blow by. When you buy rings, they should come with suggestions for ring gap from the manufacturer.

[jamies]

does the block/cylinders have any ridge?
can you post up some pics of the spark plugs?

[nathaninwa]

There is generic calculators. You just don't add .xxx amount. It's like bore times .00055 or something. My 2j is like .019/.022 and my current LS is at .025/.029. We run larger second gaps to prevent ring flutter

So like what is shown in the link I posted, also on most of the piston manufacturers web sites.

Ahhh, yes. I used what wiseco sent and even then I added a couple thousands. I'd rather have a little wider gap and deal with blow by than cracked pistons

[ewflyer]

or... fuel rich blow-by cutting away/thinning-out cylinder wall oil film? leading to ring-grab and land failure?

This comes to mind because I read an article describing exactly this sort of failure mode at Audi when they first added direct injection to their turbocharged engines.

Just a thought.

[robandnoah]

My top ring gap was .014 This equals about .oo44/ inch of bore. Looks like I learned this lesson the hard way...

Thanks guys. BTW did anybody look at my tune? I'm still uncertain about my ignition timing.

[turbo conversion]

elturbonitroso, I was pulling out .8*/lb of boost. at 18lb boost I would have been running like 20.6* timing. How much timing do you run at 12lb boost?
also do you know what your ring gaps are?

slow_hemi6, Thanks for the info. I'll check gaps tomorrow, but I'm pretty sure there too tight. I should have known better.

I converted an N/A engine to turbo with 185 lbs per cylinder static compression, and yours is 180.

At 10 lbs of boost on pump gas 93 octane I was running 12 deg. timing and at 8 lbs of boost 14 deg.

Setting timing any higher than that and I would get detonation, that will destroy rings and pistons.

To little timing as well as to much timing will rob power but to little timing won't break a motor.

I would suggest on your next engine start with very low timing to start with and If possible get it dyno tuned.

David

[Raymond_B]

What David said, you're trying to set your timing backwards. You start super low then bring it up slowly while watching for signs of detonation. Preferably on a dyno and checking the plugs between pulls. Wide band quality, calibration, and placement are very important too. Lastly, 91 octane? Is that all you have available?

[bradyzq]

B series? Is your base timing / trigger angle dialed in correctly?

[jamies]

hence why i asked for images of spark plugs this is the only way to see whats going on inside the cylinder