Well I am having issues with the new build. Some of you know it, LQ4, 370" , LS9 head gaskets, S482 turbo, 80lb injectors, A2W IC, twin 044 pumps, making 20-21psi, C14 race gas, No meth used yet.

The engine has about 60 street miles and maybe 10 track passes during tuning. 3 passes at 20psi when we were getting maxed out. Injectors are at 95% dc now so I cant get anymore out of it for now.

So I am posting this here because I'm at a little bit of a loss.

First issue to pop up was an idle problem. It got to where it wouldn't idle on its own at start up, but then catches up and idles fine. Drive it in the pits, let off the gas and the idle drops and tried to die so I have to pedal it to keep it running and it catches up and idles fine. When the idle is bad I found the FPR is at about 50psi, when static is 45psi. When the engine starts to idle right, the pressure drops to 45psi. No issues found in fuel system or fpr. Changed the IAC to be safe. no help. Unbolted the torque converter to eliminate the trany, no help.

Next problem is that the rpm just falls off at about 6k after launching. It launches, gets out about 60ft, shifts and the rpm just tanks. Like a safety kicks in. But none are enabled. Been chasing to find the issue. All data looks good on the logs so it appears to be mechanical. 3 separate tuners including EFI Source say its not in the ecm. No broken valve springs, push rods are fine, rockers fine. I am going to check the valve spring pressures which are new BTR .660 wit Ti retainers. Changed the crank and cam sensor thinking I might get lucky and have a bad crank sensor, didn't fix it.

And finally a coolant system item. 2 times I have opened the radiator cap when the engine had not been run at all, dead cold, and the system has positive pressure. Like quite a bit, enough to push the cap into my hand when it unhooked from the radiator. It would blow the cap off if I could let go fast enough. This morning I opened the radiator drain to drain the water for the head removal and it was a solid stream of water. Then opened the cap to make sure it could bleed out easily and it was under pressure and the stream slowed way down to a trickle. So there was a good amount pressure in the system. Normally once an engine cools it will actually be in a slight vacuum, that is what draws water back in from the overflow. So I plan to check the cylinder walls and probably have the heads checked to be safe.

Compression test is 160-180psi which even when the engine was fresh had the same span.
Leak down shows 12-25%.
I think some of the difference is in the rings. I didn't put the block together myself.
During the leak down, on a couple of cylinders, the test started with a bad leak, maybe 80% and then it just sealed itself up. No piston movement was noticed. Thought it may be a sticking valve or lifter. So, I pulled a head today. I noticed white deposits on the pistons and in the head chambers. I found that this inst uncommon for a turbo engine but I thought I would ask to be safe. Pics below. I did clean 1 piston top to be sure it wasn't pitting the piston. There may be a very slight pitting.

So, at this point I am going to install a new set of better lifters. Currently I use the 5315. If the springs are weakening any, Ill put in a new set. Probably a set of 2126LSR. Ill also install new push rods since the current set is a touch short and I get the sewing machine noise. Preload is correct if using the thread count/bolt turn method. But it isnt right.

 

Post pics of the plugs. I just tuned a similar combo on 22-24 psi on q16, what kind of timing and afr have you been running?

 

Those are hot spots and my guess they are from running too lean and causing insane cylinder pressures/heat. That may have caused your head gasket failure.

 

That speckling looks like aluminum flakes to me. Its hard to tell exactly. Usually Q burns extremely clean, unless you're way off on the tuneup.

Even on a safe tune up (slightly fat), the plugs usually come out with a slightly grey appearing powder on them, usually have to wipe it off to read the timing mark (at least in my experience).

 

looks like antifreeze/coolant to me.

 

Here are a couple from the good runs where there were no issues. Tune hasn't changed. The current plugs look a little rich. But there isn't any runs on them since it basically shuts down at around 6k. Also the plugs are actually a slight green tint due to the C16 being a greenish color. Pictures make them look a little lean by the gray/white coloring on the strap.

Dyno was at 700rwhp on 14psi.

Launches at 3750 and 13.6psi. Makes 20psi within .5 seconds and stays pretty solid.

In .75 seconds its at 6000-6100 AFR 10.8 , Timing 12.5 to 13.0 , PSI 19.4 to 20.0
Stays pretty flat then at 3.5 seconds, the rpm starts to rise.
At 6600 AFR 11.4 , Timing 15.6 , PSI 18.9
Trap at 6700 AFR 11.1 , Timing 16.1 , PSI 18.7

 

I'm not sure how much damage your massive detonation problem has caused, but those white specks on your pistons are aluminum oxide that previously existed as plain old aluminum in your cylinder heads. The same may be true of your spark plugs, although I can't be sure from the pictures. It doesn't look like those plugs were pulled before idle fouling could diminish the ability to properly read them. Also, a couple of those cleaner spots on the block look very similar to head gasket blowouts.

 

I'm not doubting the head gasket being pushed through at all. But looking at it, it doesn't look to be bad. Its the first time I've run multi layer head gaskets. On the last couple of attempts down the track, when the rpm dropped off the turbo was still spooling up. And when the rpm dropped, the engine wasn't able to take all the current air flow and the data log showed the boost hitting 28-29 psi before it dropped back down. Also the pictures of the pistons, the gasket is still on the block. So your looking at the gasket.

As for the plugs, yes, the truck gets driven back to the pits. I haven't pulled plugs at the end of the track yet after a run.

I have tried many times to find someone local to help with the tuning but haven't found anyone yet. So I have been tuning it with help from a member here that's up north. Makes it real hard to get right.

 

Some things off, looks like detonation to me too.

10.8 is pretty rich for race fuels. It's outside their peak power window. Too much fuel can cause detonation as well, it's not like alky based fuels that can run super rich.

I'd drop the boost down a few psi and lean it out. Then get a good plug read and go from there. Drop timing if the plug reads hot.

What kind of preload did you have on those 5315 lifters? Pretty sure those take like .040? Quite a bit Less than the GM stuff anyway.

 

I copied and pasted this from a lifter thread on how I checked the pushrods. The specs are kind of confusing though. You can find on their website the correct preload is right in my range, and then others post pictures of sheets that came with thier lifters that show .030 - .035 which means mine would be too much preload, but then I doubt I would have the sewing machine noise. I couldnt find a way to get my dial indicator mounted well to get an accurate check so I stayed with what I had. Now I have a new mount system that should allow me to get it perfect when I get it back together.

Copy .
I am also running the 5315 in my LQ4 with 578 lift. I used the 7.4 pushrod and ended up with about .056 preload. Turn the rocker bolt by hand and as soon as you feel the pushrod start to tighten up when spinning with your fingers, its at zero lash. Then crank the bolt by hand as tight as you can get it until the bolt seats. That's your preload number. I got about .75 turn of the bolt. After that you are just torqueing the bolt and not getting any more preload. I was at .8 to .9 of a full turn to reach full torque at 22lbs.

I do plan to upgrade the lifters anyway so they shouldn't be a problem later. Ill have the springs checked as well to be safe. I bought a tester for doing it on the heads but it doesnt fit so I need to remove them. Im not paying 800 bucks for the only on head tool I could find. LOL Right now I am looking for a good deal on lifters. Missed a set on here for sale.

You have seen the logs. It was running great and then this issue popped up the next time it hit the track. Only the rpm drops off. I was really thinking it was the converter and talked to Hughes a few times. They dont think it is. It seemed as the converter was locking right up at 6k and my mph wasnt high enough yet to keep running, so it drug the engine down.

So I am also looking at possible valve float causing missfires.

As for the detonation. Im not sure. There are opinions here that goes both ways now. Too lean and maybe too rich.

 

Hi Taxman, YOUR spark plugs are TERRIBLE, "glazed" and "melted".

The insulator SHOULD be viewed as a new piece of White Chalk

The above "tech" I too agree.

I would check your EMAP at WOT.
I would check the EMS TDC reference to be correct at "0" mark.
I would ask for an EGT report ?
I would ask for the Spark Instant at WOT and SP heat range ?
I would fit Autolite 3922x Racing Plugs.
I would fit FelPro 1041 Head Gaskets.

The "tech" from Forcefed86 "too rich" with Low Spark Advance WILL melt pistons/plugs = CORRECT

Lance

 

Here are pics of other plugs. I found the ones marked with the right date at 20psi. I know there isnt much difference but want to be sure I am showing the correct plug. Also the pictures are a little better. Also these are NGK BR7EF

Pay no attention the rust. These are about 6 weeks out of the engine now and we have been very humid here in Texas for a while now, they tend to rust up after being pulled.

I agree on the porcelain being white or near white. The issue I have always had is when using VP fuels, the color they add the each fuel seems to tint the plug a little. That's the green/yellowish color on the porcelain. Also you can now see the depth of this color in it with the better picture. The gray on the top edge of the porcelain is surely aluminum.

The heat range looks ok on the strap to me though. Which is on the flat before the bend.

Im not setup for EMAP and EGT yet. I plan to get the parts to measure them both though.
Now that the heads are off I will check the TDC. I checked this with the heads on with a spark plug tool, it gets close but it isnt perfect.

On the plugs. Why go with the Autolites? I always ran Autolite in the past, I went with this NGK plug on the reference of many turbo guys here use them with success.

And why go with the 1041 gasket instead of the LS9? I know the 1041 is thinner which would bump compression a little but the bore is larger so it drops it back down.

 

That looks really odd how glazed those plugs look. If photobucket wasn't a pos now I would show you the pics of he plugs on q16. I spent alot of time Dyno tuning the car and did a crank relearn with stock ECU to verify correct spark. On 22 psi I ended up on 20 degrees of timing to get the heat mark right into the bend on #5 and #7 (2 hottest plugs). I did multiple plug checks while increasing timing and boost. The plugs had no heat at all around 16-17 degrees.

 

Yea, I used Photobucket too until last night. Got tired of all the crap with ads and slow as hell running. Went to Shutterfly and its much faster but I cant share the pictures to this site.

Anyway, yea the tune needs help. Right now I am lifter shopping so I can get it back together and check for pushrod lengths. I want to add EGT and exhaust pressure sensors but one step at a time.

When it was dyno tuned we added timing until it didnt make any more power and backed it back up to where it was before that pull. We have been adjusting for the higher boost levels. So the timing should be close. Ive also been running it on the rich side to be safe, but maybe its too safe which causes other issues.

 

I have never met Pantera EFI and his shop is like 5-10 mins from my house... I'm thinking I should as he seems to be a wealth of information lol. Always has good input on things

 

Whats fuel pressure@WOT? 45lbs@ idle seems really low to me. They are only 80lbs

 

Thats another thing to add, a fuel pressure sensor so I can log it. But being a 1 to 1 ratio it should be over 65psi.

We lowered it when I first got it running because higher pressures was way too rich to idle. I was at 52psi I think. Im sure I can raise it now that its running right. We were going to do that already due to the injector DC being at 95% to see if I can get more out of it.

 

Hi Taxman, I learned how to "read" from Jerry Grant.
His FIRST statement was that the plug should look as "new" upon inspection.
Your picture states the center electrode is melted.
NOW, a better picture, in FOCUS, could tell ALL here the plug condition.
The Ground Strap should ALSO have "sharp" edges.

THE HEAT RANGE IS NOT a "by the strap" method, use the insulator NO MORE that 1/2 White.
As for the 3922X Racing Plug, MY "guess" is that the guys from Charlotte may know a few things about "bits".

The Squish remark ?

Your piston has "little" Quench as it has the Round Dish, this does NOT MATCH the head Quench Pad.

The Piston to Head distance is NOT stated, my guess is "0" though I ask that distance ?

Why not visit Silvea, tomorrow Monday 12:01 PM ?

Lance

 

Thanks for the help and info. I was trying to get better pictures but All I have right now is a phone

I always used the ground strap to set the timing. Trying to get it near the bend on the flat part.

I will check the deck height because it was supposed to be set at 0 by the machine shop.

And what is Sileva?

This truck started its build as a street strip setup. So I wasbt planning on pushing it this hard. But the no prep races caught my attention. And here I am.

 

post 15