PowerLabs

This is a continuation of Forged Motor + Bigger Blower = MUCH LESS POWER, where, essentially, I went from a stock LS2 making 597RWHP on pump gas at 10.5PSI from an Si-Trim, to a forged LS2 using a ZR-1 cam with a T-Trim at 15PSI with 100% methanol injection making 620RWHP. I was expecting to see 700 to the tire with that combo, and am extremely disappointed with the results. Furthermore, the new combo has 50 less foot pounds of torque at 2500RPM, and gets approx. 3MPG worse fuel economy.

Well, I got the heads off. The engine now has exactly 4K miles; it was broken in with JoeGibbs break-in oil (started up, idled to full operating temp, driven sub 3000RPMs for 20 mins, oil changed for Joe Gibbs break-in oil agin, then driven carefully for 500 miles, oil changed again for non synthetic to 2000 miles, then oil changed to full synthetic).
You will recall this engine compression tested 145PSI, and shows <6% leakdown cold.

Here is how it looks:












I must say, the scoring on the cylinder walls (vertical lines on the top and bottom of every single cylinder) concern me a bit. I am told it is completely normal, and the 6% leakdown seems to suggest it is not a big deal, but on an engine with 4K miles? Ummm...

My plan right now:

I'm going to CC the pistons, but I can verify that they do come up to full deck height. Assuming they check out as -11CCs, then this is in fact a 9.8:1 compression engine. My plan of action now is to take 30 thousandths off the heads (making them 59ccs, I believe?), and run a Cometic .040" head gasket. This will bring the compression ratio up to 10.5:1 . I will also have the exhaust side of the heads ported while they are out, provided I can find a place to do that inexpensively.
I'll bolt them back on and drive the car as-is. That's about all I can do to it at the time; I'm getting really tired of this whole deal, and I don't plan to keep the car for more than another year or so.

Thoughts? Comments?
And, most importantly, where can I get my heads milled and ported quickly? I'd like the car back on the road by next week if possible...

carlrx7

Holy carbon buildup!

Skunkworks

I know you don't want to hear this but I'd check cam, you've torn off enough parts that your close enough. That does not look like a 4k engine with meth. Good luck.


Mike

SinisterC6

sam, have you spoken to the engine builder, ive been following your posts and this is ridiculous

Mr.Big

that doesn't look like a 104,000 mile engine with methanol injection, wow, something is way off here...

mr. e

For porting in NJ, try Head Games. Dave is the owner. I don't know the number but if you need me to find it, PM me and I will call my bro in law, they are personal friends and Dave has done all of my bro in law's work (five cars in his stable and the one with the least hpr is making 650)

EdwardETraylorIII

Call Richard @ West Coast Cylinder Head for exceptional work and an outstanding price.

He's got a flow bench and has done many many LSx heads. He's IT as far as heads for our matters (as far as I'm concerned).

carlrx7

PL,, any oil consumption?

Nasty C6

The hone job looks like junk. if your running low tension rings you need a better finish then that.bet all the problems are in the tune.

396375

You need a shop that does it all.Take it to ECS.

SpinMonster

Richard told me on the phone that his testing showed no real power gains porting the exhaust side only on heads.

SpinMonster

I think the wide 121 LSA of the ZR1 cam is a major contributor to the lowish cranking compression. It closes the intake valve pretty late for a 211 duration cam. The Z06's narrower LSA with the same specs otherwise is a better choice for 6 liter builds. Sam can compensate for it largely with the static compression bump but in the end it would be prudent for low end TQ to go with an earlier int closing point cam.

edcmat-l1

Can you take some pictures of the plugs maybe? That is a lot of carbon build up for only 4K. They're also very wet. Is that wet oil or did you get some coolant on the pistons when removing the heads?

Was there alot of oil in the intake? I'ts possible it's from the PCV system. How was it routed?

Skunkworks

I'm not going to pretend I'm a cam expert, but back in 04 or 05 a LS1 build that I'm aware of had cam installed incorrectly (can't remember all details). Power was off throughout power band, but it sounded and acted OK. When heads were pulled pistons looked horrible, which then led to double checking cam.

The GM ZR1 cam by design may kill some low end torque do to having PD blower (not sure), but it was definitely designed to run clean. Assuming all is well with electronics (injectors, ignition coils, sensors...) something(s) is/are mechanically off.

Also I'm aware of several engines with lower CR and MUCH larger cams that yielded higher compression tests.

I'm not here to pile on, but was just saying it's allot of work to get to the point PL is at, so why not check a few more things.

PL, how does oil look when you change it?


Mike

ysb02

ECS blower cam would be cheaper than porting the heads probably.

tjwong

I agree, it looks like a LOT of oil has gone through there. Notice on the inboard side of the pistons that the piston crowns are relatively clean indicating possible ring wash meaning that the oil is passing the rings and keeping that area of the pistons clean.

PowerLabs

LME said this is normal...

Doug from ECS tuned it; I don't think the tune is the problem.

I will post pictures of the plugs; they look good.
PCV is routed as follows: Valley cover into a catch can through a one way check valve going to the intake manifold. Driver's side head capped, passenger side head runs into the air filter.

fperra

If your valley check valve wasn't working you may have been pressurizing the crank and that could explain your low power and all the oil sludge on the pistons.

user_name

You've got a bunch of oil in the combustion chambers. That's a problem. Anybody telling me different if I owned an engine with these issues would be called a liar.

If you have had that thing into boost a bunch with methanol and the pistons are STILL coated in oil, then you've got major issues.

A lot of it could be PCV, but that situation will just play out worse with blowby.

I had an ls1 that looked like that once. Turned out the block was cracked in the rear from head bolts being torqued down with coolant in them. It drank oil like crazy.

CSX4236

I am having the same problem with builder here on Long Island in NY. Brought my 08 LS3 in to get motor forged and upgrade the super charger wanted to get around 750+ hp at wheel out of it.

Before this build car had, s-trim, heads, cam and exhust last dyno they told me car made 675 at wheel, I took car a few weeks later to local shop next to my office and car made 630 at wheel ok so something not right with those numbers but I let it be.

Now get motor forged and upgrade to t-trim running 15 psi and also added meth and when picked up the car told me was making 740 at wheel showed me dyno sheets and all, and that car had alot of more left just break it in and they will retune it ok no problem. So week later take car to same shop down road and dyno car at 640 lol so again numbers are not matching anywere.

Now I know this dyno is dead on cause I have Porsche TT and car recently made 515 at wheel at tuner shop and made exactly same power at shop down road. Also this 08 C6 car made 550 at wheel with exhaust and supercharger on very first upgrade and week later took it to local dyno it down road made exactly same power. So local dyno machine is dead on in my eyes.


I sent C6 to another tuner cause tune was sloppy and car ran like crap, there was fuel problem and whole bunch of small issues that needed to be corrected. Ok we fix all problems tune car now runs and drives alot better, but best we can get on dyno is 685 at wheel.

I am quite pissed off I have spent alot of money to forge motor and upgrade supercharger to pickup what? 50 HP from what car made before upgrade, And then to top it all off all these dyno sheets were nothing but lies from shop?

Ow yeah this is icing on the cake, I also have 09 CTS-V they did full exhaust, intake, pulley upgrade and tune gave me dyno sheet for car at 580 hp at wheel and just for ****s and giggles I bring car to local dyno shop last weekend to see if numbers are true and what do you know only made 550 at wheel. Seems they like play with dyno numbers and thats just not cool.

Watch who does work on your car I think ECS will be my next shop heard nothing but good things about them.