Bad day on the dyno...

[Sieg]

Originally Posted by 71RS/SS396

The LS engines have horrible windage problems and need a lot of topend ventilation to deal with it. The path you're headed down with a larger stroke is going to make it worse since you're basically installing a bigger fan in the crankcase.

Tim - Is this the case for all versions of the LS platform?

Has the issue been resolved with the new LT1/4 and rumored LTX & LT5?

[GregWeld]

Originally Posted by Sieg

AEM referenced condensation effecting the sensor long-term, so the downward angle allows it to drain off vs in.

Downstream from the collector gets a better mixture blend from the individual primaries......as my brain perceived it when I cut the hole in my system.

Yes -- all of that -- I've seen people put them "where convenient" which meant right where any condensation would pool.

When you look at the various locations in various factory installs... they're all over the map... so I've never gotten a "clue" about the utmost perfect location. I think - High and dry - downstream of the collector for a good clean sample - and most should be good.

I could tell a funny story about the guy that put an LS2 in - and didn't bother to hook up ANY PCV... and spent quite a bit of money trying to find out what was "squealing"... including removing and replacing the transmission... Ross Perot summed it up best. That giant sucking sound....


++++++++++++++++++++++++



So Bryan.... you live in TEXAS and don't go to The Salt Lick... and haven't ever heard of Don Hardy Race Engines... which means you've never heard of Don Hardy. That's two strikes.

You also have a real good LS tuner.... that builds some serious bad ass CTSV's and late model Corvettes... up near Dallas/Ft Worth... ADVANCED MODERN PERFORMANCE in Arlington


http://www.advancedmodernperformance..._services.html

[carbuff]

Originally Posted by 71RS/SS396

The 02 should be 6-8" back from the last tube in the header, if you put it in the collector it will read the cylinder it's closest to.

That's the same basic info that I received when we placed it where we did. At this point, I'm almost 100% convinced that the mis-connected PCV catchcan is my problem. The oil has likely spattered on the sensor element, preventing it from getting a true reading.

Originally Posted by 71RS/SS396

I'm not sure that it is rich, after looking at the pics I suspect the oil it's ingesting from the pcv is what you're seeing on the pistons. You need to address your venting as this can cause a whole host of problems.

Agreed. The problem is simple: we connected it backwards. Just a simple screwup, and it's already being addressed since the can is off the car. We have to remake one hose, and it's all fixed. D'oh!

Originally Posted by 71RS/SS396

What pcv vent are you using?

The Mike Norris unit. I wasn't aware that there were general problems with the aftermarket cans?

Originally Posted by 71RS/SS396

I put a restricter in the vacuum line to slow the velocity.

Good idea.

Originally Posted by 71RS/SS396

I would also vent both valve covers to a catch can. The LS engines have horrible windage problems and need a lot of topend ventilation to deal with it. The path you're headed down with a larger stroke is going to make it worse since you're basically installing a bigger fan in the crankcase.

Not sure how to do this... Currently, the driver's side is connected to the air cleaner as the input. The passenger side is also connected to the air cleaner as input. The barb on the valley is connected to the catch can, and the other side of that is connected to the vacuum port on the TB. Those are what will be corrected when we reassemble.

From all I read on the subject, this is how it's supposed to be connected I think... I want to get the vapors out of the valley, and the fresh air from the valve covers.

[carbuff]

Originally Posted by Che70velle

Agreed, all that most systems do on these LS engines is fill the intake with an oil like gel. Bryan, have you looked at the plugs? Spark plugs are tattletales, and reading them has become a lost art. This engine shut off at 5500 I think you said, so it would be ideal to take a close looksey at the plugs.

I will try and look at them the next time I'm there. As I recall, they look like it's run rich. Definitely don't look 'correct'.

I do have oil in the intake and head ports, but again that's due to the mis-connected catch can, I think. I was trying to correct an issue with the PCV system, and instead I created one.

[carbuff]

Originally Posted by Payton King

Agreed on the oil windage. I ened up using 2 catch cans on my car to solve the problem. Just like Tim stated, you will need to pull from both valve covers and from the valley tray. Kurt Urban ( http://kurturbanperformance.net/home/ )is the man on the LS stuff, let Tim guide you to the promosed land.

Where does the fresh air enter the system if you route all of the connections to the catch cans, which have a vacuum source on the other side?

Originally Posted by Payton King

Ah, so clean!

[carbuff]

Originally Posted by GregWeld

WHAT HE SAID.....

"to do items" on your list...


Talk to Urban

Talk to Tim

Go to Salt Lick for lunch... or Franklins...

See ya at the Lonestar Roundup... 18 or us are driving down for it.

Great plan, except the Franklin wait... 3 hours for bbq! It was worth it, once...

[carbuff]

So heres today's update... The news is mixed.

First the bad news. When I pulled the passenger side head off, this is what I found:





After some head scratching, and then looking at the driver's side head, we realized that the bent valve broke the valve guide (which is powdered metal on the L92 heads from GM), and a piece of that bounced up off the valve, into the plenum, and down into the #2 cylinder. It beat up the top of the piston pretty good, and it's left shrapnel embedded into the head surface. It's fairly rough, but I'm hoping that the head can be milled to smooth out the surface without dropping the chamber size too small for my desired PTV clearance and compression ratio.

Here is the valve and broken guide:





So, onto the better news. After getting past this, and taking Eric to lunch, we loaded the rest of the shortblock into the truck and I ran it over to Texas Speed. I have decided to forego the sleeved block idea (too much time, money, and not enough bang for the buck). We unloaded it there and their head machinist took a look at it. After some discussion, they backed off their previous limit of only taking the bore to 4.010" on this block and say they can go to 4.030" on it. BUT, it's still not clear whether that will be enough to clean this up or not.

The plan at this point is for them to disassemble the short block, check all of the cylinders to see if there is any more damage (thankfully the walls on #2 don't look to be damaged, just the piston and head), and get back with me. I expect to hear from them by Wednesday. If the block is salvageable, we are going to bore it, get a new set of pistons, and put it back together. If not, I'm getting an LS3 block, boring to 4.070" and running it as a 418ci .

Now, the other thing I did today was spend an hour and a half on the phone with Brian Tooley of Brian Tooley Racing. He's been doing LS work for almost as long as the LS has been around. He originally founded TEA, which he sold to Summit Racing (didn't know that) in 2004, and he now does parts sales and cam work. I've known of him for a long time, but in my recent research, I learned that he's been spending a good bit of time learning about what works and what doesn't with the single plane intakes for the LS engines.

During our long phone call, we discussed my current cam and performance level, my current heads and alternative options, and what I would like to end up with after all of this. It turns out that he recently did a big dyno study of the effects of valve timing on performance in the LS engines with the single plane Victor Jr. (my intake) and the L92 heads (my heads) out of the box (mine have had some work done). So he had some great data to share.

We have ended up on a plan that involves me sending my heads to TEA for the repairs, then to him for some touch up work in the ports and chambers, and then back to me with his valve springs installed. He is also going to spec out a custom cam grind for me, one which allows me to run more compression (~ 11.5 to 11.75:1) and will help my midrange powerband. I'm really excited about this step!

Today was a long day of research and phone calls, then running to Eric's to tear the engine apart, running it over to TSP, then packaging up the heads to get them on the way to TEA. I had to get it all done today as I leave town tomorrow for a week... I'm still pushing to get it all back together by March 1st, which will give me 2 weeks to break it in and tune it before the Fort Worth GG and USCA the weekend after. The long pole will be the heads. I'm going to lose 2 weeks just to shipping on them. But I think the results will be worth it!

I gotta go pack now! Early flight tomorrow... More news as it trickles in from TEA and TSP.

[Payton King]

I did not vent fresh air to the motor. Both valve covers pulled through to one of the canisters and then into the port on the front of the manifold. Valley (PCV) to other canister and then to port on throttle body.

[glassman]

So Bryan, why not the heads n cam package from TSP?, curious cause thats probably the route i'm going....

[Flash68]

Sounds like you've got a good plan Brian.