Wow, that must have been a bad sound to hear! TOW was making some pretty ugly sounds too. Sadly, we may have hurt the cylinder wall when trying to determine where the noise was by continuing to crank her. :(

I can catch them with my finger nail. I don't know that a light bore is going to clean them up, and it seems that many builders shy away from more than about 0.010" bore on these blocks. I'm already at .005", so that doesn't leave much.

That's it, I'm having BBQ tonight! Although I'll go somewhere better and a little closer to home. Maybe I'll even send you a picture! ;)

OK, after catching up on the condolences and questions, I'll give a bit more of an update... Eric and I pulled the head Thursday and found the cylinder wall nicks. So on Friday we decided to pull the whole engine. Unfortunately that means dropping the transmission, which means releasing the torque arm mount (that doubles as my trans crossmember).

With Eric's lift and the appropriate tools, we had it all apart in about 3 hours as you can see above. We've stripped it down to basically a long block now as I work out my plans for the repair or replacement.

We discovered a couple of things while taking it apart. First, it seems we had the lines to my PCV catch can routed backwards. When I pulled the intake manifold, it and the intake ports had oil all over them. That explains the oil consumption problem that I've had with this engine, and perhaps also explains why my O2 sensor died back in March (and I appear to be losing the replacement now). It would also explain how dirty the chambers and pistons are when we removed the head.

We also found a few leaks along the oil pan and PS pump that explain the dirty bottom of the car that I was fighting. I'm going to replace the PS pump. Even though it was new, it's been making some nasty sounds once in a while. I ran it almost dry when the PS rack went out, so it's likely got some internal wear, so now is the time to fix it.

Back to the engine itself... I bought this engine about 5 years ago. It had been sitting for a long time, as it was apparently the engine used when this magazine article was written:

GMHTP Engine Write on LS2 with L92 heads

The guy that Golen built that engine for never finished his project, so he listed it on eBay. It was still sitting at Golen's shop, so I spoke with him about some changes before shipping it to me. After I completed the purchase, I ordered a cam and the Vic. Jr. intake and had Golen install them. Then he dynoed it and you see the plot above.

There are a lot of details I never got, so I relied on the article to fill in the blanks. Last night while reading the article, I ran across something that puzzles me. The springs used on those heads were listed as Manley Nextek beehives. I googled them and came up with this page:

http://www.manleyperformance.com/nic...lvetrain.shtml

If I can trust the information in the article (questionable, I know, but it's all I have), those springs were installed at 1.8" height and had 158# of seat pressure. They also list 345# of open pressure at 0.6" lift. The closest spring I could find from the above table is the first one, and it lists a max of 0.6" lift. I know Golen was running a cam that was slightly bigger than the cam in the article (a 242/248), so I would have expected them to have adequate clearance on the springs, but perhaps they didn't. That's my best hypothesis for what went wrong: over-lifted the spring, I'm not running aggressive lobes on this cam, so that shouldn't have been the problem...

Anyway, if you go through the rest of the parts list, the engine should have some nice pieces in it. The Callies DragSlayer crank, Compstar rods with smaller rod journals, the Mahle pistons, and some bowl work on the heads. I'll find out for sure soon when it is all torn down.

I've gone through a lot of scenarios of what I would like to do... Given more time and budget, I think I would send this block off to ERL and have them sleeve it. Then I could punch it out to a 427 or 441. I would then perhaps go with a set of LS7 heads and the single plane intake. That should net a nice bump in performance.

However, I have 2 events in March that I do not want to miss! GG is coming to Fort Worth, and USCA is coming the weekend after... I just don't see how I can pull this all together in that timeline and have time to tune it and break it in. So instead, I'm leading towards the following plan...

I drove over to Texas Speed's new facility on Friday and spent about an hour talking to them about my situation. Then can do pretty much anything I want to do in-house, except the sleeving which they don't do or sell yet. I'm planning to take the long block to them tomorrow and do the following:

- have them check the cylinder to see if it's salvageable. if so, then I will have them bore it and get a new set of pistons and rebuild it for me

- if the cylinder cannot be saved, then I will probably step up to an LS3 block and move to a 418ci. if I were to replace the ls2 block and replace just the 1 piston, that would be an option, but it wouldn't save me a lot of money in the end ($600 or so). so why not go for the cubes while I'm at it...

Either way, they should be able to use my crank and rods.

The next question is the head... At a minimum, I need a new set of springs and retainers, and 1 intake valve. They offered up a package to apply their CNC port work to my castings and do the springs, valves, retainers, etc. That's the 'low cost' option, and should be pretty good. Option two is to repair the guide, valve, seat and sell those, and replace them with one of their PRC 250 or 260cc square port heads. The smaller port volume with larger cfm should net me a bit more power. I'm leaning that direction at the moment...

Finally, while I have this opportunity, I'm seeking out a few people that seem to have a lot of knowledge in developing cam specs for single plan LS intake setups now. 5 years ago, there wasn't much knowledge in this area. But now, a lot more people have done them. I think there is some real potential in this combination with some cam optimization! I happen to be traveling to North Carolina this week, and one of these shops is located there in Mt. Airy. So I may try to swing by and have a conversation with him about my options... I would expect him to offer some insight into my head selection as well. Unfortunately I'm pretty tied to the Victor Jr. due to the work we have in my shaker to get that to all fit. Not that it's a bad intake, but there are certainly options that could be better!

Ok, that's the update for now... Again, thank you goes out to Steve for all the help this week! And also to Eric for squeezing me into the shop when he had a couple of projects coming in. We are going to slide TOW up and out of his way while the engine work comes together...

We are, of course, all suffering with you. As many of us have walked in your shoes... and we feel your pain.


There seems to be a common issue with this set up.... and that is -- a very fat fueling issue. IF this was my car I'd be searching high and low for the cause before wasting another motor. That can get expensive real quickly! Ask me how I know! LOL

There's many cause's for EFI to get false O2 readings. Leaky injector... bad MAP... a bad heating circuit allowing the sensor to cool off during idling... a burned or unseated exhaust valve... leaky exhaust... just to list a few. The O2 sensor plays a very critical role in fueling the engine... but it can only do one thing - read the oxygen in the exhaust.

The odds of having TWO failed O2 sensors with so few miles just seems very very unlikely. These things are pretty robust. Something else is awry. What that is - is your treasure hunt.

With the motor out of the car -- I'd start with the wiring - and it's routing. All of the sensors run on very low voltage. Interference from outside sources is so easily overlooked. A shared power source. A misplaced bundle zip tie wrapping a high voltage/high amperage wire bundle with some sensor wiring... a high resistance ground.

I'd leave no wire untouched. I'd review the power supply to the ECU and I'd make sure it's supply is conditioned by the battery. Basically I'd be putting a fresh set of eyeballs on every single facet of the wiring and placement of the components. There's something going on here and ya just have to find it. If nothing else you'll sleep better knowing you gave it a good look-see.

Greg,

I agree, there is an issue causing the car to run rich. I have a feeling that the catch can has contributed to this by pulling oil into the engine, then pushing it out the exhaust and into the sensor.

When we pulled the exhaust, I was actually looking for any signs of leaks. Eric has done a nice job of sealing it all up though: I saw no signs of carbon at any of the joints or welds.

It will be relatively easy for me to check continuity between the ECU and the O2 sensor connector with everything pulled apart, and I was already planning to do that. I found the pinout and wiring information from Holley, so I will use a meter to confirm the wires are all in the correct positions. The Holley HP EFI software will tell me if it thinks there is a problem with the sensor, and it was not reporting one. That doesn't mean that there isn't though. It can be working, but be 'off' as this one is acting...

I'll find the problem. And also, before I spend much time driving the car after this build, I will get it back on a dyno with a second O2 sensor again to make sure mine is reporting correctly! I definitely do NOT want to do this again!!!

I know you're on it Bryan -- I'm just searching my little cranium trying to find a reason....

And I appreciate the brain storming! :)

The other thing I'm going to try is to move the sensor from the passenger's side tube to the driver's side tube. I can rule out anything strange about one side since the 2 are isolated.

The only other thing I've contemplated is whether there is anything about using oval tubing that could cause the sensor to read strangely. I have googled to try and see if anyone else has reported anything like this, and so far I haven't found anything. I get the impression that having the sensor out of the middle / direct path of the flow can be good because there is less likelihood of any liquid hitting the sensor.

I'd run it in the collector just before your flange.... keeping it on the top of the collector the best you can.

AEM recommended my sensor be mounted at a minimum 10* downward angle.

Correct?