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Bad day on the dyno...
So this isn't the way I had hoped my first chassis dyno run would go in TOW.
http://i100.photobucket.com/albums/m...pseb0e21ee.jpg During the first pull, after warming the car up and doing a little idle tuning, the operator starts the pull. There was a little hiccup around 3500, but she kept pulling until around 5500 or so. Then BAM! She just shut down. We tried to restart her, but she wouldn't start, and there were some bad sounds... The shop owner pulled out tools and we started pulling plugs, then he pulled out a bore scope. Unfortunately we couldn't see much with that, so then he pulled out a compression tester. And guess what? On the LAST cylinder we checked (#5) due to the tri-y headers making that one a bitch, we had no compression. Next step, we pulled the coil pack and valve cover, and voila: the picture above... Looks like the coil spring broke, dropping the valve which is now bent. That's about all we could do, so we bolted the cover back on and were done... I have to given this shop their due: they really helped me out trying to find the problem instead of just kicking me out of his shop. Also thankfully, I didn't puke anything on the floor, so that probably helped. ;) And I need to give some even BIGGER props to Steve (gernon) from here. I texted him about what happened, and he offered to load up his truck and trailer to come get me. Note, the weather yesterday sucked (grey and drizzly and cold), and he was at least 90m away from me. Unfortunately that 90m turned into almost 3 hours with traffic, then an hour to load her up, then 2 hours back. I think he had 7 hours into this pickup, then he met Eric and I today at Eric's shop to unload her. Steve, I still owe you big time! Anyway, TOW is at Eric's now, and I pulled the head off today. The news is mixed... The valve certainly smacked the piston, which if that were all would be ok. But unfortunately I have 2 small nicks in the cylinder wall that you can almost see in the picture below. I cannot tell if they are deep enough to be fatal yet, but what this does mean is that the engine is coming out. :shakehead: http://i100.photobucket.com/albums/m...ps9a263ca9.jpg At the moment, I haven't fully decided what route I'm going to take. The head doesn't look like it took any real abuse, other than the guide since I'm sure it's dorked up with the bent valve. The valve seat looks ok. At a minimum, I'm going to need a bore / hone, a set of pistons, a set of sprints and retainers, and a set of valves. So a full rebuild is in store. Then it becomes a matter of what else I might do while it's all apart. I have a lot of ideas, but I'm not quite ready to turn TOW into a full blown beast. I like the mild-ish street manners yet good power on the track. But I think I can improve on the mid-range torque of my setup, Researching some of the LS sites, it seems that there is a lot of knowledge about designing cams for a single plane intake that didn't exist 5 years ago when I had this one speced. So I think a cam change is going to happen also while this is ongoing... One other thing I learned. Something is wrong with my wideband sensor. TOW has always smelled as if she was running really rich, but I could tune her in the 13.5 to 14.0 AFR range just fine. Well, the dyno WB sensor was showing numbers in the 12.0 range at cruise speeds. That would explain a lot of my frustration with the gas smell at idle and cruise. I'll be digging into this while doing this project... So tomorrow, back to Eric's. The engine is coming out, and I'll pull a plan together by early next week. This engine is SUPPOSED to have some nice pieces inside of it, so whatever I do, I will plan to reuse those (if they are actually there). If the block cannot be saved, then I may consider an LS3 block instead. Weeeeeeee....... :G-Dub: |
Sorry Bry. Dropping a valve never ends well. If I may throw out my .02, be very careful with salvage parts decisions.
I tried that once... |
Sorry to hear this, Bryan. Keep the rebuild simple so you can get back to enjoying the car. Just be sure to go with good dual springs on the valves this next time.
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Man that's a tough day. Sorry to see the mess.
We're those Comp 918 beehive springs? They're known for issues. |
Sorry to hear this Bryan. You'll fix her and it'll be better than before. A month down and some coin.....I haven't drivin my beast since i saw you in Texas, shess hurt so after i get it back from CustomWorks next week, we dive into the harness and "hopefully" fix it (cause it may be an engine in my future as well)....
Did Steve get his fired yet? |
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Bryan, sorry to see this about TOW's engine. Bummed for you but I have a feeling TOW will be coming back stronger than ever. Hope to see you get the engine repaired and TOW back on the road soon.
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Sucks man.... well, while you're in there.. :)
At least you're right in the middle of LS country down there.... Oh and nice job Steve. |
Sucks to hear it Bryan. Hope you get it back together soon.
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That sucks! I hated to see that picture and read the story. I can't wait to see TOW back running through the cones and tearizing tires!
Greg |
That sucks Bryan, but better on the dyno than out in the middle of no where. Make some improvements so you'll feel better about having it out. But don't go so far that you can't drive it this summer!
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Hate to hear what happened.
Not trying to spend all of your money but.... https://lateral-g.net/forums/showthread.php4?t=48786 |
I had that same exact thought... :D
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SO the good news is Don Hardy race engines --- an LS specialist is right there near you. That's who built the motor in the '33 --- and where Brizio gets most of his motors.
My guess on the rich condition is a pin hole or leak in the exhaust UPSTREAM from the O2 sensor - causing it to add fuel to overcome what it sees as a lean condition. Or perhaps that valve never sealed well --- and unburnt fuel is oxygen rich again fooling the sensor. Hey! You've only gone thru ONE motor --- the Mustang has eaten 4 since I've owned it.... LOL |
you'll get it...good to have steve on your side.
It might be a good time to start discussing a different name for the car. Just sayin |
Sucks to hear Bryan.
Hope you get her back to normal soon! Good luck! |
Bryan, sorry to hear. It'd be nice if money grew on trees but for most of us that would be a huge set back. Feel for you, hope things work out smooth as possible. Best of luck to you.:bang: Could find the you've got to be sshiiiiitin' me smileee.
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Bad Dyno day
Brian
Sorry to hear the LS let go I have done the same in the past along with many other engine failures Most NorCal Shelby boys who track their cars a lot tend to change their springs regularly Depends on how high you rev it. 7000 plus all the time does take its toll You could always go out on the edge and put a real Pontiac Motor in her:) I hope you get it running soon Bob |
That sucks, I hope you can save the block and you get it back in soon. Good Luck.
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Bryan - I went back and took a look at the top of your pistons and yeah ... that looks to have been running very rich.
The whole thing is really upsetting. And I'm sorry you're having these on going issues. |
Looks like your rocker bolt pulled or loosened up. I notice you didn't do a trunion upgrade on the rocker arms. I would definitely look into doing some upgrades, the trunion kits are around $140 and include longer Allen bolts to give better reliability. Doing some research after I bought my L92 Super Victor.....it seems the single plane intakes give up some torque and HP on a normally aspirated LS motor over the factory plastic intake.....around 30-40 ft/lbs in the lower RPM ranges....the Victor only seems advantageous in high RPM operation ( over 7K RPM ) I hope your also running LS3 intake valves, they are 90 grams, the L92 valves are heavy around 116grams, if you don't have LS3 hardware the hollow stem Ferrera stuf is 106 grams. The factory LS3 valves are pretty good stuff and really lightweight but, don't put a lot of spring pressure on them! If your going to rebuild the LS do yourself a big favor.....pitch the stock connecting rods for some Manley rods or Callies forged rods cheap insurance. Brian Tooley racing has some great hardware for LS valve springs.....stay away from the titanium retainers....stick with tool steel retainers....almost as light as Ti and won't flake away in operation like Ti will. If your motor builder know his stuff on LS motors he will know he needs to port the oil galleys and drill the lifter retainers for high RPM oil drain back. Hope all goes well in the refresh
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We make a stud girdle for the stock rockers.
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Sorry to hear this Brian. I have snapped the end of the crank off at 6500 and it sounded like a pencil snapping for that brief moment until bits of block and pistons came out of the oil pan.
We have all had these issues and definitely feel your pain. Its an opportunity to make TOW better. |
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Scott --- I can only see the same photos that you can i.e., the ones Bryan posted up. I can see the "dings" that Bryan mentioned but not well enough to know whether or not that is going to be able to be machined out. I think a good meal at The Salt Lick will have Bryan up and running in no time at all. |
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Those pics of the food you guys enjoyed at The Salt Lick make me hungry, every time I scan through his build thread. |
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Here she is on the floor at Eric's shop: http://i100.photobucket.com/albums/m...pskqnnjmpe.jpg And a shot of the bent valve. The seat and chamber look fine, just the valve and guide of course. http://i100.photobucket.com/albums/m...psbf0xmjgx.jpg |
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See more in a post below about where I think the problem was... Quote:
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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....
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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.
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