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1 step forward, 2 steps back. Or maybe 10 steps back in this case. Last weekend I decided to start topping off the fluids since I was getting closer to turning the key for the first time on this new build. I did get all the electrical stuff buttoned up and finalized so that I could throw the switch on one of my breakers to do the initial smoke check test and everything that I checked passed with no issues. PCM powered up, gauges powered up, fuel pump kicked on, check engine light came on, radio powered up. All electrical checked out with no blown fuses or smoke or hot wires that I could find anywhere. Fluids were topped off Saturday during the day including engine oil and trans fluid. Sunday morning I was out in the garage getting some of my kid's stuff out and noticed that one of the boxes I had sitting under the car was oil soaked. Looked at the underside of the car and found the drain plug on the oil pan to be not even finger tight - shame on me. Tightened it up and was about to go on my way when I noticed the oil stain pattern on the pan. Oil was coming out of the drain plug, but the oil witness mark was much, much higher than just from the drain plug. I followed the oil up to several small pin-holes / maybe a crack in the pan.
Monday morning I contacted the place I bought it from and they were able to get me an RMA number and a pre-paid return label to send the pan back to the manufacturer. Bad news was I had to pull the engine to get the pan out. There was no way to get the pan off the engine even with dropping the oil pump pickup tube - ask me how I know... Upon closer inspection of the inside of the pan, I was able to see some flaws in the casting that were directly above the holes/crack. These were not near any mounting holes or bosses so I didn't over-torque something or bottom out a fastener. All manufacturer torque specs were followed. This pan will arrive at the manufacturer on Tuesday and hopefully they ship out a new one to me by Friday of next week.
While the car is still down, I figured I would try to knock out the final few things that need to be fabricated / solved. I started with bolting the headers back up to the engine which I did put back in the car to save space in the garage for now. I wanted to see if I could use my existing H-pipe assembly with integrated flex couplings, and needed to see what the width was going to be from center to center of the header collectors. My old exhaust was 21" on center at the header collector and these headers maintain that distance within an 1/8" or so. The bigger issue is going to be the fore-aft offset that was not present in the small block headers. These have about a 3" fore-aft offset from driver to passenger side collectors.
I bought enough 0.063" aluminum sheet to make both my gauge panel and the cold air box, so I started on that this morning. My wife took the kids over to her brother's house and I got the green light to work on the car for a few hours. Using my cardboard template as a guide, I was able to get it cut out and bent up into my desired shape. I did have to make a trip to the hardware store for a 4 1/4" hole saw to make the opening for the intake tube. I used some 1/4" tube I had laying around to form the grommet around this opening and it fits the intake tube very snugly. Still need to figure out if I'm going to make a lid for it or not, but overall I'm pretty happy with how it turned out. I have enough room inside the airbox to service the filter without having to disassemble anything so that's a plus. I will probably be mounting my radiator overflow on the inside of this due to packaging constraints outside of it, but I still need to mock it up in the car now that I have the aluminum bent up. It will still probably get some under-hood recirc air due to the opening in the fender to the engine compartment and the opening at the bottom, but I'll cross that bridge later if necessary with some foam blockers to seal it off.
Haven't heard anything back yet on the oil pan, but in the mean time I did get the exhaust modified and welded so I can just bolt it in. The headers needed to have a ball flange welded on so I could use my current intermediate pipe assembly complete with flex couplings and H-pipe as well as have an additional O2 bung welded in for my Wideband O2 sensor since I am running a permanent Wideband.
Driver side header prepping for O2 bung:
Driver side header O2 bung welded in and ball-socket collector with 2 bolt flange welded on:
The passenger side exhaust needed to be addressed since I planned to use my existing system with these headers. The gen 1 small block headers had the collectors exiting at the same location fore-aft, but the LS headers are offset fore-aft by about 4.5" with the passenger side exiting further rearward than the driver side. This pic shows the offset I'm talking about, taken from under the car on the passenger side looking towards the driver side.
The solution was to take a little bit of length out of the header collector, the front pipe assembly and the ball-socket collector piece to result in the 4.5" offset needed. Here is the result (not sure why this pic is so much smaller than all the rest - it was taken with the same camera...)
On to the H-pipe assembly and the intermediate pipes that lead into the mufflers. This H-pipe assembly is a flow master part and is pretty nice in it's own right. I had modified it previously to remove the slight jog that it had and replace it with a straight section of pipe. I didn't like how I had it with a band clamp holding my "extension" pieces on, so we cut and welded some 10" sections on to it to eliminate my backyard solution. I don't have anything against the band clamps, but I don't like using them to form a butt-joint.
Hopefully I will hear something today on the oil pan, otherwise it will probably be mid to late next week with this weekend being Memorial Day weekend and so many people traveling / vacationing.
This past weekend, my dad came over and helped me thrash on the car to get everything put back together since I got my replacement oil pan in the mail. I tested this one to make sure that it wouldn't leak either by filling it to the brim with water and letting it sit overnight on top of a piece of cardboard. Not a drop leaked out. I've gotten pretty good at pulling the engine now, so I was able to R&R the engine on lunch this past Friday. (it helps that I literally only had to remove 3 bell housing bolts and lift it out - I had been stripping it down for a week or so to prepare for pulling the engine) The new oil pan bolted up and I used the melting method for "priming" the LS oil pump.
Replacement oil pan bolted on:
Priming the pump through the galley plug on the driver side of the block. Funnel, some fuel line and 8oz of engine oil are all it takes. They said to wait about 3 minutes, I waited 5 and still had a huge oil mess to clean up.
We got everything put together by Sunday at noon and I started running through my checklist of what I needed to check for and making sure we had all fluids topped off and put my very rough startup tune on the PCM. We decided to mount the radiator overflow in front of the core support and route the hose through an opening to the lower left.
The fuel lines were flushed with about 1/2 gallon of gas just by turning the key to the on position for the pump the "prime". I was able to get it to fire and idle, but it took about 30% throttle to get it to fire which I thought was strange but didn't really put too much thought into it, chalking it up to my very rough startup tune. I was just happy that I didn't have a stuck injector and hydrolock the engine. Oil pressure was instant. RPM was reading 600rpm when the VCM scanner showed 800rpm (no big deal, just modify the tach output signal from a default of 6 to 4 since the actual rpm was 33% higher than my tach. You calculate this on the 24x engines by taking 24/6 = 4 cylinder or 24/4 = 6 cylinder or 24/3 = 8 cylinder modes). The other thing I noticed was it sounded like it was running rough, so I took my HF temp gun and shot the header tubes. Sure enough #6 was only reading 118* and all the others were like 250-260* and it was showing a lot of misfires on cylinder 6. Long story short, I tracked it down to either a broken trigger wire, dead injector driver or best case the injector wires were in the wrong pins. According to lt1swap, the #6 injector trigger wire goes in blue connector pin 37 for my 2002 0411 PCM. I pulled the blue connector this morning and sure enough, it was pinned wrong:
As found, the yellow/black wire is the #6 injector trigger wire and was in pin 38 which is unused. The keen observer will also notice that the black wire (injector #1) was in pin 37, so it was getting an injector signal, just at the wrong time:
And fixed:
Another visual confirmation that cylinder 6 was not firing - note the discoloration on header tubes 2, 4 and 8 but tube 6 is still natural color.,
After fixing this and doing some more tweaking to my idle airflow tables, it started up with no throttle input required and no mis-fires recorded. I will be taking a video of it starting hopefully in the next few days as proof of it running. Still need to get the trans topped off and do some more cold start idle tuning in P/N and in gear, but this was a great last few days. It's hard to believe I can just turn the key and let it idle on it's own now without having to either work the choke or give throttle input or both.
Love your build! What is the top radiator hose from?
Thanks, The upper rad hose is Dayco 71703. Summit says this is for a 94-96 Chevy, Buick, Cadillac commercial chassis (similar to a roadmaster, caprice, or fleetwood) with the gen 2 LT engine lower rad hose. Has 1.25” ID on both ends which is a snug fit on my rad, but has a good fit on my water pump.
Here is the idle video, still needs work, but I have driven the car around the block and verified that it will shift up and down through the gears. I am kind of at a loss though for the startup - both cold and hot, it requires some throttle input during cranking to actually fire. I did the calibration for the running airflow (RAF) and that seemed to help idle, but it made the startup issue worse. Guessing my VE / MAF tables need more work but wouldn't mind a second set of eyes on what I've done so far.
EDIT - for some reason it won't let me upload the video. It's 1min long and was taken on my iPhone. I have attached my running tune and the log from it.
Finally got around to doing some tuning on the car, and got my VE table dialed in a little better - leaned it out from 11.5:1 with the TBSS VE table to 14.5-15.0:1. Still haven't gotten on it too hard because everything is still fresh and the tune still needs some work but I discovered an issue with the trans that needs to be addressed. I thought it was weird that there was a big rpm drop between 1st and 2nd, but just chalked it up to the gear spead and didn't think anything of it. I had what I thought was 4 distinct rpm drops and left it at that. Looking back over my logs, the trans never actually went into 2nd gear - the PCM commanded the 1-2 shift, but there was no corresponding rpm drop to go along with it. It was staying in 1st until the 2-3 shift and just going from 1 to 3. I did a quick confirmation in the VCM scanner that I could hear solenoid A and B activating, and then did a quick up and down the street test in manual 2nd. with the lever in manual 2nd, the trans did do a 1-2 upshift and 2-1 downshift so that leads me to believe that the band is working, but the intermediate sprag is not functioning correctly. I did not replace this during my rebuild because during my inspection it functioned correctly - freewheeled clockwise and locked counterclockwise during my teardown inspection. It is possible I assembled it backwards, but in any event, I will be replacing the direct drum assembly (drum, sprag and sprag outer race) including the front band just to be sure I don't have any more issues with it. Hopefully will get the trans pulled in the next few days and open it up to see what the damage is...
I will say this 6L has a ton more low end torque than the old 383 did from just the little bit of driving I have done.
Loving the LS swap. Just imagine if it was a 6.2L gen V
Thanks, I actually have the genV 6.2L L86 in my 2014 Sierra I bought brand new - it’s got a lot of power too, but I like the simplicity of the gen 3/4 especially for tuning. Gen 3 PCMs aren’t torque based so it’s much easier to tune.
Also figured out my transmission issue. I tore it down to the center support and did some investigation into the problem. I was expecting to find my intermediate sprag completely toasted and/or assembled backwards, but it looked just as good as when I assembled it a few months ago and the drum surface where the intermediate band rides looked brand new too. Sprag was assembled correctly, locked counter clockwise and free wheeled clockwise. I tried to overpower the sprag on the bench and I could not do it by hand. Digging deeper since I was at a loss, I decided to check the clearance on my intermediate clutches. It measured out to be just about 0.095" which is looser than I'd like, but "technically" within the factory spec of 0.040-0.107" Upon disassembly, I found I omitted the factory wave plate with legs which measured in at 0.045". Adding this back in brought my clearance down to 0.050" which is right on nominal for the 0.040-0.060" clearance I was shooting for.
Direct drum band surface:
Intermediate Band:
Intermediate clutches and steels. Here you can see some wear patterns from where it looks like the clutches were slipping on the steels. Nothing was hot spotted or worn down though.
And finally, the culprit. Oops:
Root cause analysis complete - my no 2nd gear was my own doing. I left out the seals on the intermediate piston. At first when I was doing my air-check on the intermediate clutch, I thought it was just a cut seal since I was seeing bubbles at the inner seal and outer seal areas. No big deal, a $3 and $4 seal. Pulled it apart and found there was no seal in either location! Apparently my air-checks upon initial build up were not thorough enough. I assembled the center support for mockup, and then never disassembled it to install the seals. Lesson learned. Good news is that I still had my overhaul kit (wife says I'm a bit of a hoarder...) and the two seals were sitting right in there. Installed and air checked on the bench, piston travels up and down now like it should.
Here is a video of the air bubbles I was seeing during my aircheck:
I know nothing about transmission building but is that tooth at about 7oclock supposed to look like that compared to the others?
Yes, this is the center support that houses the intermediate (2nd gear) piston and has different sized “teeth” that index to the case. Note the one at 5 o’clock is wider.
I've been driving and tuning the car and just overall enjoying it more than with the gen 1 sbc. Got my VE tables dialed in pretty close for now at least under 4k rpm. I think I'm close enough now to re-enable the trims and let them dial it in the rest of the way.
My derale fans are working quite well now that I've gotten the air burped out of the system. One fan will keep the engine between 199-208F. I'm using the LS3/L99 water pump which I believe has ~195F thermostat or somewhere thereabouts. I had to play with the fan settings a bit to get it to turn off while cruising down the road. I had the on/off settings as fan 1 205 on, 195 off, fan 2 210 on, 205 off and the first fan would come on and not go back off until I shut the car off. Now my settings are like this:
I did have an issue with my ATM fuses and the derale dual fan setup. This is quite a common problem and even derale advises against using a fuse for these fans now. They suggest using a 25 or 30 amp breaker instead. I went through a whole pack of fuses before figuring this out. I tried changing ground points, re-doing my wires and nothing helped. Both fans spun freely so they weren't locked up or anything like that. I did not have this problem with the previous ATC (or ATO? which ever is the normal size automotive blade fuse). I did some looking and found that they actually make an ATM size auto resetting circuit breaker in 30amp:
The other thing I have been contemplating is adding a 3rd relay to my fans to have a low and high speed setting instead of just on/off. The main purpose would be to reduce the noise of the jet taking off under my hood, lol. These fans move a ton of air, but they are very, very loud. I can hear them over the engine / exhaust with the windows up idling at a light.
In doing some RAF (running airflow) and IAC (Idle Air Controller) tuning, I can't seem to get my IAC counts at a warm idle to be anything but 0. Upon startup, they are pegged at 400, but once it crosses the boundary for adaptive idle (set to 170F) it begins closing the IAC until it reaches 0. Not sure why it's doing this if its a vacuum leak or something like that. I've tried closing my throttle body all the way down to 0.53V which is just above the point where the blade "sticks" with no change. As soon as I drive the car, the IAC starts opening / closing following my throttle movement / rpm to a point which I assume is part of the cracker / follower calibration.
I have the same fans and they are loud. If you put a meter on them that will record peak amp draw mine were spiking at about 41 amps at start up. I switched to an auto reset breaker and never looked back.
05-22-2021, 01:10 PM
