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Thread: DIY LTCC or similar system for LT1s

  1. #406
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    Quote Originally Posted by vilefly View Post
    Aroberson! You tricked us into building it! So.......THAT was your evil plan all along! We're just going to have to put the leaches on you......it's standard procedure, you know.
    Heh.
    LOL glad you guys took my idea and ran with it.

  2. #407
    Fuel Injected! spfautsch's Avatar
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    After contacting several vendors looking for two part / catalytic cured silicone, I found this single component coating on Amazon. It's roughly the consistency of paint which is what I wanted, but required several "coats" to create a nice seal around the wiring penetrations.



    Should also work well to coat the board if so desired. For now I'm just putting a dessicant pack in the case to absorb any condensation that might occur.

    Just dropped my block off with a machinist this morning. Sounds like I may be waiting 3-5 weeks to get the bores trued up and the shipping container of forged cranks to arrive. Patience is difficult for me to conjure when I walk out in the garage and see a pile of parts instead of a car.

  3. #408
    Fuel Injected! Terminal_Crazy's Avatar
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    Are they rehoning the block or boring it?
    In the pics you posted it was were hard to tell how bad the damage was.

    or are you reboring and going 383 ? or bigger?

    Mitch
    '95 Z28 M6 -Just the odd mod.
    '80 350 A3 C3 Corvette - recent addition.

  4. #409
    Fuel Injected! spfautsch's Avatar
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    Boring to 4.040. There really wasn't any damage on the walls - that picture of #6 bore must have been a product of freshly scraped off oil and poor lighting or a reflection from the inspection camera. When I pulled the pistons out I thought I would be able to hit it with a hone and be fine at 4.030 so I went ahead and ordered the reciprocating assy (383). That didn't last long - luckily they're waiting on cranks or I'd be looking for a new block or to sell the 4.030 kit.

    In the process of stripping the block down I decided to check run-out on the cam and cam bearing clearances. Turns out my cam was crooked by 0.002" cold and a little over 0.001" hot. Several hours of massaging with a centerpunch later and those numbers were cut by better than half.

    Anyway, since I was having difficulties with my telescoping bore gauges, a co-worker borrowed me his dial bore gauge to check the cam bearing clearance. I thought while I have it I should look at the bores to see how much wear there is around those scuff marks. Turns out not much at all - less than 0.0008" at the worst. What I found that needed addressing was nearly 2 thousands out of round down in the middle of the bore - a small amount of wear perpendicular to the piston pin, and 1.3-1.6 thousandths undersize when measuring along the pin / crankshaft axis. This worried me a bit so I put the heads back on and torqued them down. I nearly soiled shorts - the undersize measured on the pin axis (front to back) doubled on the four inner cylinders (3, 4, 5 & 6). At the middle of the cylinder depth the bores were close to 0.005" (five one thousandths) out of round. So the shop that bored it the first time couldn't possibly have used torque plates when it was honed. And I never checked compression because I had no reason to suspect a problem there.

    I was in such disbelief after removing the heads and measuring all the bores, seeing the ovality change from around 0.0040 to 0.0020 that I put the heads back on to make sure someone hadn't put something in my coffee.
    Last edited by spfautsch; 12-03-2018 at 06:46 PM. Reason: corrected dimensions in last sentence

  5. #410
    Fuel Injected! vilefly's Avatar
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    Looks like I won't get much done this week. Parents-in-law dropped off their completely untrained and brainless springer spaniel to watch for a week. This obsessive-compulsive water drinking maniac has a bladder the size of a walnut and is a real pest. My blinds are destroyed, 3 power cords chewwed up, carpet has lost a year of its life, have to get abusive just to get a bite to eat, house stinks of dog crap and I am now looking up dog-cooking recipies on the net. That was day one. Have 3 more days and a blizzard to go.

    I hope I can get my test bench set up soon, because this is irksome. My salvation depends upon it.

    Holy crap. Who hones without a torque plate?!?!? Time to fire a machine shop, jeez.

  6. #411
    Fuel Injected! spfautsch's Avatar
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    Been there, keep doing that. Wait until your squab finishes college (but hasn't moved out yet) and buys her own puppy that she's 100% going to take care of (promise dad). That dog will wake you to go outside 3x more frequently than your enlarged prostate summons you to the bathroom. Then, once you get used to that your wife feeds most of a 10 piece mc nugget and fries to said dog (a 40 lb border collie). Look up "dog with HGE" on the google. We own a rug doctor. I was just heading upstairs to get it so I can clean the orangish stains out of the carpet in my man cave. Wife was feeding her cheetos yesterday. I don't know what part of "don't do that, you're going to regret it" that my wife didn't understand.

    BTW, you might try making the extension cords more "accessible". I wish I could say because they learn quicker, but they don't. Depending on the breed, the "puppy" sticks around for at least the first two years. But after the puppy's gnawed up your $2800 Pella sliding door, you get a certain amount of satisfaction from hearing them yelp when the saliva makes contact with the copper.

    Yeah, I wouldn't allow the shop that did this to touch my most annoying neighbor's lawnmower. They're the reason I own a cam bearing tool. When I pulled the block out of their plastic and started looking it over the first thing I noticed were a set of gouge marks in the second cam bearing. When I confronted the owner and asked him to sell me a set of bearings and rent me the tool to fix it, after he blamed me for causing the damage while installing the cam he then told me the problem was the brand of bearing (that they didn't sell to me) and that I needed to bring it back. I told him they wouldn't be touching my engine again, thanks and go $$$$ yourself dipsh1t. I thought long and hard about checking the bores out at that point. I should have. But that was my very first experience with the 2016 strain of don't give a sh1t disease.

    I hope this machinist is going to do better. I got a tour of his shop and got to touch the torque plate. I showed him the 2016 cam bearing and tried giving him the background into why I would be checking every aspect of his work after he completes it.

  7. #412
    Fuel Injected! vilefly's Avatar
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    I finally am a little unfettered, for now. I have these on order for the coil outputs. I have a fondness for BNC connectors and shielded cables that has developed over the years, due to their inherent toughness. This way, a stray....whatever won't bite through the shielded cables too easily.
    71PfoJEtV6L._SL1200_.jpg

    To be honest, I have this one lying around, but unfortunately, there are no more to be had.
    s-l300.jpg

    To seal them, one only needs some dielectric grease.

  8. #413
    Fuel Injected! vilefly's Avatar
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    Hey spfautsch,
    I noticed a youtube post where a guy did an EFI connection conversion, but had problems above 5000rpm with the crank sensor. His pcm read a much lower RPM when he hit 5200 rpm. So I am wondering if this might match your symptoms you have been having. I suspect there is a resonant frequency problem going on. Perhaps a shielded input or filter should be installed inline to prevent this.

    Another thing, free LS pcm tuning is now available through PCMhammer and LS_droid. I think people will beat a path to your door if you make a camshaft output that is synchronous with the LS motors in terms of degrees. Despite all these changes......THIS PROJECT IS NOT OBSOLETE! I will be digging up some LS data so that you may know the timing for this.
    LS1_timing_chart2.jpg

    Looks like a simple signal. Goes high at 360* and low at 720*.
    People have been running the ls pcm with the 4x crankshaft reluctor found in the 96-up vortech and lt1 engines with success. I bet if someone grabbed a pcm from an LS motor, and programmed it to a vortech crank input, it should work with coil on plug operation.
    Last edited by vilefly; 02-17-2019 at 09:53 AM.

  9. #414
    Fuel Injected! spfautsch's Avatar
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    Quote Originally Posted by vilefly View Post
    ... a guy did an EFI connection conversion, but had problems above 5000rpm with the crank sensor. His pcm read a much lower RPM when he hit 5200 rpm. So I am wondering if this might match your symptoms you have been having. ... Perhaps a shielded input or filter should be installed inline to prevent this.
    I doubt that would be at all related. I'm fairly confident I identified the source of the stumble as an oversight I made in transitioning correctly at speeds where coils needed to be dwelled right around the 90 degree multiples (i.e. more than one TDC event ahead).

    Bear in mind that the opti has open collector outputs that are quite different from the outputs of un-amplified hall effect sensors in terms of noise immunity. I've no first-hand experience in the field but I believe most factory harnesses use either twisting or shielding around hall sensor pairs due to the nature of the signal. I noticed no such care taken with the opti lines when I spliced into my harness.

    Quote Originally Posted by vilefly View Post
    Another thing, free LS pcm tuning is now available through PCMhammer and LS_droid. I think people will beat a path to your door if you make a camshaft output that is synchronous with the LS motors in terms of degrees. ... I will be digging up some LS data so that you may know the timing for this.
    That would be very helpful (more timing info). Assuming the signal transition coincides with #1 and #6 TDC, a synthetic CMP signal would likely be so trivial to implement I'd do it just for fun. The only drawback would be the controller would need to detect sequence before the synthetic CMP signal could be properly timed, and then the PCM would finally be able to detect sequence - possibly 360 degrees later. This means start time could be higher than with a native CMP signal, and it could potentially trigger a CKP or CMP code in the LS PCM.

    I've been casually following the progress of the LS_droid stuff. It's a very significant milestone, but to be honest PCM swaps for a "nostalgia" gen 2 LT-1 wasn't the first thing I thought would result from it. My first thought was it will just make LSx engine swaps that much more ubiquitous (if that's possible).

    Whatever the case, thanks for bumping the thread. I just got the tracking # on my reciprocating assembly yesterday afternoon so I'm finally going to be able to start building in a week or so.

  10. #415
    Fuel Injected! vilefly's Avatar
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    It requires 1.5 seconds of cranking without a cam signal to set a code p0342 or p0343. If it syncs within this time......no code will be set. Codes can be disabled in the pcm with a proper flash programming. Average crank time is about 150-230rpm. So, by that reckoning, roughly 4 crank rotations without a cam signal will set the code.
    So, I think we are good.

    And now....a more detailed waveform for the crank wheel. Per degree of rotation.

    ls cam-24x crank signals.jpg
    Last edited by vilefly; 02-17-2019 at 10:15 PM.

  11. #416
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    The truck 0411 applications with a 4x crank sensor still use a distributor. You're not going to get CNP from that setup. It would require a 24X wheel under the timing cover.

  12. #417
    Fuel Injected! spfautsch's Avatar
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    Quote Originally Posted by vilefly View Post
    And now....a more detailed waveform for the crank wheel.
    I'm not sure that's of much use.

    Before I risk putting my foot further in my mouth, can you clarify your intentions? Are you saying it's possible to have the PCM handle sequencing of the ignition coils with a 4x crank reluctor?

    Edit: Sorry - after re-reading what you said here...

    Quote Originally Posted by vilefly View Post
    People have been running the ls pcm with the 4x crankshaft reluctor found in the 96-up vortech and lt1 engines with success. I bet if someone grabbed a pcm from an LS motor, and programmed it to a vortech crank input, it should work with coil on plug operation.
    I'd say I'd bet not.

    From a simple search I'm seeing the 4x wheel is non-indexed, so the CKP/CMP waveforms would look like this?

    vortec-CKP-CMP-waveform.jpg

    Or, were you thinking of using the diy-ltcc to handle sequencing the coils and just picking the EST signal from the PCM for timing?

    On the vortec setups the engine runs with injectors in batch mode until it has picked up sequence from the CMP. Having the PCM control the coils in such a setup would be wholly different because there's no margin for error with sequence. This is why the 24x system has an indexed crank reluctor.

    Honestly the only variable I would need to know is if the CMP signal goes high on #1 or #6. I think it's safe to assume #6, but I'll wait until someone comes forward wanting to try.

  13. #418
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    Ignition with 8 coils is only possible with 24x crank and 1x cam signal. A signal translator from opti signal to 24x,1x signals will allow the use of coil on plug and ls1 pcm.
    High res opti signal can be used for very accurate generator signal trigger upto a degree. The ls1 wheel is 360 degree and the 1x cam sensor in ls1 shows if the #1 or #6 is at TDC.

    A high res degree based generator will also fix the change in frequency, the higher the rpm the shorter the signal`s duration, which will be very hard to encode with time based generator.

    So for sync you need to find #1 or #6 TDC and start the 24x output from there in repeating pattern each 360 high res counts and changing the state of 1x signal from high to low each 360 degree also.

    I think you will need 2 low res slots to determine crank position and just wait for 360 degree trigger to output the 24x signal.

    I do have a busted crank with the wheel laying around so can measure the degrees of the slots manually.

  14. #419
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    Well, I don't know enough about programming the 0411 pcm to know if it won't work. Retroprogramming, if you will. I figure somewhere in the memory, the math for crank velocity can be accessed from a vortech 0411, and spliced into a ls1 binary, and possibly work. This is idealistic thinking, of course. I expect a loss of resolution, but wonder if it can be managed.

    My original thought, was to just use the pcm to handle timing and misfire detection, while letting the the diy-ltcc do its thing. Then I started imagining the above scenario. I have no immediate plans to do this just yet, because I need to learn a whole lot more about 0411 binaries.

    If everyone says it can't be done, then so be it.......I will stop pestering. Kur40's post beat my reply before I could press enter.
    Last edited by vilefly; 02-19-2019 at 04:33 AM.

  15. #420
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    Quote Originally Posted by kur4o View Post
    Ignition with 8 coils is only possible with 24x crank and 1x cam signal. A signal translator from opti signal to 24x,1x signals will allow the use of coil on plug and ls1 pcm.
    Assuming this is accurate (I tend to think it is), a hybrid setup where the diy-ltcc handled coil sequencing & dwell, generated a synthetic 1x cam signal, and picked off the EST signal for spark advance would be incredibly simple with a 4x crank reluctor.

    Quote Originally Posted by kur4o View Post
    High res opti signal can be used for very accurate generator signal trigger upto a degree.

    A high res degree based generator will also fix the change in frequency, the higher the rpm the shorter the signal`s duration, which will be very hard to encode with time based generator.
    I thought about addressing the idea of synthesizing a 24x+1x signal in my previous post, but decided against it. My concerns are with the "lossy" nature of the high res opti signal - I've logged a lot of instances where 1 or 2 degrees are lost or gained per TDC signal. I fear synthesizing a 24x signal from this info could falsely trigger misfire detection in the LS PCM. But I'd be willing to try if the right person came forward with a test mule.

    Quote Originally Posted by kur4o View Post
    I think you will need 2 low res slots to determine crank position and just wait for 360 degree trigger to output the 24x signal.
    Maybe not. If we can control both the CKP and CMP signals going to the PCM then it would probably work to just wait until sequence is detected to begin feeding both signals. This would (theoretically) add a maximum of 90 degrees of crankshaft rotation to the start sequence.

    Quote Originally Posted by kur4o View Post
    I do have a busted crank with the wheel laying around so can measure the degrees of the slots manually.
    vilefly's image of the 24x wheel's waveform in post #415 should give adequate information to work from. It's just a variation of 3 and 12 degree sequences. The beauty of it is in it's "native" form the PCM would never need to see more than 90 degrees of crank rotation to determine sequence. Ingenious.

    Doing a opti to 24x signal converter would be a relatively simple fork of the current code. As I mentioned, I would be willing to try it if the right person came along with a test mule they wouldn't mind doing some trial-and-error wiring on. It's not a conversion I'd anticipate doing myself - at least not in my current Y body where I'd have to get the CCM and the ABS/ASR modules talking, etc. I don't see that the gains to be had with the newer PCM would be worth the sacrifices in overall vehicle function and originality. Not to mention I'd really like to get my car running so I can complete this controller project!

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