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Thread: DIY LTCC or similar system for LT1s

  1. #331
    Fuel Injected! spfautsch's Avatar
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    The bearing grease seals are what make them "airtight". Obviously this is less than optimal, but the distributor really doesn't need to hold much of a vacuum. The amount of air the check valves allow the intake to pull through it is fairly small. But if the inlet hose clogs or gets pinched it could put the opti under full intake vacuum and I would imagine that could cause problems.

  2. #332
    Fuel Injected! vilefly's Avatar
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    The restrictive nature of the vacuum check valves should limit the vacuum enough to pose no threat to any bearing, I think. But the metal shielding is a bit less waterproof, I'd say. Condensation may pose a threat to a metal shielded bearing. I suppose I will have to look a bit harder. Will probably be derailed by Valentine's Day, though. Such an inconvenient holiday.

    Still drafting up a degree wheel in CAD, despite a toddler bumping my elbow at every opportunity. I noticed the slightly abnormal shape of the wheel, but I do wonder if it was pressed up flat against the scanner with a weighted object. Still, it is very useful for indexing the design properly. Thanks again. I have not superimposed one onto another yet to check for differences. And yes, I will take any scan I can get! I believe these are made by heavy chemical etching, not laser cut, as some may believe. Kind of like when etching a PC board, but with stainless steel as the material.

  3. #333
    Fuel Injected! vilefly's Avatar
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    The restrictive nature of the vacuum check valves should limit the vacuum enough to pose no threat to any bearing, I think. But the metal shielding is a bit less waterproof, I'd say. Condensation may pose a threat to a metal shielded bearing. I suppose I will have to look a bit harder. Will probably be derailed by Valentine's Day, though. Such an inconvenient holiday.

    Still drafting up a degree wheel in CAD, despite a toddler bumping my elbow at every opportunity. I noticed the slightly abnormal shape of the wheel, but I do wonder if it was pressed up flat against the scanner with a weighted object. Still, it is very useful for indexing the design properly. Thanks again. I have not superimposed one onto another yet to check for differences. And yes, I will take any scan I can get! I believe these are made by heavy chemical etching, not laser cut, as some may believe. Kind of like when etching a PC board, but with stainless steel as the material.

  4. #334
    Fuel Injected! spfautsch's Avatar
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    Distributor body, hub and shaft. Note, the rust came out of the water pump coupler when I was blowing the engine off with compressed air, it wasn't inside the opti. I guess I didn't use enough grease when I installed the coupler.

    Base diameter of the outer race

    Overall diameter of the outer race

    Depth of the shoulder

    Demonstrating how the mounting ring rests on shoulder when installed

    I may not need a bearing as bad as I originally thought, but hopefully these might enable someone to find a reasonably well suited replacement.

    After I finished taking these I did some experimentation with what I initially reported was a "garbage" remanned distributor base. The optical sensor may be a Mitsubishi - I still have reservations about using it in the car when I have an AIP sensor that is known to work in-situ. But one of the things I tried was spinning it with a drill with the controller in normal mode to see if sequencing worked. Though sequencing wasn't perfect, the impedances may be wrong because it's not also connected to the PCM as it was in the car. Out of curiosity I tried my known good AIP sensor in the other base, and it also exhibited similar sequence issues. More importantly, after spinning for 20-30 seconds at ~1000 rpm the bearing stopped making such a ridiculous racket. I'm thinking the grease just wasn't distributed through the bearing. Because there's no evidence the shaft was marked or keyed for index before disassembly, I'm starting to wonder if this might be a new old stock Delphi base. Thinking this one's a keeper after all. Just when I was starting to feel like I'd never catch a break!

  5. #335
    Fuel Injected! spfautsch's Avatar
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    Double roller timing set dropped another degree off the skew (#6 is coming in at +7, #1 at +9). I'm relatively sure the issue I was measuring initially is a case of tolerance stacking. I'm going to pull the cam out and make sure the front bearing and journal look good, but the only other explanation is that the shoulder on the cam that fits into the cam gear is also offset a few thousandths. +/- 1 degree is acceptable to me - I'll center my opti wheel at zero on one of the in-between cylinders and be happy.

    I eliminated the opti as the sole source of the problem by measuring cam ICL on both #1 and #6, and there was a similar skew.

    I still have to measure cam advance at least one more time since I went too optimistic picking the advance keyway on the initial assembly. Then dump the oil, oil pan, pull the headers so I can invert the engine and clean the mating surfaces comfortably, etc.

    I went with a Cloyes 9-3545x9 set that was almost a third of what the single roller set with water pump drive I bought last year cost ($220). I didn't hear anything to lead me to believe the chain was hitting the timing cover, but will report back if clearancing of the cover is needed - I slathered a few globs of grease on the chain before the last mock-up assembly.

    Since the double roller timing set cut about a pound of weight from the rotating mass, I ripped off the "might as well" band-aid and ordered an electric water pump and a freeze plug to close off the water pump drive hole. It's only money, right? Will run it off the recently deleted air injection pump relay.

  6. #336
    Fuel Injected! spfautsch's Avatar
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    Wanted to drop a little more information and an update.

    First, I discovered that the Delphi distributor base uses a slightly different bearing. 6003LU - as a standard order part # it has roughly the same outer diameter as the Delco bearing, but with an overall larger race that looks like could be chucked up in a lathe and cut to fit the application. Also it only has a step on one side of the race, for the retainer. Unfortunately this retainer has a larger ID than the Delco design, so you'd need to source a different retainer and bore / ream the step out of the bottom of the Delco bearing bore to use this bearing in the Delco. The Delphi base has slightly different dimensions, presumably to enable them to use this particular standard order bearing and cut it to fit thereby eliminating a special order item. Whatever the case, this bearing appears to be readily available. Also, the OE optical pickup can be made to fit the Delphi base by simply shimming it up with a couple washers. Long story short, the Delphi base is probably more rebuildable then the Delco-Remy. One thing I would want to change to the design is to make the thin retaining ring spring hardened in a shape that puts constant tension on the outer race to keep it seated, as I discovered it bends easily.

    When I got to degreeing in my cam and checking timing yesterday I was shocked to find only 1 degree total skew. Evidently there is enough slop in the fit between the cam and timing gear to allow for this. So where I was at +/- 1 degree I'm now at +/- 0.5 degree. I realize this is probably irrelevant to most of you, but I found it interesting that tolerance stacking could cause 4 degrees of skew.

  7. #337
    Fuel Injected! vilefly's Avatar
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    Still taking too long to draft up an optispark wheel, due to my laptop dieing randomly during drafting. Time for a new laptop and a qualude for the toddler. Unfortunately, it is not the same old cpu fan scenario that is typical. Perhaps I should buy a toughbook.

  8. #338
    Fuel Injected! spfautsch's Avatar
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    Quote Originally Posted by vilefly View Post
    Perhaps I should buy a toughbook.
    Tech moves so fast and can be so inexpensive I don't see much value in buying an extremely expensive piece that will last "forever" and continuing to use it well past it's point of (designed) obsolescence due the fallacy of sunk cost. I tend to buy something nice (by my extremely low standards) on clearance every 3-5 years and consider it more or less disposable. When my current rig dies (an inspiron 13 3-in-1) I'll move the ssd and memory from my old one to my new one and never miss a beat. But then I don't run windows.

    I'm not making much progress here either. I did spend some time working on the coil harness over the weekend. That was before I discovered I have a valve stem and possibly a guide, seat that are trashed. I haven't worked up the courage to pull the head yet and assess the damage fully.

  9. #339
    Fuel Injected! spfautsch's Avatar
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    I know this is ridiculously off-topic, but no-one else seems to be volunteering to build or test a prototype so you're stuck listening to me whine.

    One of the items on my "while i have the engine out" checklist was to evaluate pushrod length and determine if what I had was acceptable. Boy, did I open a can of worms.

    While I did come up with a more "correct" length and buy new pushrods, unfortunately I found as I was preparing to put the intake back on that I had already trashed all the guides in my newly LE1'd heads. Long story short, don't under any circumstances follow CompCams guide here or anything that sounds like it. It is completely and utterly incorrect. With only 100 hours on my build I have excessive guide to stem clearance from using "geometry" that was determined erroneously using said guide.

    Whatever your take on valvetrain geometry, this puts me at least two weeks if not a month (not to mention a considerable spend) away from turning the key on it again. I'm so incredibly p****d words can't do it justice.

  10. #340
    Fuel Injected! vilefly's Avatar
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    Well, that sounds horrible enough. The instructions I remember are that the rocker arm should be level @50% lift (90 degree angles at rod and valve). Although the LS engines have a higher cam location, this may not be entirely possible. I still need to obtain 8 LS coils to start my tinkering. Too many old 60s luxury cars have been showing up at my shop, and fraying my nerves trying to find parts for these badly wired fords and one failed '71 chevy truck restoration that I have to redo. We don't typically touch these project cars, but we hit a slow spot, and the boss got desparate, and said yes. Blech.
    I hate it when people try to drive something that they will never like how it operates.
    "Can you adjust the suspension so that my new truck rides softer?"
    "You just bought it. Didn't you test drive it?"
    "Um....yes."
    ".........." (incredulous raised-eyebrow stare) "How about dropping an engine block in back, lady? That'll smooth things out."

  11. #341
    Fuel Injected! Terminal_Crazy's Avatar
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    Quote Originally Posted by spfautsch View Post
    I know this is ridiculously off-topic, but no-one else seems to be volunteering to build or test a prototype so you're stuck listening to me whine.

    One of the items on my "while i have the engine out" checklist was to evaluate pushrod length and determine if what I had was acceptable. Boy, did I open a can of worms.

    While I did come up with a more "correct" length and buy new pushrods, unfortunately I found as I was preparing to put the intake back on that I had already trashed all the guides in my newly LE1'd heads. Long story short, don't under any circumstances follow CompCams guide here or anything that sounds like it. It is completely and utterly incorrect. With only 100 hours on my build I have excessive guide to stem clearance from using "geometry" that was determined erroneously using said guide.

    Whatever your take on valvetrain geometry, this puts me at least two weeks if not a month (not to mention a considerable spend) away from turning the key on it again. I'm so incredibly p****d words can't do it justice.
    Hiya Scott, I got your email - Thanks

    That sucks.
    I used the Comp Cams pushrod checker and got the smallest sweep and tried 0.050, 0.100 and 0.150 either side.
    Hmm thinking about this is making me nevous now :-)

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

  12. #342
    Fuel Injected! spfautsch's Avatar
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    Quote Originally Posted by vilefly View Post
    I still need to obtain 8 LS coils to start my tinkering.
    Mine are some new "scratch and dent" coils that I found on big auction site for a very reasonable price. The worst looking one has a small chip in the epoxy around the top.

    Quote Originally Posted by Terminal_Crazy View Post
    I used the Comp Cams pushrod checker and got the smallest sweep and tried 0.050, 0.100 and 0.150 either side.
    Hmm thinking about this is making me nevous now :-)
    With the spring loads we're running stuff is bound to wear faster, but if you follow Comp's "procedure" blindly it's a recipe for disaster. They should really take that page down because it comes up at the top of search results, and it's horribly incomplete.

    If you ended up with the smallest sweep you're probably fine - this puts the rocker at roughly a 90 degree angle to the valve stem around mid lift. My original setup with stock length pushrods had a sweep pattern close to the middle of the valve about .105" wide so I gave it no more thought. The 90 degree at mid lift method got the sweep closer to .022" but it's on the outer 1/3 of the tip. There's really no way to adjust it in without throwing out the 90 degree geometry other than having custom trunnions made with offset stud holes.

    The only reason I noticed this is because the #6 intake valve was cocking sideways and contacting the seat as the rocker started to open it. It was making a faint "clink" sound as the face of the valve was ringing like a bell.

  13. #343
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    I hope you made the measurements with modified solid lifter and soft spring, to reduce to minimum lifter bleeding.
    Mark the valve tip with same paint and get the contact mark as much as possible to mid point of the tip.

    Of course subpar guide`s material is always a possibility.

  14. #344
    Fuel Injected! spfautsch's Avatar
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    Oh, don't worry. I've learned more about rocker geometry in the last 5 days than I ever wanted to. Lloyd and I have been discussing the subject extensively. I'm debating hiring a medium to channel the ghost of Smokey Yunick to see what he thinks. I bought a new lifter to use for mock-up and blocked the plunger with a piece of bar stock so the running springs could be used, because the deflection caused by the spring pressure is a factor you want to account for also.

    I was running stock PR length last year when this damage was done. The wear pattern wasn't perfectly centered but it looked "close enough". Roughly .100" wide and roughly .030" offset towards the exhaust side of head. Obviously that wasn't "close enough".

    I used the 90 degree at mid lift method this time to give absolute minimum sweep, and then last night bought an obscenely expensive set of rocker arms that have the stud holes in the trunnions drilled .050" offset, so the roller tip will contact the valve closer to center.

  15. #345
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    The greater the force needed to push the object down, the greater the tilting of the object, if the force is applied off-center.
    That way the valve will rub the guide sideways. So the higher the pressure, the more exact center location is needed. If the spring were softer you might even not get a failure.

    Since the force will be straight centered only at the mid travel, and there will be offset either way I suggest you recalculate the spring rates and use the spring that can tolerate your RPM band and no higher.

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