Been following this thread from the beginning. Marty had sent me a message i told him i would pull my distributor out an check the gear . The has minor wear ,an no wear showing run out . Meaning the gear wear is uniform around the circumference. I looked at the cam gear from what i could see it looks ok not much of a view for the distributor hole. If my memory is correct i believe my end play was set at .005 . The TA cam bumper was pretty frustrating to set . Marty's way looks way easier , hope this helps if not raise more questions.
If a shaft wasn't perfectly straight, it would cause the gear teeth to move in and out relative to each other and could cause the gear teeth wear/failure anomaly seen on one side but not the other. A gear fitted to a shaft that was straight, but the hole on the gear wasn't machine perfectly centered could do this too. Imagine what damage would be caused if the gears were 'wobbling' around in relation to each other. They'd still work, for a while, but then you'd see something like this after some miles were put on it. Just a thought.
Perhaps some of them were watching and waiting to see what all the pros had to say about it, and since no one seems to have 'the' answer yet, I reckon it's still up for grabs, eh? Let's see...aftermarket this, aftermarket that, tolerances having to be aligned with precision instruments and custom built components costing more than even the 'hey everyone see how big Mine is' crowd is willing to pay, I'd say these engines are pretty much open season for anyone, whether it's a guy who can't figure out how to use a simple keyboard, or someone with ideas and directions that is offered up for any and all to use to advance the engineering and understanding of these wonderful machines. Either way, it's appreciated that you were seeking advice from the nobodies, even if you had to ask for it in a backhanded sort of way. Hope you're doing well, Johnny. Been a while since I've seen you post here.
It'll all get fixed. By the looks and contact wear on cam button, nothing abnormal. No galling, only shows very light pattern from ever so slightly making contact like it should. Timing gear/ chainset alignment will get triple checked, along with cam shoulder distance out from blk face. I know the roller cam shoulders seem tiny compared to flat tappet cams. Less contact surface area to distribute load/ force on blk. Something has to be creating added thrust toward blk. Oiling will get new additions to the whole mix too. Maybe 14 quarts of oil will fill the blk enough to keep everything submerged!
I recall the pattern looking off center, but my memory can be faulty. If the end play was tight and closed up during use, is it possible to have deflected the cam off center enough to hurt a tooth and train wreck the next few? Is the front cam bearing damaged or showing any witness marks in an unusual direction?
Pics of t/c inside. Unless you spot face the area square with the t/c cover gasket face, you have nothing square for cam bumper to bump off against. I didn't think the aluminum surface was going to hold .005 end play accurately, with it not being square, hence the externally adjustable hardened wear surface setup. Does the bullet look square to dist. gear to you?
Wow, you don't have to threaten me! One of your first pics shows contact at the root of the distributor gear. That's a fairly strong suggestion for deflection if there isn't contact found without load. Right now I'm seeing a chicken vs. egg thing with either the bottoming out gear chipping and deflecting everything along with the ensuing train wreck and creating a witness mark on the cam gear bolt....or, The aforementioned off-center contact pushing things off center, even though it seems like the cam and surrounding beef would win that struggle. I'm picturing a spinning top on a table (except the top of the top is wide) , and when you place your finger on it off-center, the point of contact becomes the new center and rotates everything around the new axis, and it only takes a couple thousandths to really create a problem here, kinda like the Y axis on a lathe. There's less oil on a cam bearing from 12 O clock to 3 (not looking at yours now), so it's possible to wear that direction first? Maybe I overthink things. Hopefully this offers more to think about.
While I'm in fantasy land, Adapt a mini-chuck to an old cam and drive it from the rear and you'd have the most simple and accurate fixturing possible. While I'm Red Greening it here, bolt up a hard rubber forklift wheel to the back of the cam and roll the whole deal up to the rear tire of your '86 Chevy van. Have the wife rev it up as you push the block for manual feed. (This is for humor only, in case the incredibly dense might think otherwise)
Don't worry, the bullet wasn't meant for you. , It just happened to be close by and it was all shiny and cool looking. Was ebay-ing some hunting stuff a while back. I hear you on the off center concept. The problem I'm having right now is the block is torn up enough to not be able to really check anything with accuracy. Can't install cam, gears, chain, etc. ,and rotate with that condition. Cam bearings, even the front one, look good and I am amazed they are not beat up. The front one has a witness mark where the cam groove is on frt. journal, but that's normal, (no contact). My timing set was (new) taught at assembly, but not tight enough to feel binding when rotating it. It's slightly looser now but still very nice to keep timing dead on. The snap ring in rear cam bearing bore may be extra insurance to prevent cam from ever eating my block again!. The smaller front shoulder on these rollers doesn't provide a generous surface area to hold cam from heavier contact with block, so the added oiling is really needed there. It'll be a full tear down, super clean everything and start all over.
You could leave the chain off and spin the cam in the block, even without the front cam bearing there.
I would say, more than likely he would NOT be able to spin the cam without the chain on it because of the lobe/throw interference. Unless there is a sweet spot in the crank rotation where the crank throws would be out of the way of ALL of the lobes at the same time?
The galled block face doesn't give me a smooth surface to rotate cam against. Can't accurately check distance / alignment of block face to back side of cam & crank timing gears because of the .058- .060 recessed area. That has to be restored. I'd feel better getting rid of the rough surfaces first, then do some thorough checking.
I can't help but chuckle to myself when some people seem to think that stock engines are ticking time bombs with 'inadequate' oiling, when it seems to be that they become even more so (by many times over) when you start adding all this extra stuff that has to be so precisely clearanced that any slight deviation or variance could cause the whole thing to go up like an atomic bomb. I guess you guys better have your math spot-on perfect when calculating the tolerances, eh? I need to watch and learn here--seems I am but a grasshopper in the midst of all these cerebral gurus. (seriously) One of my favorite past times is to learn new things, so I'll just continue to keep quiet and enrich myself with all this fine knowledge. Thanks to all for this wonderful opportunity.
Should be plenty of places that the rod throws wouldn't hit the lobes, and I was operating under the premise that something could be gapped between the block and maybe the timing gear. Isn't there only four close narrow ranges it would hit? I've found a few bent cams by advancing the cam by one bearing, almost like as if on V blocks and obviously dependent on how much the size increase of the journals have. Hurry! Restless minds want the answer!
