It looks like I get to do my engine again. Short version, 1971 455 rebuild to nearly all stock. Did the break-in for about 20 mins. Oil pressure, temps, timing all looking good. After about 20 minutes it started to run very rough. So I shut it down. Today I pulled the dipstick and I see more black dust in the oil than I would expect. I removed the valve covers and measured the lobe lift on several rockers. Found a couple in the back of the engine that are only lifting 0.160 or so. Cam card spec is 0.296. So I am guessing (based on reading elsewhere in this forum) the Johnson 1405J lifters did me in. I really don't know for sure yet. The lobe lift measurement is un-scientific as I don't really have a good place to mount the dial gauge base on an assembled engine and I an reading with the probe on the rocker - aligning it as close as possible in the same line and direction as the pushrod. However, some lobes were reading as high as 0.265 with this setup, so the 0.150-0.160 readings are too far from that to be just noise/technique. I am already convinced that the cam is ruined. Some details: TA cam (112 degree intake lobe), TA double groove cam bearings and Johnson 1405J lifters as mentioned earlier. Lots of assembly lube. I did the break in with Rotella oil AND I added the zinc additive as well. I am just starting trying to determine where i am at. I am inclined to run compression on all 8 cyl next. Then I guess the engine needs to come out and go back on the stand for a deeper analysis. Since I am, at the minimum in for another cam, lifters, gaskets, and a thorough cleaning ... I am open to ideas on other causes. More importantly, if the consensus is that the TA-1405J lifters (purchased March 2020) were my undoing; what should I use on the redo? I do have the original lifters that had 80,000 on them.
Do you have double valve springs? I would reset my valve lash and run again before jumping to conclusions….crap in your break-in oil is normal.
I don't think what I have is called "double" springs. The inner spring is a spiral of flat steel. However, I did leave them in there for the break in run. As mentioned, the build is close to stock.
Normal, as I said, recheck valve lash, run it again. If you’re really concerned drain the oil and look there not off the dipstick.
We held it close to 2000 for the whole time, plus or minus 200 rpm. Since it is running a Q-jet I did tape the choke into a part closed position as per the break-in thread Jim W wrote some time ago.
You can't do that,...you MUST work the throttle this forces the lifters to spin,... don't let it go under 2k but rap it up to 3500 even 4k after it's up to temp,...once it starts next time keep it below 3k for the first few min then work your way up,...keep it guessing,.... Also did you have a bunch of dry spins or did you have the distributor in correct and advanced with the carb primed for a quick fire up?
If it makes you feel better, my motor that was just built I have changed oil 2-3 times. Each time I shine a light in it and see glitter metal. Probably from used lifters.
Very quick fire up. I had primed the fuel system with an electric pump. I primed to oil pump with a drill and the distributor was in correct, timing was close. It fired immediately.
You could pull the valve covers, loosen rockers and pull some pushrods and check cam lobes on the suspect cylinders. Borescopes are cheap. If you do not see anything obvious to lobe damage, then do as 72STAGE1 said. Reset valvetrain and run it again and keep the RPM moving up an down. Unless your really concerned that you have damage and don't want to risk further, then pull the intake and put eyes on the lifters and lobes.
First off, that flat steel “ inner spring “ is a dampener, single spring, correct for your cam. If you really want to know if your cam is wiped pull the intake and the rocker assemblies and remove and inspect the lifters and pushrods. There will be no doubt. Stock deck height? Heads milled? Head gasket thickness? Check for correct pushrod length?
I have NO idea why the throttle would induce lifter spin. RPM does not spin lifters, the cam lobe taper and offset combined with lifter-bottom crown causes lifter spin, and those items aren't affected by the throttle position. If the lifters don't spin when I turn the cam by hand during engine assembly...SOMETHING IS WRONG, and the cam/lifters are in danger. (Exception for Nailheads, of course.) I've also been known to paint vertical stripes on the pushrods, then view the (hopefully spinning) pushrods through "special tool" ventilated valve covers scored from the Treasure Yard temporarily installed for camshaft/lifter break-in. Pontiac valve covers shown: If you've measured a hundred-thousandths of lobe lift loss, some lobes showing .265 and others showing only .160, readjusting the lifters and trying again isn't likely to be helpful. Stick a fork in it and turn it over...it's done. Do you have sufficient retainer-to-seal clearance? Valve springs don't coil-bind? You didn't use thick moly-based paste break-in lube on the SIDES of the lifters/lifter bores, did you? If this was me--and I had to use a flat-tappet cam--I'd damn sure have that cam Nitrided. I did that on my last couple of flat-tappet builds. Back then, it added about $120 to the cost of the cam. No doubt it's more now. Comp Cams is selling Diamond-Like Coated (DLC) lifters for Chevy. The price is extremely reasonable. As in about $120 per set of 16. So if the oil band/oil port location on a Chevy lifter can be used in a Buick engine, and if you adjust pushrod length accordingly... https://www.summitracing.com/parts/cca-812d-16 But that assumes that the rest of the lifter is decent. I won't make any promises for the quality or source of the lifter "guts". We all know who crapped in the hydraulic-flat-tappet well. But I don't know who Comp is sourcing their lifters from this week, or where they'll get them next week. Note that I have no idea if a Nitrided cam lobe is compatible with a DLC lifter bottom. I would not use "Rotella oil AND I added the zinc additive" as an initial oil fill. I have in the past, and it worked out OK, but I've moved-on from there. Rotella isn't the same product any more, either. The real answer is roller cam/roller lifters. Guys avoid that due to the expense, but which costs more--buy the rollerized parts to start with, or tear down the engine AGAIN plus pay for the anger-management sessions at the Shrink?
I have NO idea why I've never lost a cam during break in doing it the way I do it,... experience out weighs theory every time Most roller lifters are garbage now too,..so no Roller is not a guarantee of anything but a potentially more expensive failure Ive never once used and special oil either,...hell I'll still use gas station ND oil with a bottle of STP and get it done,...with lubriplate on the cam even ha He's using the TA 112 no chance of seal or guide interference with that cam But being it's common knowledge how and why a lifter spins,...it makes perfect sense that sudden changes in rpm will obviously make the ramp action on the foot/lobe happen more rapidly since the cam is spinning faster,...no difference in flipping thru the pages of a book,...faster you do it the more pages you move
If the lifters have bled down during the measurements then your process isn't accurate at all. Lifters have .100 plus of travel, if its not pumped up while your measuring the lifter will colapse that much before moving the valve. You basically have no good data here
OK... let's back up here.. First thing you need to do is cut the oil filter open.. Get a tool like this to do it.. I have this one exactly, it works excellently. https://www.amazon.com/MOCW-Filter-...rgid=pla-1746929655100&psc=1®ion_id=373786 If the cam has failed, there will be no doubt, that filter will be full of material. As to the break in.. Sounds like you had a good startup.. On the dyno, we start it, set the rpm around 2000, check and set the timing at 34*, adjust or manipulate the carb for 12-13-1 A/F ratio, and then sit and BS for 33,000 crankshaft revolutions.. rev it once in a while just for the heck of it, but it's not critical.. I have done this with 127 BBB engines, and knock on wood, never lost one camshaft... Done a dozen more on the run stand in the shop here, on motors that did not go to the dyno.. no issues.. Lifters spin due to the bottom of the lifter having a crown on it, and the lobe having a taper. RPM or increase/decrease rate of rpm has little/nothing to do with it. We run the motor at 2000 rpm because cam lobes are splash lubricated, mainly from the side clearance of the con rods. The reason, if any, to rev it a bit is to throw more oil at the camshaft. The only thing I see lacking here is oil. I don't know what I have to do to get you guys to believe me, but the ONLY oil to use is a specific break in oil.. there are several choices out there, additives are helpful, but usually not present in a large enough quantity to affect much. Products like oil are changing all the time, so history means nothing. But let's not put the cart before the horse here, cut that filter and let's see what's in it.. JW
