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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Fragment Found on Oil Drain Plug. Now with CARNAGE!
Any guess as to what this might be from?
From the looks of it, it's a casting with a small machined edge. Having pulled the distributor, it's not part of the gear. And from the size of it, it doesn't look like the cam gear is the source either.
A piece of a cam lobe? Maybe part of the timing gear set?
Check these pictures out:
No. Not clearanced or stroked. OEM Gen 1 SBC from the 70's. Had it refreshed about 30,000 miles ago. Decked, .030" over, factory forged crank, Elgin rods, Speed Pro hypereutectic pistons, standard ring pack, retro-fit roller cam, Comp short travel lifters, Crower roller rockers, 26918 Beehive springs. Nothing extraordinary.
It developed a high RPM misfire a while back (6000+) and the misfire has steadily moved lower in the rev range. Now it's about 3500 RPM or so and can be induced at part throttle. I pulled the upper valve train apart and did a quick visual for broken springs or other components but everything appeared OK. I haven't had the time to pull the intake and look deeper. Just kind of speculating at this point.
Here's a link to a thread I started regarding the misfire.
I haven't ruled out an ignition related source. I've a MSD distributor, coil and 6AL box. New wires. Plugs look good but for the first time, there appears to some evidence of detonation with the telltale small spots of metal on the porcelain.
A tear down this off-season is in the works but in the meantime, I'm taking a guess as to what the issue is.
Last edited by skinny z; 10-24-2017 at 10:39 AM.
Reason: spelling
Wow, that woud freak me out a little too, that said since you didn't find any shiny particles in the oil I think it's a piece of left over milling trash from machining the block that finally found it's way from where ever it was hiding when you assembled the engine. I'd keep a close eye on the oil for any shiny particles and press on trouble shooting the random missfire, which I feel is totally unrelated. Keep us in the loop.
No sure about a ring. How would get from the ring land and into the oil pan without carving some path through the cylinder or piston?
It appears to be a casting judging from the coarseness of the fractured edge but it's hard to tell. A piece of a cam lobe is my best guess so far. Pulling the intake would reveal that. Problem is, I can't take the car out of service for any length of time presently. It's my daily driver.
As for the oil, there IS a slight metallic shine to it but nothing out of the ordinary (I wouldn't think anyway). I saved the oil filters from the last two changes and am wanting to cut them open for an examination. What I haven't been able to find is a reasonably priced filter opener or a means of opening it with conventional tools other than sawing the top off and contaminating the filter with cutting debris.
It may a leftover from machining. That said, this engine has seen tens of thousands of miles since it was apart and fully machined (bored, decked, line bored, etc) save for a refresh about 30000 miles back. That was for rings and bearings prior to being swapped into my chassis from another.
Unrelated misfire and fragment? Possibly. I wouldn't rule anything out at this point.
Small update.
Cold starts result in a disconcerting noise the source of which I can't pinpoint. It's equally obvious from either side of the engine as well as from below. It's somewhat like a lifter/rocker tap mixing with a bearing knock. Once warmed up, the noise is all but gone.
A compression test showed one cylinder was slightly weaker than the rest.
I saw that one but the $120 price tag is a little steep. At least for my taste and needs. If I was as deep into racing as I used to be, I could justify getting it.
Thanks.
I'd come across that video but wasn't convinced it would work.
That said, now that you've brought it to my attention again, I'll give it a go.
Thanks.
(Think I'll wear my rhinoceros hide gloves though.)
A leak down test shows the best cylinders at 16% !
The worst are nearly 50% loss.
Despite possible procedural errors, I think it's fair to say this engine is toast.
And I think it's also fair to say, this is the cause of the misfire.
Heads were new when this engine was refreshed? Could be a bad bore job. Either losing the rings or oil consumption has led to carbon buildup on valve stems and burnt exhaust valves are in progress.... hard to say without more info or tearing it down.
Sorry to read the bad news. Reads like the issue is getting worse - my sympathies as it happens to us all.
I don't know how difficult it is to drop the oil pan on a third gen but if you can w/o pulling the engine it's pretty easy to inspect all the bearings from under the car - check clearances to. If not possible to drop the pan then IIWM I would pull the intake and at least look over there before pulling the motor. Might find a fixable problem.
This reminds me to epoxy in magnets in the lifter valley on my next build.
In reply:
Hard to say where the loss is. I can hear air escaping from the oil cap on the valve cover as well as the carb. Truth is, if it were escaping past the rings and pressurizing the crankcase, I'd hear it at the carb too as it would migrate back into another cylinder where the intake valve is open. Or several cylinders for that matter. It's not as evident from the tail pipe. Seeing as the heads are fresh, with less than 3000 miles, I suspect the comparatively high mileage shortblock. 30000 miles with plenty of RPM. Not to mention the countless gallons of fuel washed down the bores during the frequent and often repeated cold starts. I do however manage to keep a very lean cruise AFR but I can't say if that helps or hurts cylinder bore wear.
A recent compression test revealed low but not unreasonable cranking compression. I would think that with nearly 50% leakdown on a couple of cylinders, that the compression on those would be almost nonexistent. Guess not. Or maybe the damage has progressed between the time of the compression test and the leakdown test but that's only a thousand miles or so and none of it hard mileage (except the occasional sneak up to 5-5500 RPM listening for the misfire). I may revisit the leakdown test on the worst cylinders as the numbers seem unreasonable. Then again, I have nothing to compare it to.
Interestingly, or perhaps it's my imagination, but the misfire isn't an acute as it was before.
For what it's worth, the plugs looked good. Oil consumption is minimal with less than 1/2 quart between 3000 mile changes. That was what I expected from the age of the shortblock. It was far worse before the heads were done with 1.5 quarts between intervals.
As it sits right now, it's still a solid driver. Starts instantly even when cold and with no choke. (It's only 40F here at times). Idles at 850 RPM with 9-10 inches of vacuum despite the 288 cam although I do run 30 degrees of initial timing with the vacuum advance.
Anyway, yeah, it has to come apart.
Now I'm shopping for a stroker kit.
Not sure where the fragment came from and I probably won't know for certain until I have the short disassembled. Or at least pull off the intake and then the heads (again!). I'll do it a step at a time even though the leakdown test indicates that the cylinders are toast or somehow have I've managed to mangle my new valve job. I hope it's not the heads as they were to carry me for a while. I knew the block was getting old and a rebuild was sooner rather than later. I never liked the cam and I have a new spec. I just don't know if I'll pick one for a 355 or a 385.
As for a stoker kit, yeah, a reciprocating assembly. Unless someone like Charlie:
has a deal floating around as they sometimes do. Hey Charlie! Are you listening? I've seen a few shortblocks that they flog now and again.
In the meantime I'll take my time. Interestingly, despite the possible carnage, the car drives very well. Smooth and even. I just don't take it up the rev range much past 3000. Just enough to get past the shift points and then let it cruise. You wouldn't know it was wounded. Then again, for all I know, it'll kick out a rod and that will be the end of that.
.... Then again, for all I know, it'll kick out a rod and that will be the end of that.
Don't get all maudlin on us... I would've guessed a cracked valve spring myself, but what do we know.
I feel your pain. I would suggest continuing doing what your doing. Don't push the RPMs, just wait for more symptoms to show up further on down the road. Unless you really want to tear it apart. That invites a whole 'nuther beast. Rebuilding etc... Meaning $$$$
Last edited by UltRoadWarrior9; 10-27-2017 at 06:27 PM.
Great reply. And I'm trying not to be.
I'm pretty sure from it's history (a hard 30000 miles on the latest refresh and probably 20000 more in front of that) and the latest round of tests that the short block is toast.
I will however continue to cruise around and listen. In all truthfulness, it's running very well although I haven't gone past 3500 or so. Just enough to shift.
It should be an interesting disassembly.
No. I haven't. Other than the leak down test of a few months ago, I've paid little attention to the car. After several weeks of well below sub-zero temps, I did start it and move it in and around so as to free up the shop for another project but it ran as always. It was unreasonably cold, probably -20 (on just about any scale) and was difficult to keep an idle for the first 5 minutes or so. After that it just burbled along.
I'm undecided between buying another shortblock despite a thorough diagnosis or taking this engine apart and finding that a re-ring and re-bearing will make everything right again.
Shopping for options.
I did find an all forged American made shortblock 383 for less than 3500 USD but I've yet to decide to pull the trigger on that.
So, in the 6 months since I started this thread I haven't done anything to really investigate. I've been driving a bit but no racing. In another thread I posted up about a high RPM misfire. I figured that my pile of MSD ignition components might be going south.
I also posted about an odd engine knock/tap.
Last weekend I changed the oil and pulled a few more interesting bits from the magnetic plug.
I think I know now where the frament(s) are coming from. It may also explain the lifter noise and misfire.
Check out these pictures.
Originally Posted by skinny z
A piece of a cam lobe?
I think it's a safe bet that I've smashed a lobe (or more).
Interesting wear pattern.. ...and very similar to the wear pattern on the previous cam. Same radius too.
I'd agree with you however some other tests I did earlier this year indicate that there are probably issues with the cylinders. I suspect that, and with results that support my suspicions, that the cylinders bores are worn out. It wouldn't surprise me that there might be a couple of broken rings. One cylinder had so much leakdown, on the order of 50%, that I don't have have complete confidence in my testing procedure and will run a full gamut of tests again before it's time to put it away for the winter.
About the only reason I haven't taken it out of service already and have it torn down is that I don't like to have it disabled. It's still a comfortable grocery getter and I doubt I'm going to make it any worse with the occasional drive around.
What I would like to know is what would cause this kind of damage, going on the idea that it is a cam lobe that's in the oil pan?
Valve train bind - as in coil bind, lifters bottomed out, etc. Too much pressure on the lobes, or possibly a lifter roller turned sideways or seized. These are the retrofit link bar lifters? Broken link bar, lifter turned in its bore....
Are the heads setup for the lift of this cam? Are the springs the correct ones to match this cam and lifter combo? Pushrod length?
All of that stuff is spot on. I'm **** when it comes to valvetrains as I've been bitten before. It's a proven build with plenty of miles. And also one from a previous iteration too. My only thought so far is that perhaps there are too many miles and the springs are going away. Then that leads to component separation, especially at 6500+. If that has happened, you can guess the rest. And it shows up on your magnetic drain plug.
I think you've nailed it! That piece absolutely looks like a piece of the lobe from a cam. BTW, regarding that cam you have pictured: why is the lifter rolling on the edges of the lobes??? If you have that going on in your current setup, I'd say something is wrong there...
I agree, there is something coming apart and I think you're right about it being a cam lobe. Either way, it's an excuse for another build; I just got done pulling the 383 out of my IROC to use in the '62 C10 Step Side I'm building. I installed a new small block 454 in the IROC to replace the 383 and so far it appears it's going to be a beast!
That's what he said earlier in the thread. Also says it's a comp cam in his sig. XR288HR
Ah, missed that(don't get old).. Anyway, sounds like another cheap/ cam core hardness issue from comp. I lost 2 engines from that problem. Had to call them out on FB HRPT page for them to finally make it right.
Have they fixed that issue? I've been under the impression they make a pretty good product. Is there any indication or lot numbers/production dates to avoid? I have a cam kit on the shelf for an upcoming build. Not what I want to hear.
They finally sent me a new cam with a harder core but it was quite a while back. My understanding is they used to get their cores from crane but when crane closed they went cheap and lost some quality for awhile.
Initially after looking at the latest pic skinny posted with that piece next to a cam lobe, I thought the shiny ends of the lobe was where the lifter was contacting. My fault, that doesn't make sense...
It looks like the roller part of the lifter is very narrow compared to the width of the lobe. Is this normal?
But are you sure a lifter didn't turn sideways or the roller seize up?
I doubt spring fatigue is the source. Doesn't seem likely when using beehives.GD
That I can’t say. They’re a link bar style lifter so one turning sideways would catastrophic I would think. As for seizing up? Again, I can’t say. That’s a possibility I suppose.
Originally Posted by UltRoadWarrior9
…why is the lifter rolling on the edges of the lobes??? If you have that going on in your current setup, I'd say something is wrong there...
Originally Posted by UltRoadWarrior9
..I thought the shiny ends of the lobe was where the lifter was contacting. My fault, that doesn't make sense...
Yeah, the picture can be deceiving but I confident that the roller is where it’s supposed to be. Provided of course it’s still there at all.
Originally Posted by MSgt Luttrell
..it's an excuse for another build; I just got done pulling the 383 out of my IROC to use in the '62 C10 Step Side I'm building. I installed a new small block 454 in the IROC to replace the 383 and so far it appears it's going to be a beast!
Not that I needed another excuse. I had plans to recondition (and possibly add a stroker crank) in the off season. What I’d really like is an LSX454…But in all reality I’ll probably rebuild with as little expense as possible, get a properly spec’d cam from the likes of Vizard, Jones or Walters (no more off the shelf stuff thanks) and call it a day with a nice drivable 450 HP 355/358.
Originally Posted by TTOP350
Was this a comp roller cam by chance?
Originally Posted by GeneralDisorder
That's what he said earlier in the thread. Also says it's a comp cam in his sig. XR288HR
Originally Posted by TTOP350
They finally sent me a new cam with a harder core but it was quite a while back. My understanding is they used to get their cores from crane but when crane closed they went cheap and lost some quality for awhile.
I’ve had this cam in the family for about 15 years. Comp had a decent reputation then and I had never had any trouble with their components. I still have plenty of Comp parts: springs (two sets of 26918’s), lifters (also two sets with one them being their tool steel short travel offering), push rods, several camshafts…I had heard stories about their stuff kind of taking a turn but I think I managed to dodge that bullet. At least I hope so…
Originally Posted by TTOP350
Ah, missed that(don't get old).. Anyway, sounds like another cheap/ cam core hardness issue from comp. I lost 2 engines from that problem. Had to call them out on FB HRPT page for them to finally make it right.
This cam pre-dates those issues. And it’s been in service for a lot of miles which may have contributed to this present state of affairs.
As for getting old…too late.
What I think has happened is that my cam end play adjustment has come undone. I'm using a Cloyes 2-piece timing cover with a built in thrust button. It could very well be that I either didn't secure the adjustment sufficiently and it's somehow become damaged and now the cam may have enough for and aft movement to allow the lifters to ride on the edge of the lobe. Certainly that scenario would smash the lobes up and probably ruin the lifter too.
For now, I'll keep it running and the car mobile. I'm not sure if the misfire ties into all of this and I suspect and have made steps to correct any ignition related issues ( with a FAST HEI to replace the MSD distributor, ignition box and coil) and hope that solves it.
In the meantime, I guess I'll just have to putt around (it's still a comfortable and enjoyable car to drive) and it'll be another season of no racing.
Wow! 200 miles?
Now my cam has certainly gone more than 200 miles. Talking with a racing buddy tonight (who I got the cam and shortblock from) and looking over the records we think that there might less than 15 000 miles on this cam. That said, if there's a groove pounded into it, any lateral shift such as the end play misadjustment I described earlier, might be enough to push the "shoulder" off the lobe and end up with what I have. My recollection of the cam when I installed it was not one of any concern. Everything looked to be 100% and I proceeded with the cam swap. This 288 lobe profile is hardly aggressive and the spring pressures are modest so unless there was something fundamentally wrong with the core (as in your case TTOP) I can't see wear being an issue. Back to the end play adjustment I think.
True enough and something I've been discussing. I've always had rock steady timing via the timing light and degreed balancer however I haven't checked it since these chunks of metal started showing. A quick test might tell the tale. Something I should do away so I can confirm what kind of curve I've built. Its been so long, I don't recall what I've done. (There's that old thing again).
That's a bingo!
I've never seen this before.
Those are COMPs short travel lifters. Purchased new in 2012. About 35 000 miles old.
Anybody else have this happen? Discussions with my racing friend says scrap the remaining survivors.
It appears that other than the obvious and the cam itself, that nothing else has been caught up in this. Pushrods are straight. Valve tips look new. No broken springs (that I can see).
Since the time I reassembled the engine for a cam swap (used COMP XR288 as well as the used lifters) in 2016 it's seen about 8000 miles. Most of which have been in "limp" mode.
Ouch, that really sucks. Not sure what I'd do about the rest of the lifters but it would always be in the back of my head if/when it may fail again on another set of those lifters..
Yep. Pretty messy but it could be worse.
I've reached out to COMP to see if I can get the remaining lifters rebuilt or if they're scrap.
It'd be interesting to know which came first. The link bar letting go or something in the valve train, like the thrust button I had mentioned, giving up and stressing out the rest of the parts. It seems that link bar failures are not that uncommon whatever the brand.
You can clean and check lifters. If you are able to take them apart, lift bar rivet, if not, chuck a pushrod up in a drill press, find a socket or something for lifter to sit in, and place lifter and socket in a can of thinner, pump lifter while submerged in solvent, be amazed at how much crap comes out of bleed orfice. Pump away.
then repeat with oil instead. Make sure to pump them a lot. Then you can check leak down rate. You will know if one is bad, will be easier to pump down. Good ones, it will take quite a bit of pressure to pump them down. Can final bleed em down for adjusting or keep em pumped up. Dont matter.
I cleaned mine a few months ago and wow was there a lot of crap inside them. They are like little garbage cans.
You can clean and check lifters. If you are able to take them apart, lift bar rivet, if not, chuck a pushrod up in a drill press, find a socket or something for lifter to sit in, and place lifter and socket in a can of thinner, pump lifter while submerged in solvent, be amazed at how much crap comes out of bleed orfice. Pump away.
then repeat with oil instead. Make sure to pump them a lot. Then you can check leak down rate. You will know if one is bad, will be easier to pump down. Good ones, it will take quite a bit of pressure to pump them down. Can final bleed em down for adjusting or keep em pumped up. Dont matter.
I cleaned mine a few months ago and wow was there a lot of crap inside them. They are like little garbage cans.
The rivets prevent the lifters from being disassembled. But I can fully relate to the crap they ingest. On a previous engine, the flat tappets went south and filled the engine with metal. An overbore and cut crank followed along with an oil pump and timing set but the lifters were never serviced. Turns out the metal dust absolutely sandblasted the perforated metering discs in the lifters and the end result was further failure. That's where these short travel pieces come in and they were installed in a freshly machined short block so they had a decent start in their service life. But that said, that's more than 35 000 miles ago.
My concern at this point is their fatigue life. Are the remaining rivets ready to go too? Hard to say. Maybe COMP has an answer.
10-22-2017, 01:45 PM
