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Runs like a Bat; Sounds like a Wreck

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Back to the same old problem. Even though my engine runs well with the new cam and all, upon first cranking from cold, sounds like the bottom is about to fall out of the thing. Very disconcerting. I have this awful racket from somewhere in the bottom of the engine that sounds as if my crank is about to fall out, as best as I can describe it. I have used my stethoscope everywhere in hopes of pinpointing the darn noise but to no avail. After it warms up, the noise seems to dissipate and pretty much goes away. Pretty much meaning I can faintly hear some of it, I think, when lugging. Sounds like the crank is out of balance or about to lose a few bearings. I miked some of them when I had the pan off, but not all of them. If it was a bearing issue, surely this would have manifested itself as a blown engine by now. I have driven it spiritedly for about 2K miles since the overhaul. I need an experienced TR mechanic who will fly in for the day, listen when I crank, and say "Ah HA!. That is ....!" Taint gonna happen, I guess. This is a revoltin' development.
 
Did you plasti-gage the mains? Is the crank "walking" back and forth? (Worn thrust bearings). Is the flywheel tight? I'd be curious to know what the noise is. If warming up the engine helps decrease the noise, I'd be looking at the crank, along with the rod and main bearings. Hard to say without hearing the noise.
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All good questions and certainly ones I have asked myself already. The flywheel is new (aluminum) and I installed to specs. Of course, it was a little scary to me to crank down on an aluminum surface vs. an iron surface, even seeing the ring gear "held on" with a few little screws. But, with that kind of spinning power, if the flywheel were "lose", certainly it would fail before too long with that kind of torque and abuse from a clutch. Same applies to the bearings. They all have about 20,000 miles on them and the few that I plastiguaged (both crank and piston) were showing right down the middle for allowable specs. I dunno. The only way to really do this right is to pull the engine and do it right. Not something I really want to do at this point. Would almost be worth it to have this done by a mechanic but none in the area are competent with LBC engines.

I wonder why my stethoscope doesn't pick the sound up.

A true enigma.
 
First, make sure your oil filter has a good drain back valve. Mobile 1 filters do, Fram filters do not. I am sure other brands have good valves as well. If you don't have a good drain back valve the oil galleries will empty and it will take awhile to work the air out of the system. Noises could be connecting rod bearing/s, main bearing/s, thrust bearing, piston skirt, piston pin. The bearing noise should reduce quickly as oil pressure builds and than stay fairly constant as the engine warms. Piston slap will diminish gradually as the engine warms. Can you locate the noise to a single cylinder or a few cylinders by removing plug wires one at a time while the engine is running? Piston pin knock is a double tap noise that increases as the engine warms.
 
TR6BILL said:
If it was a bearing issue, surely this would have manifested itself as a blown engine by now.
Click to expand...

Not necessarily, Main bearings can take quite a pounding and still hold together as long as they get enough lubrication and your not pulling high rev's. I certainly would find out just what the noise is before something <span style="font-weight: bold">very costly</span> does happen. JMHO.
 
Forged or cast pistons? Forged pistons run much looser clearences, and can rattle when cold. As they expand with heat, they will become quieter. That said, the TR6 engine has REALLY small bearings.The mains are like Chevy rod bearings. I think that the manual reccommends rod bearing replacement at 30K miles.If you drive the car hard, it might be prudent to do it more often then that.I have seen problems with an aluminum flywheel, but in that case the "facing" for the clutch disc came apart, and the clutch ceased to release. Pretty obvious. As posted above, if you have a spin on filter, you might change it for another. Last, what weight and type of oil are you using?
 
I had a loose wrist pin once in an engine. Opinions varied among those who heard it. I can't remember as it was over 30 years ago, but how could that be ruled out as the noise other than what I did..a teardown?
I'm just asking, Bill; someone will know.
 
Why don't you pull the plug wires one at a time to see if the noise goes away? Don't get shocked, use something insulated. After you have driven at least 20 miles, what is the oil pressure at idle, and what is your idle rpm? You will not have good oil pressure, at idle, with the engine totally warmed up, if it is a bearing problem, after at least 20 miles. Whatever it is, it will most likely require an engine teardown.
 
I'm thinking that Jesse may be on to something with the forged pistons explanation. I remember a similar instance with a worked over Chevy Blue Flame 262 CI six cylinder years ago. The forged pistons made it sound like an ice crusher until it was warm, then you couldn't hear it run after it got hot.

Now are those pistons forged Bill?
 
No, standard AE pistons with Deves ss rings, oil at idle 60 lbs, at speed over 75 lbs. TO bearing is new and to spec. Still scratching my head. The kicker is I cannot locate it with a mechanics stethoscope, can hear every function of the engine though.
 
I have never had any positive experience with a stethscope. Also, I sent the Deves rings back, I wasn't impressed, to say the least. Hope you checked the end gaps, and followed the Triumph factory recommendations. If I remember right, Deves wanted a smaller gap than normal, and, some of the rings they sent me would have required a lot of filing, and some had to much gap. AE rings are perfect. I have never seen a Triumph idle at 60 lbs. when hot. Hot means drive it 20 miles at highway speeds. Idle means 850 rpm. If the noise goes away in seconds as the oil pressure needles rises, its the rod bearings knocking. If it takes like minutes, its anyones guess. However, you can't have a bearing loose, and have good oil pressure when hot. Did you have this problem before the camshaft failure? Did you rebuild the entire engine, or just replace the camshaft and lifters this time around?
 
Just like any job, there will be a correct tool to use for it. I have used stethoscopes, both conventional and electronic with great success over the years, but "one size does not fit all". At times, a big plastic or wooden handled screwdriver found the noise faster.

Depending on the oil being used, Bill could have a higher oil pressure than normally seen for a STOCK engine. Having a hotter cam and higher compression, 850RPM may not be his optimum idle speed. Mine is somewhere between 950-1,000 with my new cam and Bill's grind is slightly more radical than mine. The point is that what you have stated is true, but for a stock engine at 850 RPM. My engine with the Rotella Triple T 15-40W gives me 25-30lbs pressure when driven over 20 miles and is at the above stated curb idle. If Bill says he has 60, I see no reason not to believe him. because if I just touch the throttle and bring up the idle a hair, mine shoots right up to over 50 lbs.

The machinist who built my block was very happy with the fit and quality of the AE pistons and matching rings. He said that there was very little that needed to be done to make them fit perfectly in the cylinders.
 
I duno Bill I am more of a tr3 guy and have never used those roller rockers, but if I could swap that back to OE kinda easily I would just to see if it made a difference.
 
How does one add a WAV file or whatever you call them? If I can figure this out, I could post the sound the darn thing makes. That might be a help.
 
Bill,

If you have a digital recorder that you could use to record patients screaming as you drill, that will create WAV files for you.
 
If you get stuck, pm me and i'll upload it somewhere for you and give you a link.
 
Brosky said:
Bill,

If you have a digital recorder that you could use to record patients screaming as you drill, that will create WAV files for you.
Click to expand...

Haha, and don't get the recordings mixed up, you might not be able to tell them apart!
 
AltaKnight said:
Brosky said:
Bill,

If you have a digital recorder that you could use to record patients screaming as you drill, that will create WAV files for you.
Click to expand...

Haha, and don't get the recordings mixed up, you might not be able to tell them apart!
Click to expand...

Yoose guys! :nonono:
 
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