Hey y’all. My Slant Six started making a ticking sound last night and I’m looking for help identifying it. Please see this video on YouTube — in particular, at about 10 seconds and right at the end. This is happening pretty much every time I rev the car up over idle.

https://youtu.be/sW0NPuGzYYk

This is in a 1978 Volare with just over 45,000 original miles on it.
Thanks for your help.

I see three possiblilities.

1. It needs s valve adjustment.
2. A torque converter bolt has backed out and is hitting the back of the block.
3. Rod knocking.

1&2 are easy fixes, 3 not so much.

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Official Cookie and Mater Tormentor.

Do the valve adjustment procedure first.

viewtopic.php?p=72139&highlight=#72139

It probably needs it anyway.

The other 2 possibilities are unlikely but could happen.


Greg

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http://www.youtube.com/hyperpack

The engine's overdue for a valve adjustment, but there's also a separate noise going on, and it ain't no "ticking" sound, that's a knock. You want to hope it's something cheap and easy like a noisy fuel pump (easy to test: unbolt the fuel pump and pull it away from the block, then start the engine and see if the noise goes away) or loose torque converter bolts, rather than something expensive and difficult like a rod bearing.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Get a 3ft piece of heater hose and put one end to your ear and the other on different parts of the engine. You will find the knock.

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1976 Feather Duster /6 4sp
1984 W100 318 727 np241
1972 'Cuda 340 4sp
1985 D250 360 46RH

Thanks all. Let's assume the worst: it's a spun bearing but I find a capable machine shop. What would the fix involve--and are there any special concerns with a Slant Six? Is this an opportunity to rework some internals to get additional power and performance?

Or should I just find a replacement engine?

The answer depends on your answer to this question: "How reliable do you want it to be?"
I have gotten by with just taking out the offending bearing shells, shining up the rod journal on the crank with emory cloth, and installing new bearing shells. This can be done without removing the engine from the vehicle.

If you want to fix it then you'll need to disassemble the engine and have the crankshaft machined properly. Might as well do a complete rebuild at that point.

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If it was easy, everybody would be doing it.

I think before you assume the worst you should definitely do a valve adjustment, then check the other things mentioned in this thread. Those are all cheap or free (maybe you'll need to buy a set of feeler gauges for the valve adjustment, or a tube of loc-tite for your flex plate bolts).

If you do in fact have a spun rod bearing... then it depends on your abilities, how much money you want to spend, and how bad the damage is.

If the bearing didn't spin too badly, and you're super short on cash, and you're willing to slap it together and drive the car like a little old lady to keep the same bearing from just spinning again (and it still might, in 1 mile or 1000 miles), then you can do the following. Un-bolt the engine mounts, jack the engine up, block it up on the mounts to add clearance between the oil pan and K-member, drop the pan, pull the offending rod cap, clean up the journal with emory cloth, sand the mating face of the rod cap a bit to regain some clamping force, and slap it back together with a new bearing. Probably want to pull all the caps while you're in there to make sure it wasn't just the one bearing that spun.

Total cost: $35.79 set of rod bearings (assuming stock size) + $5.68 oil pan gasket + shipping from RockAuto, plus emory cloth, plus RTV to help your pan gasket actually seal. Also assembly lube for the bearings, or you can just use motor oil and try not to worry about your first startup too much.

If any of your rods are heat-checked or a bearing shell came out in pieces, then that rod really needs to be resized or replaced. If you want to ensure this doesn't just happen again, any rod with a spun bearing should be resized or replaced even if it looks fine. Rod resizing at a machine shop isn't that expensive; maybe $20 per rod if you don't remove the piston first. Or you can probably get a decent spare 225 rod from someone on this forum for the cost of shipping, but you'll probably need to have a piston put on it which requires pressing the wrist pin in.

However, the piston/rod assemblies have to come out the top, which means pulling the head. I have removed a head with the intake and exhaust manifolds still attached to save time and effort and gasket replacement, but you'll probably need two friends to help you lift it off and put it back on again. At a minimum, add a $10.57 Fel-pro head gasket (they're on clearance, and fine for a stock engine) and a $0.33 Mahle exhaust pipe flange gasket (also on clearance and probably better than the Fel-pro version) to your RockAuto order. You should also replace your valve cover gasket if you didn't do that when setting your valve lash earlier.

It's also a major pain in the ass to R&R the rods/pistons with the crankshaft still installed in the block, but not impossible. If you're not capable of this level of shenanigans, then you need to pull the engine. Once you have the engine out, you're that much closer to a full rebuild in terms of effort... but not in terms of dollars, yet. A set of main bearings, a set of cast iron piston rings, and a dingle-ball hone chucked into a borrowed hand drill aren't too much more money, but if your bores are trashed then you need to have the block machined and buy an oversized set of pistons and a full gasket/seal set. Now it's starting to add up.

It should go without saying that if you're not willing to learn about engine assembly, be as careful as possible, ask plenty of questions etc., then you'll need to pay even more money. Also, if you spun a main bearing instead of a rod bearing (less likely, but possible), then you need more machine work or another block.

Regardless of all the above, if you can disassemble the head yourself, having it decked for an increase in compression ratio is a cheap way to bump up your power (maybe $100 plus time, gaskets, etc.). But you may want to look at your ignition curve depending on how much you take off. And while you've got the head at the machine shop, you probably want to look at having your valve guides redone. If your valves were recessed, you probably want new seats installed.

...what's your budget again?

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

@SpaceFrank—thanks for the excellent ideas. Good to know there are some inexpensive options. Getting the engine rebuilt seems out of the budget as does buying a rebuilt engine. Might try to sell the car (any takers?) or find a cheap used engine (anybody have one?). More than one person (not on this forum) has said “upgrade” to a 318 or something—but I don’t think they get it. I have also considered pushing it off a cliff but I live in the flatlands of northern Illinois

Thanks again to all. I’ll put an update on this string if any.

Went out and looked at it this morning. I'll let Craig post the findings if he wants.

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Official Cookie and Mater Tormentor.

Yes, a huge thanks to Dennis for making the long drive to check out this noisy business. Turns out it’s not a torque converter bolt, unfortunately, but instead very likely the #5 rod burning up due to lack of oil (that’s on me). It didn’t help that the oil pressure sender wire was cut by the previous owner (which is also on me for not knowing that). No excuses.

Since it’s not worth $2k to rebuild a car that’s worth $2K, chalk this one up to experience. Old car, check the oil before you start it. Every time.