Technical What is this engine sound? More '54 Nash Rambler diagnosis, things are looking bad...

I agree I’ve done a few backyard overhauls etc with good results over the years. Not as good as having a machine shop getting everything dead on - I’ve had that done also- A lot depends on usage. You will be fine as long as the damage isn’t excessive on the crank if done right it should run for 10s of thousands of miles.
When you get the pan and rod caps off etc take pictures and measurements. The gang will guide you.
Dan

 

I did forget to mention - if you don't know - Plasti-Gauge is used *dry* , & don't move the crank/rod while using it. Stick a small length on the journal, then ***emble the cap/bearing, n just torque the bolts, then unbolt them, & use the printed-pkg to find the width of the squeezed/flattened Plasti-Gauge. Easy. Ideally, no scoring on journal surfaces, but even light scoring that you can catch your fingernail on, will be ok. Heavier than that, uhh, maybe. That will be a short(er)-life-fix, & will probably require heavier oil as a crutch. Older engines are capable of sustaining & operating with, a lot of damage, but it's not something to strive for. Keep the pics & notes on what you did, & find, so's later you, or next owner, can know what actually transpired.

&, a small localized repair, was the usual MO, thru maybe the early 70's. The idea of a complete total engine rebuild was *not* considered, until the quality of material(s) was a factor(read: cheap cast cranks, rods, ****-camshaft/lifter-materials, etc), somewhere ~early 70's. Btw, a re-ring(soft castiron rings) job w/bearings n gaskets was also s.o.p., before doing machine-shop-level repairs. Not considered ****/slop work, esp for a dd-situation, or a not-used-often situation. Truly traditional - if that matters... Hi-po, well, that level never changed, except to go up in intensity, & cost... .

I mentioned R&R'g all the rods n mains, since you'll be in there anyways, but at least pull them to check for scoring, wear-patterns, & too see how much junk ran through them - resulting on material-transfer onto the journals. Expect the bearing surfaces to have at least some embedded grit/etc in them. When you pull the main-caps to look at the bearing shells, iffen they look nice, the upper shells will probably be in the same condition, so's you shouldn't have to fish out the uppers just to check. Although it's still a good idea... & since you're that far... . Then it's decision-time...

& get some good engine ***embly lube, so's the bearings will live. If you don't have/can't-find any, a good subs***ute would be 50%~30weight/50%STP mixed thoroughly. It's only used there in small amounts, & will keep things "friendly" until real oil pressure arrives. FYI, iirc: Studebaker used this at the factory(late 40's era?) in it's new mills, for just this reason.

You'll do well... .

Marcus...

 

Yep, the main bearings have to keep the tight tolerance, but compression is fighting against the chamber (pushing down into the main cap) and power stroke is also full power pushing down into the mains.
The top is more to keep things aligned, spinning in place and keep the oil film.

As said, it was a common repair in the day, not a hack. Over time, the stresses and longevity of stuff has leveled out more so everything is ****ged roughly the same time. That plus time is higher cost, so it makes sense to do everything rather than small parts of the full list. Often did a valve job, then the second time did rings and bearings too. Often did bearings as a stand alone repair.

 

^^^
Yup, by the 60's, engine "life" was done ~100k, or so. 30's n 40's - lots earlier. If taken care of. But the kinda-quick "rebuilds/repairs" didn't cost all that much either, for another ~25k->50k. You'd be surprised at the reco'd changes/maintenance, wouldn't get you a week or maybe two nowadays. Due mostly to the quality of oils back then, but equally due to no filters, then by-p*** filters, then full-flow filters. & air-filtration also, esp into & thru the block, very little dirt eventually. Time & mileage 'twixt oil changes increased as things got better. By-p*** filters are really good, but full-flow filters right outta the pump - or should, actually. By-p*** can filter much finer, since it's a slower flow.

I don't remember what the N/R/H-eventually-AMC had back then, or what's been added to yours. But it'd be a good thing to have now, considering. You'll kinda get a premonition, when you drain the current oil, looking for metallic, oil-metalflake, or bits-n-pieces. None of which I hope you have.

Marcus...

 

On an International 706 diesel tractor. An unscrupulous dealer sold my FIL that tractor with harness leather replacing a bad bearing. When he bought it he wrote it off as "diesel knock". Under load pulling five bottom 16" plows it didn't last long. Dealer refused to make it good but the engine was replaced with the German engine. More HP and torque.

 

I have not read all the responses but as you said you would only drive around town and some local trips I would take the risk and do what others have said to minimize the knock. Like thicker oil and additives.

Then I would drive it and in the meantime look for a good spare engine. I don't think a good 6 cyl Nash/AMC is made of unobtainium.

 

If I have read this correctly, you drained a quart of oil, not all of it.
I always thought that if you had any amount of fuel in the engine oil, all of the oil and the filter should be replaced.
.

 

OK guys, after waiting out a week of high temps and wildfire smoke I decided to dig into this thing and see what is to be seen. I put the car in a spot in the workshop where it can be marooned for a while if need be, I put it on cribbing blocks but then I jacked the front up and slid jackstands under the rear crossmember to take some weight off of the front suspension (but not all), my thought was I didn't want all the weight on the suspension when I unbolted that tie bar (in case it would spread) but I didn't want it to hang loose either. Nothing seemed to move or "spring" when I unbolted it so I'm ***uming it's fine.

First look. I did notice that there was silicone on some of the oil pan bolts so at the very least, this pan has been off before. I also noticed what looks like a big patch of white paint on one of the counterweights, no idea what that's about. And the inside walls of the block are orange? This is what it looks like.



The pan looks pretty clean inside, certainly not a glitter bomb or anything. A little grime (and the bottom has a bit of oil in it yet, I can dump that out and take another pic) but I don't see any real crime scene here.



We were thinking the knock sounded like it was coming from the front, and I could wiggle a bit of side to side play on the #1 rod so I decided to pop that cap off and have a look. First glance at the bearing. I don't really know what I'm looking at but I can see a tiny bit of what looks like br*** showing. What does that tell us?







I rolled it out to see what the back side says, it says Clevite 77 on one side, and the other side says 3-91 CB 664P Lower A1. Is this an original bearing, or is this a replacement? Is it standard size, or oversize? I tried Googling those numbers but didn't really come up with much.





This is what the crank looks like. Doesn't look horrifically scarred anywhere, but it does look like it has a tiny bit of ridge on the outside edge where the bearing doesn't make contact.



Now I need to know what my next move is. I don't have any super accurate measuring tools but I could borrow or buy some if need be. I can take more pictures too or remove more rod caps, whatever. I want to try to fix this issue, I'm just not sure what to do next.

 

already been noted--plastigage

 

The date code on the bearing is March 1991. It's standard size, since it's not marked undersize. Definitely been worked on and seen some, but not too many, miles on it since

Gently push the rod up and sneak the upper bearing half out. Take some pictures of it....usually the upper half is where most of the wear is, the center might be all copper, that indicates it has significant wear.

You will eventually have to remove all of them, but that can wait for now, while you slowly explore things.

Good to see you diving in!

 

Can you remove the top half of the bearing there should be size ie: std .010 etc. ,the bearing and crank pin don’t look too bad. To remove the upper bearing you can gently tap the rod up a little bit. I would put some hose over the rod bolts the use a small stick of wood or plastic to get the bearing to roll out. I don’t think that bearing is causing the noise however. Does the rod move up and down a little bit without moving the piston that would indicate a wrist pin.
Dan

 

Oh...make sure the caps are marked as to which one fits which rod, before you get too far along. Some engines have numbers stamped on each rod and cap, 1 through 6, front to back. Some don't, some are marked by mechanics with dots, etc.

 

OK I put some rubber fuel line over the studs to avoid scratching up the crank, and I slid the piston up far enough to get the upper rod bearing off. I haven't touched any except for #1 so far so no chance of mixing up the caps but I'll be sure to keep them all in order one way or another.

This is what the upper bearing looks like. Definitely worn down to copper but not super evenly, more worn than the bottom for sure. Markings on the back were the same except swap out "lower" for "upper". Has a little trench dug in it for oiling, that has to be made like that I ***ume. Thought it was odd that the rod has two little oil holes in it but the bearing only has one, although I looked at the ones that Kanter sells and they only have one too so I ***ume that's right, although the new ones from Kanter don't have that little trench in them.

I was able to wiggle the rod free of the crank on #1 and the pin at the top does not feel loose or clicky, although so far I've only checked the one.











I can keep going and take more caps off, I just started at #1 because it kinda sounded like it might be coming from the front. Not sure what the upper tells us. I could definitely get some plastigauge and check clearances but I'm not sure what I'm really looking for, or if the crank itself needs to be measured? It's late so that's probably as far as I can go today but I can dig deeper tomorrow if I know what to look for.

 

One last tidbit before I go to bed. I'm a little surprised to hear that the numbers on those bearings are a date code, because there is an oil change sticker in the door jamb that marks an oil change at 35494 on 11/2/1966. The current mileage is 37853, and I know that the odometer works because I have a picture of it from the auction when I bought it and I've apparently put 3 miles on it so far. That would seem to indicate that those bearings have, at most, 2359 miles on them. (I suppose it's possible it has 102359 but I really, really don't think this car has 137K miles on it).

I'm not sure what that means, exactly, but it does strike me as odd.







I'd also like to reiterate how much I appreciate all the help I've been getting here on this car. I'm learning a ton and there's no way I would have even gotten to this point yet if it weren't for all the help I've received so I really, really do appreciate it.

 

Do you have a 2" micrometer? Although a digital or dial caliper might work...

The wear on the crank looks kind of excessive, but of course it's just a picture on the screen, so I could be wrong. But it would be neat if you could measure it, to within 0.001" accuracy, and then we'd know.

The mileage sounds about right to me.

Oh..you could also just go to the parts store and get some plastigauge, one each piece of red and green. Hopefully you don't need to buy a box of 10.

We'll give you some tips on using it tomorrow

 

Well done on digging into it. Nothing scary so far.

 

Looks like normal wear, even with the exposed copper. It will be easy to spot something bad, if it pops up.

 

Didn't The Surfaris have a hit song about that bearing? The crank doesn't look hateful, and to measure I prefer dial calipers where space is challenging. The white paint spot, that's weird I agree, but was that some form of balance marking? The inside all Gyptal, somebody took that motor to the prom at one time. Not sure that was an OEM treatment. I'll ride along here over the coming days and offer this. At least it ain't bondo dust...


Quick edit, on 2nd thought that's really strange to see steps on the sides of that journal. I have a monster of a service book at the shop, I'll try to remember to look up some detail. Rods need to have a little "elbow room" to float fore and aft on the crank as it runs. Too much is no good and noisy. Film @ 11:00...

 

The journals are a little bigger than I guessed, you need a 3" mic to measure them accurately.

 

Just to give you a little rod bearing wear reference point...these are half the rod bearings out of the Corvair I had a while ago. They have some wear on them, and the engine had a faint knock. I drove it on a 5000 mile trip in that condition, then sold the car to my brother, he got a free spare engine which had much better bearings in it, I swapped in the better bearings along with fixing some other stuff, and he continued to drive it for several years. I don't know how this relates to your engine, but I just wanted you to have the opportunity to see what some of us have seen/done about this stuff.

You can see the center wear down to copper on the the upper halves of these bearings, that I mentioned earlier. I don't see this on yours.

 

Agree with all here, and thanks Jim for the dates.
That oil pan gasket is also much newer than 1966. I can't pinpoint when Felpro started doing the blue lines, but it was later.
As said, it was sometimes done to paint the inside surfaces of engines with Glyptol to seal up the pores and aid oil drainback when rebuilding. Not factory.
Not sure of the 2 holes in the rod. Common practice now is pressure feed the mains through the block, with a cross drill feeding the rods. An uncommon thing is a single hole up thru the rod to feed the wrist pin, but that's not here, with the holes offset.
The forward/back motion is rod end play. A bit is normal. That is the spec at the far right in Jim's picture. You can check the others while still ***embled and compare by feel, and use a feeler gauges to measure. The way to feel slop in the bearing is to wiggle side to side.

I would polish the crank, clean, then measure. There are a bunch of videos on this. I'd suggest watching a few different ones and try to pick up on the common points.

The bearing looks used and worn, but not sloppy. Appears to have been run with dirty oil, same with the crank journal. Compare it to a windshield that has wipers run on it with a bunch of dirt. You get 'streaks' or scratches in the direction of the movement.
Since the engine has been redone to a decent level 30 years ago and has low miles since, Best guess was it had an issue after that oil change sticker in '66, sat for a long time, got freshened with the bearings and gaskets, then sat for a long time again. Sitting with infrequent oil changes and dry starts probably got you where it is now.This is just guessing, it may have been rebuilt earlier and the bottom end done in the 90s.

I have a feeling that this is not the one making noise.

I am not familiar with this engine's internals. The side face on the crank is different, but not unknown. The fillet looks a bit strange, though.

 

It kinda looks like it was “freshened up”at some point but without a thorough cleaning. Maybe polish the journal a little bit and see if it cleans up or just highlights deep scratches.

 

I don’t think the bearings or crank are in terrible shape. I would measure the crank in two spots 90* apart oftentimes the crank wears in an egg shape. IMO if the crank is much over .0005 out of round I would have it ground. I think the crank can be polished-hard to tell from pics- Does a finger nail catch on the crank scratches.
IIRC the engine doesn’t have a filter, dirt and maybe gasoline diluted oil more than likely caused the damage.
I can send you a 2”” - 3” mic to use if you’d like PM me. You want an accurate dimension before you order bearings.
I believe with a little polishing and new bearings you’ll be good to go. I’ve seen worse do ok with a simple bearing replacement.
Dan

 

OK all excellent info. I have a mechanic friend nearby that probably has a micrometer that I could borrow, I can ask. Or I could just buy one, here's an old Brown and Sharpe on eBay for 20 bucks. Not sure how accurate it'd still be but maybe I could check it first against something "known"? There's an old Starrett branded one on there too for the same price if those are better. There's also some new ones for that price but I have to wonder about the quality.

https://www.ebay.com/itm/1279871438...VuWSbE**0B8q35K6TQbTpBafM=|tkp:Bk9SR6z1kK**Zw


I have no problem buying plastigage either, it's cheap.

I guess my next question is, should I polish the crank with the crocus cloth before I try to measure it, or does it not matter? If I do, what grit am I looking for (someone had said 1000 grit before, I see that available pretty commonly).

I'm actually starting in on re-siding my toolshed at home today but I could order up some of that crocus cloth and get a micrometer and some plastigage coming and then when it's here I could polish up the first journal and take measurements, then maybe move onto the others from there. I just need to know if that's a good plan or not.

 

If that journal is slightly out of spec, look for some NOS slightly undersized bearings.
I’ve seen .001-.002 undersized bearings.

 

It would be surprising (but not in a bad way) to see the inside of that block all painted up like that. Can't see Nash doing that in production unless they knew they had an issue with casting debris. Nash wouldn't have been too proud to salvage a batch of blocks that way rather than s**** them. Would be a good time to also check endplay on the crank too, while you're "all up in it" like this.

Also be careful to not try re***embling the rod caps backwards on the rods. The rods and caps should both be numbered on the same side to prevent this. The big end of the rods is honed and finished with their mating caps torqued in place and shouldn't be mixed, unless they've been resized.

 

Anthony Kanter has 0.001 and 0.002 undersized bearings
@Squablow i wouldn’t use the plastigauge on the used bearings You know the bearing is worn and maybe the crank the plastigage will give you overall clearance but not how much wear on the crank I’d use a known mic. You’ll use the plastigage to verify proper clearance on the new bearings. @squirrel posted the specs above. So go ahead and get some plastigage
Dan

 

Try the water in carb to eliminate a carbon build up on a piston. the water will get the carbon off.

 

GM had a great top end engine cleaner years ago.
I think ford still has a similar product
PM-3 ??

 

since none of you have ever worked on a Rambler before, here's a little education....they did paint the inside of the block with red oxide paint. This is the 59 I had, it was all original never apart. I put new rings in it. I left the crank in, and re used the rod bearings, which were still in good condition.