Low Oil Pressure and Knock

[keithb7]

Doing some research on rods I learned a few things.

 

I found this quote on the internet. "Every spun bearing we've seen at our shop traced back to oil film failure.
Whether it's assembly error (bearing clearance insufficient) or oiling system failure (pump died or low oil level in pan or solvent contamination of the oil) or systemic pressure loss (bearing clearances opened up due to wear) the failure mode is the same. The engine loses the film of oil between crank and bearing, and the two come into direct contact. The resulting heat welds the bearing shell to the crank, which then starts the bearing spinning inside its saddle."

 

You mentioned that you saw your oil pressure drop, then the knocking started.  You changed your oil pump. Oil pressure seemed good again, but slight knock still there.  Sounds like this spun bearing happened when your oil pump lost pressure. Oil pressure could have dropped for various reasons.  You mentioned pulling over and finding your oil level quite low. It would be interesting if you took the cover off your removed oil pump and measured the gear set for wear. There are wear specs published in a Chrysler shop manual I have here. 1949 Dodge 218 engine in the book here shows several wear checks for the oil pump gear set.

 

Pushing her hard up a mountain pass may have likely had an effect too. High RPM. Heavy load uphill for a while. Heat. Stress. Unknown total miles on the engine. Possible low oil. it all added up.

 

[Polsonator2]

My engine has always had some intermittent ticking noise too that I always attributed to either normal cold start piston slap or valves.  When I get a chance I will check the inside wear clearance for the old pump

Edited April 16, 2020 by Polsonator2

[kencombs]

1 hour ago, Ulu said:

While you can rebuild some of the engine in the car, it is a total pain in the butt. Better to buy an engine hoist so you can get it out and do a complete overhaul.

Yep

Pulling the crank in the car will require removing the trans, clutch housing, flywheel, clutch, timing chain cover.  at this point you have the rear engine mounts off (clutch housing) the front mounts off (to remove timing cover).  the engine is now loose except for exhaust, a couple of wires and plumbing.

 

I wouldn't even consider it.  The engine comes out much easier than wrestling all those heavy pieces under the car.

Edited April 16, 2020 by kencombs

[Ulu]

Exactly. This procedure is only possible if your crank can be polished by hand in the car. 

 

You can pull the head and re-ring the engine, change the rod bearings, rods, wrist pins, pistons, and even the main bearings, and lap the valves right there. You can even change the cam if you remove the radiator.

 

 

But It is extremely messy and difficult to clean everything up adequately for a good reassembly, plus, getting the crankshaft out is a nightmare. You have to remove everything you need to remove to get the engine completely out, plus more.

[Polsonator2]

Ken or Ulu, when pulling the whole engine, do i only have to unbolt the bellhousing from the back of the engine? Or does that and the tranny all come out as one unit? This is my first engine pull.

Edited April 17, 2020 by Polsonator2

[Ulu]

First you’re going to remove the hood. And the battery.

 

Take the Driveshaft loose and Unhook the shifter linkage, Parking brake cable, backup lamp wire, and speedometer cable, then take the transmission out on a rolling jack. There will be extra wires if you have overdrive, and the OD cable.

 

Leave the clutch alone but unhook the linkage and the rear motor mounts. Unbolt the exhaust pipe from the manifold and remove the accelerator linkage and choke cable from the carburetor.

 

Remove the fan.

 

Drain the radiator and remove it. 

 

Remove the fuel line and wiring. 
Remove the carburetor to prevent damaging it, but if you’re very careful you can leave it on.

 

Be very careful when you pull the bordun tube & bulb out of the block. If you kink that tiny tube the  heat gauge will never work again.

 

At that point you can bolt some chains to the block, Remove the front motor mount bolts from the crossmember, and pull the whole engine.

 

Don’t smack the glass bowl on the fuel pump against the body and break it.

In my car the engine hast to tip up quite a bit to get out of the doghouse.

 

Edited April 17, 2020 by Ulu

[Ulu]

By the way, if you don’t have a repair manual for your car, there are reprints available for a very reasonable price and they are invaluable.

[Plymouthy Adams]

if you have a bud that can help removing the dog house in not that involved and will give you access lots of access and room to maneuver and also increase visibility to prevent accidents...

 

 

[Ulu]

1 minute ago, Plymouthy Adams said:

if you have a bud that can help removing the dog house in not that involved and will give you access lots of access and room to maneuver and also increase visibility to prevent accidents...

 

 

This is very true but unfortunately the bolts between the fenders and the cowl are usually very rusty.

 

If you have an engine hoist it is no problem to remove the doghouse by yourself once you get the bolts out. I removed mine without problem, But I didn’t have a problem with rusty bolts in that area.

[Plymouthy Adams]

on the AVERAGE....only the very lowest bolt on the fender at the cowl gives issue as it is the one that seems to always have a certain degree of dust and dirt holding moisture.   But as stated, that is my experience.....each person has to make the call for attack...they just need to know what options are available.....

 

working solo I set my engine and tranny today...barely nicked the paint on front corner of oil pan....dang...touched up and you would never know it now.....

 

 

[Ulu]

16 hours ago, Plymouthy Adams said:

on the AVERAGE....only the very lowest bolt on the fender at the cowl gives issue as it is the one that seems to always have a certain degree of dust and dirt holding moisture.   But as stated, that is my experience.....each person has to make the call for attack...they just need to know what options are available.....

 

working solo I set my engine and tranny today...barely nicked the paint on front corner of oil pan....dang...touched up and you would never know it now.....

 

 

I would say that every bolt on the passenger side of my car was rusty, and I oiled them and fought with them for a bit. On the driver side they were fine.

 

That looks very similar to the spridget mill that I built on my mom’s kitchen floor. I picked up the long block with the tin on it and carried it outside by hand. 

Edited April 17, 2020 by Ulu

[Plymouthy Adams]

well....not even the right country.....but I will say it is a very advanced copy of an original engine licensed to the Japanese company by the English to build....so the roots are there...

 

30% increase in HP, I get the 5 speed full synchromesh and with the OD and new rear gear ratio....30% reduction in RPM verse stock.....two doors, bucket seats 5 on the floor...having fun with this build.

[9 foot box]

Polsonator,j   Just for the the heck of it I just looked on CL, In your area. Auto parts by owner, The heading is “ engine flat head six 37 Dodge”. It’s in White Salmon. $500, If you contact the seller, ask for the engine no. It might not be a 37. If that works, you could enjoy your car with the lighter traffic and think what you want in a rebuild. My 46 P15 has a tag on the block saying to Specify Model 231. So you could put a 230 crank, rods and flywheel in your block. You got some good miles out of that engine. 

[Ulu]

14 hours ago, Plymouthy Adams said:

well....not even the right country.....but I will say it is a very advanced copy of an original engine licensed to the Japanese company by the English to build....so the roots are there...

 

30% increase in HP, I get the 5 speed full synchromesh and with the OD and new rear gear ratio....30% reduction in RPM verse stock.....two doors, bucket seats 5 on the floor...having fun with this build.

 

I've been looking at bugeye Sprites for a while.

I always wanted to sell off all the gear of my Midget and re-power with Datsun stuff. Or similar. 

I used to break MG cranks and strip gears, and curse at Lucas, the lord of random voltages.

[dpollo]

 

 

 I am not far from you (near Victoria BC)  

Careful when discussing the 218  with a Canuck.     In Canada, the 218 was larger physically and used the same  bearings as the Chrysler

we called  engines  like yours 217s  and I recently disassembled one. It was from a 50.

send me a PM if you need a crank and rod .

Edited April 24, 2020 by dpollo
removed offer of parts

[Andydodge]

Polsonator.........Dpollo offers good advice...........all Canadian Mopars from the mid 30's I believe came with the DeSoto/Chrysler sourced 25" long engine and virtually nothing interchanges with the USA shorter Plymouth & Dodge  installed 23" long engine apart from water pumps and engine mounts............we had a similar situation here in Oz but Oz mopar went one better and used both engine sizes sometimes in the same year.....makes life very enjoyable.......lol.......just make sure you know exactly what you have and need.......lol........andyd

[Polsonator2]

So here is the update on my old gal.  I decided if I have to take the whole engine out a sbc is going back in.  I went ahead and used the old wet sandpaper and shoestring trick on my rod journal to polish it up up. I mic'd it all over and it turned out nice and round and within spec to use an undersize bearing.  Put on an undersize bearing and got my clearance within factory spec. Replaced entire rod that was spun with new one. Replaced all pistons and rings, and wrist pin bushings in all rods.  Replaced pistons because of excessive ring land wear.  Some rings were broken too.  Found minimal wear and cylinders where in spec for standard replacement pistons. Also replaced all other rod bearings with standard size bearings and replaced #3 main bearing with a standard. Plastigauged rod bearings at .0015 clearance.  Plastigauged main bearings #2, #3 (replacement), #4 and all were at .002 clearance.  #3 (original that was replaced) was the only one that was over .002.  I read on here that there is mixed opinion on bearing clearance, with some opting for .002 and others tighter. Figured I will try it.  Didnt check #1 main since I would have to have the timing cover off and all the things associated with taking the cover off.  Cleaned up and de-carboned head  and painted it.  No burnt valves all seem to seat well.  Decided to just clean them up and not do a full valve job.

 

She now has 1,200 miles (and many oil changes and filters) since I did my shade tree rebuild.  Oil consumption is now almost nothing and her new rings seem to be seating well.  I think any oil dripped now is from timing cover.  No knocking and oil pressure has been 40 - 45 lbs at 30 mph+.  After a run at 60 mph she has about 38 - 40 lbs at 50+ miles an hour and 25 - 30 at 30 mph.  After leaving the freeway and driving at lower speeds oil cools and she goes back up to 30 - 40  lbs at 30 mph and 40 lbs at 40+ mph.  I am using 10w 40.  Have tried 15w 40 and pressure is about the same. 

 

If she blows up again I may actually decide to keep her flatty and do a proper rebuild since I now have experience rebuilding her but who knows..May still go for more power..  For now she will not be run as hard as I used to run her.  I know this isnt the proper way to do things but I am already happy I got 1200 miles out of her and she may or may not get many more.  Some people on here are lucky to do 500 - 1,200 miles in a year..

 

Forensically, I found a piece of piston skirt in the oil pan. It is possible that tiny metal pieces from the skirt caused the failure in rod #4s journal. Piston #1 had the broken skirt.  I still havent had a chance to check the clearance of my old oil pump to see if it was out of spec but hope to do that when I have time.

Edited June 2, 2020 by Polsonator2

[Sniper]

Nice to see you got her up and running again.

[Plymouthy Adams]

this level of fix was very common back in the day as families had so little in terms of money and if you did not do it yourself odds are it was not done....the purchase of another vehicle was often way out of the equation.  The mix and match of components like this happened often and often not recorded for the future.  Suggest you record your bearing sizes per crank journal as such and denote the rod changed position (cyl #) as that could be few grams or so out of match weight for any future teardown when you will wish to revisit the question of balance.  Good to see here running again and with care and sensible driving you may well be surprised at the longevity. 

[westaus29]

Sounds like a good compromise, should give you many miles of service. Just dont push it so hard!!

 

[keithb7]

Good job doing an in-frame clean up and repair. Well done. The good news is the car is quickly up and running for prime driving season. I like the frugal, practical approach exercised here. Shade Tree seems too condescending here. You did well. I'd likely have done it your way too.

[Sniper]

I like listening to those old radio shows.  I was listening to one, Father Knows Best I believe, and in one episode they bought a well used second hand car for the daughter and mom to use when Dad had the main car at work.  The father and son did an in frame valve job on it in the course of the episode.  So that kind of thing was common, maybe not as long lived or precise as a garage would have done, but after fixing many of the hacks on my 51 I am not sure there are too many quality mechanics out there anymore.  I have a personal motivation to do the best job I can, if I mess it up I get to figure out how to get it home and I get to do it again.  Since I am not wealthy I can only afford to do it right, not do it again.

[Polsonator2]

Here is the latest update.  After 4,342 miles after my shade tree rebuild I noticed that my oil pressure dropped again, down to 20 psi and would not climb.  Was starting to show lower 20 psi at cruise but then would go back up shortly.  Noticed glitter in my oil filter too, thought maybe leftover junk from the prior spun rod.  Thought I could hear a sound that I thought might be a spun rod again, but it sounded more like dieseling sound.   Took off oil pan today and checked all rod bearings and none were spun, which is good.  Saw glitter around crank crevices.  Checked all rod clearances and all were .002 except the #4 i spun before (now .003) and #5 needed a .001 undersized to get to .002 and I need another .001 undersized to get #2 to .0015 - .002.  Noticed that my #4 rod bearing looked like it was pitted from most likely new debris.  I will get a .003 undersize this time for #4.  When I originally plastigauged my clearances I got .0015 on all but #4 at .002.  when I checked them before they were probably closer to .002 than .0015 though, kind of in between.  

 

Upon inspecting my oil pan I found tons of glitter and then some thin long metal strips, which I think is what caused my new oil pressure loss after getting warm.  Car has great oil pressure cold.  I am thinking my oil pickup might have been clogging when warm hence lower oil pressure.  Will check main bearings next but doubt they are spun as wouldn't that produce low rumbling knock noise?  Will also check clearances again on mains whrn I inspect them.

 

My question to the group is if anyone can identify what this debris was?  I can't figure out what it was.  Appears to be super thin strips, so most likely not rings.  Doesn't look like bearing material from my new rod bearings either.  Is it potentially more leftover rod bearing material from before?  Looks almost like tin..  It is not magnetic.

Edited August 9, 2020 by Polsonator2

[DJ194950]

That can be sent out with the used oil for a analysis for a fee. They can tell from them what is/was coming apart for sure. Last I remember reading about it varied from a low of $30 up $100 for the lab work. May be worth it however if it helps prevent any preventable further damage? and very expensive repair? A web search on engine oil analysis should give some sites to look at.

 

You may want to remove and clean out your oil pressure relief valve and the  piston, you may have some particles stuck in it and holding the relief open some?

 

Add-you may also want to remove and check the oil pump and the oil crossover oil lines for junk.

 

DJ

Edited August 9, 2020 by DJ194950
add info- spell check misses some things

[Dodgeb4ya]

Doesn't' look good.