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Low Oil Pressure and Knock


Polsonator2

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Looking at the rod caps photo. I have questions about the number of reliefs for bearing lock tabs. The two caps shown don’t appear the same. Possibly an incorrect cap used on rod #4?

 

Pull the bearing half out of both caps and take another similar photo. 

Edited by keithb7
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The owner’s actions led to a pretty good engine save in my opinion. Could have been a ton worse. I’ve seen bearing halves get so hot they become molten liquid metal again, and extrude out of their bore as a liquid. 

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Here is a set of rod caps from 201.7 engine. #3 and #4. See bearing tab reliefs. 1 on each cap. In the same spots. 
 

You’re photos are fuzzy. However your caps don’t look like mine. Compare. Could it be a shadow in your pic?
 

 

D2348463-67C5-47BE-BD19-09020657BC90.jpeg

Edited by keithb7
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Could the black mark that appears to be another notch in the cap just be residue from the notch in the rod itself? Looks like there is a black mark on the other cap on the same end as the notch.

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@Polsonator2 I have a suspicion about #4 cap installation orientation. Are you able to provided clearer, sharp photos of the cap? Bearing side. Especially the details where there dark marks are, where the relief divots are for the bearing lock tabs?

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Visually, number 3 cap looks normal, number 4 cap shows evidence of the bearing spinning.

 

However, only a measurement with a micrometer can tell you if it's salvageable.

 

The bearing aligning slots look like there is no issue there. 

 

You will have to rotate the crankshaft around to work those bearings off the journal.  Then you can look at it and measure it.

 

 

 

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That’s just some really high oil consumption. I can’t imagine following you in my car for 60 miles.

 

That rod bearing looks so wiped out that I find it impossible to believe that there is no metal in your oil pan.There should be little flecks of stuff all over.

 

I don’t think it’s possible that your crankshaft journal has survived this without scoring. If it’s extremely light you might be able to buff it out with the crank in the car. Judging by that bearing I don’t think it will be light.

 

In any event that connecting rod Looks like it will need to be repaired. Also since the wrist pin oil comes from the connecting rod bearing journal you will probably find the oil passage in the rod plugged up and some wear on the wrist pin bushing.

 

You can check this by wiggling the rod up and down once you get the crank out of position. But you can’t do anything much about it with the engine assembled. You could blow some air and penetrating oil up through the passage.

 

 

 

 

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I think most my oil consumption is pushed out through upper rear main seal and the front timing cover and not as much is burned.  I consume/drip almost no oil when going 45 mph or less.

 

Here are close ups of each side of the caps.  #4 cap is right on 1st picture and left on 2nd picture.

Screenshot_20200415-162641_Gallery.jpg

Screenshot_20200415-162652_Gallery.jpg

Edited by Polsonator2
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So #4 cap has a relief for bearing lock tabs on both sides? #3 only on the one side? If so, isn't that odd?

Edited by keithb7
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7 minutes ago, keithb7 said:

So #4 cap has a relief for bearing lock tabs on both sides? #3 only on the one side? If so, isn't that odd?

 

My '56 Plymouth 230 has relief cuts for the tabs on both sides, on all rods. I think they did that so a rod could be used in either of the two orientations, wide side front or rear.  They also have oil squirt holes on both sides.  And, two of them are from another engine.  I know 'cause the stamped numbers are dups of others in the engine.  It had been bored and crank turned in the not too distant past, mileage wise.   FInding mismatched rod is not at all unusual as rebuilders often replace bad ones with used ones from other cores.

Edited by kencombs
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By chance I have  a torn down 1950 218 engine here too. I just looked there is only 1 relief cut per rod cap. You are right about rods getting mixed  up by rebuilders. I can see that happening. I was just thinking that possibly the extra relief may have eventually allowed the bearing to spin in its bore? 

Edited by keithb7
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I will report back to the group what the other rod caps look like. Now I am also curious on Keith's theory.  And I wonder too if Ken has the double hole ones on his is this something I should be concerned about (mismatched rod caps)?

Edited by Polsonator2
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6 hours ago, Polsonator2 said:

Got the oil pan off and inspected rod bearings for piston #3 and #4.  #3 looked fair but look at #4.  The scoring on the crank looks pretty bad.  I haven't looked at the other bearings as this looks like the crank is going to have to come out.  Is this something a machine shop can fix?  Or will I need a new crank?    Here is a picture of #4 rod journal

20200415_115204.jpg

That's some serious rod and crank damage.

Do it right...complete rebuild required... as from what I've read you like to drive the car a lot.... long distances and fairly hard. 

The crank will have to be machined for sure...will also need a new rod...to be balanced with the others...just the beginning on fixing an engine that has tiny metal all through it.

You might be able to haberdash it back together but it will fail again.

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To answer your question in post #26:  seems like you can cover the rod bolts with hose or tape and tap the rod and piston assembly up into the cylinder bore.  Once the rod end is clear of the two bearing shells they will probably fall out or need some gentle prying where the two halves meet. regards

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Yup. Rebuild time unfortunately. That’s too bad. I am interested in further technical study as to why this might have happened.  If ok with you @Polsonator2 I’d like to post more pics and directed questions around crank and rod details. Perhaps we can field some answers from rebuild experts here, and learn. 

Edited by keithb7
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Sure! That sounds great Keith!  It's a bummer but I have got 34,000 miles of everyday driving out of her and who knows how many miles were on the engine before I got it.  I always planned to do an eventual rebuild, just never had a reason to yet since she ran so well.  

 

Still makes me wonder why it had that one rod spun though.  The bearing had some cracked corners that did fall out when I first opened it up. The #3 journal looked fine. Bit I have not seen any metallic flakes or anything in my oil.  I have't looked at all the other bearings yet as I figured I will be rebuilding it all anyway.  I will report back though how they look.

 

As for the crankshaft, can that be removed with the block in the engine after the front fenders' radiator, etc are removed?  The repair manual made it seem like it is possible.  And does that damage look salvageable by a machine shop? It only has a slight ridge I can feel on one side.

 

Lastly, what is a typical rebuild cost if I go with a shop?  I may decide to farm this out if it is reasonable.  Any idea on how many hours a good shop would spend on a rebuild?  The one I am trying to get a hold of by me says they charge about $100 an hour plus parts.  I am in Tacoma, WA.

Edited by Polsonator2
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2 hours ago, Polsonator2 said:

Sure! That sounds great Keith!  It's a bummer but I have got 34,000 miles of everyday driving out of her and who knows how many miles were on the engine before I got it.  I always planned to do an eventual rebuild, just never had a reason to yet since she ran so well.  

 

Still makes me wonder why it had that one rod spun though.  The bearing had some cracked corners that did fall out when I first opened it up. The #3 journal looked fine. Bit I have not seen any metallic flakes or anything in my oil.  I have't looked at all the other bearings yet as I figured I will be rebuilding it all anyway.  I will report back though how they look.

 

As for the crankshaft, can that be removed with the block in the engine after the front fenders' radiator, etc are removed?  The repair manual made it seem like it is possible.  And does that damage look salvageable by a machine shop? It only has a slight ridge I can feel on one side.

 

Lastly, what is a typical rebuild cost if I go with a shop?  I may decide to farm this out if it is reasonable.  Any idea on how many hours a good shop would spend on a rebuild?  The one I am trying to get a hold of by me says they charge about $100 an hour plus parts.  I am in Tacoma, WA.


I spent $900 about 30 years ago for a complete 6cyl longblock rebuild on my core. I would expect to pay about twice that now if your crankshaft is repairable. It almost certainly is.

 

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.

Edited by Ulu
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