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Tired Engine - 33 PD - Opinions Needed


blakew
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I need some opinions on my future course of action on the tired engine I have in my 33 PD.

 

  • Oil pressure is good. 50+ starting out, and really doesn't go below 25-30 at idle when hot (need to re-verify the hot idle pressure, but I think that's close).
  • Knock under load, but not when idle.
  • Smokes some (white) - more on deceleration, but other times too - not really when under load.
  • Has some blow-by - the area behind the oil fill gets misted with oil after driving
    • Have let it at idle with a thin rag sitting on top of the oil fill tube, and I don't get any drops of oil on it, but after driving a few times, the cap seems to have some drips of oil and the area behind the fill tube (wires, distributor, block past the distributor) is wet with oil.
  • It is also running rich right now, and that is probably due to the carb float having some gas in it. Have ordered a new float.
  • The odometer has 67k miles.
  • The engine matches the car, and it looks to have never been out.
  • The overall car is pretty much original from what I can tell other than a paint-over paint job done at some point in the past.

 

I really just want to drive this car around town with the family for the next few years, and I do not want to spend $3000 on a full rebuild (no plans on doing any touring) .

 

What are my options here? What would you do? Is it possible just to refresh the engine (new mains, rings, etc while in the car without a complete overhaul)? If I can wait until winter, I could do some of those things then with the engine in the car (at least from what I have read). Or, could I just stick with it for the next few years with the light amount of driving I am doing?

 

I just wanted to gauge people's opinions that have been doing this far longer than I have. Plus, I am new to the MoPar world.

 

Thanks!

-Blake

 

Edited by blakew (see edit history)
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But you really should do some more diagnostics before making a decision.

 

Have you done a compression test? A vacuum gauge can tell you a lot too (and decent vintage manual will show the different motions of vacuum gauge needle indicating issues in the engine). The white smoke could be troublesome as one source could be a crack in the block or head allowing coolant into the combustion chambers which could be very difficult to repair.

 

The first "overhaul" my '33 PD had was with the block in left in the car: I replaced the pistons, bearings, etc. in situ. Rear main seal can be a pain. And you will only improve things if the crank is still round and cylinders are in spec for roundness and taper. Of course it is better to pull the engine and do the work with proper machine tools in a controlled environment but doing minor overhauls with the block left in the car was fairly standard practice way back then (I doubt you'll be able to find the vintage tools for boring the cylinders in situ now though). Based on your oil pressure, I'd guess the bearing clearances are still pretty good. I would not be too surprised if you find one or more pistons with broken rings and broken top land which, if the cylinders bores are still in spec, could be fixed by installing new pistons without pulling the block.

 

I put about 30,000 miles on my shade tree overhaul before I decided to disassemble everything and restore the car. So it is possible, if not recommended, to fix somethings without a full rebuild.

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I`m with ply33, if its not knocking, has good oil pressure, not overheating nor blowing vast amounts of smoke and oil consumption not excessive, I would certainly keep driving if you don't intend to put too much strain on it.

 

Back in the day these engines were usually good for 60 - 70k miles, usually with a valve grind around 30k. 

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The oil smoke is mostly from worn valve guides.  That is why it's worse on de-acceleration because the pistons are pulling vacuum and sucking oil up past the valves.  The knocking is prolly in the transmission input shaft bushing.  When you hear that noise stay on the gas and push the clutch in and it goes away as yhr motor revs without noise.  Also bearing knocks are usually pronounced with light to no load on the engine allowing things to move and knock.  There is offset load placed in the crank during acceleration that helps keep the play out of the bearings.  The oil misting is probably  ring blow by.  Sometimes you can hold  your hand over the fill tube and feel the pulsing as the engine runs.

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I have not had a chance to do a compression test, but I did want to add that the oil on the side of the block is not coming out of the oil fill as I had initially thought. After doing some driving this weekend, all of the oil is coming from the dip stick hole. It gets blown up to the area behind where the oil filter would have gone. There is no seal on the dip stick, but even with one, that seems like a lot of oil coming out from around the dip stick. Excess pressure in the crankcase from blow-by perhaps?

 

Also, the knocking is happening under load, and it does not seem to be coming from the clutch area. I can be going down a hill or on a level area with the gas on (cruising) and no sound. When I am pushing the engine from takeoff or going up a hill that is when I get the knocking sound. Head out the window, and it is coming from the engine.

 

To confirm (just because I paid closer attention to it this weekend), oil pressure is around 60 at start. 45-50 when going down the road and the engine is hot. Between 25-30 at idle when hot.

 

But hey...had an enjoyable weekend out in it, by the way.  :)

 

13495144_10153583915276440_7865005911835514382_n.jpg

Edited by blakew
Wanted to combine into one post. (see edit history)
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These engines were bulletproof. Your oil pressure is right on the mark for that engine. Mine follows my speed- 30mph,30psi-45mph,45psi-idle at 25psi. Cold start-50psi. It changes depending on the SAE number of the oil. I run SAE30 so my numbers will be set by that thickness of oil and the eventual heat of my engine. The knock is almost certainly a rod bearing. They are VERY easy to replace. A simple removal of the oil pan and replacing all the rod bearings will fix your problem. It's VERY difficult to bust one of these engines. The rings are a horse of a different color. You have to remove the head and cut off the ridge formed at the top of cylinders by age. Then,while you have the bearings off the rods,push the rod and piston straight up through the cylinder. It's very easy. The rings are almost certainly shattered onto pieces. It's a common fault. Purchase a new set of "0" Standard rings with loading springs. "0" Standard means no overbore like "10thou over". It's the rings your car most likely has now. Clean out the rings lands,that's the grooves in the piston, and slide in the rings. Rent a compression tool to compress all the rings so you can slide the piston back into the cylinder. Put LOTS of oil on your hands and on the  piston and new rings and cylinder walls while you're doing all of this. LOTS. Slide the piston down into the cylinder,slide under the car and connect the rod bear caps with the new bearing shells,with LOTS of oil on everything, and Bob's your uncle the engine will run virtually as new. Don't forget the cotter pins in the rod bearing cap bolt ends. Job takes a "Saturday" to do assuming you have everything on hand. Been there,done that. If you have any questions fire away. Believe it's not as difficult as you would think.        

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DodgeKCL:

 

Thanks for the feedback! In your opinion, would running the car until winter cause too much wear on the crank, or should I shoot for doing this sooner rather than later?

 

Also, not wanting to take the engine out at this time, how big of a deal is replacing valve guides with the engine in the car? Definitely have some worn ones with the excess smoke on deceleration (as mentioned by RageRacing above). 

Edited by blakew (see edit history)
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You can pull the guides in the car just have to make a puller or find an old one for sale.  The issue is grinding the hardened exhaust valve seats to make sure they are perfectly aligned with the guides.  Not sure if that can be done in the car.  Or rebuild that spare motor and swap them out in a couple hours.

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36 minutes ago, rageracing said:

You can pull the guides in the car just have to make a puller or find an old one for sale.  The issue is grinding the hardened exhaust valve seats to make sure they are perfectly aligned with the guides.  Not sure if that can be done in the car.  Or rebuild that spare motor and swap them out in a couple hours.

 

IIRC, the manual shows you driving the valve guides down into the tappet area and using a hammer and chisel to break off pieces as it comes down. New guides installed from above but the exhaust and intake are installed with different ends up. I suspect that loose valve guides are not quite the problem on a L-head design like your Plymouth as they are on a overhead valve design, at least with respect to oil consumption, but I could be wrong on that.

 

Service manual should have procedure for removal, install and reaming of the valve guides. Of course the trick is the first factory service manual was issued for the '34 Plymouth model year and you have a '33. But the engines are basically identical, and even very similar to the '35 and up engines that have the full length water jackets so a later service manual is pretty useful too.

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I made a collar with a thick base and used a threaded rod that fit down through the guide.  I put a nut and jam nut on the bottom and used a hardened thrust washer and nut on top.  As I tightened the top nut it pulled the guide up and out.  Ply33 is correct in the way the service book tells you to remove them.  They use the same guides but the exhaust is orientated reversed from the intake.

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With oil being forced out of the dip stick I would suggest that the breather cap must be plugged.

As for rod bearings, yes sooner would be much better than later. The knocking is on the crank shaft and to much of that and the bearing will not cure it.

If you don't do anything else  at least do the rod bearings.

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2 hours ago, JACK M said:

With oil being forced out of the dip stick I would suggest that the breather cap must be plugged.

As for rod bearings, yes sooner would be much better than later. The knocking is on the crank shaft and to much of that and the bearing will not cure it.

If you don't do anything else  at least do the rod bearings.

 

The oil filler cap is supposed to be the inlet for fresh air into the sump, the outlet is the draft tube on the back of the passenger side of the engine. You might want to check that the draft tube is not blocked (critters have been known to use the draft tube as an entry to making nests on cars that have been sitting for a long, long time). When stationary the draft tube does nothing to move air through the crankcase so if you have lots of blow by, it will come out of the filler cap as well as the draft tube.

 

Concur that you probably want to pull the pan and inspect the bearings. Rod bearings and the two middle main bearings are easy to replace if they look bad.

 

Replacing the front and rear main bearings are tough with the engine in the car but I have managed to replace the rear while in the car. The front bearing block has bolts into it from the front through the plate that holds the engine mount and needs to have the timing chain cover removed, so I think that is one for leaving for a full out of car rebuild.
 

Many of the older high mileage Mopar L-6 engines have been known to either have or soon develop broken top rings and/or top lands on the piston. Other than finding the '33 & '34 years only head gasket, pulling the head is not big a deal on these engines, so it might be a good idea to examine the top of the pistons. It is a bigger deal to replace the pistons and rings because, as noted above, you will have to get a ridge reamer to clean up the top of the cylinders to get the old ones out and a ring compressor to get new ones in.

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Ok, I think I have a decent plan to start out. I am going to check the draft tube first.

 

I will check compression first and foremost when I can.
 

Secondly, I will probably work on replacing the rod bearings and perhaps the rings (inspecting the pistons too). I may do this in stages though. At least start with the bearings and wait on the pistons for later, or maybe I'll do them all at once.

 

After I take care of those things, I will see how the oil burn is and see if there's still smoke on deceleration, I will get to the valves.

 

I will update this post for others' reference as I go forward. May be a few months, but we will see.

 

Andy Bernbaum's site seems to have most parts except for that pesky head gasket. Any good pointers on finding head gaskets out there?

 

Thanks!

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If you pull the pistons check closely around the wrist pin.  My 34 had small cracks around a couple of them.  I had a tough time finding oversized crank bearings so I sent my crank to Mile high and had it welded and reground to stock.  Egge had stock sizes.  I also got new rods and pistons from them too.

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Compression test

 

Dry

1 - 78

2 - 80

3 - 82

4 - 62

5 - 87

6 - 76

 

Wet

1 - 100

2 - 98

3 - 88

4 - 76 

5 - 89

6 - 88

 

(May have not got enough oil down in #5 and #3 for the wet test)

 

# 4 seems to be the weakest and improved by 14psi when wet. 

Edited by blakew (see edit history)
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They told me at service school years ago that if the lowest is within 15% of the highest it is acceptable.

That would be for factory specs in the marine industry.

Yours is outside of that.

But I have seen engines run for a long time when out of that range.

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31 minutes ago, JACK M said:

They told me at service school years ago that if the lowest is within 15% of the highest it is acceptable.

That would be for factory specs in the marine industry.

Yours is outside of that.

But I have seen engines run for a long time when out of that range.

I drove my '33 PD with a bad miss at idle for a year or two and several thousand miles. When I finally got around to checking the compression I had about 60# in three cylinders and zero in the other three. Other than being hard to start in cold weather, having a rough idle, and lacking a little power it ran fine. These old engines can perform remarkably when in very poor condition.

 

In my case the exhaust valves were badly burned and at least one piston had a broken top land and broken top ring. Taper and out of round weren't too bad and the crank was round and close to spec, so I put in new bearings, pistons, rings and valves. All with the engine in the car, the car in the parking lot of the apartment complex I lived in at the time. And that was the first time I'd ever had an engine apart so I was not, and am still not, an engine rebuild expert. Drove it after that for about 30K to 35K miles before I took the whole car apart for a full restoration along with a professional engine rebuild.

 

Based on the symptoms listed, I'd probably drive the car but not push it too hard. When time and money become available, a minor in car overhaul much like I did decades ago might be enough. But if you have the wherewithal, pulling the engine and doing it right would, of course, be better.

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When I put new rings in my Dodge 8, I rented the ridge removal tool and its operator from an engine reconditioning shop. He came out to my garage and stood on top of the engine while doing it. Took less than an hour I think (but it was nearly 20 years ago so memory could be foggy).

 

The hard part was getting the head off and back on. It is heavy and you are leaning in over the mudguard. Hopefully the 6 cyl. head would only weight 3/4 as much!

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Gentlemen, I compliment you all on your knowledge of these wonderful engines. There's just one point that I'd like to ask about as the man who owns this car might not be as knowledgeable as most of you. Is there a chance that his "knock" is simply pre ignition? Also, my first thought was that the draft tube might be clogged, as it seems that there is some force, I hate to use the word pressure, pushing out the mist at the fill tube.

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I have run a long pieces of plastic used to declog sink drains up the draft tube, and it went all the way up to the elbow going into the block without hitting any blockage.

 

I was honestly expecting one or more of my cylinders to show a much lower compression since there is so much oil that comes out of the dip stick hole. Might have to explore the draft tube a little more too as I'm not sure that blowby is the sole cause of the oil coming out based on those compression readings.

 

Also, not sure if this adds to the discussion, but it seems like the "knocking" is noticeable after the engine is fully up to temp.

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  • 2 weeks later...

Ok, I'm starting to order parts now for "the freshening." I am going to be doing all rod bearings, possibly some of the main bearings (the ones I can get to while in-car), and all the rings while checking landings on the pistons, etc. All will be "0" over. Getting a head gasket and oil pan gasket set.

 

Anything else I should be looking at replacing while I'm in it?

 

Not really going to be doing the valves yet. I might at some point, but not at this time unless I find something major with the head off. However, is there something I should be looking at in regards to the valves at this time (common faults/issues)?

 

Thanks, guys!

-Blake

 

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  • 2 weeks later...

Three questions (sorry if my questions are newbie...this will be my first time replacing bearings).

 

1) When replacing the main bearings while in-car, is there a special process I should follow to get the top half of the bearing out and replaced?

2) If my oil pressure is good like it is, should I even worry about any of the mains at this point?

3) I don't have a hand crank for my engine. Is there an easy to find, cheap hand-crank out there that would work when I need to turn the engine getting at the rod bearings? Or should it just be easy to turn the crank without a handle?

 

Thank you!

 

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Been a lot of years since I did this but as I recall:

 

1. The old non-factory manuals showed using a small brass rivet with a head larger in diameter than the oil hole in the crank (so it won't fall in) and with thinner head than the thickness of the bearing (so it won't damage the bearing seat). Put the rivet in the hole in the crank and rotate the crank to remove the top bearing shell. If I recall correctly, I did not have to do that as I could catch a little of the lip and rotate it around with the crank.

 

2. If the oil pressure is good, the bottom half of the old bearing looks good, and the clearance checks out okay with plasti-gauge I would be sorely tempted to just re-install the old bearing bottoms and call it good. I'd measure the crank for diameter and roundness. If the crank is out of round or has a damaged surface then your looking at pulling the ending out to do it right. You want to check the diameter to verify the bearings you plan on putting in will have the correct clearance.

 

3. With the head off and transmission in neutral you should be able to rotate the crank by hand using the crank counterweights as places to grab. I assume you will be working under the car and it would be a hassle to crawl out to use a crank anyway. You probably want to work on only one bearing at a time too so the crank has pretty good support (worst one being the rear because of the weight of the flywheel).

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Thanks! Any quick tips on removing the oil pan while in-car? Doesn't seem to want to traverse all the way out. Didn't really want to remove the steering linkage or a cross-member to get it out, but I may have to do one or the other from the looks of it.

 

Otherwise, the head is off. I'm doing a little bit as I have time. Project at work and young kids means I get to do this in spurts.

 

28545061995_1b52f32f2c_c.jpg

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To drop the oil pan you will have to remove the drag link from the steering arm. Mark its relation to the splined shaft somehow as it can go on in many different angles and having a non-centered steering wheel is annoying. And the free play in the steering box is such that you want the steering wheel centered to have things adjusted correctly.

 

Can't see in your photo too well, but it does look like several pistons (#3 & #4 at least) have broken top lands. Is that a gouge on the wall of #4 of is it something else?

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42 minutes ago, Reg Evans said:

I took the oil pan off my 33PD with the engine in the car to remove all the sludge in the bottom of the pan.  Was not a problem. 

 

I've had the pan off a number of times over the years, most recently about a year ago to inspect the cotter pins on the rod bolts. Every time I've done it, I've had to remove the drag link to get enough clearance to remove the pan. I don't have a lift and that might change things, maybe if the front axle drops enough in relation to the frame and engine you might not need to drop the drag link.

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2 hours ago, Reg Evans said:

As you know I have a lift Tod.  I don't remember having to drop the drag link .....BUT....that doesn't necessarily mean I didn't.  Getting old ya know.

 

Yeah, a bit jealous of you about that lift. My new garage as a bit more vertical clearance than the one at the old house. Not enough for a full height lift though but I could probably use something like the lift shown on this video.

 

I did have the pan off while the car was on the lift at a shop owned by a friend of mine but that was so long ago I don't remember if I had to remove the drag link. It could be that with the additional vertical clearance you can angle the pan enough to clear the drag link.

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1 hour ago, blakew said:

I think pistons 3&4 we're suffering from bad angles and lighting. Here's a closeup. 

 

Those look reasonable. Probably was just the lighting and angle of the first photo that got me confused.

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Pistons #3 and #4 out. Ridge reamer worked wonders. The ridge wasn't too bad, but it would have probably caused issues with the pistons coming out for sure.

 

Broken oil (bottom) rings on both pistons, but all others seem to be intact. #4 gave me the worst compression out of the lot, but visually, there wasn't much difference between #3 and #4.

 

Top side of bearing for #3 rod was a little rough, but top side of bearing for #4 was super bad.

 

About time to clean the oil screen too, I'd say.

 

Pictures below.

 

28686478265_4b7959f480_c.jpg

 

28069366724_1aeb1b0078_c.jpg

 

28654360666_e404434359.jpg

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57 minutes ago, blakew said:

Anyone have a good source for piston rings that will work on original pistons? Was hoping to avoid buying brand new pistons.

 

My one experience trying that resulted in a pretty bad failure in probably less than 10,000 miles. Apparently I got the vertical clearance between the slot and the rings too loose and the rings slamming against the upper and lower parts of the grooves in the pistons broke the top land. A piece of the debris ended up on the top of the piston in the squish area of the combustion chamber which resulted in a piston being rocked sideways enough to break the skirt. Fortunately the cylinder was not damaged so I was able to install new pistons and rings.

 

My take away, being only a shade tree mechanic, was that getting a set of rings from the same vendor as the pistons and having them assure me that they were correct was the way to go. I guess if you really know what you are doing and have some way to fit the thickness of the rings properly to the grooves in the pistons (in addition to the diameter to the cylinder), you could get away with new rings only. But that person is not me, and based on your questions, I suspect it isn't you either.

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Definitely not me either. heh Thanks for mentioning that about your experience, by the way. That pushes me to the decision I need to make.

 

I guess I'll need to get a set of 000 pistons too then. $Fun$

 

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20 hours ago, blakew said:

Definitely not me either. heh Thanks for mentioning that about your experience, by the way. That pushes me to the decision I need to make.

 

I guess I'll need to get a set of 000 pistons too then. $Fun$

 

I would think if you got the rings from a quality source say like TRW that they would fit your pistons. There should be some specs somewhere that shows what the ring groove width is supposed to be and you should be able to measure them with a quality set of calipers. If your ring grooves are worn you should be able to notice it with the rings that are currently on them.

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