Refresh or Rebuild?

[Bob Riding]

I'm just starting the removal of my 230 donor engine to replace the 218 in the wagon. After watching all of @keithb7 videos, I think I can handle the job!  Thanks, Keith!

 

It is a running engine and actually sounds pretty good, except for a slight tapping sound that increases with rpm. 

I disconnected the driveline yesterday and plan to remove the 3spd from the block today so I can get it out. 

View it here:  '56 Plymouth flathead running

I did some compression tests and here are the results. The engine was up to operating temp on test 1, but on re-testing the next day, it was only slightly warm on test 2. Test 3 was done immediately following 2, but with a teaspoon of engine oil added to each cylinder. 

 

Cylinder         1        2        3        4        5        6

Test 1           110     112     115     121     120    130

Test 2           115     120    118     128     128    138

Test 3 w oil  125     135    130    130     138    145

 

A couple of observations/questions:

 

1. Would the differences between test 2 and 3 be traceable to rings, valves or possibly both?  I am definitely planning to lap the valves.
2. The service manual says the compression pressure should be 120-150 psi. How much does that change once the motor is broken in? The engine is listed as having a compression ratio of 7.6 to 1.
3. How does that 7.6 to 1 ratio change if the cylinder pressures are lower? Does a 10% pressure drop in the cylinders equate with a 10% loss of power?
4. The PO had some work done on the engine and the head was off - there is a new head gasket, water pump, fuel pump, gas tank, etc. How can I tell if he had the head shaved- i.e. what is the factory thickness of a 1956 Plymouth head? I couldn't find it in the service manual.
5. My brother-in-law, who has rebuilt all kinds of engines, wonders if the tapping noise may be a rod bearing or a wrist pin, and thinks that I should do a complete teardown.

 

Enough questions! Thanks for the help

 

          

 

[plymouthcranbrook]

Could the tapping be lifters?  Have they been adjusted?

[Bob Riding]

No they haven't  I thought that too, but my brother-in-law didn't think so, based on the sound. Once I pull the motor, I'll go through the valve train and check the clearances.

 

 

 

Edited August 22, 2022 by Bob Riding

[nonstop]

Before pulling the engine, check the valve adjustment.  The ticking could be various things, but the easiest and cheapest solution is to make sure the valves are adjusted.  I started down the same rabbit hole, and the valve adjustment was just what the engine needed.  Also, could it be an exhaust leak?

[Bryan G]

Valves tend to get quieter as things warm up. With everything adjusted properly & up to temperature, that engine should be exceptionally quiet. 

 

I used to hear folks suggest "pull the pan" but I never thought it worth effort. But, really not such a chore on these...and then you'll know what you're dealing with. Worth it just to have things cleaned out.

Edited August 23, 2022 by Bryan G

[keithb7]

I feel somewhat responsible for the outcome here. Lol. I'm leaning toward a loose tappet to valve clearance if it sounds more like a "tick" than a knock! Hard to tell from here thought.

 

It appears Bob that you have not yet decided if you need to rebuild or simply refresh your engine. Your compression numbers are respectable. I suspect #4 has a valve seal issues. Do you have any idea what the oil pressure was when the engine is running? Plan a refresh, then take the head and oil pan off.  Take some measurements of cylinder taper and out of round. Top cylinder ridge? Any cylinder scratches or grooves you can feel with your fingernail? Disassemble valve train. View witness marks on valve sealing surfaces once you lap them a few times. Nice wider, even, round sealing ring? Or thinner in some areas and off-square? Try and measure valve movement in guide? How much is there? Measure crank end thrust. Over 7 thou? Pull rod and a main caps and use plasti-gauge. Clearances? Tapered clearances? Inspect crank bearings and journal surfaces and measure. Grooves? Nicks? Wear ridge felt? Journal taper wear?

 

The list above will tell you if your block needs machining work or not. If all appears well. Perhaps a refresh of new rings, lap valves, roll-in new rod bearings might be all you want to do/ It might be just fine with minimal intrusive repair work. 

 

If wear is excessive new parts won't help much or last very long. Ending up wasting your time and money invested in new parts.  If you're going in this far, might as well budget front and rear crank seals. A speedi-sleeve may be required on the front crank pulley to seal it up so be sure to clean it up an inspect. Then there is the timing chain. Sloppy? Starter. Heat riser mechanism in exhaust manifold? Carb rebuild? Generator up to snuff? How old is that mechanical fuel pump?  If you don't know the history, the rad should be sent to rad shop and thoroughly cleaned and tested. Any refreshed or rebuilt engine will love an efficient rad.

 

Good luck whatever you decide. We're here to help if needed.

[Bob Riding]

Great advice everyone- I appreciate learning new stuff and your willingness to help. I will keep you posted. News at 11 as they say!

[vintage6t]

If the engine sat for a long time you could have a few sticky valves. The simplest thing you can do is add some marvel mystery oil to the crankcase and then run the engine for a while to see if things quite down. 

 

Also cylinder compression is relative to each other. Don't worry too much about the absolute reading unless it's way out of the acceptable range. Test with plugs out and throttle open. You don't want more than a 10% variance across all.

[Sam Buchanan]

Listening to the video, the engine sounds good from the passenger (valves) side. But when the camera moves to the driver's side a distinct knock is present. I think valve train noise would be more noticeable on the passenger side, not the driver side. I suspect there is something to do with crank/rods/pistons that is causing the deep knock that I hear on the left side of the engine.

[Bob Riding]

7 hours ago, vintage6t said:

If the engine sat for a long time you could have a few sticky valves. The simplest thing you can do is add some marvel mystery oil to the crankcase and then run the engine for a while to see if things quite down. 

 

Also cylinder compression is relative to each other. Don't worry too much about the absolute reading unless it's way out of the acceptable range. Test with plugs out and throttle open. You don't want more than a 10% variance across all.

Great idea... I will do that today.

 

 

[kencombs]

I could be wrong, again, but that noise sound like a piston.  Not pin, but a cracked one or something on top of one.   Sounds high in the engine and sort of hollow sounding.    Maybe use a length of hose as a stethoscope to further isolate.    
 

now remember this, I have very poor hearing and listened to it on my phone Bluetooth linked to my hearing aids.  So take this for what it’s worth

[Sniper]

9 hours ago, Sam Buchanan said:

Listening to the video, the engine sounds good from the passenger (valves) side. But when the camera moves to the driver's side a distinct knock is present.

 

yes indeed and that noise is worry some.  I'd take the fan belt off and makes sure it isn't water pump/fan related.  Oil pressure tends to go to pot with a rod knock, what's that look like?

[Bob Riding]

23 hours ago, Bob Riding said:

Great idea... I will do that today.

 

 

No change. But it did start to overheat, which it hasn't done before. Time to come apart!

[Bob Riding]

15 hours ago, Sniper said:

 

yes indeed and that noise is worry some.  I'd take the fan belt off and makes sure it isn't water pump/fan related.  Oil pressure tends to go to pot with a rod knock, what's that look like?

Gauge doesn't work. Aftermarket gauge also no go.

[Sniper]

1 hour ago, Bob Riding said:

Gauge doesn't work. Aftermarket gauge also no go.

 

Are you saying that both the stock and the aftermarket oil pressure gauge reads nothing with the engine running?  Or that you don't have either one installed?

[Bob Riding]

3 hours ago, Sniper said:

 

Are you saying that both the stock and the aftermarket oil pressure gauge reads nothing with the engine running?  Or that you don't have either one installed?

Neither one works. Time to pull it and check the bottom end.

[gwaggonercpa]

I pulled plug wires until the "knock' got quieter on my 55.  At least I knew where to look first when I pulled the engine.

[Los_Control]

First thing disconnect the fan belt. Make sure the noise is not from a water pump or generator bearing.

 

While the noise if it was a rod bearing, is kinda a tink tink tink noise

If it was a main bearing, more of a thunk  thunk  thunk noise

If the noise is in-between it could be a wrist pin ... with a tap  tap  tap  noise.    <---- where I think your noise falls into. Assuming not bearings on wp or genny.

Or it could be a valve train issue where just a good cleaning & oiling & all is fine again.

 

 

 

[Bob Riding]

Good news- I think. Looks like the motor was rebuilt in 2002 with .030 over pistons, .010 over rod bearings and .020 over main bearings. The valves look pretty good and after doing the @keithb7 tests, I'm pretty happy. I will do the kerosine drip test next. If the tapping noise is coming from the bottom end, what should I look for when I remove the caps? 

[keithb7]

You are going to buy plasti-gauge. 1-4 thou or so size. You pull off a cap. Wipe oil off cap and crank journal. Place a 1" or so piece of plasti-gauge. Reinstall cap, and torque to proper specs. Then again remove cap. Measure width of plastigauge. This is how you test oil clearances, and taper wear. The plasti-gauge will be fatter at one end than the other, if the wear is tapered. You need to do this, one cap at a time, for all con-rod caps and main caps.   This will tell you exactly what is going on in the bottom end. Do not take off all caps at the same time. Mark them so they go back on the exact same way they came off. If you have a knock, very good chance you will visually see the disaster unfolding, without needing plastigauge. Best practice is to measure them all though. Definitely report back with your findings! 

[Bob Riding]

Success! Got the water distribution out in one piece, ala @keithb7 's flat bar/vicegrip technique. It took an hour or so of loosening the tube with lube and tapping the steel bar on each side.

Before I take it to the machine shop for magnfluxing and hot-tanking, I want to do any work that will create debris that the machine shop cleaning will remove.

To port/polish (or gasket match) or not, is the next question. I measured both the block and intake /exhaust openings  and they all measure out at about the same diameter- 1.3".

Does it make any sense to spend the effort to match them if they are already the same diameter, even though the gasket diameter is larger? 

I'm going with Langdon's split exhaust, which also measure at 1.3" dia.

[Sniper]

What yo really don't want regarding port matching is the exhaust manifold port smaller than the block, the lip will inhibit flow.  On the intake side you do not want the block port smaller than the intake manifold port, same issue.

 

Now some will gasket match the ports and as you can see in your picture the opening in the gasket is larger than your manifold, which some will grind to match the gasket opening.  there are many obstructions to flow in the ports, the guides being a big one.  Not sure anything you might do to the ports would matter till you trimmed the guides.

[Bob Riding]

1 hour ago, Sniper said:

What yo really don't want regarding port matching is the exhaust manifold port smaller than the block, the lip will inhibit flow.  On the intake side you do not want the block port smaller than the intake manifold port, same issue.

 

Now some will gasket match the ports and as you can see in your picture the opening in the gasket is larger than your manifold, which some will grind to match the gasket opening.  there are many obstructions to flow in the ports, the guides being a big one.  Not sure anything you might do to the ports would matter till you trimmed the guides.

Very interesting. Is trimming the guides commonly done? It seems like alot of work for a non-race motor.

[Los_Control]

I believe it was a wise man who once said

Speed kills ..... buy a flathead & live forever 

[Sniper]

34 minutes ago, Bob Riding said:

Very interesting. Is trimming the guides commonly done? It seems like alot of work for a non-race motor.

 

I only know one other guy that trims the guides, the freewheeling Tony Smith.  He's working on determining the best route to go for airflow in a flathead. 

 

As for the work, no more or less involved than porting and frankly doing one without the other is wasting time, imo.