Engine gunk question

[Oberstar]

Gents, I have a question- Dodge 230 out of a 43 WC52 3/4T truck.  Compression averages 87psi in all cylinders, and oil pressure at 48lbs.  We have been scraping the thickets mixture of old oil, grease, and dirt off of the front, bottom, and rear of the motor, entire clutch housing, and transmission.  I made the mistake of not taking before and after pics of the scraping result. 

My question is this- if you have a motor that runs well, but is now out of the frame, should I consider replacing the timing cover seal, pan gasket, and rear main seal??  I want to leave well enough alone and not throw money at an issue, but what in the world could have caused inches of hardened muck to cover an entire motor bottom end, clutch housing and transmission like that??  Is that just normal accumulation through its 70 years of life?  Here's a pic of the frame rail underneath the steering gear.  This is after cleaning...

Edited May 4, 2017 by Oberstar

[Merle Coggins]

7 minutes ago, Oberstar said:

...but what in the world could have caused inches of hardened muck to cover an entire motor bottom end, clutch housing and transmission like that??  Is that just normal accumulation through its 70 years of life?

Yes...

i don't know if it's possible to completely seal up these engines. There always seems to be a little seapage from somewhere. However, if the engine is out already it might be a good time to open it up a bit. You could remove the oil pan to clean out any sludge buildup, then replace the rear main seal and pan gasket. Also remove the valve covers to clean out the sludge buildup in there. (Do this before reinstalling the oil pan). And the timing chain cover/front seal wouldn't be too much more work at that time too. 

It may also be a good time to open up, and flush, the cooling system. But opening that can of worms may lead to the water distribution tube, which can cause colorful language to flow. 

[JBNeal]

I have lost the Polaroids, but I pulled the oil pan from my '49 and made a softball-sized ball with all of the sludge I had scraped out...I also knocked out the freeze plugs and sludge was in there too, enough to completely cover the lower holes and could easily be see thru the upper holes...had to fashion a scraper out of a wire coat hanger to get the sludge out of the water jacket behind cyl#6...and yes, there was quite a pile of dirt grease and oil that I scraped off of the engine and transmission; the transmission was so badly covered it looked like a filthy beach ball, and the rear axle differential was almost as bad...once I cleaned them all out and put new seals in, I noticed seepage, and eventually came to realize that the old hard seals had cut small grooves in the mating shaft surfaces that required SKF sleeves...live and learn, I reckon