Engine number...and a troubling knock

[Severe Duty]

Hi, I'm new to this forum. I have a 1942 Type A WC 1/2 ton with I believe to be a 230CID engine. At the front, driver's side of the block is a rough machined face, about 3x1/2 inches overall and located at the top of the block, which has a block serial number, I think. It is hand-stamped 00000420 but that doesn't feel right to me. I would not be surprised if there are more numbers or letters that I cannot read. There's enough scale/rust to have obliterated other numbers or letters by now. Anyone say with confidence that this is a good block number?
I wouldn't think this is a new question, so I looked around this forum for a 'thread history' on engine topics, but I didn't notice any way to search the site for old postings. Is there a way to search old thread posts so as to keep threads fresh?

Also, there is a really troubling sporadic knocking sound from the rear part of the block when first starting up and it tends to go away after about 30-45 seconds of idling. If I had to guess, it may be a loose connecting rod that tightens up when expanded by engine warmth. Any thoughts on this?

Thanks!

ADDED Comment: I have not yet put a oil pressure gage in-line, and when I do, what are the operating parameters that I should be looking for?

[Gordon Maney]

Welcome to the group. The search function is only available to Power Wagon Advertiser subscribers and premium forum users.

What does your oil pressure do as it warms up?

I am sure someone will offer some informed comment on your engine number question.

[Charles Talbert]

Hi, I'm new to this forum. I have a 1942 Type A WC 1/2 ton with I believe to be a 230CID engine. At the front, driver's side of the block is a rough machined face, about 3x1/2 inches overall and located at the top of the block, which has a block serial number, I think. It is hand-stamped 00000420 but that doesn't feel right to me. I would not be surprised if there are more numbers or letters that I cannot read. There's enough scale/rust to have obliterated other numbers or letters by now. Anyone say with confidence that this is a good block number?
I wouldn't think this is a new question, so I looked around this forum for a 'thread history' on engine topics, but I didn't notice any way to search the site for old postings. Is there a way to search old thread posts so as to keep threads fresh?

Also, there is a really troubling sporadic knocking sound from the rear part of the block when first starting up and it tends to go away after about 30-45 seconds of idling. If I had to guess, it may be a loose connecting rod that tightens up when expanded by engine warmth. Any thoughts on this?

Thanks!

ADDED Comment: I have not yet put a oil pressure gage in-line, and when I do, what are the operating parameters that I should be looking for?

Sounds like you have a little loose motion somewhere until oil pressure hits it. Definitely check it out further. Good oil pressure is 30 psi at idle and 60 psi at higher throttle once the engine is warmed up to normal operating temp.

[Gordon(Scotland)]

Hmm

I don't like the sound of that knock, even if it does go away. I think you need to pull the sump and check the bearings, especially the big ends as the crank restriction means you can still have oil prssure when a big end is on its' way out. Another possibility is loose flywheel-to-crank bolts. No big deal, but lots of dismantling to fix.

Engine type / date? Look under the distributor for a casting date, that'll give us a clue. If there is no real code on theboss it could be - anything, and that number could just be an in-house ID for a replacement.

[Charles Talbert]

More than likely you do have a rod or main bearing issue in the works or on the way down. Also most likely the oil pressure will lose some psi as a result, it very well may not be a low enough reading to throw up a red flag considering psi alone. A knock is always something that should be investigated promptly in any case regardless of oil pressure reading.

Usual scenerio when the flywheel mounting bolts are loose, you will get the knocking noise at idle, generally it will go away as RPM's pick up, but will return and be a factor all the time at idle speed RPM. Usual scenerios don't always play out, never just discount any possibility, however if you are convinced that oil pressure is a factor with the noise, I would suggest a thorough investigation into the bearing areas first. If you are able to isolate what appears a likely suspect, be sure to check the crank journal closely also; don't just assume it is all a bearing issue and no journal wear.

Good luck on the hunt.

[Severe Duty]

Engine knock gut feeling

My gut feeling is an internal, loose, expanded or worn component(s). I plan to make a notation/chart of oil pressures at varying scenarios, idle cold through 2000 RPM warm; if nothing else it will chart a history for future reference. I'll then drop the pan and be ready for bad news. Thanks all for your replies. And, I wasn't aware of the loose flywheel bolts, etc. I'll be looking at that too!

Steven Johnson
Kingsburg, Calif.

[Blisters]

I would like to add my 2 cents and note from personal experience that the "good" oil pressures kindly already posted are found on a fairly tight engine. I have a nice-running 1940 truck with a very old engine and it's oil pressures in the summer with 20w50 oil are about 8-9 psi hot idling to 20 psi hot at about 2000 to 2500 rpm.

-Ken J

[Charles Talbert]

I would like to add my 2 cents and note from personal experience that the "good" oil pressures kindly already posted are found on a fairly tight engine. I have a nice-running 1940 truck with a very old engine and it's oil pressures in the summer with 20w50 oil are about 8-9 psi hot idling to 20 psi hot at about 2000 to 2500 rpm.

-Ken J

While these readings could be considered common in a well worn engine that you figure runs nicely. The fact is that readings this low are most likely related to seriously worn cam bushings as well as other serious wear in oil critical areas.

When wear is to the point of causing readings this low, if the readings are accurate, especially with 50 weight oil in the pan, damage is not just with easily replaced bearing inserts; but major components are suffering also, like the cam and crankshaft. One is not doing himself a favor continuing to run an engine with these low readings. When it breaks down to the point that a rebuild is forced, there could well be damage to major components that would have taken them to the point of not being reusable.

I've seen a few that went like this and the owners could not believe the parts bill at rebuild time. This was brought on solely because they went till they could go no longer, the result was having to replace major items such as the crankshaft, camshaft, etc, because wear was past the usable limit. More than likely if the engine had been torn down for rebuild before pushing to the brink, cost would have been significantly less, and several major components could have been reused instead of going in the scrap pile.

Of course it's up to the individual what they do when readings get obvious, these are just facts we have seen over the years that you can take to the bank.

[Blisters]

Sounds like you have a little loose motion somewhere until oil pressure hits it. Definitely check it out further. Good oil pressure is 30 psi at idle and 60 psi at higher throttle once the engine is warmed up to normal operating temp.

I don't know where you got those pressures from but they are not correct for a WWII Dodge 1/2 ton truck. According to my original copy of "Maintenance Manual 1/2 Ton 4 x 4 Chassis Dodge Trucks Built for United States Army", T/M 10-1443, part 14 of the Operating Instructions Group on page 5, "The oil pressure gauge (3, Fig. 1), should register about 15 pounds pressure when the engine is running at slow idle speed, but at speeds above 30 miles per hour, the gauge should show from 30 to 40 pounds pressure."

I promise you that the worn engine I am referring to DOES "run nicely"; I have a newly-rebuilt engine properly tuned "by the book", and compared to that, this engine runs nearly as well after it warms up. While a range of 8 to 20 psi is not ideal (I never said it was), I rather doubt it is a pressure indicating imminent engine disintegration, from my experience.

Certainly the knock described by Severe Duty needs investigation; certainly preventive maintenance such as replacing bearings before journal destruction is desirable.

Very few people here have $2,000 to $4,000 to sink into rebuilding an engine for a hobby truck which they are unlikely to fully load and then fly down the highway up hills at top speed. A range of 30 to 60 psi seems pretty unrealistic, and is not supported by documentation. No offense, I just disagree with the range you opined.

I note that you own a shop- obviously there is a lot of experience there. What do you charge for the work you recommended?

-Ken J

[Charles Talbert]

I don't know where you got those pressures from but they are not correct for a WWII Dodge 1/2 ton truck. According to my original copy of "Maintenance Manual 1/2 Ton 4 x 4 Chassis Dodge Trucks Built for United States Army", T/M 10-1443, part 14 of the Operating Instructions Group on page 5, "The oil pressure gauge (3, Fig. 1), should register about 15 pounds pressure when the engine is running at slow idle speed, but at speeds above 30 miles per hour, the gauge should show from 30 to 40 pounds pressure."

I promise you that the worn engine I am referring to DOES "run nicely"; I have a newly-rebuilt engine properly tuned "by the book", and compared to that, this engine runs nearly as well after it warms up. While a range of 8 to 20 psi is not ideal (I never said it was), I rather doubt it is a pressure indicating imminent engine disintegration, from my experience.

Certainly the knock described by Severe Duty needs investigation; certainly preventive maintenance such as replacing bearings before journal destruction is desirable.

Very few people here have $2,000 to $4,000 to sink into rebuilding an engine for a hobby truck which they are unlikely to fully load and then fly down the highway up hills at top speed. A range of 30 to 60 psi seems pretty unrealistic, and is not supported by documentation. No offense, I just disagree with the range you opined.

I note that you own a shop- obviously there is a lot of experience there. What do you charge for the work you recommended?

-Ken J

I didn't intend to say your engine would self destruct today. I'm saying that those readings are too low, and that it is a very real possibility that you can expect worse than normal wear on major components as a result if you continue forward knowing these facts. That is your business exclusively however. I did not make this post as an advertisement for my business. We build a lot of engines, the proven facts I quoted are a result of looking at many.

Our charges related to building engines run according to what the customer wants done. Our labor rate is currently $65 per hour. It would be that plus the cost of parts, supplies, and outside services such as machining.