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youngfeller

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I drove to CT in Sept for the NE Model A Meet in my 31 Tudor. I had trouble going up some hills. Brought it to a shop.
Here is what they told me.

They did a dry and wet compression test. Each of the 4 cylinders are around 37 lbs.

They did a leak down test, it is on the higher side, possibly rings or valves leaking?

Removed oil drain tube and valve cover-checked all valves and they are in spec.

It seems to be using more oil but the dipstick is not frothy. No smoke from the exhaust.

What do we think?
 
Here's an idea for a winter project/experiment: Do a '40's-'50's style in-frame valve and ring job like what was done to keep the old car going a while longer (often quite a bit longer). All you need are a set of rings and a gasket set. Rent or borrow a ridge reamer and a cylinder hone. Hand lap the valves (if you keep them in order you won't need to readjust-the clearance won't change that much unless you need a new valve). Adjust the rods and mains. You will amazed at the difference in power (unless you run into a cracked piston or something else unexpected-not likely since you know the engine).
The never-got-their hands dirty armchair experts may say it can't be done but I've done quite a few engines this way over the years with good results. And it will only cost around $150 and your time.
 
With a bit of room in a heated garage for the engine hoist, it isn't very hard to do an easier job and pull the engine for that work. I've pulled my engine and reinstalled it twice by myself.
 
From your sign on name, Young Feller, I am going to assume you are young and starting out in the Model A hobby. The Model A is a perfect car to learn on. As 40 Delux posted (post #3) a ring and valve job is recommended. Get a copy of Les Andrews "Red Book", see https://www.snydersantiqueauto.com/product.htm?pid=980031&cat=41621. Join a local Model A club and don't be afraid to ask for help there and on the Barn. While you have the engine apart, check the bearings, as 40 Delux suggested.

The easiest way to work on the engine is with it out of the car on an engine stand. You may be able to borrow tools you need from your club members.

Where are you located?
 
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Ditto J Franklin, you have a tired engine that needs a professional rebuilding. If you do opt to rebuild your engine, have modern insert bearings installed in the mains & rods.
 
Bob Bidonde said:
Ditto J Franklin, you have a tired engine that needs a professional rebuilding. If you do opt to rebuild your engine, have modern insert bearings installed in the mains & rods.
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I think this recommendation is premature since the OP knows nothing about the state of his crankshaft and bearings. Having a block bored out, new pistons fitted, and a valve job (a) can be done by many local, non-Model-A shops and (b) is dramatically cheaper than redoing the bearings.
 
Pull the head. Measure the bores. If less than .010 wear you may be able to ridge team and hone. You will also discover if the engine has been ridge reamed and bored before. If you have .005 or .006 wear you would be in good shape. Drop the pan and inspect the bearings. See if there are any shims. Inspect the rods for shims and condition of Babbitt then decide what to do.
 
I’m not a fan of doing things that might not need to be done.

Is you car leaving a trail of blue smoke when you take your foot of the gas going down a steep hill? If the answer is yes. Your most likely in need of a rebuild. If no. I would take a good look at your valves.

How does the engine sound when running?

Enjoy.
 
Bob Bidonde said:
Ditto J Franklin, you have a tired engine that needs a professional rebuilding. If you do opt to rebuild your engine, have modern insert bearings installed in the mains & rods.
Click to expand...

I crushed 3 A blocks that were inserted and spun out, nothing but junk. Every block that goes from babbitt to insert has been essentially ruined. Inserts have a layer of babbitt on them, but since you are putting a steel shell so close to the crank, all it needs is one overheated bearing to bite onto the crank and destroy the block. There is a reason Caterpillar still uses babbitt bearings in their diesel engines. I am going to have a special mold developed to put inserted engines back to babbitt so we won't lose anymore engines to this destructive practice. And before anyone flips out, I have had modern engines fail the same way with spun bearings, and am of the opinion that the slight convenience of replacing shells is not worth the risk of destroying an expensive engine block.
 
Fullraceflathead said:
I'm curious couldn't you have used those 3 blocks to use for prototyping your new style bearing?
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At the time, no. the webbing around the rear main on 2 of the blocks had split and nothing was aligned so even if I made a custom mold, I could not have made it based on those blocks. I want to base the new mold around a block bored for inserts but has not been run so I can get the mold shape right.
 
Engine is worn. Could be rings or valves. If it's not tapping or knocking, the next question is how mechanically inclined are you and/or how much you want to spend? If it isn't rapping and tapping, it could be your bearings are ok, and you could get some more miles from her with a ring and valve job which would cost significantly less than a full rebuild. If you can turn a wrench, a ring and valve job would be a nice winter project to take on. Are you a member of a local club where you can call on the expertise of some gray-beards for help?
 
Sunny the Model A said:
I crushed 3 A blocks that were inserted and spun out, nothing but junk. Every block that goes from babbitt to insert has been essentially ruined. Inserts have a layer of babbitt on them, but since you are putting a steel shell so close to the crank, all it needs is one overheated bearing to bite onto the crank and destroy the block. There is a reason Caterpillar still uses babbitt bearings in their diesel engines. I am going to have a special mold developed to put inserted engines back to babbitt so we won't lose anymore engines to this destructive practice. And before anyone flips out, I have had modern engines fail the same way with spun bearings, and am of the opinion that the slight convenience of replacing shells is not worth the risk of destroying an expensive engine block.
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I'm not surprised about your 3 cylinder blocks that were junked. Line boring equipment intended to bore Babbitt is too flimsly and cannot hold the tolerances needed for inserts.

An overheated bearing is due to poor machine work, a bent crankshaft, lack of lubrication, or overloading.

Pouring Babbitt to replace an insert is a bad idea because Babbitt has very little strength and the bond to cast iron is mechanical.

Consider brazing the main bearing bores and line bore them to 0.020 bigger than your crankshaft journals. Then pour Babbitt and again line bore to the finished size.

Braze will tin to cast iron and Babbitt will tin to braze. There is no mechanical bond.

According to my June 1947 Federal Mogul catalog, Caterpillar started using inserts in 1918 for their 5 Ton Tractor and inserts were used in every engine up to D8's including the pony gasoline engines used to start the big diesels. The part number for the 5 Ton Tractor connecting rod is 7015B, and the part number for a set of main bearings is 101M. When the crop is ready for harvest, time is precious and there is no time to pour and machine Babbitt bearings.
 
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