Flathead advice and help needed

D

Desoto291Hemi

Senior Member
Hi guys,
I just got validated a while ago and was gonna post as soon as I could.
I have just purchased my first flathead and I’m trying to learn all I can.
It is a 49 Mercury,,,I should have it in a few days,,,and will begin immediately to disassemble and check for cracks and defects.
I plan to completely tear it down
Then take to my machine shop guys to mag and check for any problems.
From what I have learned already,,,it seems the most common places are the head bolt areas to the water passage openings.
The valve to cylinder openings,,,and the pan rail area.
What other obvious things should I look for.
Thanks for all your help guys,,,I will need it.

Tommy
 
You have the possible crack locations correct But there is one more location for cracks the lifter/valve area the wall thats on the other side of the water jacket I have found cracks in this area on a few blocks most machine shops never mag check in this area.. Another area of concern is the buildup of sand type material in the water passages especially between the rear cylinders on both sides of the block. That material needs to be scraped out of the water passages by hand. Welcome to the world of Flathead fun good luck with your new project.
Ronnieroadster
 
Congratulations! Be sure to check and see if the crank has a 4 in stroke like 49 Mercs came with. Besides doing what has already been mentioned above, take lots of photos as you disassemble it. Be sure to mark all the bearing caps and don't interchange them. Also, save all engine parts and don't throw anything away. Hope you were able to get the Merc flywheel,clutch and pressure plate too. You didn't say what you plans are but, be sure to ask plenty of questions on the fordbarn BEFORE you jump in with both feet.
 
A pressure test might be a better approach than just mag testing. A test plates are bolted on and air pressure applied to the water jackets. Pressure testing can locate cracks missed by mag testing alone.
 
My plans are to do a complete rebuild and add some power at the same time.
Nothing radical,,,just a strong engine
As a matter of fact,,,I will just go ahead and lay out my plan now.

1.
Get the block serviced and see that it is good.
Bore it somewhat,,,,not to the max,,,just a good oversize.
Deck it and clean up all the machined surfaces.
I am not sure yet about relieving the block for more flow,,still reading up on that.

2.
Clean and check the crank,,,see if the journals are okay,,,service as needed.
Balance assembly after the rods and pistons have been weighed for the bobweight.
Use good quality bearings throughout the assembly.

3.
Rods,,,,clean and check,,,shotpeen for strength,,,,resize and check for any defects.

4.
Pistons,,,,,I want to use a good brand of pistons,,,not the most expensive,,this is not a racing engine,,,just a nice hot engine.
I don’t think I will use the 4 ring system,,,I believe 3 rings will be fine.
Being that the pistons will be a modern aluminum piston and will be machined with a barrel shape to fit better in the bore ,and not prone to a lot of skirt movement.

5.
The camshaft will probably be a nice Isky grind,,,not sure yet.
I have looked at some,,somewhere in the .365 range maybe,,,not sure ,,,still early.
I would like to use the adjustable lifters if I can,,,,is that a good idea,,,I have just began to read about them.

6.
Valves,,,,,I would like to use a good stainless valve to be safe.
I would like to go bigger than stock,,,if I can?
I am considering going with a1.625 intake if I can make it fit?
The exhaust would probably be a 1.57,,,,I am still in the thinking stage with this.
I know most engines always used a slightly larger intake being that the mass of the fuel and the air is not as great after the combustion cycle,,,,no fuel droplets in the exhaust.

7.
The heads,,,,, I am thinking about a nice aluminum head,,,with a better chamber shaped to increase compression. I believe that compression within reason is free horsepower.
The aluminum ones have added capacity for more cooling water flow and fins to increase the cooling ability,,,,especially after the shutdown,(act as a heat sink),,,to help remove heat from the deck surface?
Although it uses bolts right now,,I plan to upgrade to studs for strength .

8.
Intake,,,,still don’t have a good direction there yet,,,but I am just starting here.
I am thinking a dual carb or single 4 barrel,,,,,not a bunch of carbs,,,,too much to keep up with I think.

9.
Ignition,,,planning on adapting a SBC dual point distributor,,I like dual points and believe that it will work great. I have a nice Accel dual point,,and several others,,,just plan on the Accel at this point.

That is about as far as I have gotten so far,,,still thinking and studying my options.

I am still in the planning stage here,,,any ideas?

Tommy
 
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Some good reading material: Ol Ron's and JWL's books and some others I like.

JWL's book goes through modifications one at a time with dyno runs to see what works.
 

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Tommy,

It would be nice to know what kind of car this is going into. A fenderless Model A hot rod vs. a '51 Mercury sedan would probably need different cam grinds, at least.

Denny
 
Hey Denny,

Man I figured some guys from the Hamb were here too,,,,probably a lot I guess,,lol.

Well,,at this time I plan on a hot rod style of car.
You know I was working on my Desoto 291 Hemi,,,and I still Am,,,,but I got an opportunity for a Flathead,,,and figured I had better jump on it too.
This will be a project that takes a couple of years probably,,just to learn all I can and finance all the parts needed to do it.

Tommy
 
The reason I asked is that if you are planning on putting this engine in a relatively heavy car, such as a post war Ford or Mercury, you can't do much better than a stock "8CM" Mercury cam. When I put the '51 Merc in my '51 Ford, I had purchased an Isky MAX-1 cam that I was going to use. After a bunch of back and forth, both here and elsewhere, I decided to keep the stock cam. So far it seems to have been the proper decision. It's not a waste though, as I now have the MAX-1 in an engine I built to put in a "T" tub I have in progress.
 
Times 2 on what tubman says.....if you have an 8CM Merc cam in good condition...use it.
I think tubman is a Hemi man too, he knows his stuf. Have fun flathead'n !
 
Do most of you guys run two temp gauges being that the water does not mix between left and right banks?
In case a thermostat sticks on one side or one pump goes bad.
Because as much as it cost to build it,,,I don’t want to risk a failure!

Tommy
 
On a stock setup there are two senders, one the controls the temperature reading on the gauge, the other one is an on/off switch that operates at a predetermined temperature. A lot of people use two separate gauges on a non-stock application.
 
Desoto291Hemi said:
My plans are to do a complete rebuild and add some power at the same time.
Nothing radical,,,just a strong engine
As a matter of fact,,,I will just go ahead and lay out my plan now.

1.
Get the block serviced and see that it is good.
Bore it somewhat,,,,not to the max,,,just a good oversize.
Deck it and clean up all the machined surfaces.
I am not sure yet about relieving the block for more flow,,still reading up on that.

2.
Clean and check the crank,,,see if the journals are okay,,,service as needed.
Balance assembly after the rods and pistons have been weighed for the bobweight.
Use good quality bearings throughout the assembly.

3.
Rods,,,,clean and check,,,shotpeen for strength,,,,resize and check for any defects.

4.
Pistons,,,,,I want to use a good brand of pistons,,,not the most expensive,,this is not a racing engine,,,just a nice hot engine.
I don’t think I will use the 4 ring system,,,I believe 3 rings will be fine.
Being that the pistons will be a modern aluminum piston and will be machined with a barrel shape to fit better in the bore ,and not prone to a lot of skirt movement.

5.
The camshaft will probably be a nice Isky grind,,,not sure yet.
I have looked at some,,somewhere in the .365 range maybe,,,not sure ,,,still early.
I would like to use the adjustable lifters if I can,,,,is that a good idea,,,I have just began to read about them.

6.
Valves,,,,,I would like to use a good stainless valve to be safe.
I would like to go bigger than stock,,,if I can?
I am considering going with a1.625 intake if I can make it fit?
The exhaust would probably be a 1.57,,,,I am still in the thinking stage with this.
I know most engines always used a slightly larger intake being that the mass of the fuel and the air is not as great after the combustion cycle,,,,no fuel droplets in the exhaust.

7.
The heads,,,,, I am thinking about a nice aluminum head,,,with a better chamber shaped to increase compression. I believe that compression within reason is free horsepower.
The aluminum ones have added capacity for more cooling water flow and fins to increase the cooling ability,,,,especially after the shutdown,(act as a heat sink),,,to help remove heat from the deck surface?
Although it uses bolts right now,,I plan to upgrade to studs for strength .

8.
Intake,,,,still don’t have a good direction there yet,,,but I am just starting here.
I am thinking a dual carb or single 4 barrel,,,,,not a bunch of carbs,,,,too much to keep up with I think.

9.
Ignition,,,planning on adapting a SBC dual point distributor,,I like dual points and believe that it will work great. I have a nice Accel dual point,,and several others,,,just plan on the Accel at this point.

That is about as far as I have gotten so far,,,still thinking and studying my options.

I am still in the planning stage here,,,any ideas?

Tommy
Click to expand...


Some 'bench racing' thoughts:
1. No need to relieve. You'll just lose compression and won't gain airflow unless you have a large engine at high RPM, and a radical cam (plus a super trick porting job). Air has mass, therefore has inertia and resists changing direction (which hinders flow). So air is flowing upward as it enters the cylinder, then through the transfer area and down into the cylinder. If we can change its direction gradually the flow will be greater. Forcing the air to make a sharp turn out of the port, through the relief, and another sharp turn into the cylinder will hinder flow. Since you lost compression to make the relief, and won't have much extra flow through the relief, you end up with a net loss at normal street engine speeds.
6. Larger valves. Will the ports flow good enough to take advantage of
the larger valves? Most of the reading I've done indicates the ports are the limiting factor in airflow, not the valves.
7. Aluminum heads. They look pretty, but they take heat out of the combustion chamber and put it into the cooling system so quickly that some efficiency and power are lost.
9. Since this is a street engine, make sure your Accel unit has vacuum advance for better fuel mileage.
 
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