Flathead question...

OoltewahSpeedShop

OoltewahSpeedShop

Member
I have a '53 Ford flathead with a 4" Mercury crank. It got some water damage in the cylinders. It is .060 over now. According to my engine man it will clean up at .080 over.

Now here's my question... All the best piston manufacturers offer .125 or .188 over pistons. I can get an .080 over piston, but should I just go on to .125 and get a better piston?

Pros and Cons guys.

Thanks,
Kevin
 
We had this exact same discussion today, and came to the very same conclusion, Ronnie.

If you're gonna be a bear, might as well be a grizzly.... is the expression, I do believe.
 
Going to a 3-5/16" bore should not be a problem with an 8ba block. That should still leave enough wall thickness for at least another rebuild. If you have any concerns have a sonic test run to check wall thickness before boring.
 
Egge makes one of the best pistons on the market for a street engine along with modern rings, proper tuning, you should get 100,00 miles from them. I set mine at .0025"
 
They are also a 4 ring piston that works well along with all 4 grooves filled correct. :)

Ronnie
 
The Egge Hypereutectic (high silicon) pistones are 3-ring for less piston drag. I just wished they would make them in smaller oversizes like .060", .080" and .100". This is a very practical application of modern technology.

Kerby
 
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The 3 ring pistons are #ep 1110 start at .125"over are cast alum not Hypereutectic. I phoned them today to get some info on them for a customer and was told they are cast alum not Hypereutectic they make they for a merc also. but .125" over.
 
I don't know what amount of silicon added to the aluminum actually puts them in the hypereutectic formula range (somewhere around 12%) but the high silicon content is why they can be clearanced so close. The expansion coefficient is less on high silicon aluminum castings than the older aluminum casting formulas. They don't need T-slots or any of that antique technology stuff for sure. I've also heard that above 25% silicon content the metal starts to lose its strength. The Hypereutectic term only means that the silicon amount is above the normal soluability rate for molten aluminum.

Forged pistons are way hard but they need a fair amount of clearance because of that too.

Kerby
 
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They stated all their cast flathead pistons are the same alloy three and four ring..
Which is a acceptable response they will all be good.
 
We ran 3 3/8 on street engines for years, I still have a 296 running. Had a track engine at 3 7/16. My ecoono engine is 3 5/16+20 (Egge) 125 isn't much to worry about, but you could get it sonic tested.
 
I have heard about sonic testing for 30 years, never had it done. Checked around today and kinda got laughed at. More than one person said "That stuff went out with the Flatheads"

Are most 8ba engines safe at .125 over? Is a wall thickness check necessary? I'm sure core shift was an issue, but how bad were they?
 
OoltewahSpeedShop said:
Ok, as stated above, this is NOT a restoration project, so stock engine facts don't really apply to this one. I'm looking for advise on what the logical, streetable bore size would be on an 8ba.
Click to expand...

Believe me, any tech flathead question you have is fair game over there, stock, street or strip.

TM
 
Theres no replacement for displacement, go big 3 3/8, 286 is nice size. I have three cars at .125 and one out to .188 they all run great.
 
Most 8BA blocks should take a .125 overbore with no problems. Heavily rusted water jackets would make for a question mark.
 
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