8BA Left Bank/Right Bank Difference at Valves

L

leon bee

Well-known member
I'm doing my third engine and still learning. This time I have the left side valves kissing the head. An apparently flawless 1BA block, but it's history is unknown. I'm not yet asking anyone what I'm gonna do about it, I'd like to hear about how and why the two sides are different.....the right side valves don't hit.

I've read 100 pages of old posts the last few years and I've read about this deal. But can't recall any specifics and it could take a long time to relocate any of that info. Any thoughts appreciated, thanks!
 
Maybe because the left and right side valves are at different angles.
 

Attachments

  • image-asset.jpg
    image-asset.jpg
    89.5 KB · Views: 161
Last edited:
The different valve angles were before the 59 series engines. Beginning with the 59 series the valve angles were the same on both sides

Sorry, this is incorrect information...the valve angles were changed for the 59 series, moving them further from the cylinders, but all Ford flathead engines have had different valve angles on each back since inception.
 
Brian said:
The different valve angles were before the 59 series engines. Beginning with the 59 series the valve angles were the same on both sides

Sorry, this is incorrect information...the valve angles were changed for the 59 series, moving them further from the cylinders, but all Ford flathead engines have had different valve angles on each back since inception.
Click to expand...

Should have said " valve location from the cylinder bore is the same on 59 and later engines.
Bill
 
You'll find that the overall valve height on the Driver's side is roughly .040 higher than the passenger's side. You should NEVER try to correct this - as it is part of the design - due to the offset crank centerline and differing valve angles. It is important to note - the valve lengths are the SAME on both sides.

I have seen incompetent machine shops screw up blocks by "decking" them to make it the same on both sides (which create differing compression heights on both sides - which is 100% wrong).

I have also seen machine shops try to "sink the valve seats" on the Driver's side to make them the same height as on the Passenger's side . . . only to then have to change the valve lengths for the .040 too long of valves they now had on one side - also 100% wrong!

The valves angles from 32 - 42 were the same. Changes were made in the 59x engine series and they are the same for the 1945 - 1953 engines -> the 59x - 8BA.

Attached are two PDF cross-section views that I created from my CAD models to show the detailed dimensions for the two . . . get your magnifying glasses out! LOL

Note: I show a crankshaft throw of 4.125 and a crank pin diameter of 2.00" - these 'stroker motor' dimensions are not pertinent to this discussion. ;)

View attachment FlatheadFordEngineCrossSection-32-42.PDF

View attachment FlatheadFordEngineCrossSection-59A-8BA.PDF
 
Last edited:
That’s why you must recut the valve pockets to run the earlier heads on the 59 engine. KR Wilson made a fixture and cutter for this.
 
You must log in or register to reply here.
Back
Top