Boring a flathead

Tim Ayers said:
Vergil:




If you have the time and are willing to cut open a center exhaust port, I'd for one would love to see it. I have a feeling I may have gotten a little carried away with my grinder in these as well.
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Tim I have a few pictures of the center port I will load and share, at the time I cut the block and took the pictures I didn't get any good ones of the center port but I may see what the old block looks like and maybe get better pictures.

Vergil
 
I did some Flow work on the modified port in my book and saw very little improvement over just shaping it similar to Mike Bishops work. I square up the side of the port nearest to the block eng leaving aprox. 1/4" gasket surface. What surprised me was how well the exhaust flowed in comparison to the intake. Well within the 80%.
 
Vergil said:
Tim I have a few pictures of the center port I will load and share, at the time I cut the block and took the pictures I didn't get any good ones of the center port but I may see what the old block looks like and maybe get better pictures.

Vergil
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Vergil:

You are the man! Thanks.

Tim
 
Ol' Ron said:
I did some Flow work on the modified port in my book and saw very little improvement over just shaping it similar to Mike Bishops work. I square up the side of the port nearest to the block eng leaving aprox. 1/4" gasket surface. What surprised me was how well the exhaust flowed in comparison to the intake. Well within the 80%.
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Ron that surprises me on the modified exhaust port shown in your book, I thought for sure it would show better flow than the results, good information.

Tim these are the pictures I have, the first ones shows where the cut was and if you need the floor of the port thickness I can get that for you. The machining on the intake ports shown in the picture was an idea for a fuel injection setup that didn't happen.

Vergil

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tim ayers, i hope this is the view your`e looking for.
tom
vergil is not only good, he`s FAST.
 

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Hot Coupe & Vergil:

Thank you very much. I better step away from the grinder before I hit water. I didn't think it was that thin there.

As 'Ol Ron and cam grinder Pete say, "You got to build a few to learn a lot." (or something like that)
 
I fully agree with Bruce, Ol Ron and others that the exhaust ports are not the problem some folks have professed. I was quite suprised at the smoothness of the internal exhaust passages from the factory. Henry did a good job, except at the end port exit; but that area can be filled either with a metal insert, or better, with a high-temp moldable material. Then ground, smoothed, etc. Tim, don't worry about the back pressure. You don't want any and anyone who tells you otherwise is blowing smoke.
Jim
 
Thanks Virgil and tom for your pictures. I've never seen this much detail of the castings. In my book I moved the end exhaust to eliminate the exit bend, and was disappointed in the results. Some builders have suggested that because the exhaust is expelled under pressure the flow bench isn't the right tool to measure the difference. I will find some pictures of the ports I use in my street engines not sure how well they work either. The older I get the less I know.
 
Ron sent me a picture of the exhaust port after it was modified so will share it, nice work Ron.

Vergil

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used to run a 3 7/16 x 4 flatmotor @ Sanford Maine back in the mid 50's, always wondered if i met Walt at one of these meets-- i had purchsed the block from a fellow named Garvin Cooper @ new england speed--he used to run @ Norwood Arena.
 
One of the best threads on the Ford Barn in my opinion. Love to learn from the Masters. In fact I always thought it would be so cool to have a Flathead "Summit" where the best of the best could gather in one place and share knowledge and experience. I could envision cool seminars covering subjects like porting and camshaft design. How about cracked block repair? Flathead trivia games and such. Maybe a little dyno flogging to put theory to the test. I really think this could be a great thing.
 
robert dick said:
used to run a 3 7/16 x 4 flatmotor @ Sanford Maine back in the mid 50's, always wondered if i met Walt at one of these meets-- i had purchsed the block from a fellow named Garvin Cooper @ new england speed--he used to run @ Norwood Arena.
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I have an 8BA block that is bored to 3 7/16". The pistons are cast and they are for the 3 3/4" stroke. That's about 275 cubes the hard way. The block is in tough shape though, gonna take some TLC to bring her back to life.
 
So I've got an extra 8BA block that's bored to .125 over(3.312) with one cyl sleeved, Can it be safely bored more? I know that every one recommends "sonic testing" but I don't think anyone here can do that.
When you say "sonic" here, the guy says "Bring me back one of those footlong hotdogs while your there".
 
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